SEC Filing | Mallinckrodt

View:

Download DOC

Download PDF

Download XLS

Prepared by R.R. Donnelley Financial -- Form S-3

As filed with the Securities and Exchange Commission on March 28, 2002

Registration No. 333-

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

QUESTCOR PHARMACEUTICALS, INC.

(Exact Name of Registrant as Specified in Its Charter)

CALIFORNIA		2834		33-0476164
(State or Other Jurisdiction of Incorporation or Organization)		(Primary Standard Industrial Classification Code Number)		(I.R.S. Employer Identification Number)

3260 Whipple Road

Union City, California 94587

(510) 400-0700

(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant’s Principal Executive Offices)

Agent For Service:		Copies To:
Charles J. Casamento		David A. Hahn, Esq.
Chief Executive Officer		Latham & Watkins
Questcor Pharmaceuticals, Inc.		701 B Street, Suite 2100
3260 Whipple Road		San Diego, California 92101
Union City, California 94587		(619) 236-1234
(510) 400-0700

Approximate date of commencement of proposed sale to the public: From time to time after the effective date of this Registration Statement.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box. ¨

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box. x

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ¨

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ¨

If delivery of the prospectus is expected to be made pursuant to Rule 434, please check the following box. ¨

CALCULATION OF REGISTRATION FEE




Title of Securities to be Registered	Amount to be Registered(1)	Proposed Maximum Offering Price Per Share(2)	Proposed Maximum Offering Price(2)	Amount of Registration Fee

Common Stock, no par value per share	4,467,087	$1.795	$8,018,421.17	$737.70

(1)

Includes 2,848,100 shares of common stock issuable upon conversion or redemption of debentures and 1,618,987 shares of common stock issuable upon exercise of warrants.

(2)

Estimated solely for the purpose of calculating the registration fee in accordance with Rule 457(c) based on the average of the high and low reported sales prices on the American Stock Exchange on March 25, 2002.

The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the Registration Statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

SUBJECT TO COMPLETION—DATED MARCH 28, 2002

The information in this prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and it is not a solicitation of an offer to buy these securities in any state where the offer or sale is not permitted.

PROSPECTUS

4,467,087 Shares

QUESTCOR PHARMACEUTICALS, INC.

Common Stock

This prospectus relates to up to 4,467,087 shares of our common stock, which may be offered for sale by the selling stockholders named in this prospectus. The shares offered by this prospectus are issuable upon conversion or redemption of debentures and exercise of warrants which were previously issued to the selling stockholders. The shares of common stock to which this prospectus relates may be sold from time to time by the selling stockholders directly or through one or more broker-dealers, in one or more transactions on the American Stock Exchange, in the over-the-counter market, in negotiated transactions or otherwise, at prices related to the prevailing market prices or at negotiated prices. We will not receive any of the proceeds from the sale of the shares of common stock sold by the selling stockholders.

Our common stock is listed on the American Stock Exchange under the symbol “QSC.” On March 27, 2002, the last sale price of our common stock as reported on the American Stock Exchange was $1.85.

See “Risk Factors” beginning on page 4 for factors that you should consider before investing in the shares of our common stock.

Neither the Securities and Exchange Commission nor any state securities commission has approved of disapproved of these securities or passed upon the adequacy or accuracy of the prospectus.

The date of this prospectus is , 2002.

TABLE OF CONTENTS

		Page
Questcor Pharmaceuticals, Inc.		3
Risk Factors		4
Special Note Regarding Forward Looking Statements		12
Use of Proceeds		13
Description of Debentures and Warrants		13
Selling Stockholders		13
Plan of Distribution		15
Legal Matters		16
Experts		16
Where to Find Additional Information		16

WE HAVE NOT AUTHORIZED ANY PERSON TO MAKE A STATEMENT THAT DIFFERS FROM WHAT IS IN THIS PROSPECTUS. IF ANY PERSON DOES MAKE A STATEMENT THAT DIFFERS FROM WHAT IS IN THIS PROSPECTUS, YOU SHOULD NOT RELY ON IT. THIS PROSPECTUS IS NOT AN OFFER TO SELL, NOR IS IT SEEKING AN OFFER TO BUY, THESE SECURITIES IN ANY STATE WHERE THE OFFER OR SALE IS NOT PERMITTED. THE INFORMATION IN THIS PROSPECTUS IS COMPLETE AND ACCURATE AS OF ITS DATE, BUT THE INFORMATION MAY CHANGE AFTER THAT DATE.

The terms “Questcor,” “Company,” “we,” “our,” “ours” and “us” refer to Questcor Pharmaceuticals, Inc. and its consolidated subsidiaries, unless the context requires otherwise, and not to the selling stockholders. All references to “common stock” refer to our common stock, no par value per share.

QUESTCOR PHARMACEUTICALS, INC.

We are an integrated specialty pharmaceutical company focused on the development, acquisition, and marketing of acute care and critical care hospital/specialty pharmaceutical and related healthcare products. Since the completion of our merger with RiboGene, Inc. in November 1999, we have focused our resources on: i) acquiring new products, ii) increasing the sales of our existing products, and iii) out-licensing and partnering our research and development stage products.

Our strategy includes acquiring marketed or near-to-market products that complement existing products and, where appropriate, forming corporate alliances to facilitate and fund the clinical development of our drug candidates. We currently market four products through our internal sales force in the U.S. We expect to launch a fifth product in the U.S. in the first half of 2002, and we market a sixth product in Italy through a strategic partner. Our current products target pediatric neurologists, gastroenterologists, nephrologists, transplant centers and nuclear medicine centers.

The four products we currently market in the U.S. are: HP Acthar^® Gel (“Acthar”), an injectable drug that helps patients with infantile spasm, or West Syndrome; Ethamolin^®, an injectable drug used to treat esophageal varices that have recently bled; and Glofil^™125 and Inulin in Sodium Chloride, which are both injectable agents that assess kidney function by measuring glomerular filtration rate. Additionally, we earn royalties from our strategic partner, Crinos Industria Farmacobiologica S.p.A., on sales in Italy of Pramidin^®, an intranasal form of metoclopramide for the treatment of various gastrointestinal disorders. We recently acquired the U.S. rights to market VSL#3^™, a patented probiotic. We intend to market VSL#3 as a dietary supplement, to promote normal gastrointestinal function.

Consistent with our efforts to focus on sales and marketing, we have reduced spending on research and development. Accordingly, we have entered into several agreements with pharmaceutical and biotechnology companies to further the development of certain technology acquired from RiboGene. In January 2002, we signed a revised Letter of Understanding with Fabre Kramer Pharmaceuticals, which anticipates a license agreement whereby Fabre Kramer will manage and provide funding for the clinical development programs for Hypnostat^™ (an intranasal triazolam for insomnia) and Panistat^™ (an intranasal alprazolam for panic disorders). Our antifungal drug discovery program has been partnered with Tularik, Inc. of South San Francisco, CA; our antiviral drug discovery program has been partnered with Rigel Pharmaceuticals, Inc. of South San Francisco, CA; and our antibacterial program has been partnered with Dainippon Pharmaceuticals Co., Ltd. of Osaka, Japan.

Our executive offices are located at 3260 Whipple Road, Union City, California 94587. Our telephone number is (510) 400-0700.

RISK FACTORS

You should carefully consider the following risk factors, in addition to the other information included in this prospectus, before purchasing our shares of common stock. Each of these risks could adversely affect our business, financial condition and results of operations, as well as adversely affect the value of an investment in our common stock.

We have a history of operating losses and may never generate sufficient revenue to achieve profitability

We have a history of consistent operating losses. Further substantial operating losses are expected to continue over the next year. If we are unable to achieve our sales forecast and maintain expenses in a way that allows us to reach “breakeven” by the end of 2002, substantial operating losses will continue to occur. To date, our revenues have been generated principally from sales of Acthar, Ethamolin, Glofil-125, and Inulin, the licensing of rights to commercialize certain research technology and the manufacturing of our proprietary topical triple antibiotic wound care product for our over-the-counter marketing partner, NutraMax Products, Inc. During 2001, we discontinued the Neoflo product line and we discontinued all work on Cordox. We do not expect Hypnostat, Panistat, Migrastat, Ceresine, or any of the compounds we currently have in pre-clinical testing to be commercially available for a number of years, if at all. Further, our revenues from the sale of Emitasol will also be dependent on FDA approval and the development of Emitasol in conjunction with a new strategic partner which has not yet been obtained. In December 2001, we acquired the U.S. rights to market VSL#3, a patented probiotic. We intend to begin generating sales of VSL#3 in the first half of 2002. Our ability to achieve a consistent, profitable level of operations will be dependent in large part upon our ability to:

•

finance operations with external capital until positive cash flows are achieved,

•

finance and acquire additional marketed products,

•

increase sales of current products,

•

finance the future growth of our sales/marketing and customer service organization,

•

enter into agreements with corporate partners for the development of Emitasol,

•

properly and timely perform the transfer of the manufacturing of our products to new contract manufacturers including receiving the appropriate approvals from the FDA and other regulatory authorities, and

•

continue to receive products from our sole-source contract manufacturers on a timely basis and at acceptable costs.

With the exception of VSL#3, no new product launches are planned. There can be no assurance that sufficient revenues from the sale of our products will be generated, nor can there be assurance that we will ever generate sufficient revenues and be able to contain costs and expenses to become profitable.

Our inability to secure additional funding could lead to a loss of your investment

Although we recently completed a $4.0 million convertible debenture offering with institutional investors, there can be no assurance that this investment combined with our cash on hand will be adequate to fund operations or reach cash flow breakeven. There can also be no assurance that further capital investments will materialize, or that such investments can be completed at attractive terms to us, or that we will receive any additional capital investments at all. In order to conduct our operating activities, we will require substantial additional capital resources in order to acquire new products, increase sales of existing products, and maintain our operations. Our future capital requirements will depend on many factors, including the following:

•

existing product sales performance,

•

sales performance of VSL#3,

•

cost maintenance and potential future expansion of our sales force,

•

achieving lower cost of goods sold and better operating efficiencies,

•

obtaining product from our sole-source contract manufacturers and completing the site transfer to new contract manufacturers,

•

acquiring additional product candidates, and

•

the status of the equity markets, in general, and investor’s tolerance for risk.

Based on our internal forecast and projections, we believe that our cash on hand at December 2001, together with the $4.0 million of cash raised through the issuance of the convertible debentures and the cash to be generated through the expected sales of our products, will be sufficient to fund operations through December 31, 2002. We anticipate obtaining additional financing through corporate partnerships and public or private debt or equity financing. However, additional financing may not be available to us on acceptable terms, if at all. Further, additional equity financings will be dilutive to our shareholders. If sufficient capital is not available, then we may be required to delay, reduce the scope of, eliminate or divest one or more of our product acquisition or manufacturing efforts. There can be no assurance we will be able to achieve cash flow breakeven by the end of 2002 or that our existing cash resources will be adequate to fund operations beyond the end of 2002.

Our reliance on contract manufacturers could adversely affect our business

We will rely on third party contract manufacturers to produce the clinical supplies for Emitasol, Ceresine, our marketed products, Acthar, Ethamolin, Glofil-125, Inulin and VSL#3, and other products that we may develop or commercialize in the future. Third party manufacturers may not be able to meet our needs with respect to timing, quantity or quality. All of our manufacturers are sole-source manufacturers and no alternative suppliers exist. In addition, we do not have contracts in place with the contract manufacturer for Ethamolin nor the bulk product for Inulin. We are negotiating a supply agreement with Aventis for that finished product, but we do not have a contract in place for the supply of Acthar’s active pharmaceutical ingredient. We are also attempting to transfer the finished product manufacturing for Acthar and Ethamolin. If we are unable to contract for a sufficient supply of our required products and substances on acceptable terms, or if we should encounter delays or difficulties in our relationships with our manufacturers, or if the site transfers and the corresponding approval by the FDA and other regulatory authorities does not occur on a timely basis at the appropriate costs to us, we will lose sales and our clinical testing could be delayed, leading to a delay in the submission of products for regulatory approval or the market introduction and subsequent sales of these products. Moreover, contract manufacturers that we may use must continually adhere to current good manufacturing practices regulations enforced by the FDA. If the facilities of these manufacturers cannot pass an inspection, the FDA approval of our products will not be granted. During December of 2001, we were on backorder for Ethamolin and Acthar due to manufacturing constraints at two of our third party contract manufacturers. At this time, we are currently on backorder for Ethamolin. There is no guarantee that we will not have backorders in the future for Ethamolin and Acthar or any of our current or future products. Failure to obtain products for sale for any reason will have a material adverse impact on our financial condition.

We rely heavily on sales of Acthar

For the quarter and the year ended December 31, 2001, Acthar revenues comprised 75% and 41%, respectively, of our total product revenues. We expect that Acthar could contribute to a significant portion of our revenues for 2002. Although our goal is to actively promote Acthar, and we have no reason to believe Acthar will not be successful, there can be no assurance that the strong demand for Acthar will continue and that we will continue to generate significant revenues from sales of Acthar. If the demand for Acthar declines, or if we are forced to reduce the price, or if the cost to produce Acthar increases, our revenue and results from operations could be adversely affected.

We will be dependent on key personnel

We are highly dependent on the services of Charles J. Casamento, Chairman, President, and Chief Executive Officer and Kenneth R. Greathouse, Vice President of Commercial Operations. While Mr. Casamento has executed an employment agreement, there can be no assurance that Mr. Casamento or Mr. Greathouse will continue to be employed by us in the future. The loss of Mr. Casamento, Mr. Greathouse or both could materially harm our business. The future potential growth and expansion of our business is expected to place increased demands on our management skills and resources. Although some increases in staffing levels are expected during 2002, these future demands are expected to require a substantial increase in management personnel to perform operational work as well as the development of additional expertise by existing management personnel. Accordingly, recruiting and retaining management and operational personnel to perform sales and marketing, business development, regulatory affairs, medical affairs and contract manufacturing in the future will also be critical to our success. There can be no assurance that we will be able to attract and retain skilled and experienced management and operational personnel on acceptable terms given the intense competition among numerous pharmaceutical and biotechnology companies, universities and other research institutions for such personnel.

Our products may not be accepted by the market

Our current development program focuses on Emitasol (intranasal metoclopramide). Emitasol could be developed for two indications: diabetic gastroparesis and delayed onset emesis associated with cancer chemotherapy patients. The diabetic gastroparesis drug candidate was being developed in collaboration with a subsidiary of Shire Pharmaceutical Group plc in the U.S. and had completed a Phase II clinical trial in the treatment of diabetic gastroparesis. With the expiration in July 2001 of the exclusive option to develop Emitasol held by Shire, development under this collaboration stopped. Further development of Emitasol is on hold pending our entering into an agreement with a future partner to fund the development of Emitasol. We also have two intranasal drug candidates, on which pilot trials have been conducted: Migrastat for migraine headache and Hypnostat for insomnia. There is no guarantee that any of these drugs will successfully complete Phase III testing. Clinical trial results are frequently susceptible to varying interpretations by scientists, medical personnel, regulatory personnel, statisticians and others, which may delay, limit or prevent further clinical development or regulatory approvals of a product candidate. Also, the length of time that it takes for us to complete clinical trials and obtain regulatory approval for product marketing can vary by product and by the indicated use of a product. We expect that the failure of one or more of these drugs to successfully pass Phase III testing would likely have a materially adverse effect on our future results of operations.

Additionally, any products that we successfully develop, if approved for marketing, may never achieve market acceptance. These products, if successfully developed, will compete with drugs and therapies manufactured and marketed by major pharmaceutical and other biotechnology companies. Physicians, patients or the medical community in general may not accept and utilize the products that we may develop or that our corporate partners may develop.

The degree of market acceptance of any products that we develop will depend on a number of factors, including:

•

the establishment and demonstration of the clinical efficacy and safety of the product candidates,

•

their potential advantage over alternative treatment methods and competing products,

•

reimbursement policies of government and third-party payors, and

•

our ability to market and promote the products effectively.

The failure of our products to achieve market acceptance could materially harm our business.

We have no experience marketing VSL#3

We intend to market VSL#3 as a dietary supplement. Dietary supplements typically are not reimbursable by healthcare providers. This may limit our sales of VSL#3. We also do not know what the demand for VSL#3 will be. These factors may adversely and materially impact our ability to meet forecasted sales in 2002 and beyond.

Control by existing shareholders

Sigma-Tau Finanziaria S.p.A and its affiliates beneficially own, directly or indirectly, approximately 38% of our outstanding common stock as of March 25, 2002. Accordingly, these shareholders may control the outcome of certain shareholder votes, including votes concerning the election of directors, the adoption or amendment of provisions in our Articles of Incorporation, and the approval of mergers and other significant corporate transactions. This level of concentrated ownership may have the effect of delaying or preventing a change in the management or voting control of us.

Our business could be harmed by intense competition

The biotechnology and pharmaceutical industries are intensely competitive and subject to rapid and significant technological change. A number of companies are pursuing the development of pharmaceuticals and products which target the same diseases and conditions that we will target. For example, there are products on the market that compete with Acthar, Ethamolin, Glofil-125, Inulin, and VSL#3. Moreover, technology controlled by third parties that may be advantageous to our business may be acquired or licensed by competitors of ours, preventing us from obtaining this technology on favorable terms, or at all.

Our ability to compete will depend on our abilities to create and maintain scientifically advanced technology and to develop and commercialize pharmaceutical products based on this technology, as well as our ability to attract and retain qualified personnel, obtain patent protection or otherwise develop proprietary technology or processes and secure sufficient capital resources for the expected substantial time period between technological conception and commercial sales of products based upon our technology.

Many of the companies developing competing technologies and products have significantly greater financial resources and expertise in development, manufacturing, obtaining regulatory approvals and marketing than we do. Other smaller companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. Academic institutions, government agencies and other public and private research organizations may also seek patent protection and establish collaborative arrangements for clinical development, manufacturing and marketing of products similar to ours. These companies and institutions will compete with us in recruiting and retaining qualified sales and marketing and management personnel as well as in acquiring technologies complementary to our programs. We will face competition with respect to:

•

product efficacy and safety,

•

the timing and scope of regulatory approvals,

•

availability of resources,

•

reimbursement coverage,

•

price, and

•

patent position, including potentially dominant patent positions of others.

There can be no assurance that our competitors will not succeed in developing technologies and drugs that are more effective or less costly than any which we are developing or which would render our technology and future drugs obsolete and noncompetitive. In addition, our competitors may succeed in obtaining the approval of the FDA or other regulatory approvals for drug candidates more rapidly than we will. Companies that complete

clinical trials, obtain required regulatory agency approvals and commence commercial sale of their drugs before their competitors may achieve a significant competitive advantage, including patent and FDA marketing exclusivity rights that would delay our ability to market specific products. There can be no assurance that drugs resulting from the joint efforts of our existing or future collaborative partner, will be able to compete successfully with competitors’ existing products or products under development or that we will obtain regulatory approval in the U.S. or elsewhere.

Successful late stage Phase III clinical trials for such potentially important treatments as diabetic gastroparesis and delayed onset emesis will require the enrollment of many patients. Together, the cost of these trials, if funded solely by us, will exceed our current financial resources.

If we fail to maintain or enter into new contracts related to collaborations and in-licensed or acquired technology and products, our business could adversely be affected

Our business model has been dependent on our ability to enter into licensing and acquisition arrangements with commercial or academic entities to obtain technology or marketed products for development and commercialization. There is no assurance we can enter into any new agreements in the future. Disputes may arise regarding the inventorship and corresponding rights in inventions and know-how resulting from the joint creation or use of intellectual property by us and our licensors or scientific collaborators. We may not be able to negotiate additional license and acquisition agreements in the future on acceptable terms, if at all. In addition, current license and acquisition agreements may be terminated, and we may not be able to maintain the exclusivity of our exclusive licenses.

There can be no assurance that any collaborators will commit sufficient development resources, technology, regulatory expertise, manufacturing, marketing and other resources towards developing, promoting and commercializing products incorporating our discoveries. Further, competitive conflicts may arise among these third parties that could prevent them from working cooperatively with us. The amount and timing of resources devoted to these activities by the parties could depend on the achievement of milestones by us and otherwise generally may be controlled by other parties. In addition, we expect that our agreements with future collaborators will likely permit the collaborators to terminate their agreements upon written notice to us. This type of termination would substantially reduce the likelihood that the applicable research program or any lead candidate or candidates would be developed into a drug candidate, would obtain regulatory approvals and would be manufactured and successfully commercialized. Therefore, any such termination could materially harm our business.

There can be no assurance that any of our collaborations will be successful in developing and commercializing products or that we will receive milestone payments or generate revenues from royalties sufficient to offset our significant investment in product development and other costs. Disagreements with our collaborators could lead to delays or interruptions in, or termination of, development and commercialization of certain potential products or could require or result in litigation or arbitration, which could be time-consuming and expensive and could have a material adverse effect on our business.

Our collaboration agreement with Shire Pharmaceuticals Group plc presents a great amount of uncertainty

Under a collaboration agreement between Shire (after its acquisition of Roberts Pharmaceuticals) and us, Shire had the option to acquire exclusive North American rights to Emitasol. This option expired in July 2001. Under that collaboration agreement, we were obligated to fund one-half of the clinical development expenses for Emitasol up to an aggregate of $7 million. Through December 31, 2001, we have made development payments for Emitasol, under the terms of the agreement with Shire, totaling $4.6 million, which consists of $4.1 million paid to Shire and approximately $500,000 paid to other parties for allowable expenses, including patent and trademark costs.

Shire asserts we owe $348,000 in development expenses incurred by it under the collaboration agreement prior to the expiration of the option. We have requested that Shire return certain items to us, including the manufacturing and clinical data it obtained over the course of the agreement, the transfer of the INDs relating to Emitasol (which is substantially complete) and the assignment of the intellectual property relating to Emitasol generated in the course of the development program. While Shire has returned some of these items, we are still in discussion with them as to the resolution of other open items. The failure to quickly resolve any open items on favorable terms relating to this collaboration could have a material adverse impact on our ability to find a new partner to continue the development of Emitasol. Additionally, Shire holds all of our outstanding 2,155,715 Series A preferred shares which represents a beneficial ownership percentage of approximately 5.33% as of March 25, 2002. If we are unable to settle our disagreements with Shire quickly, we may end up in a protracted contract dispute with this major shareholder which may have unpredictable and material adverse effects on our business.

Our business could be harmed if we are unable to protect our proprietary rights

Our success will depend in part on our ability to:

•

obtain patents for our products and technologies,

•

protect trade secrets,

•

operate without infringing upon the proprietary rights of others, and

•

prevent others from infringing on our proprietary rights.

We will only be able to protect our proprietary rights from unauthorized use by third parties to the extent that these rights are covered by valid and enforceable patents or are effectively maintained as trade secrets and are otherwise protectable under applicable law. We will attempt to protect our proprietary position by filing U.S. and foreign patent applications related to our proprietary products, technology, inventions and improvements that are important to the development of our business.

The patent positions of biotechnology and biopharmaceutical companies involve complex legal and factual questions and, therefore, enforceability cannot be predicted with certainty. Patents, if issued, may be challenged, invalidated or circumvented. Thus, any patents that we own or license from third parties may not provide any protection against competitors. Pending patent applications we may file in the future, or those we may license from third parties, may not result in patents being issued. Also, patent rights may not provide us with proprietary protection or competitive advantages against competitors with similar technology. Furthermore, others may independently develop similar technologies or duplicate any technology that we have developed or we will develop. The laws of some foreign countries may not protect our intellectual property rights to the same extent as do the laws of the U.S.

In addition to patents, we rely on trade secrets and proprietary know-how. We currently seek protection, in part, through confidentiality and proprietary information agreements. These agreements may not provide meaningful protection or adequate remedies for proprietary technology in the event of unauthorized use or disclosure of confidential and proprietary information. The parties may not comply or may breach these agreements. Furthermore, our trade secrets may otherwise become known to, or be independently developed by competitors.

Our success will further depend, in part, on our ability to operate without infringing the proprietary rights of others. There can be no assurance that our activities will not infringe on patents owned by others. We could incur substantial costs in defending ourselves in suits brought against any licensor or us. Should our products or technologies be found to infringe on patents issued to third parties, the manufacture, use and sale of our products could be enjoined, and we could be required to pay substantial damages. In addition, we, in connection with the development and use of our products and technologies, may be required to obtain licenses to patents or other proprietary rights of third parties. No assurance can be given that any licenses required under any such patents or proprietary rights would be made available on terms acceptable to us, if at all.

Our business and product approvals must comply with strict government regulation

Any products that we develop are subject to regulation by federal, state and local governmental authorities in the U.S., including the FDA, and by similar agencies in other countries. Any product that we develop must receive all relevant regulatory approvals or clearances before it may be marketed in a particular country. The regulatory process, which includes extensive preclinical studies and clinical trials of each product to establish its safety and efficacy, is uncertain, can take many years and requires the expenditure of substantial resources. Data obtained from preclinical and clinical activities are susceptible to varying interpretations which could delay, limit or prevent regulatory approval or clearance. In addition, delays or rejections may be encountered based upon changes in regulatory policy during the period of product development and the period of review of any application for regulatory approval or clearance for a product. Delays in obtaining regulatory approvals or clearances could:

•

adversely affect the marketing, selling and distribution of any products that our corporate partners or we develop,

•

impose significant additional costs on our corporate partners and us,

•

diminish any competitive advantages that we or our corporate partners may attain, and

•

adversely affect our ability to receive royalties and generate revenues and profits.

Regulatory approval, if granted, may entail limitations on the indicated uses for which a new product may be marketed that could limit the potential market for the product. Product approvals, once granted, may be withdrawn if problems occur after initial marketing. Furthermore, manufacturers of approved products are subject to pervasive review, including compliance with detailed regulations governing FDA good manufacturing practices. The FDA has recently revised the good manufacturing practices regulations. Failure to comply with applicable regulatory requirements can result in warning letters, fines, injunctions, civil penalties, recall or seizure of products, total or partial suspension of production, refusal of the government to grant marketing applications and criminal prosecution.

In addition, we cannot predict the extent of government regulations or the impact of new governmental regulations that might have an adverse effect on the development, production and marketing of our products. We may be required to incur significant costs to comply with current or future laws or regulations.

We may not be reimbursed by third party payors

In both domestic and foreign markets, sales of our products will depend in part on the availability of reimbursement from third-party payors such as state and federal governments (for example, under Medicare and Medicaid programs in the U.S.) and private insurance plans. VSL#3 currently does not qualify for any reimbursements by third party payors. In certain foreign markets, the pricing and profitability of our products generally are subject to government controls. In the U.S., there have been, and we expect there will continue to be, a number of state and federal proposals that limit the amount that state or federal governments will pay to reimburse the cost of drugs. In addition, we believe the increasing emphasis on managed care in the U.S. has and will continue to put pressure on the price and usage of our products, which may impact product sales. Further, when a new therapeutic is approved, the reimbursement status and rate of such a product is uncertain. In addition, current reimbursement policies for existing products may change at any time. Changes in reimbursement or our failure to obtain reimbursement for our products may reduce the demand for, or the price of, our products, which could result in lower product sales or revenues which could have a material adverse effect on us and our results of operations.

In the U.S., proposals have called for substantial changes in the Medicare and Medicaid programs. If such changes are enacted, they may require significant reductions from currently projected government expenditures for these programs. Driven by budget concerns, Medicaid managed care systems have been under consideration in several states. If the Medicare and Medicaid programs implement changes that restrict the access of a significant population of patients to its innovative medicines, our business could be materially affected.

Legislation in the U.S. requires us to give rebates to state Medicaid agencies based on each state’s reimbursement of pharmaceutical products under the Medicaid program. We also must give discounts or rebates on purchases or reimbursements of pharmaceutical products by certain other federal and state agencies and programs. There can be no assurance that these discounts and rebates may become burdensome to us, which may adversely affect our current business and future product development.

Our sales are affected by the availability of reimbursement on non-prescription products

In the U.S. and other significant markets, sales of our products may be affected by the availability of reimbursement from the government or other third parties, such as insurance companies. It is difficult to predict the reimbursement status of newly approved, novel biotechnology and pharmaceutical products, and current reimbursement policies for existing products may change. In certain foreign markets, governments have issued regulations relating to the pricing and profitability of pharmaceutical companies. There have been proposals in the U.S. (at both the federal and state level) to implement such controls. The growth of managed care in the U.S. also has placed pressure on the pricing of healthcare products. These pressures can be expected to continue.

We will incur costs associated with expanding the business

Management expects to grow the business in areas in which we can be most competitive, either through in-licensing, collaborations or acquisitions of products or companies. In connection with these efforts, we may incur significant charges, costs and expenses which could impact our profitability, including impairment losses, restructuring charges, the write-off of purchased in-process technologies, transaction-related expenses, costs associated with integrating new businesses and the cost of amortizing goodwill and other intangibles.

Our stock price is subject to volatility

The price of our stock, like that of other specialty pharmaceutical companies, is subject to significant volatility. Any number of events, both internal and external to us, may affect the stock price. These include, without limitation, the quarterly and yearly revenues and earnings, results of clinical trials conducted by us, our partners or by our competitors; announcement by us or our competitors regarding product development efforts, including the status of regulatory approval applications; the outcome of legal proceedings, including claims filed by us against third parties to enforce our patents and claims filed by third parties against us relating to patents held by the third parties; the launch of competing products; the resolution of (or failure to resolve) disputes with collaboration partners; corporate restructuring by us; licensing activities by us; and the acquisition or sale by us of products, products in development or businesses.

In connection with our research and development collaborations, from time to time we invest in equity securities of our corporate partners. The price of these securities also is subject to significant volatility and may be affected by, among other things, the types of events that affect our stock. Changes in the market price of these securities may impact our profitability.

Our business may be affected by product liability and availability of insurance

Our business will expose us to potential liability risks that are inherent in the testing, manufacturing and marketing of pharmaceutical products. The use of any drug candidates ultimately developed by us or our collaborators in clinical trials may expose us to product liability claims and possible adverse publicity. These risks will expand for any of our drug candidates that receive regulatory approval for commercial sale. Product liability insurance for the pharmaceutical industry is generally expensive, if available at all. We currently have product liability insurance, however, there can be no assurance that we will be able to maintain insurance coverage at acceptable costs or in a sufficient amount, if at all, or that a product liability claim would not harm our reputation, stock price or our business.

We could be adversely affected by litigation

Although there are currently no lawsuits pending against us, we could be adversely affected by litigation. Potential litigation could arise from a number of factors including disputes with past, current and future employees and partners, class action litigation relating to shareholder lawsuits or product liability claims, frivolous lawsuits filed on behalf of manufactured plaintiffs or any other items not foreseen at this time. We believe we have adequate insurance to protect ourselves against certain claims but there can be no assurance that this insurance coverage will be of any use against any future claims. If we were to become subject to any lawsuit, regardless of its nature and claims, our time and resources, including that of management, could be severely impacted. This in turn could have a material adverse impact on our financial condition.

FORWARD-LOOKING STATEMENTS

This prospectus contains and incorporates by reference forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. These forward-looking statements are subject to a number of risks, uncertainties and assumptions about us, including, among other things, those set forth elsewhere in this prospectus under the heading “Risk Factors.” You can identify these forward-looking statements by forward-looking words such as “believe,” “may,” “could,” “will,” “estimate,” “continue,” “anticipate,” “intend,” “seek,” “plan,” “expect,” “should,” “would” and similar expressions in this prospectus.

We undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. In light of these risks and uncertainties, the forward-looking events and circumstances discussed in this prospectus may not occur and actual results could differ materially from those anticipated or implied in the forward-looking statements.

USE OF PROCEEDS

We are registering the shares of our common stock offered by this prospectus for the account of the selling stockholders identified in the section of this prospectus entitled “Selling Stockholders.” All of the net proceeds from the sale of our common stock by this prospectus will go to the selling stockholders who offer and sell their shares of our common stock. We will not receive any part of the proceeds from the sale of these securities.

DESCRIPTION OF DEBENTURES AND WARRANTS

We originally issued to the selling stockholders on March 15, 2002 (i) $4,000,000 of 8% convertible debentures and (ii) warrants to purchase common stock. We agreed to pay interest on the debentures at a rate of 8% per annum on a quarterly basis. The debentures are convertible into 2,531,646 shares of our authorized but unissued common stock at a fixed conversion price of $1.58 per share, which was calculated based on 105% of the five day average closing sale price of our common stock immediately prior to the closing date. The debentures mature on March 15, 2005. At maturity, under certain circumstances we may redeem any outstanding debentures for stock. We also issued warrants to the selling stockholders to acquire an aggregate of 1,618,987 shares of our authorized but unissued common stock at an exercise price of $1.70 per share, which was calculated based on 115% of the fifteen day average closing sale price of our common stock immediately prior to the closing date. The warrants are exercisable through March 15, 2006. The terms and conditions of the debentures and warrants are more fully described in the debenture agreements for those debentures and warrant agreements for those warrants, which are filed as exhibits to the registration statement of which this prospectus forms a part.

SELLING STOCKHOLDERS

The shares offered by this prospectus are issuable upon the conversion or redemption of debentures and the exercise of warrants which we originally issued to the selling stockholders. We are registering 2,848,100 shares of common stock issuable to the selling stockholders upon conversion or redemption of the debentures and 1,618,987 shares of common stock issuable to the selling stockholders upon exercise of the warrants.

The following table provides the name of each selling stockholder and the number of shares of our common stock offered by each selling stockholder under this prospectus. Because the selling stockholders may sell all or part of their shares of our common stock under this prospectus and since this offering is not being underwritten on a firm commitment basis, we cannot estimate the number and percentage of shares of our common stock that the selling stockholders will hold at the end of the offering covered by this prospectus.

	Shares Beneficially Owned Before the Offering				Shares Beneficially Owned After the Offering
Name	Number		Percent		Shares Being Offered		Number	Percent
SF Capital Partners Ltd.	2,341,771	(1)	5.0	%(2)	2,341,771	(1)	—	—
Defiante Farmaceutica Unipessoal L.D.A.	2,025,316	(3)	5.0	%	2,025,316	(3)	—	—
Robert Schacter	57,000	(4)	*		57,000	(4)	—	—
Eric Sloane	23,750	(5)	*		23,750	(5)	—	—
Thomas J. Griesel	14,250	(6)	*		14,250	(6)	—	—
Financial West Group	5,000	(7)	*		5,000	(7)

Ownership is less than 1%

(1)

Includes 1,265,823 shares of common stock issuable upon conversion of a debenture, an additional 316,454 shares of common stock which may be issued by Questcor upon redemption of a debenture, and 759,494 shares of common stock issuable upon exercise of a warrant. The debenture and warrant issued to SF Capital Partners Ltd. contain provisions limiting SF Capital Partners Ltd.’s ability to convert the debenture and/or exercise the warrant to the extent that such exercise would result in SF Capital Partners Ltd. beneficially owning (for purposes of Section 13(d) of the Securities Exchange Act of 1934) more than 4.99% of our common stock, and such provision could be waived by SF Capital Partners Ltd. on no less than sixty one days notice to us.

(2)

Ownership percentage based on 1,265,823 shares of common stock issuable upon conversion of a debenture and 759,494 shares of common stock issuable upon exercise of a warrant. The debenture and warrant issued to SF Capital Partners Ltd. contain provisions limiting SF Capital Partners Ltd.’s ability to convert the debenture and/or exercise the warrant to the extent that such exercise would result in SF Capital Partners Ltd. beneficially owning (for purposes of Section 13(d) of the Securities Exchange Act of 1934) more than 4.99% of our common stock, and such provision could be waived by SF Capital Partners Ltd. on no less than sixty one days notice to us.

(3)

Includes 1,265,823 shares of common stock issuable upon conversion of a debenture and 759,493 shares of common stock issuable upon exercise of a warrant.

(4)

Includes 57,000 shares of common stock issuable upon exercise of a warrant.

(5)

Includes 23,750 shares of common stock issuable upon exercise of a warrant.

(6)

Includes 14,250 shares of common stock issuable upon exercise of a warrant.

(7)

Includes 5,000 shares of common stock issuable upon exercise of a warrant.

Pursuant to agreements between us and the selling stockholders, we agreed to file a registration statement covering the shares of common stock issuable to the selling stockholders.

None of the selling stockholders has any position, office or other material relationship with us or any of our affiliates, nor have they had any position, office or material relationship with us or any of our affiliates within the past three years, except as follows: Defiante Farmaceutica Unipessoal L.D.A. is a wholly owned subsidiary of Sigma Tau Finanziaria S.p.A. Sigma Tau Finanziaria S.p.A and its affiliates beneficially own approximately 38% of our outstanding common stock as of March 25, 2002.

PLAN OF DISTRIBUTION

The selling stockholders and any of their pledgees, assignees and successors-in-interest may, from time to time, sell any or all of their shares of common stock on any stock exchange, market or trading facility on which the shares are traded or in private transactions. These sales may be at fixed or negotiated prices. The selling stockholders may use any one or more of the following methods when selling shares:

•

ordinary brokerage transactions and transactions in which the broker-dealer solicits purchasers;

•

block trades in which the broker-dealer will attempt to sell the shares as agent but may position and resell a portion of the block as principal to facilitate the transaction;

•

purchases by a broker-dealer as principal and resale by the broker-dealer for its account;

•

an exchange distribution in accordance with the rules of the applicable exchange;

•

privately negotiated transactions;

•

short sales;

•

broker-dealers may agree with the selling stockholders to sell a specified number of such shares at a stipulated price per share;

•

a combination of any such methods of sale; and

•

any other method permitted pursuant to applicable law

The selling stockholders may also sell shares under Rule 144 under the Securities Act of 1933, if available, rather than under this prospectus.

Broker-dealers engaged by the selling stockholders may arrange for other brokers-dealers to participate in sales. Broker-dealers may receive commissions or discounts from the selling stockholders (or, if any broker-dealer acts as agent for the purchaser of shares, from the purchaser) in amounts to be negotiated. The selling stockholders do not expect these commissions and discounts to exceed what is customary in the types of transactions involved.

The selling stockholders may from time to time pledge or grant a security interest in some or all of the shares of common stock or warrants owned by them and, if they default in the performance of their secured obligations, the pledgees or secured parties may offer and sell the shares of common stock from time to time under this prospectus, or under an amendment to this prospectus under Rule 424(b)(3) or other applicable provision of the Securities Act of 1933 amending the list of selling stockholders to include the pledgee, transferee or other successors in interest as selling stockholders under this prospectus.

The selling stockholders and any broker-dealers or agents that are involved in selling the shares may be deemed to be “underwriters” within the meaning of the Securities Act of 1933 in connection with such sales. In such event, any commissions received by such broker-dealers or agents and any profit on the resale of the shares purchased by them may be deemed to be underwriting commissions or discounts under the Securities Act of 1933. The selling stockholders have informed Questcor that they do not have any agreement or understanding, directly or indirectly, with any person to distribute the common stock.

Questcor is required to pay all fees and expenses incident to the registration of the shares. Questcor has agreed to indemnify the selling stockholders against certain losses, claims, damages and liabilities, including liabilities under the Securities Act of 1933. .

LEGAL MATTERS

The legality of our common stock offered by this prospectus will be passed upon by Latham & Watkins, San Diego, California.

EXPERTS

Ernst & Young, LLP, independent auditors, have audited our consolidated financial statements and schedule included in our Annual Report on Form 10-K for the year ended December 31, 2001, as set forth in their report, which is incorporated by reference in this prospectus and elsewhere in the registration statement. Our consolidated financial statements and schedule are incorporated by reference in reliance on Ernst & Young LLP’s report, given on their authority as experts in accounting and auditing.

WHERE TO FIND ADDITIONAL INFORMATION

We file annual, quarterly and special reports, proxy statements and other information with the SEC. You may read and copy materials we have filed with the SEC at the SEC’s Public Reference Room at 450 Fifth Street, N.W., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for further information on the operation of its Public Reference Room. Our SEC filings also are available to the public on the SEC’s Internet site at www.sec.gov. In addition, you may obtain a copy of our SEC filings at no cost by writing or telephoning our Chief Financial Officer at:

Questcor Pharmaceuticals, Inc.

3260 Whipple Road

Union City, California 94587

(510) 400-0700

The SEC allows us to “incorporate by reference” in this prospectus information we file with the SEC, which means that we may disclose important information in this prospectus by referring you to the document that contains the information. The information incorporated by reference is considered to be a part of this prospectus, and later information filed with the SEC will update and supersede this information. Questcor incorporates by reference the documents listed below and any future filings it makes with the SEC under Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, until the offering of securities covered by this prospectus is completed:

•

Our Annual Report on Form 10-K for the fiscal year ended December 31, 2001 filed with the SEC on March 19, 2002;

•

Our Definitive Proxy Statement on Schedule 14A filed with the SEC on March 28, 2002; and

•

The description of our common stock contained in our (formerly Cypros Pharmaceutical Corporation) Registration Statement on Form 8-A filed with the SEC on October 26, 1992, as amended;

All documents filed by us pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act subsequent to the date this Registration Statement is filed with the SEC and prior to the filing of a post-effective amendment which indicates that all securities offered have been sold or which deregisters all securities then remaining unsold shall be deemed to be incorporated by reference in this Registration Statement and to be a part of it from the respective dates of filing of such documents. Any statement contained in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement contained herein or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.

We have filed with the SEC a Registration Statement on Form S-3 under the Securities Act of 1933, relating to the securities that may be offered by this prospectus. This prospectus is a part of that Registration Statement, but does not contain all of the information in the Registration Statement. For more detail concerning Questcor and any securities offered by this prospectus, you may examine the Registration Statement and the exhibits filed with it at the offices of the SEC.

You should rely only on the information provided or incorporated by reference in this prospectus or in the applicable supplement to this prospectus. You should not assume that the information in this prospectus and the applicable supplement is accurate as of any date other than the date on the front cover of the document.

PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14. Other Expenses of Issuance and Distribution

Our estimated expenses in connection with the distribution of the securities being registered are as set forth in the following table:

SEC Registration Fee	$	737.70
Legal Fees and Expenses		20,000
Accounting Fees and Expenses		7,500
Printing and Engraving Expenses		5,000
Miscellaneous		6,762.30

Total	$	40,000

All of the above items except the registration fee are estimates.

Item 15. Indemnification of Directors and Officers

Section 317 of the California General Corporation Law authorizes a court to award, or a corporation’s Board of Directors to grant, indemnity to directors and officers who are parties or are threatened to be made parties to any proceeding (with exceptions) by reason of the fact that the person is or was an agent of the corporation, against expenses, judgments, fines, settlements and other amounts actually and reasonably incurred in connection with the proceeding if that person acted in good faith and in a manner the person reasonably believed to be in the best interests of the corporation. This limitation on liability has no effect on a director’s liability (i) for acts or omissions that involve intentional misconduct or a knowing and culpable violation of law, (ii) for acts or omissions that a director believes to be contrary to the best interests of the corporation or its security holders or that involve the absence of good faith on the part of the director, (iii) relating to any transaction from which a director derived an improper personal benefit, (iv) for acts or omissions that show a reckless disregard for the director’s duty to the corporation or its security holders in circumstances in which the director was aware, or should have been aware, in the ordinary course of performing a director’s duties, of a risk of a serious injury to the corporation or its security holders, (v) for acts or omissions that constitute an unexcused pattern of inattention that amounts to an abdication of the directors’ duty to the corporation or its security holders, (vi) under Section 310 of the California General Corporation Law (concerning contracts or transactions between the corporation and a director) or (vii) under Section 316 of the California General Corporation Law (directors’ liability for improper dividends, loans and guarantees). The provision does not extend to acts or omissions of a director in his capacity as an officer. Further, the provision has no effect on claims arising under federal or state securities laws and does not affect the availability of injunctions and other equitable remedies available to our security holders for any violation of a director’s fiduciary duty to us or our security holders. Although the validity and scope of the legislation underlying the provision have not yet been interpreted to any significant extent by the California courts, the provision may relieve directors of monetary liability to us for grossly negligent conduct, including conduct in situations involving attempted takeovers of Questcor.

In accordance with Section 317, our Amended and Restated Articles of Incorporation (the “Articles”), limit the liability of a director to Questcor or our security holders for monetary damages to the fullest extent permissible under California law, and authorizes Questcor to provide indemnification to its agents (including officers and directors), subject to the limitations set forth above. Our Bylaws further provide for indemnification of corporate agents to the maximum extent permitted by the California General Corporation Law.

Pursuant to the authority provided in the Articles, we have asked our shareholders to approve a form of indemnification agreement for our officers and directors and plan to enter into indemnification agreements with

II-1

each of our officers and directors, indemnifying them against potential liabilities that may arise as a result of their service and providing for other protection.

We also maintain insurance policies that insure our officers and directors against liabilities arising from their positions.

The foregoing summaries are necessarily subject to the complete text of the statute, the Articles, the Bylaws and the agreements referred to above and are qualified in their entirety by reference thereto.

Item 16. Exhibits

The Exhibit Index is attached hereto on page E-1.

Item 17. Undertakings

(a) The undersigned registrant hereby undertakes:

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

(ii) To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the SEC pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

(iii) To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in this registration statement; provided, however, that subparagraphs (a)(1)(i) and (a)(1)(ii) above do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in periodic reports filed with or furnished to the SEC by the Registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in this registration statement;

provided, however, that the undertakings set forth in paragraphs (a)(1)(i) and (a)(1)(ii) above do not apply if the Registration Statement is on Form S-3, Form S-8 or Form F-3, and the information required to be included in a post-effective amendment by those paragraphs is contained in periodic reports filed with or furnished to the Commission by the Company pursuant to Section 13 or 15(d) of the Exchange Act that are incorporated by reference in this Registration Statement.

(2) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered herein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(b) The undersigned registrant hereby further undertakes that, for the purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’s annual report pursuant to Section 13(a) or

II-2

Section 15(d) of the Securities Exchange Act of 1934 that is incorporated by reference in this registration statement shall be deemed to be a new registration statement relating to the securities offered herein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(c) Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to existing provisions or otherwise, the registrant has been advised that in the opinion of the SEC such indemnification is against public policy as expressed in the Securities Act of 1933 and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act of 1933 and will be governed by the final adjudication of such issue.

II-3

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Union City, County of Alameda, State of California, on March 28, 2002.

QUESTCOR PHARMACEUTICALS, INC.

By: /s/ CHARLES J. CASAMENTO

Charles J. Casamento

Chairman, President and Chief Executive Officer

POWER OF ATTORNEY

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed below by the following persons in the capacities and on the dates indicated.

Each person whose signature appears below hereby constitutes and appoints Charles J. Casamento and Timothy E. Morris, and each of them, his or her true and lawful attorney-in-fact and agent, with full power of substitution and resubstitution for him in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement, or any registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, and to file the same, with exhibits thereto and other documents in connection therewith or in connection with the registration of the common stock offered hereby under the Securities Act of 1933, with the SEC, granting unto such attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary in connection with such matters and hereby ratifying and confirming all that such attorneys-in-fact and agents, and each of them, may do or cause to be done by virtue hereof.

Signature	Title	Date

/s/ CHARLES J. CASAMENTO Charles J. Casamento	Chairman, President and Chief Executive Officer and Director (Principal Executive Officer)	March 28, 2002

/s/ TIMOTHY E. MORRIS Timothy E. Morris	Vice President, Finance & Administration, and Chief Financial Officer (Principal Financial and Accounting Officer)	March 28, 2002

/s/ ROBERT F. ALLNUTT Robert F. Allnutt	Director	March 28, 2002

/s/ FRANK J. SASINOWSKI Frank J. Sasinowski	Director	March 28, 2002

/s/ JON S. SAXE Jon S. Saxe	Director	March 28, 2002

/s/ JOHN T. SPITZNAGEL John T. Spitznagel	Director	March 28, 2002

/s/ ROGER G. STOLL Roger G. Stoll	Director	March 28, 2002

/s/ VIRGIL D. THOMPSON Virgil D. Thompson	Director	March 28, 2002

II-4

EXHIBIT INDEX

Exhibit Number		Description

4.1(1)		Form of Common Stock Certificate.

4.3.1*		Securities Purchase Agreement between the Company and SF Capital Partners Ltd. dated March 15, 2002.

4.3.2*		Convertible Debenture between the Company and SF Capital Partners Ltd. dated March 15, 2002.

4.3.3*		Registration Rights Agreement between the Company and SF Capital Partners Ltd. dated March 15, 2002.

4.3.4*		Warrant between the Company and SF Capital Partners Ltd. dated March 15, 2002.

4.4.1*		Securities Purchase Agreement between the Company and Defiante Farmaceutica Unipessoal L.D.A. dated March 15, 2002.

4.4.2*		Convertible Debenture between the Company and Defiante Farmaceutica Unipessoal L.D.A. dated March 15, 2002.

4.4.3*		Registration Rights Agreement between the Company and Defiante Farmaceutica Unipessoal L.D.A. dated March 15, 2002.

4.4.4*		Warrant between the Company and Defiante Farmaceutica Unipessoal L.D.A. dated March 15, 2002.

4.5*		Warrant between the Company and Robert Schacter dated March 15, 2002.

4.6*		Warrant between the Company and Eric Sloane dated March 15, 2002.

4.7*		Warrant between the Company and Thomas J. Griesel dated March 15, 2002.

4.8*		Warrant between the Company and Financial West Group dated March 15, 2002.

5.1*		Opinion of Latham & Watkins.

23.1		Consent of Latham & Watkins (contained in Exhibit 5.1).

23.2*		Consent of Ernst & Young LLP, Independent Auditors.

24.1		Powers of Attorney (contained on the signature page of this Registration Statement).

(1)

Filed as an exhibit to Questcor’s, formerly Cypros Pharmaceutical Corporation, Registration Statement on Form 8-A, as amended (File No. 33-51682), and incorporated herein by reference.

Filed herewith.

EXHIBIT 4.3.1 SECURITIES PURCHASE AGREEMENT ----------------------------- This Securities Purchase Agreement (this "Agreement") is dated as of March 15, 2002 by and between Questcor Pharmaceuticals, Inc., a California corporation (the "Company"), and SF Capital Partners Ltd., a British Virgin Islands company (the "Purchaser"). WHEREAS, subject to the terms and conditions set forth in this Agreement and pursuant to Section 4(2) of the Securities Act of 1933 (the "Securities Act"), and Rule 506 promulgated thereunder, the Company desires to issue and sell to Purchaser, and the Purchaser desires to purchase from the Company, securities of the Company as more fully described in this Agreement. NOW, THEREFORE, IN CONSIDERATION of the mutual covenants contained in this Agreement, and for other good and valuable consideration the receipt and adequacy of which are hereby acknowledged, the Company and the Purchaser agrees as follows: ARTICLE I DEFINITIONS 1.1. Definitions. In addition to the terms defined elsewhere in this ----------- Agreement: (a) capitalized terms that are not otherwise defined herein that are defined in the Debenture shall have the meanings given to such terms in the Debenture, and (b) the following terms have the meanings indicated in this Section 1.1: "Affiliate" means any Person that, directly or indirectly through one or more intermediaries, controls or is controlled by or is under common control with a Person, as such terms are used in and construed under Rule 144. "Closing" means the closing of the purchase and sale of the Debenture and Warrants pursuant to Section 2.1. "Closing Date" means the date of the Closing. "Closing Price" means, for any date, the price determined by the first of the following clauses that applies: (a) if the Common Stock is then listed or quoted on an Eligible Market, the closing sale price per share of the Common Stock for such date (or the nearest preceding date) on the primary Eligible Market on which the Common Stock is then listed or quoted; (b) if the Common Stock is not then listed or quoted on an Eligible Market and if prices for the Common Stock are then quoted on the OTC Bulletin Board, the closing sale price per share of the Common Stock for such date (or the nearest preceding date) on the OTC Bulletin Board; (c) if the Common Stock is not then listed or quoted on the OTC Bulletin Board and if prices for the Common Stock are then reported in the "Pink Sheets" published by the National Quotation Bureau Incorporated (or a similar organization or agency succeeding to its functions of reporting prices), the most recent sale price per share of the Common Stock so reported; or -1-

(d) in all other cases, the fair market value of a share of Common Stock as determined by an independent appraiser selected in good faith by the Purchaser. "Commission" means the Securities and Exchange Commission. "Common Stock" means the common stock of the Company, no par value per share, and any securities into which such common stock may hereafter be reclassified. "Company Counsel" means Latham & Watkins, San Diego, California. "Debenture" means $2,000,000 in aggregate principal amount of the Company's 8% Convertible Debentures issued to the Purchaser at the Closing, in the form of Exhibit A. --------- "Effective Date" means the date that an Underlying Shares Registration Statement is first declared effective by the Commission. "Effectiveness Date" means the date on which an Underlying Shares Registration Statement is required to become effective pursuant to the Registration Rights Agreement. "Eligible Market" means any of the New York Stock Exchange, the American Stock Exchange, the Nasdaq National Market or the Nasdaq SmallCap Market. "Exchange Act" means the Securities Exchange Act of 1934, as amended. "Losses" means any and all losses, claims, damages, liabilities, settlement costs and expenses, including without limitation costs of preparation and reasonable attorneys' fees. "Person" means an individual or corporation, partnership, trust, incorporated or unincorporated association, joint venture, limited liability company, joint stock company, government (or an agency or subdivision thereof) or other entity of any kind. "Proceeding" means an action, claim, suit, investigation or proceeding (including, without limitation, an investigation or partial proceeding, such as a deposition). "Registration Rights Agreement" means the Registration Rights Agreement, dated as of the date of this Agreement, among the Company and the Purchaser, in the form of Exhibit B. --------- "Rule 144" means Rule 144 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. "Securities" means the Debenture, the Warrants and the Underlying Shares. "Securities Act" means the Securities Act of 1933, as amended. -2-

"Transaction Documents" means this Agreement, the Debenture, the Warrants, the Transfer Agent Instructions, the Registration Rights Agreement and any other documents or agreements executed in connection with the transactions contemplated hereunder. "Transfer Agent Instructions" means the Transfer Agent Instructions, in the form of Exhibit D, executed by the Company and delivered to and --------- acknowledged in writing by the Company's transfer agent. "Underlying Shares" means the shares of Common Stock issuable upon conversion of the Debenture and upon exercise of the Warrants. "Underlying Shares Registration Statement" means a registration statement meeting the requirements set forth in the Registration Rights Agreement and covering the resale of the Underlying Shares by the Purchaser. "Warrants" means collectively the Common Stock purchase warrants, in the form of Exhibit C delivered to the Purchaser at the Closing in accordance --------- with Section 2.2. ARTICLE II PURCHASE AND SALE 2.1. Closing. The Closing shall take place via facsimile immediately ------- following the execution hereof, or by such other method or at such location or time as the parties may agree. 2.2. Closing Deliveries. ------------------ (a) At the Closing, the Company shall deliver or cause to be delivered to the Purchaser the following: (i) The Debenture in the principal amount of $2,000,000, registered in the name of the Purchaser; (ii) a Warrant, registered in the name of the Purchaser, pursuant to which the Purchaser shall have the right to acquire a number of shares of Common Stock equal to 60% of the number of Underlying Shares issuable upon conversion in full of the principal amount of Debentures issued to the Purchaser at the Closing; (iii) the legal opinion of Company Counsel, in agreed form; (iv) the Transfer Agent Instructions; and (v) the Registration Rights Agreement duly executed by the Company. (b) At the Closing, the Purchaser shall deliver or cause to be delivered to the Company the following: -3-

(i) $2,000,000 in United States dollars, in immediately available funds, by wire transfer to an account designated in writing by the Company for such purpose; and (ii) the Registration Rights Agreement duly executed by the Purchaser. ARTICLE III REPRESENTATIONS AND WARRANTIES 3.1. Representations and Warranties of the Company. The Company hereby --------------------------------------------- makes the following representations and warranties to the Purchaser: (a) Organization and Qualification. The Company is an entity duly ------------------------------ incorporated or otherwise organized, validly existing and in good standing under the laws of the State of California, with the requisite corporate power and authority to own and use its properties and assets and to carry on its business as currently conducted. The Company is not in violation of any of the provisions of its articles of incorporation or bylaws. The Company is duly qualified to do business and is in good standing as a foreign corporation or other entity in each jurisdiction in which the nature of the business conducted or property owned by it makes such qualification necessary, except where the failure to be so qualified or in good standing, as the case may be, would not reasonably be expected to, individually or in the aggregate: (i) adversely affect the legality, validity or enforceability of any Transaction Document, (ii) have or result in a material adverse effect on the results of operations, assets, business or condition (financial or otherwise) of the Company, or (iii) adversely impair the Company's ability to perform fully on a timely basis its obligations under any of the Transaction Documents (any of (i), (ii) or (iii), a "Material Adverse Effect"). (b) Authorization; Enforcement. The Company has the requisite -------------------------- corporate power and authority to enter into and to consummate the transactions contemplated by each of the Transaction Documents and otherwise to carry out its obligations thereunder. The execution and delivery of each of the Transaction Documents by the Company and the consummation by it of the transactions contemplated thereby have been duly authorized by all necessary action on the part of the Company and no further action is required by the Company. Each of the Transaction Documents has been (or upon delivery will be) duly executed by the Company and, when delivered in accordance with the terms hereof, will constitute the valid and binding obligation of the Company enforceable against the Company in accordance with its terms. (c) No Conflicts. The execution, delivery and performance of the ------------ Transaction Documents by the Company and the consummation by the Company of the transactions contemplated thereby do not and will not: (i) conflict with or violate any provision of the Company's articles of incorporation or bylaws, or (ii) subject to obtaining the Required Approvals (as defined below), conflict with, or constitute a default (or an event that with notice or lapse of time or both would become a default) under, or give to others any rights of termination, amendment, acceleration or cancellation (with or without notice, lapse of time or both) of, any agreement, credit facility, debt or other instrument (evidencing a Company debt or -4-

otherwise) or other understanding to which the Company is a party or by which any property or asset of the Company is bound or affected, or (iii) result in a violation of any law, rule, regulation, order, judgment, injunction, decree or other restriction of any court or governmental authority to which the Company is subject (including federal and state securities laws and regulations), or by which any property or asset of the Company is bound or affected; except in the case of each of clauses (ii) and (iii), such as would not reasonably be expected to, individually or in the aggregate, have or result in a Material Adverse Effect. (d) Filings, Consents and Approvals. To the Company's knowledge, ------------------------------- the Company is not required to obtain any consent, waiver, authorization or order of, give any notice to, or make any filing or registration with, any court or other federal, state, local or other governmental authority or other Person in connection with the execution, delivery and performance by the Company of the Transaction Documents, other than (i) the filings required under Section 4.8, (ii) the filing with the Commission of the Underlying Shares Registration Statement, (iii) the application(s) to each applicable Trading Market for the listing of the Underlying Shares for trading thereon in the time and manner required thereby, and (iv) applicable Blue Sky filings (collectively, the "Required Approvals"). (e) Issuance of the Securities. The Securities are duly -------------------------- authorized and, when issued and paid for in accordance with the applicable Transaction Documents, will be duly and validly issued, fully paid and nonassessable, free and clear of all liens, claims or encumbrances (other than liens, claims or encumbrances granted by Purchaser) ("Liens"). The Company has reserved from its duly authorized capital stock a sufficient number of Underlying Shares to enable it to comply with its conversion and exercise obligations under the Debenture and the Warrants, respectively. (f) Capitalization. The number of shares and type of all -------------- authorized, issued and outstanding capital stock of the Company is set forth in the Disclosure Materials (as defined below). No securities of the Company are entitled to preemptive or similar rights, and no Person has any right of first refusal, preemptive right, right of participation, or any similar right to participate in the transactions contemplated by the Transaction Documents. Except as a result of the purchase and sale of the Securities and except as disclosed in the Disclosure Materials, there are no outstanding options, warrants, script rights to subscribe to, calls or commitments of any character whatsoever relating to, or securities, rights or obligations convertible into or exchangeable for, or giving any Person any right to subscribe for or acquire, any shares of Common Stock, or contracts, commitments, understandings or arrangements by which the Company is or may become bound to issue additional shares of Common Stock, or securities or rights convertible or exchangeable into shares of Common Stock. The issuance and sale of the Securities will not obligate the Company to issue shares of Common Stock or other securities to any Person (other than the Purchasers) and will not result in a right of any holder of Company securities to adjust the exercise, conversion, exchange or reset price under such securities. (g) SEC Reports; Financial Statements. The Company has filed all --------------------------------- reports required to be filed by it under the Exchange Act, including pursuant to Section 13(a) or 15(d) thereof, for the two years preceding the date hereof (or such shorter period as the Company was required by law to file such material) (the foregoing materials being collectively referred to -5-

herein as the "SEC Reports" and, together with the Schedules to this Agreement and the draft Form 10-K provided to Purchaser on March 13, 2002 (the "Draft Form 10-K"), the "Disclosure Materials") on a timely basis or has received a valid extension of such time of filing and has filed any such SEC Reports prior to the expiration of any such extension. The Company has delivered to the Purchasers a copy of all SEC Reports filed within the ten (10) days preceding the date hereof. As of their respective dates, the SEC Reports complied in all material respects with the requirements of the Exchange Act and the rules and regulations of the Commission promulgated thereunder, and none of the SEC Reports, when filed, contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading. The financial statements of the Company included in the SEC Reports comply in all material respects with applicable accounting requirements and the rules and regulations of the Commission with respect thereto as in effect at the time of filing. Such financial statements have been prepared in accordance with generally accepted accounting principles applied on a consistent basis during the periods involved ("GAAP"), except as may be otherwise specified in such financial statements or the notes thereto, and fairly present in all material respects the financial position of the Company and its consolidated subsidiaries as of and for the dates thereof and the results of operations and cash flows for the periods then ended, subject, in the case of unaudited statements, to normal, immaterial, year-end audit adjustments. (h) Material Changes. Since the date of the latest audited ---------------- financial statements included within the SEC Reports, except as specifically disclosed in the Disclosure Materials: (i) there has been no event, occurrence or development that has had or that would reasonably be expected to result in a Material Adverse Effect, (ii) the Company has not incurred any liabilities (contingent or otherwise) other than (A) trade payables and accrued expenses incurred in the ordinary course of business consistent with past practice and (B) liabilities not required to be reflected in the Company's financial statements pursuant to GAAP or required to be disclosed in filings made with the Commission, (iii) the Company has not altered its method of accounting or the identity of its auditors, (iv) the Company has not declared or made any dividend or distribution of cash or other property to its stockholders or purchased, redeemed or made any agreements to purchase or redeem any shares of its capital stock, and (v) except as disclosed in the Disclosure Materials, the Company has not issued any equity securities to any officer, director or Affiliate, except pursuant to existing Company stock purchase and stock option plans. (i) Litigation. To the Company's knowledge, there is no action, ---------- suit, inquiry, notice of violation, proceeding or investigation pending or threatened against the Company or any of its respective properties before or by any court, arbitrator, governmental or administrative agency or regulatory authority (federal, state, county, local or foreign) (collectively, an "Action") which: (i) adversely affects or challenges the legality, validity or enforceability of any of the Transaction Documents or the Securities or (ii) would reasonably be expected to, if there were an unfavorable decision, individually or in the aggregate, have or result in a Material Adverse Effect. To the Company's knowledge and except as disclosed on Schedule 3.1(j), the Company, including any director or officer thereof, is not and has not been the subject of any Action involving a claim of violation of or liability under federal or state securities laws or a claim of breach of fiduciary duty. -6-

(j) Compliance. To the Company's knowledge, it is not: (i) in ---------- default under or in violation of (and no event has occurred that has not been waived that, with notice or lapse of time or both, would result in a default by the Company under), nor has the Company received notice of a claim that it is in default under or that it is in violation of, any indenture, loan or credit agreement or any other agreement or instrument to which it is a party or by which it or any of its properties is bound (whether or not such default or violation has been waived), (ii) in violation of any order of any court, arbitrator or governmental body, or (iii) in violation of any statute, rule or regulation of any governmental authority, except in each case as would not reasonably be expected to, individually or in the aggregate, have or result in a Material Adverse Effect. (k) Labor Relations. No material labor problem exists or, to the --------------- knowledge of the Company, is imminent with respect to any of the employees of the Company. (l) Regulatory Permits. The Company possesses all certificates, ------------------ authorizations and permits issued by the appropriate federal, state, local or foreign regulatory authorities necessary to conduct its business as described in the Disclosure Materials, except where the failure to possess such permits would not reasonably be expected to, individually or in the aggregate, have or result in a Material Adverse Effect ("Material Permits"), and the Company has not received any notice of proceedings relating to the revocation or modification of any Material Permit. (m) Title to Assets. The Company has good and marketable title in --------------- fee simple to all real property owned by it that is material to the business of the Company and good and marketable title in all personal property owned by it that is material to the business of the Company, in each case free and clear of all Liens, except for Liens as do not materially affect the value of such property and do not materially interfere with the use made and proposed to be made of such property by the Company. Any real property and facilities held under lease by the Company is held by it under valid, subsisting and enforceable leases of which the Company is in compliance in all material respects. (n) Patents and Trademarks. To the Company's knowledge, the ---------------------- Company has, or have rights to use, all patents, patent applications, trademarks, trademark applications, service marks, trade names, copyrights, licenses and other similar rights that are necessary or material for use in connection with its businesses as described in the Disclosure Materials and which the failure to so have would reasonably be expected to have a Material Adverse Effect (collectively, the "Intellectual Property Rights"). The Company has not received a written notice or otherwise has reason to believe that the Intellectual Property Rights used by the Company violates or infringes upon the rights of any Person. To the knowledge of the Company, all such Intellectual Property Rights are enforceable and there is no existing infringement by another Person of any of the Intellectual Property Rights. (o) Insurance. The Company is insured by, to the Company's --------- knowledge, insurers of recognized financial responsibility against such losses and risks and in such amounts as are prudent and customary in the businesses in which the Company is engaged. The Company has no reason to believe that it will not be able to renew its existing insurance -7-

coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be necessary to continue its business without a significant increase in cost. (p) Transactions With Affiliates and Employees. Except as set ------------------------------------------ forth in Disclosure Materials, none of the officers or directors of the Company and, to the knowledge of the Company, none of the employees of the Company is presently a party to any transaction with the Company (other than for services as employees, officers and directors), including any contract, agreement or other arrangement providing for the furnishing of services to or by, providing for rental of real or personal property to or from, or otherwise requiring payments to or from any officer, director or such employee or, to the knowledge of the Company, any entity in which any officer, director, or any such employee has a substantial interest or is an officer, director, trustee or partner. (q) Internal Accounting Controls. The Company maintains a system ---------------------------- of internal accounting controls sufficient to provide reasonable assurance that (i) transactions are executed in accordance with management's general or specific authorizations, (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain asset accountability, (iii) access to assets is permitted only in accordance with management's general or specific authorization, and (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences. (r) Certain Fees. Except for the fees described in Schedule ------------ 3.1(s), all of which are payable by the Company to the registered broker-dealers named therein, no brokerage or finder's fees or commissions are or will be payable by the Company to any broker, financial advisor or consultant, finder, placement agent, investment banker, bank or other Person with respect to the transactions contemplated by this Agreement, and the Company has not taken any action that would cause any Purchaser to be liable for any such fees or commissions. The Company agrees that the Purchasers shall have no obligation with respect to any fees or with respect to any claims made by or on behalf of any Person for fees of the type contemplated by this Section in connection with the transactions contemplated by this Agreement. (s) Private Placement. Assuming the accuracy of the ----------------- representations and warranties of the Purchasers set forth in Sections 3.2(b)-(f), the offer, issuance and sale of the Securities to the Purchasers as contemplated hereby are exempt from the registration requirements of the Securities Act. (t) Form S-3 Eligibility. To the Company's knowledge, it is -------------------- eligible to register its Common Stock for resale by the Purchasers under Form S-3 promulgated under the Securities Act. (u) Listing and Maintenance Requirements. The Company has not, in ------------------------------------ the 12 months preceding the date hereof, received notice from any Trading Market on which the Common Stock is or has been listed or quoted to the effect that the Company is not in compliance with the listing or maintenance requirements of such Trading Market. The Company is, and has no reason to believe that it will not in the foreseeable future continue to be, in compliance with all such listing and maintenance requirements. The issuance and sale of the -8-

Securities hereunder does not contravene the rules and regulations of the Trading Market and no shareholder approval is required for the Company to fulfill its obligations under the Transaction Documents. (v) Registration Rights. Except as described in Schedule 3.1(w), ------------------- --------------- the Company has not granted or agreed to grant to any Person any rights (including "piggy-back" registration rights) to have any securities of the Company registered with the Commission or any other governmental authority that have not been satisfied. (w) Application of Takeover Protections. The Company and its ----------------------------------- Board of Directors have taken all necessary action, if any, in order to render inapplicable any control share acquisition, business combination, poison pill (including any distribution under a rights agreement) or other similar anti-takeover provision under the Company's Certificate of Incorporation (or similar charter documents) or the laws of its state of incorporation that is or would reasonably be expected to become applicable to the Purchasers as a result of the Purchasers and the Company fulfilling their obligations or exercising their rights under the Transaction Documents, including without limitation as a result of the Company's issuance of the Securities and the Purchasers' ownership of the Securities. (x) Seniority. Except as disclosed in the Debenture of even date --------- herewith, as of the date of this Agreement, no indebtedness of the Company is senior to the Debentures in right of payment, whether with respect to interest or upon liquidation or dissolution, or otherwise, other than indebtedness secured by purchase money security interests (which is senior only as to underlying assets covered thereby) and capital lease obligations (which is senior only as to the property covered thereby). (y) Disclosure. To the Company's knowledge, neither it nor any ---------- other Person acting on its behalf has provided any of the Purchasers or their agents or counsel with any information that the Company believes constitutes, material nonpublic information; except for the Draft Form 10-K, which Draft Form 10-K shall be filed no later than three (3) Trading Days following the Closing. The Company understands and confirms that the Purchasers will rely on the foregoing representations in effecting transactions in securities of the Company. All disclosure provided to the Purchasers regarding the Company, its business and the transactions contemplated hereby, including the Schedules to this Agreement, furnished by or on behalf of the Company are true and correct and do not contain any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements made therein, in light of the circumstances under which they were made, not misleading. The Company acknowledges and agrees that no Purchaser makes or has made any representations or warranties with respect to the transactions contemplated hereby other than those specifically set forth in Section 3.2. ----------- (z) Investment Company. The Company is not, and is not an ------------------ Affiliate of, an "investment company" within the meaning of the Investment Company Act of 1940, as amended. 3.2. Representations and Warranties of the Purchaser. The Purchaser ----------------------------------------------- hereby represents and warrants to the Company as follows: -9-

(a) Organization; Authority. The Purchaser is an entity duly ----------------------- organized, validly existing and in good standing under the laws of the jurisdiction of its organization with the requisite corporate or partnership power and authority to enter into and to consummate the transactions contemplated by the Transaction Documents and otherwise to carry out its obligations thereunder. The purchase by such Purchaser of the Securities to be acquired by it has been duly authorized by all necessary action on the part of such Purchaser. Each of this Agreement and the Registration Rights Agreement has been duly executed by such Purchaser, and when delivered by such Purchaser in accordance with the terms hereof, will constitute the valid and legally binding obligation of such Purchaser, enforceable against it in accordance with its terms. (b) Investment Intent. Such Purchaser is acquiring the Securities ----------------- as principal for its own account for investment purposes only and not with a view to or for distributing or reselling such Securities or any part thereof, without prejudice, however, to such Purchaser's right, subject to the provisions of this Agreement, at all times to sell or otherwise dispose of all or any part of such Securities pursuant to an effective registration statement under the Securities Act or under an exemption from such registration and in compliance with applicable federal and state securities laws. Nothing contained herein shall be deemed a representation or warranty by such Purchaser to hold Securities for any period of time. Such Purchaser is acquiring the Securities hereunder in the ordinary course of its business. Such Purchaser does not have any agreement or understanding, directly or indirectly, with any Person to distribute any of the Securities. (c) Purchaser Status. At the time such Purchaser was offered the ---------------- Securities, it was, and at the date hereof it is, and on each date on which it exercises any Warrants or converts any Debentures, it will be an "accredited investor" as defined in Rule 501(a) under the Securities Act. Such Purchaser has not been formed solely for the purpose of acquiring the Securities. (d) Experience of such Purchaser. Such Purchaser, either alone or ---------------------------- together with its representatives, has such knowledge, sophistication and experience in business and financial matters so as to be capable of evaluating the merits and risks of the prospective investment in the Securities, and has so evaluated the merits and risks of such investment. Such Purchaser is able to bear the economic risk of an investment in the Securities and, at the present time, is able to afford a complete loss of such investment. (e) Access to Information. Such Purchaser acknowledges that it --------------------- has reviewed the Disclosure Materials and has been afforded: (i) the opportunity to ask such questions as it has deemed necessary of, and to receive answers from, representatives of the Company concerning the terms and conditions of the offering of the Securities and the merits and risks of investing in the Securities; (ii) access to information about the Company and its financial condition, results of operations, business, properties, management and prospects sufficient to enable it to evaluate its investment; and (iii) the opportunity to obtain such additional information that the Company possesses or can acquire without unreasonable effort or expense that is necessary to make an informed investment decision with respect to the investment. Neither such inquiries nor any other investigation conducted by or on behalf of such Purchaser or its representatives or counsel shall modify, amend or affect such Purchaser's right to -10-

rely on the truth, accuracy and completeness of the Disclosure Materials and the Company's representations and warranties contained in the Transaction Documents. (f) General Solicitation. Such Purchaser is not purchasing the -------------------- Securities as a result of any advertisement, article, notice or other communication regarding the Securities published in any newspaper, magazine or similar media or broadcast over television or radio or presented at any seminar or any other general solicitation or general advertisement. (g) Reliance. Such Purchaser understands and acknowledges that: -------- (i) the Securities are being offered and sold to it without registration under the Securities Act in a private placement that is exempt from the registration provisions of the Securities Act and (ii) the availability of such exemption depends in part on, and the Company will rely upon the accuracy and truthfulness of, the foregoing representations and such Purchaser hereby consents to such reliance. The Company acknowledges and agrees that the Purchaser makes or has made any representations or warranties with respect to the transactions contemplated hereby other than those specifically set forth in this Section 3.2. ARTICLE IV OTHER AGREEMENTS OF THE PARTIES 4.1. Transfer Restrictions. --------------------- (a) The Securities may only be disposed of by the Purchaser in compliance with state and federal securities laws. In connection with any transfer of Securities other than pursuant to an effective registration statement, to the Company, to an Affiliate of a Purchaser or to a Person managed or advised by the same Person as manager or adviser to such Purchaser or in connection with a pledge as contemplated in Section 4.1(b), the Company may require the transferor thereof to provide to the Company an opinion of counsel selected by the transferor, the form and substance of which opinion shall be reasonably satisfactory to the Company, to the effect that such transfer does not require registration of such transferred Securities under the Securities Act. As a condition of transfer, any such transferee shall restate the representations and warranties of such Purchaser under Section 3.2 and agree in writing to be bound by the terms of this Agreement and shall have the rights of a Purchaser under this Agreement and the Registration Rights Agreement. (b) The Purchaser agrees to the imprinting, so long as is required by this Section 4.1(b), of the following legend on any certificate -------------- evidencing Securities: [NEITHER] THESE SECURITIES [NOR THE SECURITIES INTO WHICH THESE SECURITIES ARE [EXERCISABLE] [CONVERTIBLE] HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE -11-

"SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO THE TRANSFEROR TO SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY ACCEPTABLE TO THE COMPANY. THESE SECURITIES AND THE SECURITIES ISSUABLE UPON EXERCISE OF THESE SECURITIES MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER LOAN SECURED BY SUCH SECURITIES. The Company acknowledges and agrees that the Purchaser may from time to time pledge pursuant to a bona fide margin agreement or grant a security interest in some or all of the Securities and, if required under the terms of such arrangement, such Purchaser may transfer pledged or secured Securities to the pledgees or secured parties. Such a pledge or transfer would not be subject to approval of the Company and no legal opinion of the pledgee, secured party or pledgor shall be required in connection therewith. Further, no notice shall be required of such pledge. At the Purchaser's expense, the Company will execute and deliver such reasonable documentation as a pledgee or secured party of Securities may reasonably request in connection with a pledge or transfer of the Securities, including the preparation and filing of any required prospectus supplement under Rule 424(b)(3) of the Securities Act or other applicable provision of the Securities Act to appropriately amend the list of Selling Stockholders thereunder. (c) Certificates evidencing Securities shall not contain any legend (including the legend set forth in Section 4.1(b)): (i) following a sale of such Securities pursuant to the Underlying Shares Registration Statement in which the prospectus delivery requirement was satisfied, or (ii) following any sale of such Securities pursuant to Rule 144, or (iii) if such Securities are eligible for sale under Rule 144(k), or (iv) if such legend is not required under applicable requirements of the Securities Act (including judicial interpretations and pronouncements issued by the Staff of the Commission). If all or any portion of a Debenture or Warrant is converted or exercised (as applicable) at a time when the Underlying Shares are eligible for sale under Rule 144(k), such Underlying Shares shall be issued free of all legends. The Company agrees that following the Effective Date or at such time as such legend is no longer required under this Section 4.1(c), it will, no later than three Trading Days following the delivery by a Purchaser to the Company or the Company's transfer agent of a certificate representing Securities issued with a restrictive legend, deliver or cause to be delivered to such Purchaser a certificate representing such Securities that is free from all restrictive and other legends. The Company may not make any notation on its records or give instructions to any transfer agent of the Company that enlarge the restrictions on transfer set forth in this Section. -12-

4.2. Acknowledgment of Dilution. The Company acknowledges that the -------------------------- issuance of the Securities will result in dilution of the outstanding shares of Common Stock. The Company further acknowledges that its obligations under the Transaction Documents, including without limitation its obligation to issue the Underlying Shares pursuant to the Transaction Documents, are unconditional and absolute and not subject to any right of set off, counterclaim, delay or reduction, regardless of the effect of any such dilution or any claim that the Company may have against any Purchaser. 4.3. Furnishing of Information. As long as any Purchaser owns ------------------------- Securities, the Company covenants to timely file (or obtain extensions in respect thereof and file within the applicable grace period) all reports required to be filed by the Company after the date hereof pursuant to the Exchange Act. Upon the request of any Purchaser, the Company shall deliver to such Purchaser a written certification of a duly authorized officer as to whether it has complied with the preceding sentence. As long as any Purchaser owns Securities, if the Company is not required to file reports pursuant to such laws, it will prepare and furnish to the Purchasers and make publicly available in accordance with Rule 144(c) such information as is required for the Purchasers to sell the Securities under Rule 144. 4.4. Integration. The Company shall not, and shall use commercially ----------- reasonable efforts to ensure that no Affiliate of the Company shall, sell, offer for sale or solicit offers to buy or otherwise negotiate in respect of any security (as defined in Section 2 of the Securities Act) that would be integrated with the offer or sale of the Securities in a manner that would require the registration under the Securities Act of the sale of the Securities to the Purchasers, or that would be integrated with the offer or sale of the Securities for purposes of the rules and regulations of any Trading Market. 4.5. Reservation and Listing of Securities. The Company shall maintain ------------------------------------- a reserve from its duly authorized shares of Common Stock to comply with its conversion and exercise obligations under the Debentures and Warrants pursuant to the Transaction Documents. 4.6. Conversion and Exercise Procedures. The form of Election to ---------------------------------- Purchase included in the Warrants and the forms of Conversion Notice included in the Debentures set forth the totality of the procedures required in order to exercise the Warrants or convert the Debentures. No additional legal opinion or other information or instructions shall be necessary to enable the Purchasers to exercise their Warrants or convert their Debentures. The Company shall honor exercises of the Warrants and conversions of the Debentures and shall deliver Underlying Shares in accordance with the terms, conditions and time periods set forth in the Transaction Documents. 4.7. Subsequent Placements. --------------------- (a) From the Closing Date and for 180 days thereafter, the Company shall not, directly or indirectly, offer, sell or grant any option to purchase, or otherwise dispose of, or announce any offer, sale, grant or any option to purchase or other disposition (collectively, a "Subsequent Placement") of any of its Common Stock or other securities which entitle the holder thereof to receive Common Stock, including without limitation any debt, preferred stock -13-

or other instrument or security that is, at any time during its life and under any circumstances, convertible into or exchangeable for Common Stock. (b) The restrictions contained in Section 4.7(a) shall not apply to: (i) the granting of options to, or the purchase of shares by, employees, consultants, officers and directors of the Company pursuant to any stock option plan or employee stock purchase plan duly adopted by the Company prior to the date hereof or to the issuance of Common Stock upon exercise of such options, or (ii) issuances of shares of Common Stock pursuant to a Strategic Transaction. A "Strategic Transaction" shall mean a transaction or relationship in which the Company issues Common Stock to a Person which is, itself or through its subsidiaries, an operating company in a business related to the business of the Company and in which the Company receives material benefits in addition to the investment of funds, but shall not include a transaction in which the Company is issuing securities primarily for the purpose of raising capital or to an entity whose primary business is investing in securities. (c) The restriction contained in Section 4.7(a) shall be extended for any number of Trading Days during such period in which: (i) trading in the Common Stock is suspended by any Trading Market, or (ii) the Underlying Shares Registration Statement is not effective or (iii) the prospectus included in the Underlying Shares Registration Statement may not be used by the Purchasers for the resale of Registrable Securities thereunder. 4.8. Securities Laws Disclosure; Publicity. The Company shall, not ------------------------------------- later than the Closing Date, issue a press release reasonably acceptable to the Purchaser disclosing all material terms of the transactions contemplated hereby. The Company and the Purchaser shall consult with each other in issuing any press releases with respect to the transactions contemplated hereby. Notwithstanding the foregoing, the Company shall not publicly disclose the name of any Purchaser, or include the name of the Purchaser in any filing with the Commission or any regulatory agency or Trading Market, without the prior written consent of such Purchaser, except to the extent such disclosure is required by law or Trading Market regulations, in which case the Company shall provide the Purchaser with prior notice of such disclosure. 4.9. Non-Public Information. The Company covenants and agrees that ---------------------- neither it nor any other Person acting on its behalf has provided or will provide the Purchaser or its agents or counsel with any information that the Company believes constitutes material non-public information, unless prior thereto such Purchaser shall have executed a written agreement regarding the confidentiality and use of such information. The Company understands and confirms that each Purchaser shall be relying on the foregoing representations in effecting transactions in securities of the Company. 4.10. Use of Proceeds. The Company shall use the net proceeds from the --------------- sale of the Securities hereunder for working capital purposes and not for the satisfaction of any portion of the Company's debt (other than payment of trade payables and accrued expenses in the ordinary course of the Company's business and prior practices), to redeem any Company equity or equity-equivalent securities or to settle any outstanding litigation. -14-

4.11. Indemnification of Purchasers. The Company will indemnify and ----------------------------- hold the Purchaser and its directors, officers, shareholders, partners, employees and agents (each, a "Purchaser Party") harmless from any and all losses, liabilities, obligations, claims, contingencies, damages, costs and expenses, including all judgments, amounts paid in settlements, court costs and reasonable attorneys' fees and costs of investigation (collectively, "Losses") that any such Purchaser Party may suffer or incur as a result of or relating to: (a) any misrepresentation, breach or inaccuracy, or any allegation by a third party that, if true, would constitute a breach or inaccuracy, of any of the representations, warranties, covenants or agreements made by the Company in this Agreement or in the other Transaction Documents; or (b) any cause of action, suit or claim brought or made against such Purchaser Party and arising solely out of or solely resulting from the execution, delivery, performance or enforcement of this Agreement or any of the other Transaction Documents and without causation by any other activity, obligation, condition or liability pertaining to such Purchaser and not to the transactions contemplated by this Agreement. The Company will reimburse such Purchaser for its reasonable legal and other expenses (including the cost of any investigation, preparation and travel in connection therewith) incurred in connection therewith, as such expenses are incurred. 4.12. Shareholders Rights Plan. In the event that a shareholders ------------------------ rights plan is adopted by the Company, no claim will be made or enforced by the Company or any other Person that any Purchaser is an "Acquiring Person" under any such plan or in any way would reasonably be expected to be deemed to trigger the provisions of such plan by virtue of receiving Securities under the Transaction Documents. ARTICLE V MISCELLANEOUS 5.1. Fees and Expenses. The Company has agreed to pay $20,000 to the ----------------- Purchaser as a contribution toward due diligence, legal and other fees and expenses incurred in connection with the investigation and negotiation of the transaction and the preparation and negotiation of the Transaction Documents. At the Closing, the Company will pay $20,000 to Purchaser via wire transfer of immediately available funds. Other than as specified above, each party shall pay the fees and expenses of its advisers, counsel, accountants and other experts, if any, and all other expenses incurred by such party incident to the negotiation, preparation, execution, delivery and performance of this Agreement. The Company shall pay all transfer agent fees, stamp taxes and other taxes and duties levied in connection with the issuance of any Securities. 5.2. Entire Agreement. The Transaction Documents, together with the ---------------- Exhibits and Schedules thereto, contain the entire understanding of the parties with respect to the subject matter hereof and supersede all prior agreements and understandings, oral or written, with respect to such matters, which the parties acknowledge have been merged into such documents, exhibits and schedules. At or after the Closing, and without further consideration, the Company will execute and deliver to the Purchaser such further documents as may be reasonably requested in order to give practical effect to the intention of the parties under the Transaction Documents. -15-

5.3. Notices. Any and all notices or other communications or ------- deliveries required or permitted to be provided hereunder shall be in writing and shall be deemed given and effective on the earliest of (a) the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section prior to 6:30 p.m. (New York City time) on a Trading Day, (b) the next Trading Day after the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section on a day that is not a Trading Day or later than 6:30 p.m. (New York City time) on any Trading Day, (c) the Trading Day following the date of mailing, if sent by U.S. nationally recognized overnight courier service, or (d) upon actual receipt by the party to whom such notice is required to be given. The addresses for such notices and communications are those set forth on the signature pages hereof, or such other address as may be designated in writing hereafter, in the same manner, by such Person. 5.4. Amendments; Waivers. No provision of this Agreement may be waived ------------------- or amended except in a written instrument signed, in the case of an amendment, by the Company and the Purchaser or, in the case of a waiver, by the party against whom enforcement of any such waiver is sought. No waiver of any default with respect to any provision, condition or requirement of this Agreement shall be deemed to be a continuing waiver in the future or a waiver of any subsequent default or a waiver of any other provision, condition or requirement hereof, nor shall any delay or omission of either party to exercise any right hereunder in any manner impair the exercise of any such right. 5.5. Construction. The headings herein are for convenience only, do ------------ not constitute a part of this Agreement and shall not be deemed to limit or affect any of the provisions hereof. The language used in this Agreement will be deemed to be the language chosen by the parties to express their mutual intent, and no rules of strict construction will be applied against any party. 5.6. Successors and Assigns. This Agreement shall be binding upon and ---------------------- inure to the benefit of the parties and their successors and permitted assigns. The Company may not assign this Agreement or any rights or obligations hereunder without the prior written consent of the Purchaser. Purchaser may assign its rights under this Agreement and the Registration Rights Agreement to any Person to whom such Purchaser assigns or transfers any Securities. 5.7. No Third-Party Beneficiaries. This Agreement is intended for the ---------------------------- benefit of the parties hereto and their respective successors and permitted assigns and is not for the benefit of, nor may any provision hereof be enforced by, any other Person, except as otherwise set forth in Section 4.11. 5.8. Governing Law; Venue; Waiver of Jury Trial. All questions ------------------------------------------ concerning the construction, validity, enforcement and interpretation of this Agreement shall be governed by and construed and enforced in accordance with the internal laws of the State of New York, without regard to the principles of conflicts of law thereof. Each party hereto hereby irrevocably waives personal service of process and consents to process being served in any such Proceeding by mailing a copy thereof via registered or certified mail or overnight delivery (with evidence of delivery) to such party at the address in effect for notices to it under this Agreement and agrees that such service shall constitute good and sufficient service of process and notice thereof. -16-

Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by law. Each party hereto hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Agreement or the transactions contemplated hereby. If either party shall commence a Proceeding to enforce any provisions of a Transaction Document, then the prevailing party in such Proceeding shall be reimbursed by the other party for its reasonable attorneys fees and other costs and expenses incurred with the investigation, preparation and prosecution of such Proceeding. 5.9. Survival. The representations, warranties, agreements and -------- covenants contained herein shall survive for a period of eighteen (18) months following the Closing and the delivery, exercise and/or conversion of the Securities, as applicable. 5.10. Execution. This Agreement may be executed in two or more --------- counterparts, all of which when taken together shall be considered one and the same agreement and shall become effective when counterparts have been signed by each party and delivered to the other party, it being understood that both parties need not sign the same counterpart. In the event that any signature is delivered by facsimile transmission, such signature shall create a valid and binding obligation of the party executing (or on whose behalf such signature is executed) with the same force and effect as if such facsimile signature page were an original thereof. 5.11. Severability. If any provision of this Agreement is held to be ------------ invalid or unenforceable in any respect, the validity and enforceability of the remaining terms and provisions of this Agreement shall not in any way be affected or impaired thereby and the parties will attempt to agree upon a valid and enforceable provision that is a reasonable substitute therefor, and upon so agreeing, shall incorporate such substitute provision in this Agreement. 5.12. Rescission and Withdrawal Right. Notwithstanding anything to the ------------------------------- contrary contained in (and without limiting any similar provisions of) the Transaction Documents, whenever the Purchaser exercises a right, election, demand or option under a Transaction Document and the Company does not timely perform its related obligations within the periods therein provided, then such Purchaser may rescind or withdraw, in its sole discretion from time to time upon written notice to the Company, any relevant notice, demand or election in whole or in part without prejudice to its future actions and rights. 5.13. Replacement of Securities. If any certificate or instrument ------------------------- evidencing any Securities is mutilated, lost, stolen or destroyed, the Company shall issue or cause to be issued in exchange and substitution for and upon cancellation thereof, or in lieu of and substitution therefor, a new certificate or instrument, but only upon receipt of evidence reasonably satisfactory to the Company of such loss, theft or destruction and customary and reasonable indemnity, if requested. The applicants for a new certificate or instrument under such circumstances shall also pay any reasonable third-party costs associated with the issuance of such replacement Securities. 5.14. Remedies. In addition to being entitled to exercise all rights -------- provided herein or granted by law, including recovery of damages, the Purchaser and the Company will be entitled to specific performance under the Transaction Documents. The parties agree that -17-

monetary damages may not be adequate compensation for any loss incurred by reason of any breach of obligations described in the foregoing sentence and hereby agrees to waive in any action for specific performance of any such obligation the defense that a remedy at law would be adequate. 5.15. Payment Set Aside. To the extent that the Company makes a ----------------- payment or payments to the Purchaser pursuant to any Transaction Document or a Purchaser enforces or exercises its rights thereunder, and such payment or payments or the proceeds of such enforcement or exercise or any part thereof are subsequently invalidated, declared to be fraudulent or preferential, set aside, recovered from, disgorged by or are required to be refunded, repaid or otherwise restored to the Company, a trustee, receiver or any other person under any law (including, without limitation, any bankruptcy law, state or federal law, common law or equitable cause of action), then to the extent of any such restoration the obligation or part thereof originally intended to be satisfied shall be revived and continued in full force and effect as if such payment had not been made or such enforcement or setoff had not occurred. 5.16. Usury. To the extent it may lawfully do so, the Company hereby ----- agrees not to insist upon or plead or in any manner whatsoever claim, and will resist any and all efforts to be compelled to take the benefit or advantage of, usury laws wherever enacted, now or at any time hereafter in force, in connection with any claim, action or proceeding that may be brought by the Purchaser in order to enforce any right or remedy under any Transaction Document. Notwithstanding any provision to the contrary contained in any Transaction Document, it is expressly agreed and provided that the total liability of the Company under the Transaction Documents for payments in the nature of interest shall not exceed the maximum lawful rate authorized under applicable law (the "Maximum Rate"), and, without limiting the foregoing, in no event shall any rate of interest or default interest, or both of them, when aggregated with any other sums in the nature of interest that the Company may be obligated to pay under the Transaction Documents exceed such Maximum Rate. It is agreed that if the maximum contract rate of interest allowed by law and applicable to the Transaction Documents is increased or decreased by statute or any official governmental action subsequent to the date hereof, the new maximum contract rate of interest allowed by law will be the Maximum Rate of interest applicable to the Transaction Documents from the effective date forward, unless such application is precluded by applicable law. If under any circumstances whatsoever, interest in excess of the Maximum Rate is paid by the Company to the Purchaser with respect to indebtedness evidenced by the Transaction Documents, such excess shall be applied by such Purchaser to the unpaid principal balance of any such indebtedness or be refunded to the Company, the manner of handling such excess to be at such Purchaser's election. 5.17. Independent Nature of Purchaser's Obligations and Rights. -------------------------------------------------------- Nothing contained herein or in any Transaction Document, and no action taken by the Purchaser pursuant thereto shall constitute the Purchaser as a partnership, an association, a joint venture or any other kind of entity with any other party, or create a presumption that the Purchaser is in any way acting in concert with respect to such obligations or the transactions contemplated hereby. * * * * * -18-

IN WITNESS WHEREOF, the parties hereto have caused this Securities Purchase Agreement to be duly executed by their respective authorized signatories as of the date first indicated above. QUESTCOR PHARMACEUTICALS, INC. By: /s/ Timothy E. Morris --------------------------------- Name: Timothy E. Morris ------------------------------- Title: Chief Financial Officer ------------------------------ Address for Notice: ------------------ Questcor Pharmaceuticals, Inc. Attention: President 3260 Whipple Road Union City, California 94587 With a copy to: -------------- David A. Hahn, Esq. Latham & Watkins 701 B Street, Suite 2100 San Diego, California 92101 SF CAPITAL PARTNERS LTD. By: /s/ Brian Davidson --------------------------------- Name: Brian Davidson ------------------------------- Title: Authorized Signatory ------------------------------ Address for Notice: ------------------ SF Capital Partners Ltd. Attention: Brian H. Davidson 1500 West Market Street, Suite 200 Mequon, Wisconsin 53092 -19-

EXHIBIT 4.3.2 NEITHER THIS DEBENTURE NOR THE SECURITIES ISSUABLE UPON CONVERSION OF THIS DEBENTURE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO THE TRANSFEROR TO SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY ACCEPTABLE TO THE COMPANY. THIS DEBENTURE AND THE SECURITIES ISSUABLE UPON CONVERSION OF THIS DEBENTURE MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER LOAN SECURED BY SUCH SECURITIES. $2,000,000 Original Issue Date: March 15, 2002 QUESTCOR PHARMACEUTICALS, INC. 8% CONVERTIBLE DEBENTURE THIS DEBENTURE is a duly authorized and issued debenture of Questcor Pharmaceuticals, Inc., a corporation organized under the laws of the state of California (the "Company"), designated as its 8% Convertible Debenture due March 15, 2005 or such earlier or later date as the debenture is required or permitted to be repaid as provided hereunder. FOR VALUE RECEIVED, the Company promises to pay to the order of SF Capital Partners Ltd. or its registered assigns (the "Holder") the principal sum of two million dollars ($2,000,000) plus any accrued and unpaid interest thereon, on March 15, 2005, or such earlier date as the Debenture is required or permitted to be repaid as provided hereunder (the "Maturity Date). This Debenture is subject to the following additional provisions: 1. Definitions. In addition to the terms defined elsewhere in this ----------- Debenture, (a) capitalized terms that are not otherwise defined herein that are defined in the Securities Purchase Agreement, dated as of March 15, 2002 among the Company and the original Holder (the "Purchase Agreement") have the meanings given to such terms in the Purchase Agreement, and (b) the following terms have the meanings indicated in this Section 1: "Bankruptcy Event" means any of the following events: (a) the Company commences a case or other proceeding under any bankruptcy, reorganization, arrangement, adjustment of debt, relief of debtors, dissolution, insolvency or liquidation or similar law of any jurisdiction relating to the Company; (b) there is commenced against the Company any such case or proceeding that is not dismissed within 60 days after commencement; (c) the Company is adjudicated insolvent or bankrupt or any order

of relief or other order approving any such case or proceeding is entered; (d) the Company suffers any appointment of any custodian or the like for it or any substantial part of its property that is not discharged or stayed within 60 days; (e) the Company makes a general assignment for the benefit of creditors; (f) the Company fails to pay, or states that it is unable to pay, its debts generally as they become due; (g) the Company calls a meeting of its creditors with a view to arranging a composition, adjustment or restructuring of its debts; or (h) the Company , by any act or failure to act, expressly indicates its consent to, approval of or acquiescence in any of the foregoing or takes any corporate or other action for the purpose of effecting any of the foregoing. "Change of Control" means the occurrence of any of the following in one or a series of related transactions or events: (i) an acquisition after the date hereof by an individual or legal entity or "group" (as described in Rule 13d-5(b)(1) under the Exchange Act) of more than 50% of the voting rights or equity interests in the Company; (ii) during any period of two consecutive years, individuals who, at the beginning of such period constitute the Company's board of director's (the "Board"), together with any new director whose election by the Board or nomination for election by the Company's shareholders was approved by a vote of at least two-thirds (2/3) of the directors then in office either who were directors at the beginning of the two-year period, or whose election or nomination was previously so approved, cease for any reason to constitute a majority of the board; (iii) a merger, consolidation or business combination of the Company or a sale of more than 50% of the assets of the Company in connection with which the Company is not the surviving entity of or if following such transaction or series of transactions, the holders of the Company's securities prior to the first such transaction do not continue to hold at least half of the voting rights and equity interests in of the surviving entity or acquirer of such assets; (iv) a recapitalization, reorganization or other transaction involving the Company that constitutes or results in a transfer of more than 50% of the voting rights or equity interests in the Company; (v) a "Rule 13e-3 transaction" as defined in Rule 13e-3 under the Exchange Act with respect to the Company, or (vi) the execution by the Company of an agreement providing for any of the foregoing events. "Closing Price" means, for any date, the price determined by the first of the following clauses that applies: (a) if the Common Stock is then listed or quoted on an Eligible Market, the closing sale price per share of the Common Stock for such date (or the nearest preceding date) on the primary Eligible Market on which the Common Stock is then listed or quoted; (b) if the Common Stock is not then listed or quoted on an Eligible Market and if prices for the Common Stock are then quoted on the OTC Bulletin Board, the closing sale price per share of the Common Stock for such date (or the nearest preceding date) on the OTC Bulletin Board; (c) if the Common Stock is not then listed or quoted on the OTC Bulletin Board and if prices for the Common Stock are then reported in the "Pink Sheets" published by the National Quotation Bureau Incorporated (or a similar organization or agency succeeding to its functions of reporting prices), the most recent sale price per share of the Common Stock so reported; or (d) in all other cases, the fair market value of a share of Common Stock as determined by an independent appraiser selected in good faith by the Holder. -2-

"Conversion Price" means $1.58, as adjusted pursuant to the terms of this Debenture. "Eligible Market" means any of the New York Stock Exchange, the American Stock Exchange, the Nasdaq National Market or the Nasdaq Small Cap Market. "Equity Conditions" means, with respect to a specified issuance of Common Stock, that each of the following conditions is satisfied: (i) the number of authorized but unissued and otherwise unreserved shares of Common Stock is sufficient for such issuance; (ii) such shares of Common Stock are registered for resale by the Holder pursuant to an effective registration statement, and the prospectus thereunder shall be available for use by the Holder to sell such shares or all such shares may be sold without volume restrictions pursuant to Rule 144(k) under the Securities Act; (iii) the Common Stock is listed or quoted (and is not suspended from trading) on an Eligible Market and such shares of Common Stock are approved for listing upon issuance; (iv) such issuance would be permitted in full without violating Section 12 hereof or the rules or regulations of any Trading ---------- Market; (v) no Bankruptcy Event has occurred; and (vi) the Company is not in default with respect to any material obligation hereunder or under any other Transaction Document. "Interest Payment Date" means each March 31, June 30, September 30 and December 31, except if such date is not a Trading Day, in which case such interest shall be payable on the next succeeding Trading Day. "Mandatory Prepayment Amount" means the sum of: (i) 110% of the principal amount of Debentures to be prepaid, plus all accrued and unpaid interest thereon not paid or accreted to the principal amount of this Debenture under Section 2, and (ii) all other amounts, costs, expenses and liquidated damages which may be due in respect of such Debentures. "Original Issue Date" means the date of the first issuance of any Debentures, regardless of the number of transfers of any particular Debenture. "Prepayment Price" means the sum of: (i) the principal amount of Debentures to be prepaid, plus all accrued and unpaid interest thereon, and (ii) all other amounts, costs, expenses and liquidated damages which may be due in respect of such Debentures. "Trading Day" means (a) any day on which the Common Stock is traded on its primary Trading Market, or (b) if the Common Stock is not then listed or quoted for trading on an Eligible Market, then a day on which trading occurs on the New York Stock Exchange (or any successor thereto). "Trading Market" means the American Stock Exchange or any other national securities exchange, market or trading or quotation facility on which the Common Stock is then listed or quoted. "Underlying Shares" means the shares of Common Stock issuable upon conversion of principal amount and interest under the Debentures. -3-

"Underlying Shares Registration Statement" means a registration statement meeting the requirements set forth in the Registration Rights Agreement, covering the resale of the Underlying Shares and naming the Holder as a "selling stockholder" thereunder. 2. Interest. -------- (a) The Company shall pay interest to the Holder on the aggregate unconverted and then outstanding principal amount of this Debenture at the rate of 8% per annum, payable quarterly in arrears on each Interest Payment Date. Interest shall be calculated on the basis of a 360-day year and shall accrue daily commencing on the Original Issue Date. (b) If the Company is required but fails to pay interest in cash on any Interest Payment Date, the Holder may (but shall not be required to), by notice to the Company, treat such interest as if it had been added to the principal amount of this Debenture as of such Interest Payment Date. 3. Registration of Debentures. The Company shall register the -------------------------- Debentures upon records to be maintained by the Company for that purpose (the "Debenture Register") in the name of each record holder thereof from time to time. The Company may deem and treat the registered Holder of this Debenture as the absolute owner hereof for the purpose of any conversion hereof or any payment of interest hereon, and for all other purposes, absent actual notice to the contrary. 4. Registration of Transfers and Exchanges. The Company shall register --------------------------------------- the transfer of any portion of this Debenture in the Debenture Register upon surrender of this Debenture to the Company at its address for notice set forth herein. Upon any such registration or transfer, a new debenture, in substantially the form of this Debenture (any such new debenture, a "New Debenture"), evidencing the portion of this Debenture so transferred shall be issued to the transferee and a New Debenture evidencing the remaining portion of this Debenture not so transferred, if any, shall be issued to the transferring Holder. The acceptance of the New Debenture by the transferee thereof shall be deemed the acceptance by such transferee of all of the rights and obligations of a holder of a Debenture. This Debenture is exchangeable for an equal aggregate principal amount of Debentures of different authorized denominations, as requested by the Holder surrendering the same. No service charge or other fee will be imposed in connection with any such registration of transfer or exchange. Transfers of this Debenture and the shares of Common Stock issuable on conversion thereof hereby are governed by Section 4.1 of the Purchase Agreement. 5. Conversion; Payment in Shares ----------------------------- (a) Conversion Prior to Maturity Date. The Holder may, at its --------------------------------- option, convert all or any portion of this Debenture into Common Stock at the Conversion Price, at any time prior to a Maturity Date. (b) Conversion Notice. A Holder may convert principal under this ----------------- Debenture into Common Stock at any time and from time to time from and after the Original Issue Date, by delivering to the Company a completed and signed form of conversion notice -4-

attached hereto as Exhibit A (a "Conversion Notice"). The date any such --------- Conversion Notice together with a schedule in the form of Schedule 1 attached ---------- hereto (the "Conversion Schedule") is delivered to the Company (as determined in accordance with the notice provisions hereof) is a "Conversion Date." (c) Payment in Shares. At the Company's option, it may repay the ----------------- Debenture at the Maturity Date by delivering freely tradeable, registered shares of its Common Stock to Holder; provided that (i) it delivers irrevocable, written notice of such election at least twenty (20) Trading Days prior to the Maturity Date and (ii) all Equity Conditions have been satisfied. For the purposes of repayment of the Debenture in shares of Common Stock, such shares shall be valued at 90% of the average of the Closing Price for the twenty (20) Trading Days prior to the Maturity Date. Such shares shall be delivered to Holder within at least three (3) days of the Maturity Date via the Depository Trust Corporation DWAC System. 6. Mechanics of Conversion. ----------------------- (a) The number of Underlying Shares issuable upon any conversion hereunder shall equal the outstanding principal amount of this Debenture to be converted and any interest that has been added to such principal amount in accordance with Section 2 hereof, divided by the Conversion Price. (b) Upon conversion of this Debenture, the Company shall promptly (but in no event later than three (3) Trading Days after the Conversion Date): issue or cause to be issued and cause to be delivered to or upon the written order of the Holder and in such name or names as the Holder may designate a certificate for the Underlying Shares issuable upon such conversion which, unless required by the Purchase Agreement, shall be free of any restrictive legend. The Holder, or any Person so designated by the Holder to receive Underlying Shares, shall be deemed to have become holder of record of such Underlying Shares as of the Conversion Date. If it is eligible to participate in the Depositary Trust Corporation DWAC system and no legends are required to be included on the Underlying Shares pursuant to the Purchase Agreement, the Company shall, upon request of the Holder, use commercially reasonable efforts to deliver Underlying Shares hereunder electronically through the Depository Trust Corporation or another established clearing corporation performing similar functions. (c) To effect conversions hereunder, the Holder shall be required to physically surrender this Debenture to the Company, at which time the Company shall reissue a new certificate of debenture reflecting the lowering of the outstanding principal amount of this Debenture in an amount equal to the applicable conversion. (d) The Company's obligations to issue and deliver Underlying Shares upon conversion of this Debenture in accordance with the terms hereof are absolute and unconditional, irrespective of any action or inaction by the Holder to enforce the same, any waiver or consent with respect to any provision hereof, the recovery of any judgment against any Person or any action to enforce the same, or any setoff, counterclaim, recoupment, limitation or termination, or any breach or alleged breach by the Holder or any other Person of any obligation to the Company or any violation or alleged violation of law by the Holder or any other Person, -5-

and irrespective of any other circumstance which might otherwise limit such obligation of the Company to the Holder in connection with the issuance of such Underlying Shares. (e) If by the fifth Trading Day after a Conversion Date the Company fails to deliver to the Holder such certificate or certificates in the manner required pursuant to Section 6(b), then the Holder will have the right to rescind such conversion. (f) If by the fifth Trading Day after a Conversion Date the Company fails to deliver to the Holder such certificate or certificates in the manner required pursuant to Section 6(b), and if after such seventh Trading Day the Holder purchases (in an open market transaction or otherwise) shares of Common Stock to deliver in satisfaction of a sale by such Holder of the Underlying Shares which the Holder anticipated receiving upon such conversion (a "Buy-In"), then the Company shall (A) pay in cash to the Holder (in addition to any remedies available to or elected by the Holder) the amount by which (x) the Holder's total purchase price (including brokerage commissions, if any) for the shares of Common Stock so purchased exceeds (y) the amount obtained by multiplying (1) the aggregate number of Underlying Shares that the Company was required to deliver to the Holder in connection with the conversion at issue by (2) the closing sale price of the Common Stock at the time of the obligation giving rise to such purchase obligation and (B) at the option of the Holder, either reinstate the portion of the Debenture and equivalent number of Underlying Shares for which such conversion was not honored or deliver to the Holder the number of shares of Common Stock that would have been issued had the Company timely complied with its conversion and delivery obligations hereunder. For example, if the Holder purchases Common Stock having a total purchase price of $11,000 to cover a Buy-In with respect to an attempted conversion of Debentures with a market price on the date of conversion totaling $10,000, under clause (A) of the immediately preceding sentence, the Company shall be required to pay the Holder $1,000. The Holder shall provide the Company written notice, which written notice shall include such supporting documentation as reasonably necessary to substantiate the amounts payable, indicating the amounts payable to the Holder in respect of the Buy-In. 7. Events of Default. ----------------- (a) "Event of Default" means the occurrence of any one of the following events (whatever the reason and whether it shall be voluntary or involuntary or effected by operation of law or pursuant to any judgment, decree or order of any court, or any order, rule or regulation of any administrative or governmental body): (i) any default in the payment (free of any claim of subordination) of principal, interest or liquidated damages in respect of any Debentures, as and when the same becomes due and payable (whether on a Conversion Date or the Maturity Date or by acceleration or otherwise) and such failure is not cured within ten (10) Trading Days after notice of such default is first given to the Company by the Holder; (ii) a Bankruptcy Event; -6-

(iii) the Common Stock is not listed or quoted, or is suspended from trading, on an Eligible Market for two (2) consecutive Trading Days or for an aggregate of five (5) Trading Days (which need not be consecutive Trading Days); (iv) the Company fails for any reason to deliver a certificate evidencing any Underlying Shares to a Holder within five Trading Days after delivery of such certificate is required pursuant to the terms hereof or the exercise or conversion rights of the Holder pursuant to the Transaction Documents are otherwise suspended (including by reason of a public document filed by the Company of its intention to no longer honor conversions of any Debentures) for any reason; (v) the Company fails to have available a sufficient number of authorized but unissued and otherwise unreserved shares of Common Stock available to issue Underlying Shares upon any conversion hereunder; (vi) the Company fails to make any cash payment required under the Transaction Documents (including, but limited to, the payment of a "Buy-In" pursuant to Section 6(f) hereunder or a Mandatory Prepayment Amount pursuant to Section 7) and such failure is not cured within ten (10) Trading Days after notice of such default is first given to the Company by the Holder; (vii) the occurrence of a Change of Control; or (viii) the Company defaults in the timely performance of any other obligation under the Transaction Documents and such default continues uncured for a period of thirty (30) days after the date on which notice of such default is first given to the Company by the Holder (it being understood that no prior notice need be given in the case of a default that cannot reasonably be cured within thirty (30) days). (b) At any time or times following the occurrence of an Event of Default, the Holder shall have the option to elect, by notice to the Company (an "Event Notice"), to accelerate the unpaid and unconverted principal and interest due hereunder and require the Company to pay an amount equal to the then outstanding principal amount of the Debenture plus any accrued and unpaid interest thereon; provided, however, if the Event Notice is a result of Section 7(a)(vii), the Company shall pay Holder the Mandatory Prepayment Amount. The Company shall pay such relevant amount to the Holder no later than the third Trading Day following the date of delivery of the Event Notice, and upon receipt thereof the Holder shall deliver the original Debenture so repurchased to the Company (to the extent such documents have been delivered to the Holder). (c) Subsequent to the delivery of an Event Notice pursuant to the terms hereof, the Company hereby waives any presentment, demand, protest or other notice of any kind, and the Holder may immediately and without expiration of any grace period enforce any and all of its rights and remedies hereunder and all other remedies available to it under applicable law. Any Event Notice may be rescinded and annulled by the Holder at any time prior to payment hereunder. No such rescission or annulment shall affect any subsequent Event of Default or impair any right consequent thereto. -7-

8. Ranking. This Debenture ranks pari passu with all other Debentures ------- now or hereafter issued pursuant to the Transaction Documents. No indebtedness of the Company is senior to this Debenture in right of payment, whether with respect of interest, damages or upon liquidation or dissolution or otherwise. Other than that certain accounts receivable arrangement between the Company and Pacific Business Funding dated January 2, 2002, the Company will not, and will not permit any to, directly or indirectly, enter into, create, incur or assume any indebtedness of any kind, on or with respect to any of its property or assets now owned or hereafter acquired or any interest therein or any income or profits therefrom, that is senior in any respect to the Company's obligations under the Debentures, other than indebtedness secured by purchase money security interests (which will be senior only as to the underlying assets covered thereby) and indebtedness under capital lease obligations (which will be senior only as to the assets covered thereby); provided, however, the Company may grant security interests to a third party with respect to those assets acquired from such third party as part of an acquisition of a currently marketable product from such third party. 9. Charges, Taxes and Expenses. Issuance of certificates for --------------------------- Underlying Shares upon conversion of (or otherwise in respect of) this Debenture shall be made without charge to the Holder for any issue or transfer tax, withholding tax, transfer agent fee or other incidental tax or expense in respect of the issuance of such certificate, all of which taxes and expenses shall be paid by the Company; provided, however, that the Company shall not be required to pay any tax which may be payable in respect of any transfer involved in the registration of any certificates for Underlying Shares or Debentures in a name other than that of the Holder. The Holder shall be responsible for all other tax liability that may arise as a result of holding or transferring this Debenture or receiving Underlying Shares in respect hereof. 10. Reservation of Underlying Shares. The Company covenants that it -------------------------------- will at all times reserve and keep available out of the aggregate of its authorized but unissued and otherwise unreserved Common Stock, solely for the purpose of enabling it to issue Underlying Shares as required hereunder, the number of Underlying Shares which are then issuable and deliverable upon the conversion of (and otherwise in respect of) this entire Debenture (taking into account the adjustments of Section 11), free from preemptive rights or any other ---------- contingent purchase rights of persons other than the Holder. The Company covenants that all Underlying Shares so issuable and deliverable shall, upon issuance in accordance with the terms hereof, be duly and validly authorized, issued and fully paid and nonassessable. 11. Certain Adjustments. The Conversion Price is subject to adjustment ------------------- from time to time as set forth in this Section 11. ---------- (a) Stock Dividends and Splits. If the Company, at any time while -------------------------- this Debenture is outstanding, (i) pays a stock dividend on its Common Stock or otherwise makes a distribution on any class of capital stock that is payable in shares of Common Stock, (ii) subdivides outstanding shares of Common Stock into a larger number of shares, or (iii) combines outstanding shares of Common Stock into a smaller number of shares, then in each such case the Conversion Price shall be multiplied by a fraction of which the numerator shall be the number of shares of Common Stock outstanding immediately before such event and of which the denominator shall be the number of shares of Common Stock outstanding immediately after such event. -8-

(b) Pro Rata Distributions. If the Company, at any time while ---------------------- this Debenture is outstanding, distributes to all holders of Common Stock and not to the Holder (i) evidences of its indebtedness, (ii) any security (other than a distribution of Common Stock covered by the preceding paragraph), (iii) rights or warrants to subscribe for or purchase any security, or (iv) any other asset (in each case, "Distributed Property"), then upon any conversion of this Debenture that occurs after such record date, the Holder shall be entitled to receive, in addition to the Underlying Shares otherwise issuable upon such conversion, the Distributed Property that the Holder would have been entitled to receive in respect of such number of Underlying Shares had the Holder been the record holder of such Underlying Shares immediately prior to such record date. (c) Fundamental Transactions. If, at any time while this ------------------------ Debenture is outstanding: (i) the Company effects any merger or consolidation of the Company with or into another Person, (ii) the Company effects any sale of all or substantially all of its assets in one or a series of related transactions, (iii) any tender offer or exchange offer (whether by the Company or another Person) is completed pursuant to which holders of Common Stock are permitted to tender or exchange their shares for other securities, cash or property, or (iv) the Company effects any reclassification of the Common Stock or any compulsory share exchange pursuant to which the Common Stock is effectively converted into or exchanged for other securities, cash or property (in any such case, a "Fundamental Transaction"), then upon any subsequent conversion of this Debenture, the Holder shall have the right to receive, for each Underlying Share that would have been issuable upon such conversion absent such Fundamental Transaction, the same kind and amount of securities, cash or property as it would have been entitled to receive upon the occurrence of such Fundamental Transaction if it had been, immediately prior to such Fundamental Transaction, the holder of one share of Common Stock (the "Alternate Consideration"). For purposes of any such conversion, the determination of the Conversion Price shall be appropriately adjusted to apply to such Alternate Consideration based on the amount of Alternate Consideration issuable in respect of one share of Common Stock in such Fundamental Transaction, and the Company shall apportion the Conversion Price among the Alternate Consideration in a reasonable manner reflecting the relative value of any different components of the Alternate Consideration. If holders of Common Stock are given any choice as to the securities, cash or property to be received in a Fundamental Transaction, then the Holder shall be given the same choice as to the Alternate Consideration it receives upon any conversion of this Debenture following such Fundamental Transaction. To the extent necessary to effectuate the foregoing provisions, any successor to the Company or surviving entity in such Fundamental Transaction shall issue to the Holder a new debenture consistent with the foregoing provisions and evidencing the Holder's right to convert such debenture into Alternate Consideration. The terms of any agreement pursuant to which a Fundamental Transaction is effected shall include terms requiring any such successor or surviving entity to comply with the provisions of this paragraph (c) and insuring that this Debenture (or any such replacement security) will be similarly adjusted upon any subsequent transaction analogous to a Fundamental Transaction. (d) Calculations. All calculations under this Section 11 shall be ------------ ---------- made to the nearest cent or the nearest 1/100th of a share, as applicable. The number of shares of Common Stock outstanding at any given time shall not include shares owned or held by or for the account of the Company, and the disposition of any such shares shall be considered an issue or sale of Common Stock. -9-

(e) Notice of Adjustments. Upon the occurrence of each adjustment --------------------- pursuant to this Section 11, the Company at its expense will promptly compute ---------- such adjustment in accordance with the terms hereof and prepare a certificate describing in reasonable detail such adjustment and the transactions giving rise thereto, including all facts upon which such adjustment is based. Upon written request, the Company will promptly deliver a copy of each such certificate to the Holder. (f) Notice of Corporate Events. If the Company: (i) declares a -------------------------- dividend or any other distribution of cash, securities or other property in respect of its Common Stock, including without limitation any granting of rights or warrants to subscribe for or purchase any capital stock of the Company , (ii) authorizes or approves, enters into any agreement contemplating or solicits stockholder approval for any Fundamental Transaction or (iii) authorizes the voluntary dissolution, liquidation or winding up of the affairs of the Company, then the Company shall deliver to the Holder a notice describing the material terms and conditions of such transaction, at least twenty (20) calendar days prior to the applicable record or effective date on which a Person would need to hold Common Stock in order to participate in or vote with respect to such transaction, and the Company will take all steps reasonably necessary in order to insure that the Holder is given the practical opportunity to convert this Debenture prior to such time so as to participate in or vote with respect to such transaction; provided, however, that the failure to deliver such notice or any defect therein shall not affect the validity of the corporate action required to be described in such notice. 12. Limitation on Conversion. (a) Notwithstanding anything to the ------------------------ contrary contained herein, the number of shares of Common Stock that may be acquired by the Holder upon any conversion of this Debenture shall be limited to ensure that, following such conversion, the total number of shares of Common Stock then beneficially owned by such Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act, does not exceed 4.999% of the total number of issued and outstanding shares of Common Stock (including for such purpose the shares of Common Stock issuable upon such conversion). For such purposes, beneficial ownership shall be determined in accordance with Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder. Each delivery of a Conversion Notice by the Holder will constitute a representation by the Holder that it has evaluated the limitation set forth in this paragraph and determined that issuance of the full number of Underlying Shares requested in such Conversion Notice is permitted under this paragraph. By written notice to the Company, the Holder may waive the provisions of this Section, but (i) any such waiver will not be effective until the 61st day after such notice is delivered to the Company, and (ii) any such waiver will apply only to the Holder and not to any other holder of Debentures. (b) Notwithstanding anything to the contrary contained herein, the number of shares of Common Stock that may be acquired by the Holder upon any conversion of this Debenture shall be limited to ensure that, following such conversion, the total number of shares of Common Stock then beneficially owned by such Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act, does not exceed 9.999% of the total number of issued and outstanding shares of Common Stock (including for such purpose the shares of Common Stock issuable upon such conversion). For such purposes, beneficial ownership shall -10-

be determined in accordance with Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder. Each delivery of a Conversion Notice by the Holder will constitute a representation by the Holder that it has evaluated the limitation set forth in this paragraph and determined that issuance of the full number of Underlying Shares requested in such Conversion Notice is permitted under this paragraph. By written notice to the Company, the Holder may waive the provisions of this Section, but (i) any such waiver will not be effective until the 61st day after such notice is delivered to the Company, and (ii) any such waiver will apply only to the Holder and not to any other holder of Debentures. (c) The aggregate number of shares of Common Stock that may be acquired by the Holders upon conversion or redemption of this Debenture and exercise of the Warrant (as defined in the Purchase Agreement) shall be limited to ensure that, following such conversion, redemption or exercise, as the case may be, the total aggregate number of shares of Common Stock issued to the Holders does not exceed 19.999% of the total number of issued and outstanding shares of Common Stock at the time of Closing (as adjusted for any dividends, splits or combinations). 13. Optional Prepayment. ------------------- (a) The Company shall have the right, exercisable at any time and from time to time after the first year anniversary of the Original Issue Date and upon twenty (20) Trading Days' prior written notice (which notice shall be irrevocable) to the affected Holders (an "Optional Prepayment Notice"), to prepay all of the outstanding principal amount of the Debentures for which Conversion Notices have not previously been delivered or for which an Event of Default shall not have been declared, provided, that the following conditions -------- are satisfied: (i) the average of the closing sale price of the Common Stock for the twenty (20) consecutive Trading Days prior to the delivery of the Optional Prepayment Notice is equal to or greater than 200% of the Conversion Price, and (ii) the Equity Conditions have been satisfied as of the date that the Optional Prepayment Notice is delivered through the Optional Prepayment Date. (b) The prepayment price applicable to prepayments under Section 13(a) shall equal the Prepayment Price and shall be paid in cash on the twentieth (20th) Trading Day following the date that the Company delivers the Optional Prepayment Notice (the "Optional Prepayment Date"). Any such prepayment shall be free of any claim of subordination. The Holders shall have the right to tender, and the Company shall honor, Conversion Notices delivered prior to the expiration of the fifteenth Trading Day after delivery of an Optional Prepayment Notice for such Debentures. (c) If any portion of the Prepayment Price shall not be paid by the Company by the expiration of the Optional Prepayment Date, the Prepayment Price shall be increased by an amount equal to 18% per annum (or such lower maximum amount of interest permitted to be charged under applicable law), to accrue daily from the date such interest is due hereunder through and including the date of payment (which amount shall be paid as liquidated damages and not as a penalty). In addition, if any portion of the Prepayment Price remains unpaid by the Optional Prepayment Date, the Holder subject to such prepayment may elect by written notice to the Company to demand conversion in accordance with the formula and the time period therefor set forth in Section 5 of any portion of the principal amount of Debentures -11-

for which the Prepayment Price, plus accrued liquidated damages and accrued interest thereon, has not been paid in full (the "Unpaid Prepayment Principal Amount").If the Holder elects the option above, the Company shall, within three Trading Days after such election is deemed delivered hereunder, deliver to the Holder the shares of Common Stock issuable upon conversion of the Unpaid Prepayment Principal Amount subject to such conversion demand and otherwise perform its obligations hereunder with respect thereto. (d) Except pursuant to this Section 13, the outstanding principal amount and interest under this Debenture shall not be subject to prepayment by the Company without the prior written consent of the Holder. 14. Fractional Shares. The Company shall not be required to issue or ----------------- cause to be issued fractional Underlying Shares on conversion of this Debenture. If any fraction of an Underlying Share would, except for the provisions of this Section, be issuable upon conversion of this Debenture, the number of Underlying Shares to be issued will be rounded up to the nearest whole share. 15. Notices. Any and all notices or other communications or deliveries ------- hereunder (including without limitation any Conversion Notice) shall be in writing and shall be deemed given and effective on the earliest of (i) the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section prior to 6:30 p.m. (New York City time) on a Trading Day, (ii) the next Trading Day after the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section on a day that is not a Trading Day or later than 6:30 p.m. (New York City time) on any Trading Day, (iii) the Trading Day following the date of mailing, if sent by nationally recognized overnight courier service, or (iv) upon actual receipt by the party to whom such notice is required to be given. The addresses for such communications shall be: (i) if to the Company, to the address set forth in the Purchase Agreement, or (ii) if to the Holder, to the address or facsimile number appearing on the Company's stockholder records or such other address or facsimile number as the Holder may provide to the Company in accordance with this Section. 16. Miscellaneous. ------------- (a) This Debenture shall be binding on and inure to the benefit of the parties hereto and their respective successors and assigns. This Debenture may be amended only in writing signed by the Company and the Holder and their successors and assigns. (b) Subject to Section 16(a), above, nothing in this Debenture ------------- shall be construed to give to any person or corporation other than the Company and the Holder any legal or equitable right, remedy or cause under this Debenture. This Debenture shall inure to the sole and exclusive benefit of the Company and the Holder. (c) Governing Law; Venue; Waiver of Jury Trial. All questions ------------------------------------------ concerning the construction, validity, enforcement and interpretation of this Debenture shall be governed by and construed and enforced in accordance with the internal laws of the State of New York, without regard to the principles of conflicts of law thereof. Each party hereto hereby irrevocably waives personal service of process and consents to process being served in any such -12-

Proceeding by mailing a copy thereof via registered or certified mail or overnight delivery (with evidence of delivery) to such party at the address in effect for notices to it under this Debenture and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by law. Each party hereto hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Debenture or the transactions contemplated hereby. If either party shall commence a Proceeding to enforce any provisions of this Debenture, then the prevailing party in such Proceeding shall be reimbursed by the other party for its reasonable attorneys fees and other costs and expenses incurred with the investigation, preparation and prosecution of such Proceeding. (d) The headings herein are for convenience only, do not constitute a part of this Debenture and shall not be deemed to limit or affect any of the provisions hereof. (e) In case any one or more of the provisions of this Debenture shall be invalid or unenforceable in any respect, the validity and enforceability of the remaining terms and provisions of this Debenture shall not in any way be affected or impaired thereby and the parties will attempt in good faith to agree upon a valid and enforceable provision which shall be a commercially reasonable substitute therefor, and upon so agreeing, shall incorporate such substitute provision in this Debenture. (f) No provision of this Debenture may be waived or amended except in a written instrument signed, in the case of an amendment, by the Company and the Holder or, or, in the case of a waiver, by the Holder. No waiver of any default with respect to any provision, condition or requirement of this Debenture shall be deemed to be a continuing waiver in the future or a waiver of any subsequent default or a waiver of any other provision, condition or requirement hereof, nor shall any delay or omission of either party to exercise any right hereunder in any manner impair the exercise of any such right. (g) In addition to being entitled to exercise all rights provided herein or granted by law, including recovery of damages, each Holder will be entitled to specific performance of the obligations of the Company hereunder. The parties hereto agree that monetary damages may not be adequate compensation for any loss incurred by reason of any breach of its obligations described herein and hereby agrees to waive in any action for specific performance of any such obligation the defense that a remedy at law would be adequate. [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK SIGNATURE PAGE FOLLOWS] -13-

IN WITNESS WHEREOF, the Company has caused this Debenture to be duly executed by a duly authorized officer as of the date first above indicated. QUESTCOR PHARMACEUTICALS, INC. By: /s/ Timothy E. Morris -------------------------------------------------- Name: Timothy E. Morris ------------------------------------------------ Title: Chief Financial Officer ----------------------------------------------- -14-

EXHIBIT A --------- CONVERSION NOTICE The undersigned hereby elects to convert the principal amount of Debenture set forth below into shares of common stock, no par value per share (the "Common Stock"), of Questcor Pharmaceuticals, Inc. (the "Company") according to the conditions hereof, as of the date written below. If shares are to be issued in the name of a person other than the undersigned, the undersigned will pay all transfer taxes payable with respect thereto and is delivering herewith such certificates and opinions as reasonably requested by the Company in accordance therewith. No fee will be charged to the holder for any conversion, except for such transfer taxes, if any. Conversion calculations: --------------------------------------------------------------- Date to Effect Conversion --------------------------------------------------------------- Principal amount of Debentures owned prior to conversion --------------------------------------------------------------- Principal amount of Debentures to be Converted (including of interest added under Section 2(b) --------------- of the Debenture) --------------------------------------------------------------- Number of shares of Common Stock to be issued --------------------------------------------------------------- Applicable Conversion Price --------------------------------------------------------------- Principal amount of Debentures owned subsequent to Conversion --------------------------------------------------------------- Name of Holder By: ------------------------------------------------- Name: ----------------------------------------------- Title: ---------------------------------------------- [ ] By the delivery of this Notice of Conversion the undersigned represents and warrants to the Company that its ownership of the Common Stock does not exceed the amounts determined in accordance with Section 13(d) of the Exchange Act, specified under Section 12 of the Debenture.

Schedule 1 CONVERSION SCHEDULE ------------------- 8% Convertible Debentures in the aggregate principal amount of $2,000,000 issued by Questcor Pharmaceuticals, Inc. This Conversion Schedule reflects conversions made under the above referenced Debentures. Dated: - ------------------------------------------------------------------------------------------ Date of Conversion Aggregate Principal Aggregate Applicable Conversion Amount of Debentures Principal Price with Respect to Converted Debentures Amount of Debentures Remaining Subsequent to Conversion - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ -2-

EXHIBIT 4.3.3 REGISTRATION RIGHTS AGREEMENT This Registration Rights Agreement (this "Agreement") is made and --------- entered into as of March 15, 2002, by and between Questcor Pharmaceuticals, Inc. a California corporation (the "Company"), and SF Capital Partners Ltd., a ------- British Virgin Islands company (the "Purchaser"). --------- This Agreement is made pursuant to the Securities Purchase Agreement, dated as of the date hereof among the Company and the Purchaser (the "Purchase -------- Agreement"). - --------- The Company and the Purchaser hereby agree as follows: 1. Definitions. Capitalized terms used and not otherwise defined ----------- herein that are defined in the Purchase Agreement shall have the meanings given such terms in the Purchase Agreement. As used in this Agreement, the following terms shall have the following meanings: "Debentures" means the 8% Convertible Debentures issued to the ---------- Purchaser in accordance with the Purchase Agreement. "Effectiveness Date" means the earlier of (a) the 90th day following ------------------ the Closing Date (or the 120th day if the Commission notifies the Company that it will be subject to a second comment letter) and (b) the fifth Trading Day following the date on which the Company is notified by the Commission that such Registration Statement will not be reviewed or is no longer subject to further review and comments. "Effectiveness Period" shall have the meaning set forth in Section -------------------- 2(a). "Filing Date" means, with respect to the initial Registration ----------- Statement required to be filed hereunder, the 30th day following the Closing Date. "Holder" or "Holders" means the holder or holders, as the case may be, ------ ------- from time to time of Registrable Securities. "Indemnified Party" shall have the meaning set forth in Section 5(c). ----------------- "Indemnifying Party" shall have the meaning set forth in Section 5(c). ------------------ "Losses" shall have the meaning set forth in Section 5(a). ------ "Proceeding" means an action, claim, suit, investigation or proceeding ---------- (including, without limitation, an investigation or partial proceeding, such as a deposition), whether commenced or threatened. "Prospectus" means the prospectus included in a Registration Statement ---------- (including, without limitation, a prospectus that includes any information previously omitted from a prospectus filed as part of an effective registration statement in reliance upon Rule 430A promulgated under the Securities Act), as amended or supplemented by any prospectus

supplement, with respect to the terms of the offering of any portion of the Registrable Securities covered by the Registration Statement, and all other amendments and supplements to the Prospectus, including post-effective amendments, and all material incorporated by reference or deemed to be incorporated by reference in such Prospectus. "Registrable Securities" means the shares of Common Stock issuable ---------------------- upon: (i) conversion of the Debentures and (ii) exercise of the Warrants. "Registration Statement" means the initial registration statement ---------------------- required to be filed hereunder and any additional registration statements contemplated by Section 2(d), including (in each case) the Prospectus, amendments and supplements to such registration statement or Prospectus, including pre- and post-effective amendments, all exhibits thereto, and all material incorporated by reference or deemed to be incorporated by reference in such registration statement. "Rule 144" means Rule 144 promulgated by the Commission pursuant to -------- the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. "Rule 415" means Rule 415 promulgated by the Commission pursuant to -------- the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. "Rule 424" means Rule 424 promulgated by the Commission pursuant to -------- the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. "Warrants" means the Common Stock purchase warrants issued under the -------- Purchase Agreement. 2. Registration. ------------ (a) On or prior to the Filing Date, the Company shall prepare and file with the Commission a Registration Statement covering the resale of not less than 2,341,771 Registrable Securities (or such lesser amount as required by the SEC) for an offering to be made on a continuous basis pursuant to Rule 415. The Registration Statement shall be on Form S-3 (except if the Company is not then eligible to register for resale the Registrable Securities on Form S-3, in which case such registration shall be on another appropriate form in accordance herewith) and shall contain (except if otherwise required by the Commission) the "Plan of Distribution" attached hereto as Annex A. The Company shall use -------------------- ------- commercially reasonable efforts to cause the Registration Statement to become effective and remain effective as provided herein. The Company shall use commercially reasonable efforts to cause the Registration Statement to be declared effective under the Securities Act as promptly as possible after the filing thereof, but in any event prior to its Effectiveness Date, and shall use commercially reasonable efforts to keep the Registration Statement continuously effective under the Securities Act until the date which is the earlier of four (4) years from the Closing Date or the date when all Registrable Securities covered by such Registration Statement have been sold or may be sold without volume restrictions pursuant to Rule 144(k) as determined by the counsel to the -2-

Company pursuant to a written opinion letter to such effect, addressed and acceptable to the Company's transfer agent and the affected Holders (the "Effectiveness Period"). -------------------- (b) The Company shall give written notice to the Holders of the Registrable Securities (which notice pursuant to clauses (ii)-(v) hereof shall be accompanied by an instruction to suspend the use of the Prospectus pursuant to the terms of Section 2(b)(v) and is referred to herein as a "Deferral Notice"): (i) when the Registration Statement or any amendment thereto has been filed with the Commission and when the Registration Statement or any post-effective amendment thereto has become effective; (ii) of any request by the Commission for amendments or supplements to the Registration Statement or the prospectus included therein or for additional information; (iii) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or the initiation of any proceedings for that purpose; (iv) of the receipt by the Company or its legal counsel of any notification with respect to the suspension of the qualification of the Registrable Securities for sale in any jurisdiction; and (v) of (A) the happening of any event that requires the Company to make changes in the Registration Statement or the Prospectus in order that the Registration Statement or the Prospectus does not contain an untrue statement of a material fact nor omit to state a material fact required to be stated therein or necessary to make the statements therein (in the case of the Prospectus, in light of the circumstances under which they were made) not misleading, or (B) the occurrence or existence of any pending corporate development, public filing with the Commission or other similar event with respect to the Company that, in the reasonable discretion of the Company, makes it necessary to suspend the availability of a Registration Statement and the related Prospectus. The Company shall be entitled to exercise its right to deliver a Deferral Notice under this Section 2(b) to suspend the availability of the Registration Statement or any prospectus, without incurring or accruing any obligation to pay liquidated damages pursuant to Section 2(c) (except for a Deferral Notice pursuant to Section 2(b)(v)(B) for which the Company shall remain obligated to pay liquidated damages), for one or more periods not to exceed ten (10) consecutive days in any 120-day period, and not to exceed, in the aggregate, thirty (30) days in any 365-day period (such period during which the availability of the Registration Statement and any prospectus is suspended being a "Deferral Period"). (c) If: (a) any Registration Statement is not filed on or prior to the Filing Date or (b) a Registration Statement filed hereunder is not declared effective by the Commission by the Effectiveness Date, or (c) after a Registration Statement is filed with and -3-

declared effective by the Commission, such Registration Statement ceases to be effective as to all Registrable Securities to which it is required to relate at any time prior to the expiration of the Effectiveness Period without being succeeded within fifteen Trading Days by an amendment to such Registration Statement or by a subsequent Registration Statement filed with and declared effective by the Commission or (d) the Common Stock is not listed or quoted, or is suspended from trading on the American Stock Exchange for a period of two consecutive Trading Days (any such failure or breach being referred to as an "Event," and for purposes of clause (a) or (b) the date on which such Event ----- occurs, or for purposes of clause (c) the date which such fifteen Trading Day-period is exceeded, being referred to as "Event Date"), then beginning on ---------- each such Event Date the Company shall pay to each Holder an amount in cash, as liquidated damages and not as a penalty, equal to 1.00% per 30 day period of the aggregate purchase price paid by such Holder pursuant to the Purchase Agreement, which shall accrue on a daily basis until the applicable Event shall have been cured, during the first 90 day period, and increasing to 2.00% per 30 day period thereafter, of the aggregate purchase price paid by such Holder pursuant to the Purchase Agreement, which shall accrue on a daily basis until the applicable Event shall have been cured. Notwithstanding the foregoing, a Event Date shall be deemed not to have occurred and be continuing in relation to the Registration Statement or the related Prospectus if the Company has delivered a Deferral Notice pursuant to Section 2(b) of this Agreement and the Deferral Period shall not have extended past the periods permitted by Section 2(b)(v). If the Company fails to pay any liquidated damages pursuant to this Section in full within seven days after the date payable, the Company will pay interest thereon at a rate of 18% per annum (or such lesser maximum amount that is permitted to be paid by applicable law) to the Holder, accruing daily from the date such liquidated damages are due until such amounts, plus all such interest thereon, are paid in full. 3. Registration Procedures ----------------------- In connection with the Company's registration obligations hereunder, the Company shall: (a) Not less than two (2) Trading Days prior to the filing of the Registration Statement or any related Prospectus or any amendment or supplement thereto, the Company shall, (i) furnish to the Holders copies of all such documents proposed to be filed (including documents incorporated or deemed incorporated by reference) which documents will be subject to the review of such Holders, and (ii) cause its officers and directors, counsel and independent certified public accountants to respond to such inquiries from Holders as shall be necessary, in the reasonable opinion of respective counsel to enable the Holder to conduct a reasonable investigation within the meaning of the Securities Act. (b) (i) Prepare and file with the Commission such amendments, including post-effective amendments, to the Registration Statement and the Prospectus used in connection therewith as may be necessary to keep the Registration Statement continuously effective as to the applicable Registrable Securities for the Effectiveness Period and prepare and file with the Commission such additional Registration Statements in order to register for resale under the Securities Act all of the Registrable Securities; (ii) cause the related Prospectus to be amended or supplemented by any required Prospectus supplement, and as so supplemented or amended to be filed pursuant to Rule 424; (iii) respond as promptly as reasonably possible, and -4-

in any event within twenty days, to any comments received from the Commission with respect to the Registration Statement or any amendment thereto and, as promptly as reasonably possible provide the Holders true and complete copies of all correspondence from and to the Commission relating to the Registration Statement; and (iv) comply in all material respects with the provisions of the Securities Act and the Exchange Act with respect to the disposition of all Registrable Securities covered by the Registration Statement during the applicable period in accordance with the intended methods of disposition by the Holders thereof set forth in the Registration Statement as so amended or in such Prospectus as so supplemented. (c) Notify the Holders of Registrable Securities to be sold as promptly as reasonably possible (and, in the case of (i)(A) below, not less than three Trading Days prior to such filing) and (if requested by any such Person) confirm such notice in writing no later than one Trading Day following the day (i)(A) when a Prospectus or any Prospectus supplement or post-effective amendment to the Registration Statement is proposed to be filed; (B) when the Commission notifies the Company whether there will be a "review" of such Registration Statement and whenever the Commission comments in writing on such Registration Statement (the Company shall provide true and complete copies thereof and all written responses thereto to each of the Holders); and (C) with respect to the Registration Statement or any post-effective amendment, when the same has become effective; (ii) of any request by the Commission or any other Federal or state governmental authority for amendments or supplements to the Registration Statement or Prospectus or for additional information; (iii) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement covering any or all of the Registrable Securities or the initiation of any Proceedings for that purpose; (iv) of the receipt by the Company of any notification with respect to the suspension of the qualification or exemption from qualification of any of the Registrable Securities for sale in any jurisdiction, or the initiation or threatening of any Proceeding for such purpose; and (v) of the occurrence of any event or passage of time that makes the financial statements included in the Registration Statement ineligible for inclusion therein or any statement made in the Registration Statement or Prospectus or any document incorporated or deemed to be incorporated therein by reference untrue in any material respect or that requires any revisions to the Registration Statement, Prospectus or other documents so that, in the case of the Registration Statement or the Prospectus, as the case may be, it will not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they were made, not misleading; provided that if the Company notifies the Holders in accordance with paragraphs (ii) through (v) of Section 2(b) above to suspend the use of the Prospectus until the end of the Deferral Period, then the Initial Purchasers and the Holders shall suspend use of such prospectus until the Company has notified the Holders in accordance with Section 6(d). (d) Use best efforts to avoid the issuance of, or, if issued, obtain the withdrawal of (i) any order suspending the effectiveness of the Registration Statement, or (ii) any suspension of the qualification (or exemption from qualification) of any of the Registrable Securities for sale in any jurisdiction, at the earliest practicable moment. (e) Furnish to each Holder, without charge, at least one conformed copy of the Registration Statement and each amendment thereto, including financial statements and schedules, all documents incorporated or deemed to be incorporated therein by reference, -5-

and all exhibits to the extent requested by such Person (including those previously furnished or incorporated by reference) promptly after the filing of such documents with the Commission. (f) Promptly deliver to each Holder, without charge, as many copies of the Prospectus or Prospectuses (including each form of prospectus) and each amendment or supplement thereto as such Persons may reasonably request. The Company hereby consents to the use of such Prospectus and each amendment or supplement thereto by each of the selling Holders in connection with the offering and sale of the Registrable Securities covered by such Prospectus and any amendment or supplement thereto. (g) Prior to any public offering of Registrable Securities, use commercially reasonable efforts to register or qualify or cooperate with the selling Holders in connection with the registration or qualification (or exemption from such registration or qualification) of such Registrable Securities for offer and sale under the securities or Blue Sky laws of such jurisdictions within the United States as any Holder requests in writing, to keep each such registration or qualification (or exemption therefrom) effective during the Effectiveness Period and to do any and all other acts or things necessary or advisable to enable the disposition in such jurisdictions of the Registrable Securities covered by a Registration Statement; provided, that the -------- Company shall not be required to qualify generally to do business in any jurisdiction where it is not then so qualified or subject the Company to any tax in any such jurisdiction where it is not then so subject. (h) Cooperate with the Holders to facilitate the timely preparation and delivery of certificates representing Registrable Securities to be delivered to a transferee pursuant to a Registration Statement, which certificates shall be free, to the extent permitted by the Purchase Agreement, of all restrictive legends, and to enable such Registrable Securities to be in such denominations and registered in such names as any such Holders may request. (i) Upon the occurrence of any event contemplated by Section 3(c)(v), as promptly as reasonably possible, prepare a supplement or amendment, including a post-effective amendment, to the Registration Statement or a supplement to the related Prospectus or any document incorporated or deemed to be incorporated therein by reference, and file any other required document so that, as thereafter delivered, neither the Registration Statement nor such Prospectus will contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they were made, not misleading. (j) Comply with all applicable rules and regulations of the Commission. (k) The Company may require each Holder of Registrable Securities to be sold pursuant to the Registration Statement to furnish to the Company such information regarding the Holder and the distribution of the Registrable Securities as the Company may from time to time be reasonably required to include in the Registration Statement, and the Company may exclude from such registration the Registrable Securities of any Holder that unreasonably fails to furnish such information within a reasonable time after receiving such request. -6-

4. Registration Expenses. All fees and expenses incident to the --------------------- performance of or compliance with this Agreement by the Company shall be borne by the Company whether or not any Registrable Securities are sold pursuant to the Registration Statement. The fees and expenses referred to in the foregoing sentence shall include, without limitation, (i) all registration and filing fees (including, without limitation, fees and expenses (A) with respect to filings required to be made with the Trading Market on which the Common Stock is then listed for trading, and (B) in compliance with applicable state securities or Blue Sky laws), (ii) expenses of printing certificates for Registrable Securities (iii) messenger, telephone and delivery expenses, (iv) Securities Act liability insurance, if the Company so desires such insurance, and (v) fees and expenses of all other Persons retained by the Company in connection with the consummation of the transactions contemplated by this Agreement. In addition, the Company shall be responsible for all of its internal expenses incurred in connection with the consummation of the transactions contemplated by this Agreement (including, without limitation, all salaries and expenses of its officers and employees performing legal or accounting duties), the expense of any annual audit and the fees and expenses incurred in connection with the listing of the Registrable Securities on any securities exchange as required hereunder. 5. Indemnification --------------- (a) Indemnification by the Company. The Company shall, ------------------------------ notwithstanding any termination of this Agreement, indemnify and hold harmless each Holder, the officers, directors, agents, brokers, investment advisors and employees of each of them, each Person who controls any such Holder (within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act) and the officers, directors, agents and employees of each such controlling Person, to the fullest extent permitted by applicable law, from and against any and all losses, claims, damages, liabilities, costs (including, without limitation, reasonable costs of preparation and reasonable attorneys' fees) and expenses (collectively, "Losses"), as incurred, arising out of or relating to ------ any untrue or alleged untrue statement of a material fact contained in the Registration Statement, any Prospectus or any form of prospectus or in any amendment or supplement thereto or in any preliminary prospectus, or arising out of or relating to any omission or alleged omission of a material fact required to be stated therein or necessary to make the statements therein (in the case of any Prospectus or form of prospectus or supplement thereto, in light of the circumstances under which they were made) not misleading, except to the extent, but only to the extent, that (1) such untrue statements or omissions are based solely upon information regarding such Holder furnished in writing to the Company by such Holder expressly for use therein, or to the extent that such information relates to such Holder or such Holder's proposed method of distribution of Registrable Securities and was reviewed and expressly approved in writing by such Holder expressly for use in the Registration Statement, such Prospectus or such form of Prospectus or in any amendment or supplement thereto (it being understood that the Holder has approved Annex A hereto for this purpose) or (2) in the case of an occurrence of an event of the type specified in Section 3(c)(ii)-(v), the use by such Holder of an outdated or defective Prospectus after the Company has notified such Holder in writing that the Prospectus is outdated or defective and prior to the receipt by such Holder of the Advice contemplated in Section 6(d). The Company shall notify the Holders promptly of the institution, threat or assertion of any Proceeding of which the Company is aware in connection with the transactions contemplated by this Agreement. -7-

(b) Indemnification by Holders. Each Holder shall, severally and -------------------------- not jointly, indemnify and hold harmless the Company, its directors, officers, agents and employees, each Person who controls the Company (within the meaning of Section 15 of the Securities Act and Section 20 of the Exchange Act), and the directors, officers, agents or employees of such controlling Persons, to the fullest extent permitted by applicable law, from and against all Losses, as incurred, arising solely out of or based solely upon: (x) such Holder's failure to comply with the prospectus delivery requirements of the Securities Act or (y) any untrue statement of a material fact contained in any Registration Statement, any Prospectus, or any form of prospectus, or in any amendment or supplement thereto, or arising solely out of or based solely upon any omission of a material fact required to be stated therein or necessary to make the statements therein not misleading to the extent, but only to the extent, that such untrue statement or omission is contained in any information so furnished in writing by such Holder to the Company specifically for inclusion in such Registration Statement or such Prospectus or to the extent that (1) such untrue statements or omissions are based solely upon information regarding such Holder furnished in writing to the Company by such Holder expressly for use therein, or to the extent that such information relates to such Holder or such Holder's proposed method of distribution of Registrable Securities and was reviewed and expressly approved in writing by such Holder expressly for use in the Registration Statement (it being understood that the Holder has approved Annex A hereto for this purpose), such Prospectus or such form of Prospectus or in any amendment or supplement thereto or (2) in the case of an occurrence of an event of the type specified in Section 3(c)(ii)-(v), the use by such Holder of an outdated or defective Prospectus after the Company has notified such Holder in writing that the Prospectus is outdated or defective and prior to the receipt by such Holder of the Advice contemplated in Section 6(d). In no event shall the liability of any selling Holder hereunder be greater in amount than the dollar amount of the net proceeds received by such Holder upon the sale of the Registrable Securities giving rise to such indemnification obligation. (c) Conduct of Indemnification Proceedings. If any Proceeding -------------------------------------- shall be brought or asserted against any Person entitled to indemnity hereunder (an "Indemnified Party"), such Indemnified Party shall promptly notify the ----------------- Person from whom indemnity is sought (the "Indemnifying Party") in writing, and ------------------ the Indemnifying Party shall assume the defense thereof, including the employment of counsel reasonably satisfactory to the Indemnified Party and the payment of all fees and expenses incurred in connection with defense thereof; provided, that the failure of any Indemnified Party to give such notice shall not relieve the Indemnifying Party of its obligations or liabilities pursuant to this Agreement, except (and only) to the extent that it shall be finally determined by a court of competent jurisdiction (which determination is not subject to appeal or further review) that such failure shall have proximately and materially adversely prejudiced the Indemnifying Party. An Indemnified Party shall have the right to employ separate counsel in any such Proceeding and to participate in the defense thereof, but the fees and expenses of such counsel shall be at the expense of such Indemnified Party or Parties unless: (1) the Indemnifying Party has agreed in writing to pay such fees and expenses; (2) the Indemnifying Party shall have failed promptly to assume the defense of such Proceeding and to employ counsel reasonably satisfactory to such Indemnified Party in any such Proceeding; or (3) the named parties to any such Proceeding (including any impleaded parties) include both such Indemnified Party and the Indemnifying Party, and such Indemnified Party shall have been advised by counsel that a -8-

conflict of interest is likely to exist if the same counsel were to represent such Indemnified Party and the Indemnifying Party (in which case, if such Indemnified Party notifies the Indemnifying Party in writing that it elects to employ separate counsel at the expense of the Indemnifying Party, the Indemnifying Party shall not have the right to assume the defense thereof and such counsel shall be at the expense of the Indemnifying Party). The Indemnifying Party shall not be liable for any settlement of any such Proceeding effected without its written consent, which consent shall not be unreasonably withheld. No Indemnifying Party shall, without the prior written consent of the Indemnified Party, effect any settlement of any pending Proceeding in respect of which any Indemnified Party is a party, unless such settlement includes an unconditional release of such Indemnified Party from all liability on claims that are the subject matter of such Proceeding. All fees and expenses of the Indemnified Party (including reasonable fees and expenses to the extent incurred in connection with investigating or preparing to defend such Proceeding in a manner not inconsistent with this Section) shall be paid to the Indemnified Party, as incurred, within ten Trading Days of written notice thereof to the Indemnifying Party (regardless of whether it is ultimately determined that an Indemnified Party is not entitled to indemnification hereunder; provided, that the Indemnifying Party may require -------- such Indemnified Party to undertake to reimburse all such fees and expenses to the extent it is finally judicially determined that such Indemnified Party is not entitled to indemnification hereunder). (d) Contribution. If a claim for indemnification under Section ------------ 5(a) or 5(b) is unavailable to an Indemnified Party (by reason of public policy or otherwise), then each Indemnifying Party, in lieu of indemnifying such Indemnified Party, shall contribute to the amount paid or payable by such Indemnified Party as a result of such Losses, in such proportion as is appropriate to reflect the relative fault of the Indemnifying Party and Indemnified Party in connection with the actions, statements or omissions that resulted in such Losses as well as any other relevant equitable considerations. The relative fault of such Indemnifying Party and Indemnified Party shall be determined by reference to, among other things, whether any action in question, including any untrue or alleged untrue statement of a material fact or omission or alleged omission of a material fact, has been taken or made by, or relates to information supplied by, such Indemnifying Party or Indemnified Party, and the parties' relative intent, knowledge, access to information and opportunity to correct or prevent such action, statement or omission. The amount paid or payable by a party as a result of any Losses shall be deemed to include, subject to the limitations set forth in Section 5(c), any reasonable attorneys' or other reasonable fees or expenses incurred by such party in connection with any Proceeding to the extent such party would have been indemnified for such fees or expenses if the indemnification provided for in this Section was available to such party in accordance with its terms. The parties hereto agree that it would not be just and equitable if contribution pursuant to this Section 5(d) were determined by pro rata --- ---- allocation or by any other method of allocation that does not take into account the equitable considerations referred to in the immediately preceding paragraph. Notwithstanding the provisions of this Section 5(d), no Holder shall be required to contribute, in the aggregate, any amount in excess of the amount by which the proceeds actually received by such Holder from the sale of the Registrable Securities subject to the Proceeding exceeds the amount of any damages that such Holder has otherwise -9-

been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. The indemnity and contribution agreements contained in this Section are in addition to any liability that the Indemnifying Parties may have to the Indemnified Parties. 6. Miscellaneous ------------- (a) Remedies. In the event of a breach by the Company or by a -------- Holder, of any of their obligations under this Agreement, each Holder or the Company, as the case may be, in addition to being entitled to exercise all rights granted by law and under this Agreement, including recovery of damages, will be entitled to specific performance of its rights under this Agreement. The Company and each Holder agree that monetary damages would not provide adequate compensation for any losses incurred by reason of a breach by it of any of the provisions of this Agreement and hereby further agrees that, in the event of any action for specific performance in respect of such breach, it shall waive the defense that a remedy at law would be adequate. (b) No Piggyback on Registrations. Except as and to the extent ----------------------------- specified in Schedule 6(b) hereto, neither the Company nor any of its security ------------- holders (other than the Holders in such capacity pursuant hereto) may include securities of the Company in the Registration Statement other than the Registrable Securities, and the Company shall not after the date hereof enter into any agreement providing any such right to any of its security holders. Except as and to the extent specified in Schedule 6(b) hereto, the Company has ------------- not previously entered into any agreement granting any registration rights with respect to any of its securities to any Person which have not been fully satisfied. (c) Compliance. Each Holder covenants and agrees that it will ---------- comply with the prospectus delivery requirements of the Securities Act as applicable to it in connection with sales of Registrable Securities pursuant to the Registration Statement. (d) Discontinued Disposition. Each Holder agrees by its ------------------------ acquisition of such Registrable Securities that, upon receipt of a notice from the Company of the occurrence of any event of the kind described in Section 3(c), such Holder will forthwith discontinue disposition of such Registrable Securities under the Registration Statement until such Holder's receipt of the copies of the supplemented Prospectus and/or amended Registration Statement or until it is advised in writing (the "Advice") by the Company that the use of the ------ applicable Prospectus may be resumed, and, in either case, has received copies of any additional or supplemental filings that are incorporated or deemed to be incorporated by reference in such Prospectus or Registration Statement. The Company may provide appropriate stop orders to enforce the provisions of this paragraph. (e) Piggy-Back Registrations. If at any time during the ------------------------ Effectiveness Period there is not an effective Registration Statement covering all of the Registrable Securities and the Company shall determine to prepare and file with the Commission a registration statement relating to an offering for its own account or the account of others under the Securities Act of any of its equity securities, other than on Form S-4 or Form S-8 (each as promulgated -10-

under the Securities Act) or their then equivalents relating to equity securities to be issued solely in connection with any acquisition of any entity or business or equity securities issuable in connection with stock option or other employee benefit plans, then the Company shall send to each Holder written notice of such determination and, if within fifteen days after receipt of such notice, any such Holder shall so request in writing, the Company shall include in such registration statement all or any part of such Registrable Securities such holder requests to be registered, subject to customary underwriter cutbacks applicable to all holders of registration rights. (f) Amendments and Waivers. The provisions of this Agreement, ---------------------- including the provisions of this sentence, may not be amended, modified or supplemented, and waivers or consents to departures from the provisions hereof may not be given, unless the same shall be in writing and signed by the Company and a majority of the Holders of the then outstanding Registrable Securities. Notwithstanding the foregoing, a waiver or consent to depart from the provisions hereof with respect to a matter that relates exclusively to the rights of certain Holders and that does not directly or indirectly affect the rights of other Holders may be given by Holders of at least a majority of the Registrable Securities to which such waiver or consent relates; provided, however, that the -------- ------- provisions of this sentence may not be amended, modified, or supplemented except in accordance with the provisions of the immediately preceding sentence. (g) Notices. Any and all notices or other communications or ------- deliveries required or permitted to be provided hereunder shall be in writing and shall be deemed given and effective on the earliest of (i) the date of transmission, if such notice or communication is delivered via facsimile at the facsimile telephone number specified in this Section prior to 6:30 p.m. (New York City time) on a Trading Day, (ii) the Trading Day after the date of transmission, if such notice or communication is delivered via facsimile at the facsimile telephone number specified in this Agreement later than 6:30 p.m. (New York City time) on any date and earlier than 11:59 p.m. (New York City time) on such date, (iii) the Trading Day following the date of mailing, if sent by nationally recognized overnight courier service, or (iv) upon actual receipt by the party to whom such notice is required to be given. The address for such notices and communications shall be as follows: If to the Company: Questcor Pharmaceuticals, Inc. Attention: President 3620 Whipple Road Union City, California 94587 If to the Purchaser: SF Capital Partners Ltd. Attention: Brian H. Davidson 1500 West Market Street, Suite 200 Mequon, WI 53092 If to any other Person who is then the registered Holder: To the address of such Holder as it appears in the stock transfer books of the Company. -11-

or such other address as may be designated in writing hereafter, in the same manner, by such Person. (h) Successors and Assigns. This Agreement shall inure to the ---------------------- benefit of and be binding upon the successors and permitted assigns of each of the parties and shall inure to the benefit of each Holder. The Company may not assign its rights or obligations hereunder without the prior written consent of each Holder. Each Holder may assign their respective rights hereunder in the manner and to the Persons as permitted under the Purchase Agreement. (i) Execution and Counterparts. This Agreement may be executed in -------------------------- any number of counterparts, each of which when so executed shall be deemed to be an original and, all of which taken together shall constitute one and the same Agreement. In the event that any signature is delivered by facsimile transmission, such signature shall create a valid binding obligation of the party executing (or on whose behalf such signature is executed) the same with the same force and effect as if such facsimile signature were the original thereof. (j) Governing Law. All questions concerning the construction, ------------- validity, enforcement and interpretation of this Agreement shall be governed by and construed and enforced in accordance with the internal laws of the State of New York, without regard to the principles of conflicts of law thereof. Each party hereto hereby irrevocably waives personal service of process and consents to process being served in any such Proceeding by mailing a copy thereof via registered or certified mail or overnight delivery (with evidence of delivery) to such party at the address in effect for notices to it under this Agreement and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by law. Each party hereto hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Agreement or the transactions contemplated hereby. If either party shall commence a Proceeding to enforce any provisions of a Transaction Document, then the prevailing party in such Proceeding shall be reimbursed by the other party for its reasonable attorneys fees and other costs and expenses incurred with the investigation, preparation and prosecution of such Proceeding. (k) Cumulative Remedies. The remedies provided herein are ------------------- cumulative and not exclusive of any remedies provided by law. (l) Severability. If any term, provision, covenant or restriction ------------ of this Agreement is held by a court of competent jurisdiction to be invalid, illegal, void or unenforceable, the remainder of the terms, provisions, covenants and restrictions set forth herein shall remain in full force and effect and shall in no way be affected, impaired or invalidated, and the parties hereto shall use their reasonable efforts to find and employ an alternative means to achieve the same or substantially the same result as that contemplated by such term, provision, covenant or restriction. It is hereby stipulated and declared to be the intention of the parties that they would have executed the remaining terms, provisions, covenants and restrictions without including any of such that may be hereafter declared invalid, illegal, void or unenforceable. -12-

(m) Headings. The headings in this Agreement are for convenience -------- of reference only and shall not limit or otherwise affect the meaning hereof. (n) Independent Nature of Purchaser's Obligations and Rights. -------------------------------------------------------- Nothing contained herein or in any other agreement or document delivered at any closing, and no action taken by the Purchaser pursuant hereto or thereto, shall be deemed to constitute the Purchasers as a partnership, an association, a joint venture or any other kind of entity with any other party, or create a presumption that the Purchaser is in any way acting in concert with any third party with respect to such obligations or the transactions contemplated by this Agreement. [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK SIGNATURE PAGE TO FOLLOW] -13-

IN WITNESS WHEREOF, the parties have executed this Registration Rights Agreement as of the date first written above. QUESTCOR PHARMACEUTICALS, INC. By: /s/ Timothy E. Morris ---------------------------- Name: Timothy E. Morris -------------------------- Title: Chief Financial Officer ------------------------- SF CAPITAL PARTNERS LTD. By: /s/ Brian Davidson ---------------------------- Name: Brian Davidson -------------------------- Title: Authorized Signatory ------------------------- -14-

Annex A ------- Plan of Distribution -------------------- The selling stockholders and any of their pledgees, assignees and successors-in-interest may, from time to time, sell any or all of their shares of common stock on any stock exchange, market or trading facility on which the shares are traded or in private transactions. These sales may be at fixed or negotiated prices. The selling stockholders may use any one or more of the following methods when selling shares: . ordinary brokerage transactions and transactions in which the broker-dealer solicits purchasers; . block trades in which the broker-dealer will attempt to sell the shares as agent but may position and resell a portion of the block as principal to facilitate the transaction; . purchases by a broker-dealer as principal and resale by the broker-dealer for its account; . an exchange distribution in accordance with the rules of the applicable exchange; . privately negotiated transactions; . short sales . broker-dealers may agree with the selling stockholders to sell a specified number of such shares at a stipulated price per share; . a combination of any such methods of sale; and . any other method permitted pursuant to applicable law. The selling stockholders may also sell shares under Rule 144 under the Securities Act, if available, rather than under this prospectus. Broker-dealers engaged by the selling stockholders may arrange for other brokers-dealers to participate in sales. Broker-dealers may receive commissions or discounts from the selling stockholders (or, if any broker-dealer acts as agent for the purchaser of shares, from the purchaser) in amounts to be negotiated. The selling stockholders do not expect these commissions and discounts to exceed what is customary in the types of transactions involved. The selling stockholders may from time to time pledge or grant a security interest in some or all of the shares of common stock or Warrants owned by them and, if they default in the performance of their secured obligations, the pledgees or secured parties may offer and sell the shares of common stock from time to time under this prospectus, or under an amendment to this prospectus under Rule 424(b)(3) or other applicable provision of the Securities Act of 1933 amending the list of selling stockholders to include the pledgee, transferee or other successors in interest as selling stockholders under this prospectus.

The selling stockholders also may transfer the shares of common stock in other circumstances, in which case the transferees, pledgees or other successors in interest will be the selling beneficial owners for purposes of this prospectus. The selling stockholders and any broker-dealers or agents that are involved in selling the shares may be deemed to be "underwriters" within the meaning of the Securities Act in connection with such sales. In such event, any commissions received by such broker-dealers or agents and any profit on the resale of the shares purchased by them may be deemed to be underwriting commissions or discounts under the Securities Act. The selling stockholders have informed the Company that they do not have any agreement or understanding, directly or indirectly, with any person to distribute the Common Stock. The Company is required to pay all fees and expenses incident to the registration of the shares. The Company has agreed to indemnify the selling stockholders against certain losses, claims, damages and liabilities, including liabilities under the Securities Act. -2-

EXHIBIT 4.3.4 NEITHER THESE SECURITIES NOR THE SECURITIES INTO WHICH THESE SECURITIES ARE EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO THE TRANSFEROR TO SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY ACCEPTABLE TO THE COMPANY. THESE SECURITIES AND THE SECURITIES ISSUABLE UPON EXERCISE OF THESE SECURITIES MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER LOAN SECURED BY SUCH SECURITIES. QUESTCOR PHARMACEUTICALS, INC. WARRANT ------- Warrant No. Date of Original Issuance: March 15, 2002 --- Questcor Pharmaceuticals, Inc., a California corporation (the "Company"), hereby certifies that, for value received, SF Capital Partners Ltd. or its registered assigns (the "Holder"), is entitled to purchase from the Company up to a total of 759,494 shares of common stock, no par value per share (the "Common Stock"), of the Company (each such share, a "Warrant Share" and all such shares, the "Warrant Shares") at an exercise price (as adjusted from time to time as provided in Section 9, the "Exercise Price") per Warrant Share equal to $1.70, at any time and from time to time from and after the date hereof and through and including March 15, 2006 (the "Expiration Date"), and subject to the following terms and conditions: 1. Definitions. In addition to the terms defined elsewhere in this Warrant, ----------- capitalized terms that are not otherwise defined herein and that are defined in the Securities Purchase Agreement, dated as of March 15, 2002, between the Company and the original Holder (the "Purchase Agreement"), shall have the meanings given to such terms in the Purchase Agreement. 2. Registration of Warrant. The Company shall register this Warrant, upon ----------------------- records to be maintained by the Company for that purpose (the "Warrant Register"), in the name of the record Holder hereof from time to time. The Company may deem and treat the registered Holder of this Warrant as the absolute owner hereof for the purpose of any exercise hereof or any distribution to the Holder, and for all other purposes, absent actual notice to the contrary.

3. Registration of Transfers. The Company shall register the transfer of ------------------------- any portion of this Warrant in the Warrant Register, upon surrender of this Warrant, with the Form of Assignment attached hereto duly completed and signed, to the Transfer Agent or to the Company at its address specified herein. Upon any such registration or transfer, a new warrant to purchase Common Stock, in substantially the form of this Warrant (any such new warrant, a "New Warrant"), evidencing the portion of this Warrant so transferred shall be issued to the transferee and a New Warrant evidencing the remaining portion of this Warrant not so transferred, if any, shall be issued to the transferring Holder. The acceptance of the New Warrant by the transferee thereof shall be deemed the acceptance by such transferee of all of the rights and obligations of a holder of a Warrant. 4. Exercise and Duration. Subject to the provisions of Section 11, this --------------------- Warrant shall be exercisable by the registered Holder at any time and from time to time on or after the date hereof to and including the Expiration Date. At 6:30 p.m., New York City time on the Expiration Date, the portion of this Warrant available for exercise and not exercised prior thereto shall be and become void and of no value. 5. Delivery of Warrant Shares. -------------------------- (a) Upon delivery of the Form of Election to Purchase to the Company (with the attached Warrant Shares Exercise Log) at its address for notice set forth in Section 13 and upon payment of the Exercise Price multiplied by the number of Warrant Shares that the Holder intends to purchase hereunder, the Company shall promptly (but in no event later than three Trading Days after the Date of Exercise (as defined herein)) issue and deliver to the Holder, a certificate for the Warrant Shares issuable upon such exercise free of restrictive legends unless otherwise required by the Purchase Agreement. The Company shall, upon request of the Holder, if available, use its best efforts to deliver Warrant Shares hereunder electronically through the Depository Trust Corporation or another established clearing corporation performing similar functions, provided, that, the Company may, but will not be required to change its transfer agent if its current transfer agent cannot deliver Warrant Shares electronically through the Depository Trust Corporation. A "Date of Exercise" means the date on which the Holder shall have delivered to the Company (i) the Form of Election to Purchase attached hereto (with the Warrant Exercise Log attached to it), appropriately completed and duly signed and (ii) payment of the Exercise Price for the number of Warrant Shares so indicated by the Holder to be purchased. (b) If by the fifth Trading Day after a Date of Exercise the Company fails to deliver the required number of Warrant Shares in the manner required pursuant to Section 5(a), then the Holder will have the right to rescind such exercise. (c) If by the fifth Trading Day after a Date of Exercise the Company fails to deliver the required number of Warrant Shares in the manner required pursuant to Section 5(a), and if after such fifth Trading Day the Holder purchases (in an open market transaction or otherwise) shares of Common Stock to deliver in satisfaction of a sale by the Holder of the Warrant Shares which the Holder anticipated receiving upon such exercise (a "Buy-In"), then the Company shall (1) pay in cash to the Holder the amount by which (x) the Holder's total purchase -2-

price (including brokerage commissions, if any) for the shares of Common Stock so purchased exceeds (y) the amount obtained by multiplying (A) the number of Warrant Shares that the Company was required to deliver to the Holder in connection with the exercise at issue by (B) the Closing Price of the Common Stock at the time of the obligation giving rise to such purchase obligation and (2) at the option of the Holder, either reinstate the portion of the Warrant and equivalent number of Warrant Shares for which such exercise was not honored or deliver to the Holder the number of shares of Common Stock that would have been issued had the Company timely complied with its exercise and delivery obligations hereunder. For example, if the Holder purchases Common Stock having a total purchase price of $11,000 to cover a Buy-In with respect to an attempted exercise of shares of Common Stock with a market price on the date of exercise totaled $10,000, under clause (1) of the immediately preceding sentence the Company shall be required to pay the Holder $1,000. The Holder shall provide the Company written notice, which written notice shall include such supporting documentation as reasonably necessary to substantiate the amounts payable, indicating the amounts payable to the Holder in respect of the Buy-In. (d) The Company's obligations to issue and deliver Warrant Shares in accordance with the terms hereof are absolute and unconditional, irrespective of any action or inaction by the Holder to enforce the same, any waiver or consent with respect to any provision hereof, the recovery of any judgment against any Person or any action to enforce the same, or any setoff, counterclaim, recoupment, limitation or termination, or any breach or alleged breach by the Holder or any other Person of any obligation to the Company or any violation or alleged violation of law by the Holder or any other Person, and irrespective of any other circumstance which might otherwise limit such obligation of the Company to the Holder in connection with the issuance of Warrant Shares. Nothing herein shall limit a Holder's right to pursue any other remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific performance and/or injunctive relief with respect to the Company's failure to timely deliver certificates representing shares of Common Stock upon exercise of the Warrant as required pursuant to the terms hereof. 6. Charges, Taxes and Expenses. Issuance and delivery of certificates for --------------------------- shares of Common Stock upon exercise of this Warrant shall be made without charge to the Holder for any issue or transfer tax, withholding tax, transfer agent fee or other incidental tax or expense in respect of the issuance of such certificates, all of which taxes and expenses shall be paid by the Company; provided, however, that the Company shall not be required to pay any tax which may be payable in respect of any transfer involved in the registration of any certificates for Warrant Shares or Warrants in a name other than that of the Holder. The Holder shall be responsible for all other tax liability that may arise as a result of holding or transferring this Warrant or receiving Warrant Shares upon exercise hereof. 7. Replacement of Warrant. If this Warrant is mutilated, lost, stolen or ---------------------- destroyed, the Company shall issue or cause to be issued in exchange and substitution for and upon cancellation hereof, or in lieu of and substitution for this Warrant, a New Warrant, but only upon receipt of evidence reasonably satisfactory to the Company of such loss, theft or destruction and customary and reasonable indemnity, if requested. Applicants for a New Warrant under such circumstances shall also comply with such other reasonable regulations and procedures and pay such other reasonable third-party costs as the Company may prescribe. -3-

8. Reservation of Warrant Shares. The Company covenants that it will at all ----------------------------- times reserve and keep available out of the aggregate of its authorized but unissued and otherwise unreserved Common Stock, solely for the purpose of enabling it to issue Warrant Shares upon exercise of this Warrant as herein provided, the number of Warrant Shares which are then issuable and deliverable upon the exercise of this entire Warrant. The Company covenants that all Warrant Shares so issuable and deliverable shall, upon issuance and the payment of the applicable Exercise Price in accordance with the terms hereof, be duly and validly authorized, issued and fully paid and nonassessable. 9. Certain Adjustments. The Exercise Price and number of Warrant Shares ------------------- issuable upon exercise of this Warrant are subject to adjustment from time to time as set forth in this Section 9. (a) Stock Dividends and Splits. If the Company, at any time while this -------------------------- Warrant is outstanding, (i) pays a stock dividend on its Common Stock or otherwise makes a distribution on any class of capital stock that is payable in shares of Common Stock, (ii) subdivides outstanding shares of Common Stock into a larger number of shares, or (iii) combines outstanding shares of Common Stock into a smaller number of shares, then in each such case the Exercise Price shall be multiplied by a fraction of which the numerator shall be the number of shares of Common Stock outstanding immediately before such event and of which the denominator shall be the number of shares of Common Stock outstanding immediately after such event. (b) Pro Rata Distributions. If the Company, at any time while this ---------------------- Warrant is outstanding, distributes to all holders of Common Stock (i) evidences of its indebtedness, (ii) any security (other than a distribution of Common Stock covered by the preceding paragraph), (iii) rights or warrants to subscribe for or purchase any security, or (iv) any other asset (in each case, "Distributed Property"), then, at the request of any Holder delivered before the 90th day after the record date fixed for determination of stockholders entitled to receive such distribution, the Company will deliver to such Holder, within five Trading Days after such request (or, if later, on the effective date of such distribution), the Distributed Property that such Holder would have been entitled to receive in respect of the Warrant Shares for which such Holder's Warrant could have been exercised immediately prior to such record date. If such Distributed Property is not delivered to a Holder pursuant to the preceding sentence, then upon any exercise of the Warrant that occurs after such record date, such Holder shall be entitled to receive, in addition to the Warrant Shares otherwise issuable upon such conversion, the Distributed Property that such Holder would have been entitled to receive in respect of such number of Warrant Shares had the Holder been the record holder of such Warrant Shares immediately prior to such record date. (c) Fundamental Transactions. If, at any time while this Warrant is ------------------------ outstanding: (i) the Company effects any merger or consolidation of the Company with or into another Person, (ii) the Company effects any sale of all or substantially all of its assets in one or a series of related transactions, (iii) any tender offer or exchange offer (whether by the Company or another Person) is completed pursuant to which holders of Common Stock are permitted to tender or exchange their shares for other securities, cash or property, or (iv) the Company effects any reclassification of the Common Stock or any compulsory share exchange pursuant to which the Common Stock is effectively converted into or exchanged for other securities, cash or -4-

property (in any such case, a "Fundamental Transaction"), then the Holder shall have the right thereafter to receive, upon exercise of this Warrant, the same amount and kind of securities, cash or property as it would have been entitled to receive upon the occurrence of such Fundamental Transaction if it had been, immediately prior to such Fundamental Transaction, the holder of the number of Warrant Shares then issuable upon exercise in full of this Warrant (the "Alternate Consideration"). For purposes of any such exercise, the determination of the Exercise Price shall be appropriately adjusted to apply to such Alternate Consideration based on the amount of Alternate Consideration issuable in respect of one share of Common Stock in such Fundamental Transaction, and the Company shall apportion the Exercise Price among the Alternate Consideration in a reasonable manner reflecting the relative value of any different components of the Alternate Consideration. If holders of Common Stock are given any choice as to the securities, cash or property to be received in a Fundamental Transaction, then the Holder shall be given the same choice as to the Alternate Consideration it receives upon any exercise of this Warrant following such Fundamental Transaction. At the Holder's option and request, any successor to the Company or surviving entity in such Fundamental Transaction shall issue to the Holder a new warrant substantially in the form of this Warrant and consistent with the foregoing provisions and evidencing the Holder's right to purchase the Alternate Consideration for the aggregate Exercise Price upon exercise thereof. The terms of any agreement pursuant to which a Fundamental Transaction is effected shall include terms requiring any such successor or surviving entity to comply with the provisions of this paragraph (c) and insuring that the Warrant (or any such replacement security) will be similarly adjusted upon any subsequent transaction analogous to a Fundamental Transaction. (d) Number of Warrant Shares. Simultaneously with any adjustment to ------------------------ the Exercise Price pursuant to paragraphs (a) or (b) of this Section, the number of Warrant Shares that may be purchased upon exercise of this Warrant shall be increased or decreased proportionately, so that after such adjustment the aggregate Exercise Price payable hereunder for the adjusted number of Warrant Shares shall be the same as the aggregate Exercise Price in effect immediately prior to such adjustment. (e) Calculations. All calculations under this Section 9 shall be made ------------ to the nearest cent or the nearest 1/100th of a share, as applicable. The number of shares of Common Stock outstanding at any given time shall not include shares owned or held by or for the account of the Company, and the disposition of any such shares shall be considered an issue or sale of Common Stock. (f) Notice of Adjustments. Upon the occurrence of each adjustment --------------------- pursuant to this Section 9, the Company at its expense will promptly compute such adjustment in accordance with the terms of this Warrant and prepare a certificate setting forth such adjustment, including a statement of the adjusted Exercise Price and adjusted number or type of Warrant Shares or other securities issuable upon exercise of this Warrant (as applicable), describing the transactions giving rise to such adjustments and showing in detail the facts upon which such adjustment is based. Upon written request, the Company will promptly deliver a copy of each such certificate to the Holder and to the Company's Transfer Agent. (g) Notice of Corporate Events. If the Company (i) declares a dividend -------------------------- or any other distribution of cash, securities or other property in respect of its Common Stock, including -5-

without limitation any granting of rights or warrants to subscribe for or purchase any capital stock of the Company or any Subsidiary, (ii) authorizes or approves, enters into any agreement contemplating or solicits stockholder approval for any Fundamental Transaction or (iii) authorizes the voluntary dissolution, liquidation or winding up of the affairs of the Company, then the Company shall deliver to the Holder a notice describing the material terms and conditions of such transaction, at least twenty (20) calendar days prior to the applicable record or effective date on which a Person would need to hold Common Stock in order to participate in or vote with respect to such transaction, and the Company will take all steps reasonably necessary in order to insure that the Holder is given the practical opportunity to exercise this Warrant prior to such time so as to participate in or vote with respect to such transaction; provided, however, that the failure to deliver such notice or any defect therein shall not affect the validity of the corporate action required to be described in such notice. 10. Payment of Exercise Price. The Holder shall pay the Exercise Price in ------------------------- one of the following manners: (a) Cash Exercise. The Holder may deliver immediately available funds; ------------- or (b) Cashless Exercise. The Holder may satisfy its obligation to pay ----------------- the Exercise Price through a "cashless exercise" in which event the Company shall issue to the Holder the number of Warrant Shares determined as follows: X = Y [(A-B)/A] where: X = the number of Warrant Shares to be issued to the Holder. Y = the number of Warrant Shares with respect to which this Warrant is being exercised. A = the average of the Closing Prices for the five Trading Days immediately prior to (but not including) the Exercise . Date. B = the Exercise Price. For purposes of Rule 144 promulgated under the Securities Act, it is intended, understood and acknowledged that the Warrant Shares issued in a cashless exercise transaction shall be deemed to have been acquired by the Holder, and the holding period for the Warrant Shares shall be deemed to have commenced, on the date this Warrant was originally issued pursuant to the Purchase Agreement. 11. Limitation on Exercise. (a) Notwithstanding anything to the contrary ---------------------- contained herein, the number of shares of Common Stock that may be acquired by the Holder upon any exercise of this Warrant (or otherwise in respect hereof) shall be limited to the extent necessary to insure that, following such exercise (or other issuance), the total number of shares of Common Stock then beneficially owned by such Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act, does not exceed 4.999% of the total number of issued and outstanding shares of Common Stock (including for such purpose the shares of Common Stock -6-

issuable upon such exercise). For such purposes, beneficial ownership shall be determined in accordance with Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder. Each delivery of an Exercise Notice hereunder will constitute a representation by the Holder that it has evaluated the limitation set forth in this paragraph and determined that issuance of the full number of Warrant Shares requested in such Exercise Notice is permitted under this paragraph. By written notice to the Company, the Holder may waive the provisions of this Section but (i) any such waiver will not be effective until the 61st day after such notice is delivered to the Company, and (ii) any such waiver will apply only to the Holder and not to any other holder of Warrants. (b) Notwithstanding anything to the contrary contained herein, the number of shares of Common Stock that may be acquired by the Holder upon any exercise of this Warrant (or otherwise in respect hereof) shall be limited to the extent necessary to insure that, following such exercise (or other issuance), the total number of shares of Common Stock then beneficially owned by such Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act, does not exceed 9.999% of the total number of issued and outstanding shares of Common Stock (including for such purpose the shares of Common Stock issuable upon such exercise). For such purposes, beneficial ownership shall be determined in accordance with Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder. Each delivery of an Exercise Notice hereunder will constitute a representation by the Holder that it has evaluated the limitation set forth in this paragraph and determined that issuance of the full number of Warrant Shares requested in such Exercise Notice is permitted under this paragraph. By written notice to the Company, the Holder may waive the provisions of this Section but (i) any such waiver will not be effective until the 61st day after such notice is delivered to the Company, and (ii) any such waiver will apply only to the Holder and not to any other holder of Warrants. (c) The aggregate number of shares of Common Stock that may be acquired by the Holders upon exercise of this Warrant and conversion or redemption of the Debenture (as defined in the Purchase Agreement) shall be limited to ensure that, following such conversion, redemption or exercise, as the case may be, the total aggregate number of shares of Common Stock issued to the Holders does not exceed 19.999% of the total number of issued and outstanding shares of Common Stock at the time of Closing (as adjusted for any dividends, splits or combinations). 12. No Fractional Shares. No fractional shares of Warrant Shares will be -------------------- issued in connection with any exercise of this Warrant. In lieu of any fractional shares which would, otherwise be issuable, the Company shall pay cash equal to the product of such fraction multiplied by the Closing Price of one Warrant Share as reported on the Eligible Market on the date of exercise. 13. Notices. Any and all notices or other communications or deliveries ------- hereunder (including without limitation any Exercise Notice) shall be in writing and shall be deemed given and effective on the earliest of (i) the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section prior to 6:30 p.m. (New York City time) on a Trading Day, (ii) the next Trading Day after the date of transmission, if -7-

such notice or communication is delivered via facsimile at the facsimile number specified in this Section on a day that is not a Trading Day or later than 6:30 p.m. (New York City time) on any Trading Day, (iii) the Trading Day following the date of mailing, if sent by nationally recognized overnight courier service, or (iv) upon actual receipt by the party to whom such notice is required to be given. The addresses for such communications shall be: (i) if to the Company, to Questcor Pharmaceuticals, Inc., Attention: President, 3620 Whipple Road, Union City, California 94587 or (ii) if to the Holder, to the address or facsimile number appearing on the Warrant Register or such other address or facsimile number as the Holder may provide to the Company in accordance with this Section. 14. Warrant Agent. The Company shall serve as warrant agent under this ------------- Warrant. Upon thirty (30) days' notice to the Holder, the Company may appoint a new warrant agent. Any corporation into which the Company or any new warrant agent may be merged or any corporation resulting from any consolidation to which the Company or any new warrant agent shall be a party or any corporation to which the Company or any new warrant agent transfers substantially all of its corporate trust or shareholders services business shall be a successor warrant agent under this Warrant without any further act. Any such successor warrant agent shall promptly cause notice of its succession as warrant agent to be mailed (by first class mail, postage prepaid) to the Holder at the Holder's last address as shown on the Warrant Register. 15. Miscellaneous. ------------- (a) This Warrant shall be binding on and inure to the benefit of the parties hereto and their respective successors and assigns. Subject to the preceding sentence, nothing in this Warrant shall be construed to give to any Person other than the Company and the Holder any legal or equitable right, remedy or cause of action under this Warrant. This Warrant may be amended only in writing signed by the Company and the Holder and their successors and assigns. (b) All questions concerning the construction, validity, enforcement and interpretation of this Warrant shall be governed by and construed and enforced in accordance with the internal laws of the State of New York, without regard to the principles of conflicts of law thereof. Each party hereto hereby irrevocably waives personal service of process and consents to process being served in any such suit, action or proceeding by mailing a copy thereof via registered or certified mail or overnight delivery (with evidence of delivery) to such party at the address in effect for notices to it under this Warrant and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by law. Each party hereto (including its affiliates, agents, officers, directors and employees) hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Warrant or the transactions contemplated hereby. If either party shall commence an action or proceeding to enforce any provisions of this Warrant, then the prevailing party in such action or proceeding shall be reimbursed by the other party for its reasonable attorneys fees and other costs and expenses incurred with the investigation, preparation and prosecution of such action or proceeding. -8-

(c) The headings herein are for convenience only, do not constitute a part of this Warrant and shall not be deemed to limit or affect any of the provisions hereof. (d) In case any one or more of the provisions of this Warrant shall be invalid or unenforceable in any respect, the validity and enforceability of the remaining terms and provisions of this Warrant shall not in any way be affected or impaired thereby and the parties will attempt in good faith to agree upon a valid and enforceable provision which shall be a commercially reasonable substitute therefor, and upon so agreeing, shall incorporate such substitute provision in this Warrant. [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK, SIGNATURE PAGE FOLLOWS] -9-

IN WITNESS WHEREOF, the Company has caused this Warrant to be duly executed by its authorized officer as of the date first indicated above. QUESTCOR PHARMACEUTICALS, INC. By: /s/ Timothy E. Morris ---------------------------------- Name: Timothy E. Morris -------------------------------- Title: Chief Financial Officer ------------------------------- -10-

FORM OF ELECTION TO PURCHASE To Questcor Pharmaceuticals, Inc.: In accordance with Warrant No. issued to the undersigned, the --- undersigned hereby elects to purchase shares of common stock ------------- ("Common Stock"), no par value per share, of Questcor Pharmaceuticals, Inc. and, if such Holder is not utilizing the cashless exercise provisions set forth in this Warrant, encloses herewith $ in cash, certified or official bank -------- check or checks, which sum represents the aggregate Exercise Price (as defined in the Warrant) for the number of shares of Common Stock to which this Form of Election to Purchase relates. By its delivery of this Form of Election To Purchase, the Holder represents and warrants to the Company that in giving effect to the exercise evidenced hereby the Holder will not beneficially own in excess of the number of shares of Common Stock (determined in accordance with Section 13(d) of the Securities Exchange Act of 1934) permitted to be owned under Section 11of this Warrant to which this notice relates. The undersigned requests that certificates for the shares of Common Stock issuable upon this exercise be issued in the name of SOCIAL SECURITY OR TAX IDENTIFICATION NUMBER: -------------------------------------------- NAME AND ADDRESS: -------------------------------------------- -------------------------------------------- --------------------------------------------

Warrant Shares Exercise Log --------------------------- - ---------------------------------------------------------------------------- Date Number of Warrant Number of Warrant Number of Warrant Shares Available to Shares Exercised Shares Remaining to be Exercised be Exercised - ---------------------------------------------------------------------------- - ----------------------------------------------------------------------------

FORM OF ASSIGNMENT [To be completed and signed only upon transfer of Warrant] FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers unto the right represented by the -------------------------------- within Warrant to purchase shares of Common Stock of Questcor ------------ Pharmaceuticals, Inc. to which the within Warrant relates and appoints attorney to transfer said right on the books of Questcor - ---------------- Pharmaceuticals, Inc. with full power of substitution in the premises. Dated: , --------------- ---- ------------------------------------------ (Signature must conform in all respects to name of holder as specified on the face of the Warrant) ------------------------------------------ Address of Transferee ------------------------------------------ ------------------------------------------ In the presence of: - -------------------

EXHIBIT 4.4.1 SECURITIES PURCHASE AGREEMENT ----------------------------- This Securities Purchase Agreement (this "Agreement") is dated as of March 15, 2002 by and between Questcor Pharmaceuticals, Inc., a California corporation (the "Company"), and Defiante Farmaceutica Unipessoal L.D.A., a Portuguese company (the "Purchaser"). WHEREAS, subject to the terms and conditions set forth in this Agreement and pursuant to Section 4(2) of the Securities Act of 1933 (the "Securities Act"), and Rule 506 promulgated thereunder, the Company desires to issue and sell to Purchaser, and the Purchaser desires to purchase from the Company, securities of the Company as more fully described in this Agreement. NOW, THEREFORE, IN CONSIDERATION of the mutual covenants contained in this Agreement, and for other good and valuable consideration the receipt and adequacy of which are hereby acknowledged, the Company and the Purchaser agrees as follows: ARTICLE I DEFINITIONS 1.1. Definitions. In addition to the terms defined elsewhere in this ----------- Agreement: (a) capitalized terms that are not otherwise defined herein that are defined in the Debenture shall have the meanings given to such terms in the Debenture, and (b) the following terms have the meanings indicated in this Section 1.1: "Affiliate" means any Person that, directly or indirectly through one or more intermediaries, controls or is controlled by or is under common control with a Person, as such terms are used in and construed under Rule 144. "Closing" means the closing of the purchase and sale of the Debenture and Warrants pursuant to Section 2.1. "Closing Date" means the date of the Closing. "Closing Price" means, for any date, the price determined by the first of the following clauses that applies: (a) if the Common Stock is then listed or quoted on an Eligible Market, the closing sale price per share of the Common Stock for such date (or the nearest preceding date) on the primary Eligible Market on which the Common Stock is then listed or quoted; (b) if the Common Stock is not then listed or quoted on an Eligible Market and if prices for the Common Stock are then quoted on the OTC Bulletin Board, the closing sale price per share of the Common Stock for such date (or the nearest preceding date) on the OTC Bulletin Board; (c) if the Common Stock is not then listed or quoted on the OTC Bulletin Board and if prices for the Common Stock are then reported in the "Pink Sheets" published by the National -1-

Quotation Bureau Incorporated (or a similar organization or agency succeeding to its functions of reporting prices), the most recent sale price per share of the Common Stock so reported; or (d) in all other cases, the fair market value of a share of Common Stock as determined by an independent appraiser selected in good faith by the Purchaser. "Commission" means the Securities and Exchange Commission. "Common Stock" means the common stock of the Company, no par value per share, and any securities into which such common stock may hereafter be reclassified. "Company Counsel" means Latham & Watkins, San Diego, California. "Debenture" means $2,000,000 in aggregate principal amount of the Company's 8% Convertible Debentures issued to the Purchaser at the Closing, in the form of Exhibit A. --------- "Effective Date" means the date that an Underlying Shares Registration Statement is first declared effective by the Commission. "Effectiveness Date" means the date on which an Underlying Shares Registration Statement is required to become effective pursuant to the Registration Rights Agreement. "Eligible Market" means any of the New York Stock Exchange, the American Stock Exchange, the Nasdaq National Market or the Nasdaq SmallCap Market. "Exchange Act" means the Securities Exchange Act of 1934, as amended. "Losses" means any and all losses, claims, damages, liabilities, settlement costs and expenses, including without limitation costs of preparation and reasonable attorneys' fees. "Person" means an individual or corporation, partnership, trust, incorporated or unincorporated association, joint venture, limited liability company, joint stock company, government (or an agency or subdivision thereof) or other entity of any kind. "Proceeding" means an action, claim, suit, investigation or proceeding (including, without limitation, an investigation or partial proceeding, such as a deposition). "Registration Rights Agreement" means the Registration Rights Agreement, dated as of the date of this Agreement, among the Company and the Purchaser, in the form of Exhibit B. --------- "Rule 144" means Rule 144 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. "Securities" means the Debenture, the Warrants and the Underlying Shares. -2-

"Securities Act" means the Securities Act of 1933, as amended. "Transaction Documents" means this Agreement, the Debenture, the Warrants, the Transfer Agent Instructions, the Registration Rights Agreement and any other documents or agreements executed in connection with the transactions contemplated hereunder. "Transfer Agent Instructions" means the Transfer Agent Instructions, in the form of Exhibit D, executed by the Company and delivered to and --------- acknowledged in writing by the Company's transfer agent. "Underlying Shares" means the shares of Common Stock issuable upon conversion of the Debenture and upon exercise of the Warrants. "Underlying Shares Registration Statement" means a registration statement meeting the requirements set forth in the Registration Rights Agreement and covering the resale of the Underlying Shares by the Purchaser. "Warrants" means collectively the Common Stock purchase warrants, in the form of Exhibit C delivered to the Purchaser at the Closing in accordance --------- with Section 2.2. ARTICLE II PURCHASE AND SALE 2.1. Closing. The Closing shall take place via facsimile immediately ------- following the execution hereof, or by such other method or at such location or time as the parties may agree. 2.2. Closing Deliveries. ------------------ (a) At the Closing, the Company shall deliver or cause to be delivered to the Purchaser the following: (i) The Debenture in the principal amount of $2,000,000, registered in the name of the Purchaser; (ii) a Warrant, registered in the name of the Purchaser, pursuant to which the Purchaser shall have the right to acquire a number of shares of Common Stock equal to 60% of the number of Underlying Shares issuable upon conversion in full of the principal amount of Debentures issued to the Purchaser at the Closing; (iii) the Transfer Agent Instructions; and (iv) the Registration Rights Agreement duly executed by the Company. -3-

(b) At the Closing, the Purchaser shall deliver or cause to be delivered to the Company the following: (i) $2,000,000 in United States dollars, in immediately available funds, by wire transfer to an account designated in writing by the Company for such purpose; and (ii) the Registration Rights Agreement duly executed by the Purchaser. ARTICLE III REPRESENTATIONS AND WARRANTIES 3.1. Representations and Warranties of the Company. The Company hereby --------------------------------------------- makes the following representations and warranties to the Purchaser: (a) Organization and Qualification. The Company is an entity duly ------------------------------ incorporated or otherwise organized, validly existing and in good standing under the laws of the State of California, with the requisite corporate power and authority to own and use its properties and assets and to carry on its business as currently conducted. The Company is not in violation of any of the provisions of its articles of incorporation or bylaws. The Company is duly qualified to do business and is in good standing as a foreign corporation or other entity in each jurisdiction in which the nature of the business conducted or property owned by it makes such qualification necessary, except where the failure to be so qualified or in good standing, as the case may be, would not reasonably be expected to, individually or in the aggregate: (i) adversely affect the legality, validity or enforceability of any Transaction Document, (ii) have or result in a material adverse effect on the results of operations, assets, business or condition (financial or otherwise) of the Company, or (iii) adversely impair the Company's ability to perform fully on a timely basis its obligations under any of the Transaction Documents (any of (i), (ii) or (iii), a "Material Adverse Effect"). (b) Authorization; Enforcement. The Company has the requisite -------------------------- corporate power and authority to enter into and to consummate the transactions contemplated by each of the Transaction Documents and otherwise to carry out its obligations thereunder. The execution and delivery of each of the Transaction Documents by the Company and the consummation by it of the transactions contemplated thereby have been duly authorized by all necessary action on the part of the Company and no further action is required by the Company. Each of the Transaction Documents has been (or upon delivery will be) duly executed by the Company and, when delivered in accordance with the terms hereof, will constitute the valid and binding obligation of the Company enforceable against the Company in accordance with its terms. (c) No Conflicts. The execution, delivery and performance of the ------------ Transaction Documents by the Company and the consummation by the Company of the -4-

transactions contemplated thereby do not and will not: (i) conflict with or violate any provision of the Company's articles of incorporation or bylaws, or (ii) subject to obtaining the Required Approvals (as defined below), conflict with, or constitute a default (or an event that with notice or lapse of time or both would become a default) under, or give to others any rights of termination, amendment, acceleration or cancellation (with or without notice, lapse of time or both) of, any agreement, credit facility, debt or other instrument (evidencing a Company debt or otherwise) or other understanding to which the Company is a party or by which any property or asset of the Company is bound or affected, or (iii) result in a violation of any law, rule, regulation, order, judgment, injunction, decree or other restriction of any court or governmental authority to which the Company is subject (including federal and state securities laws and regulations), or by which any property or asset of the Company is bound or affected; except in the case of each of clauses (ii) and (iii), such as would not reasonably be expected to, individually or in the aggregate, have or result in a Material Adverse Effect. (d) Filings, Consents and Approvals. To the Company's knowledge, ------------------------------- the Company is not required to obtain any consent, waiver, authorization or order of, give any notice to, or make any filing or registration with, any court or other federal, state, local or other governmental authority or other Person in connection with the execution, delivery and performance by the Company of the Transaction Documents, other than (i) the filings required under Section 4.8, (ii) the filing with the Commission of the Underlying Shares Registration Statement, (iii) the application(s) to each applicable Trading Market for the listing of the Underlying Shares for trading thereon in the time and manner required thereby, and (iv) applicable Blue Sky filings (collectively, the "Required Approvals"). (e) Issuance of the Securities. The Securities are duly -------------------------- authorized and, when issued and paid for in accordance with the applicable Transaction Documents, will be duly and validly issued, fully paid and nonassessable, free and clear of all liens, claims or encumbrances (other than liens, claims or encumbrances granted by Purchaser) (the "Liens"). The Company has reserved from its duly authorized capital stock a sufficient number of Underlying Shares to enable it to comply with its conversion and exercise obligations under the Debenture and the Warrants, respectively. (f) Capitalization. The number of shares and type of all -------------- authorized, issued and outstanding capital stock of the Company is set forth in the Disclosure Materials. No securities of the Company are entitled to preemptive or similar rights, and no Person has any right of first refusal, preemptive right, right of participation, or any similar right to participate in the transactions contemplated by the Transaction Documents. Except as a result of the purchase and sale of the Securities and except as disclosed in the Disclosure Materials, there are no outstanding options, warrants, script rights to subscribe to, calls or commitments of any character whatsoever relating to, or securities, rights or obligations convertible into or exchangeable for, or giving any Person any right to subscribe for or acquire, any shares of Common Stock, or contracts, commitments, understandings or arrangements by which the Company is or may become bound to issue additional shares of Common Stock, or securities or rights convertible or -5-

exchangeable into shares of Common Stock. The issuance and sale of the Securities will not obligate the Company to issue shares of Common Stock or other securities to any Person (other than the Purchasers) and will not result in a right of any holder of Company securities to adjust the exercise, conversion, exchange or reset price under such securities. (g) SEC Reports; Financial Statements. The Company has filed all --------------------------------- reports required to be filed by it under the Exchange Act, including pursuant to Section 13(a) or 15(d) thereof, for the two years preceding the date hereof (or such shorter period as the Company was required by law to file such material) (the foregoing materials being collectively referred to herein as the "SEC Reports" and, together with the Schedules to this Agreement and the draft Form 10-K provided to Purchaser on March 13, 2002 (the "Draft Form 10-K"), the "Disclosure Materials") on a timely basis or has received a valid extension of such time of filing and has filed any such SEC Reports prior to the expiration of any such extension. The Company has delivered to the Purchasers a copy of all SEC Reports filed within the ten (10) days preceding the date hereof. As of their respective dates, the SEC Reports complied in all material respects with the requirements of the Exchange Act and the rules and regulations of the Commission promulgated thereunder, and none of the SEC Reports, when filed, contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading. The financial statements of the Company included in the SEC Reports comply in all material respects with applicable accounting requirements and the rules and regulations of the Commission with respect thereto as in effect at the time of filing. Such financial statements have been prepared in accordance with generally accepted accounting principles applied on a consistent basis during the periods involved ("GAAP"), except as may be otherwise specified in such financial statements or the notes thereto, and fairly present in all material respects the financial position of the Company and its consolidated subsidiaries as of and for the dates thereof and the results of operations and cash flows for the periods then ended, subject, in the case of unaudited statements, to normal, immaterial, year-end audit adjustments. (h) Material Changes. Since the date of the latest audited ---------------- financial statements included within the SEC Reports, except as specifically disclosed in the Disclosure Materials: (i) there has been no event, occurrence or development that has had or that would reasonably be expected to result in a Material Adverse Effect, (ii) the Company has not incurred any liabilities (contingent or otherwise) other than (A) trade payables and accrued expenses incurred in the ordinary course of business consistent with past practice and (B) liabilities not required to be reflected in the Company's financial statements pursuant to GAAP or required to be disclosed in filings made with the Commission, (iii) the Company has not altered its method of accounting or the identity of its auditors, (iv) the Company has not declared or made any dividend or distribution of cash or other property to its stockholders or purchased, redeemed or made any agreements to purchase or redeem any shares of its capital stock, and (v) except as disclosed in the Disclosure Materials, the Company has not issued any equity securities to any officer, director or Affiliate, except pursuant to existing Company stock purchase and stock option plans. -6-

(i) Litigation. To the Company's knowledge, there is no action, ---------- suit, inquiry, notice of violation, proceeding or investigation pending or threatened against the Company or any of its respective properties before or by any court, arbitrator, governmental or administrative agency or regulatory authority (federal, state, county, local or foreign) (collectively, an "Action") which: (i) adversely affects or challenges the legality, validity or enforceability of any of the Transaction Documents or the Securities or (ii) would reasonably be expected to, if there were an unfavorable decision, individually or in the aggregate, have or result in a Material Adverse Effect. To the Company's knowledge and except as disclosed on Schedule 3.1(j), the Company, including any director or officer thereof, is not and has not been the subject of any Action involving a claim of violation of or liability under federal or state securities laws or a claim of breach of fiduciary duty. (j) Compliance. To the Company's knowledge, it is not: (i) in ---------- default under or in violation of (and no event has occurred that has not been waived that, with notice or lapse of time or both, would result in a default by the Company under), nor has the Company received notice of a claim that it is in default under or that it is in violation of, any indenture, loan or credit agreement or any other agreement or instrument to which it is a party or by which it or any of its properties is bound (whether or not such default or violation has been waived), (ii) in violation of any order of any court, arbitrator or governmental body, or (iii) in violation of any statute, rule or regulation of any governmental authority, except in each case as would not reasonably be expected to, individually or in the aggregate, have or result in a Material Adverse Effect. (k) Labor Relations. No material labor problem exists or, to the --------------- knowledge of the Company, is imminent with respect to any of the employees of the Company. (l) Regulatory Permits. The Company possesses all certificates, ------------------ authorizations and permits issued by the appropriate federal, state, local or foreign regulatory authorities necessary to conduct its business as described in the Disclosure Materials, except where the failure to possess such permits would not reasonably be expected to, individually or in the aggregate, have or result in a Material Adverse Effect ("Material Permits"), and the Company has not received any notice of proceedings relating to the revocation or modification of any Material Permit. (m) Title to Assets. The Company has good and marketable title in --------------- fee simple to all real property owned by it that is material to the business of the Company and good and marketable title in all personal property owned by it that is material to the business of the Company, in each case free and clear of all Liens, except for Liens as do not materially affect the value of such property and do not materially interfere with the use made and proposed to be made of such property by the Company. Any real property and facilities held under lease by the Company is held by it under valid, subsisting and enforceable leases of which the Company is in compliance in all material respects. -7-

(n) Patents and Trademarks. To the Company's knowledge, the ---------------------- Company has, or have rights to use, all patents, patent applications, trademarks, trademark applications, service marks, trade names, copyrights, licenses and other similar rights that are necessary or material for use in connection with its businesses as described in the Disclosure Materials and which the failure to so have would reasonably be expected to have a Material Adverse Effect (collectively, the "Intellectual Property Rights"). The Company has not received a written notice or otherwise has reason to believe that the Intellectual Property Rights used by the Company violates or infringes upon the rights of any Person. To the knowledge of the Company, all such Intellectual Property Rights are enforceable and there is no existing infringement by another Person of any of the Intellectual Property Rights. (o) Insurance. The Company is insured by, to the Company's --------- knowledge, insurers of recognized financial responsibility against such losses and risks and in such amounts as are prudent and customary in the businesses in which the Company is engaged. The Company has no reason to believe that it will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be necessary to continue its business without a significant increase in cost. (p) Transactions With Affiliates and Employees. Except as set ------------------------------------------ forth in Disclosure Materials, none of the officers or directors of the Company and, to the knowledge of the Company, none of the employees of the Company is presently a party to any transaction with the Company (other than for services as employees, officers and directors), including any contract, agreement or other arrangement providing for the furnishing of services to or by, providing for rental of real or personal property to or from, or otherwise requiring payments to or from any officer, director or such employee or, to the knowledge of the Company, any entity in which any officer, director, or any such employee has a substantial interest or is an officer, director, trustee or partner. (q) Internal Accounting Controls. The Company maintains a system ---------------------------- of internal accounting controls sufficient to provide reasonable assurance that (i) transactions are executed in accordance with management's general or specific authorizations, (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain asset accountability, (iii) access to assets is permitted only in accordance with management's general or specific authorization, and (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences. (r) Certain Fees. Except for the fees described in Schedule ------------ 3.1(s), all of which are payable by the Company to the registered broker-dealers named therein, no brokerage or finder's fees or commissions are or will be payable by the Company to any broker, financial advisor or consultant, finder, placement agent, investment banker, bank or other Person with respect to the transactions contemplated by this Agreement, and the Company has not taken any action that would cause any Purchaser to be liable for any such fees or commissions. The Company agrees that the Purchasers shall have no obligation with respect to any fees or with -8-

respect to any claims made by or on behalf of any Person for fees of the type contemplated by this Section in connection with the transactions contemplated by this Agreement. (s) Private Placement. Assuming the accuracy of the ----------------- representations and warranties of the Purchasers set forth in Sections 3.2(b)-(f), the offer, issuance and sale of the Securities to the Purchasers as contemplated hereby are exempt from the registration requirements of the Securities Act. (t) Form S-3 Eligibility. To the Company's knowledge, it is -------------------- eligible to register its Common Stock for resale by the Purchasers under Form S-3 promulgated under the Securities Act. (u) Listing and Maintenance Requirements. The Company has not, in ------------------------------------ the 12 months preceding the date hereof, received notice from any Trading Market on which the Common Stock is or has been listed or quoted to the effect that the Company is not in compliance with the listing or maintenance requirements of such Trading Market. The Company is, and has no reason to believe that it will not in the foreseeable future continue to be, in compliance with all such listing and maintenance requirements. The issuance and sale of the Securities hereunder does not contravene the rules and regulations of the Trading Market and no shareholder approval is required for the Company to fulfill its obligations under the Transaction Documents. (v) Registration Rights. Except as described in Schedule 3.1(w), ------------------- --------------- the Company has not granted or agreed to grant to any Person any rights (including "piggy-back" registration rights) to have any securities of the Company registered with the Commission or any other governmental authority that have not been satisfied. (w) Application of Takeover Protections. The Company and its ----------------------------------- Board of Directors have taken all necessary action, if any, in order to render inapplicable any control share acquisition, business combination, poison pill (including any distribution under a rights agreement) or other similar anti-takeover provision under the Company's Certificate of Incorporation (or similar charter documents) or the laws of its state of incorporation that is or would reasonably be expected to become applicable to the Purchasers as a result of the Purchasers and the Company fulfilling their obligations or exercising their rights under the Transaction Documents, including without limitation as a result of the Company's issuance of the Securities and the Purchasers' ownership of the Securities. (x) Seniority. Except as disclosed in the Debenture of even date --------- herewith, as of the date of this Agreement, no indebtedness of the Company is senior to the Debentures in right of payment, whether with respect to interest or upon liquidation or dissolution, or otherwise, other than indebtedness secured by purchase money security interests (which is senior only as to underlying assets covered thereby) and capital lease obligations (which is senior only as to the property covered thereby). -9-

(y) Disclosure. To the Company's knowledge, neither it nor any ---------- other Person acting on its behalf has provided any of the Purchasers or their agents or counsel with any information that the Company believes constitutes, material nonpublic information; except for the Draft Form 10-K, which Draft Form 10-K shall be filed no later than three (3) Trading Days following the Closing. The Company understands and confirms that the Purchasers will rely on the foregoing representations in effecting transactions in securities of the Company. All disclosure provided to the Purchasers regarding the Company, its business and the transactions contemplated hereby, including the Schedules to this Agreement, furnished by or on behalf of the Company are true and correct and do not contain any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements made therein, in light of the circumstances under which they were made, not misleading. The Company acknowledges and agrees that no Purchaser makes or has made any representations or warranties with respect to the transactions contemplated hereby other than those specifically set forth in Section 3.2. ----------- (z) Investment Company. The Company is not, and is not an ------------------ Affiliate of, an "investment company" within the meaning of the Investment Company Act of 1940, as amended. 3.2. Representations and Warranties of the Purchaser. The Purchaser ----------------------------------------------- hereby represents and warrants to the Company as follows: (a) Organization; Authority. The Purchaser is an entity duly ----------------------- organized, validly existing and in good standing under the laws of the jurisdiction of its organization with the requisite corporate or partnership power and authority to enter into and to consummate the transactions contemplated by the Transaction Documents and otherwise to carry out its obligations thereunder. The purchase by such Purchaser of the Securities to be acquired by it has been duly authorized by all necessary action on the part of such Purchaser. Each of this Agreement and the Registration Rights Agreement has been duly executed by such Purchaser, and when delivered by such Purchaser in accordance with the terms hereof, will constitute the valid and legally binding obligation of such Purchaser, enforceable against it in accordance with its terms. (b) Investment Intent. Such Purchaser is acquiring the Securities ----------------- as principal for its own account for investment purposes only and not with a view to or for distributing or reselling such Securities or any part thereof, without prejudice, however, to such Purchaser's right, subject to the provisions of this Agreement, at all times to sell or otherwise dispose of all or any part of such Securities pursuant to an effective registration statement under the Securities Act or under an exemption from such registration and in compliance with applicable federal and state securities laws. Nothing contained herein shall be deemed a representation or warranty by such Purchaser to hold Securities for any period of time. Such Purchaser is acquiring the Securities hereunder in the ordinary course of its business. Such Purchaser does not have any agreement or understanding, directly or indirectly, with any Person to distribute any of the Securities. -10-

(c) Purchaser Status. At the time such Purchaser was offered the ---------------- Securities, it was, and at the date hereof it is, and on each date on which it exercises any Warrants or converts any Debentures, it will be an "accredited investor" as defined in Rule 501(a) under the Securities Act. Such Purchaser has not been formed solely for the purpose of acquiring the Securities. (d) Experience of such Purchaser. Such Purchaser, either alone or ---------------------------- together with its representatives, has such knowledge, sophistication and experience in business and financial matters so as to be capable of evaluating the merits and risks of the prospective investment in the Securities, and has so evaluated the merits and risks of such investment. Such Purchaser is able to bear the economic risk of an investment in the Securities and, at the present time, is able to afford a complete loss of such investment. (e) Access to Information. Such Purchaser acknowledges that it --------------------- has reviewed the Disclosure Materials and has been afforded: (i) the opportunity to ask such questions as it has deemed necessary of, and to receive answers from, representatives of the Company concerning the terms and conditions of the offering of the Securities and the merits and risks of investing in the Securities; (ii) access to information about the Company and its financial condition, results of operations, business, properties, management and prospects sufficient to enable it to evaluate its investment; and (iii) the opportunity to obtain such additional information that the Company possesses or can acquire without unreasonable effort or expense that is necessary to make an informed investment decision with respect to the investment. Neither such inquiries nor any other investigation conducted by or on behalf of such Purchaser or its representatives or counsel shall modify, amend or affect such Purchaser's right to rely on the truth, accuracy and completeness of the Disclosure Materials and the Company's representations and warranties contained in the Transaction Documents. (f) General Solicitation. Such Purchaser is not purchasing the -------------------- Securities as a result of any advertisement, article, notice or other communication regarding the Securities published in any newspaper, magazine or similar media or broadcast over television or radio or presented at any seminar or any other general solicitation or general advertisement. (g) Reliance. Such Purchaser understands and acknowledges that: -------- (i) the Securities are being offered and sold to it without registration under the Securities Act in a private placement that is exempt from the registration provisions of the Securities Act and (ii) the availability of such exemption depends in part on, and the Company will rely upon the accuracy and truthfulness of, the foregoing representations and such Purchaser hereby consents to such reliance. The Company acknowledges and agrees that the Purchaser makes or has made any representations or warranties with respect to the transactions contemplated hereby other than those specifically set forth in this Section 3.2. -11-

ARTICLE IV OTHER AGREEMENTS OF THE PARTIES 4.1. Transfer Restrictions. --------------------- (a) The Securities may only be disposed of by the Purchaser in compliance with state and federal securities laws. In connection with any transfer of Securities other than pursuant to an effective registration statement, to the Company, to an Affiliate of a Purchaser or to a Person managed or advised by the same Person as manager or adviser to such Purchaser or in connection with a pledge as contemplated in Section 4.1(b), the Company may require the transferor thereof to provide to the Company an opinion of counsel selected by the transferor, the form and substance of which opinion shall be reasonably satisfactory to the Company, to the effect that such transfer does not require registration of such transferred Securities under the Securities Act. As a condition of transfer, any such transferee shall restate the representations and warranties of such Purchaser under Section 3.2 and agree in writing to be bound by the terms of this Agreement and shall have the rights of a Purchaser under this Agreement and the Registration Rights Agreement. (b) The Purchaser agrees to the imprinting, so long as is required by this Section 4.1(b), of the following legend on any certificate -------------- evidencing Securities: [NEITHER] THESE SECURITIES [NOR THE SECURITIES INTO WHICH THESE SECURITIES ARE [EXERCISABLE] [CONVERTIBLE] HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO THE TRANSFEROR TO SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY ACCEPTABLE TO THE COMPANY. THESE SECURITIES AND THE SECURITIES ISSUABLE UPON EXERCISE OF THESE SECURITIES MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER LOAN SECURED BY SUCH SECURITIES. -12-

The Company acknowledges and agrees that the Purchaser may from time to time pledge pursuant to a bona fide margin agreement or grant a security interest in some or all of the Securities and, if required under the terms of such arrangement, such Purchaser may transfer pledged or secured Securities to the pledgees or secured parties. Such a pledge or transfer would not be subject to approval of the Company and no legal opinion of the pledgee, secured party or pledgor shall be required in connection therewith. Further, no notice shall be required of such pledge. At the Purchaser's expense, the Company will execute and deliver such reasonable documentation as a pledgee or secured party of Securities may reasonably request in connection with a pledge or transfer of the Securities, including the preparation and filing of any required prospectus supplement under Rule 424(b)(3) of the Securities Act or other applicable provision of the Securities Act to appropriately amend the list of Selling Stockholders thereunder. (c) Certificates evidencing Securities shall not contain any legend (including the legend set forth in Section 4.1(b)): (i) following a sale of such Securities pursuant to the Underlying Shares Registration Statement in which the prospectus delivery requirement was satisfied, or (ii) following any sale of such Securities pursuant to Rule 144, or (iii) if such Securities are eligible for sale under Rule 144(k), or (iv) if such legend is not required under applicable requirements of the Securities Act (including judicial interpretations and pronouncements issued by the Staff of the Commission). If all or any portion of a Debenture or Warrant is converted or exercised (as applicable) at a time when the Underlying Shares are eligible for sale under Rule 144(k), such Underlying Shares shall be issued free of all legends. The Company agrees that following the Effective Date or at such time as such legend is no longer required under this Section 4.1(c), it will, no later than three Trading Days following the delivery by a Purchaser to the Company or the Company's transfer agent of a certificate representing Securities issued with a restrictive legend, deliver or cause to be delivered to such Purchaser a certificate representing such Securities that is free from all restrictive and other legends. The Company may not make any notation on its records or give instructions to any transfer agent of the Company that enlarge the restrictions on transfer set forth in this Section. 4.2. Acknowledgment of Dilution. The Company acknowledges that the -------------------------- issuance of the Securities will result in dilution of the outstanding shares of Common Stock. The Company further acknowledges that its obligations under the Transaction Documents, including without limitation its obligation to issue the Underlying Shares pursuant to the Transaction Documents, are unconditional and absolute and not subject to any right of set off, counterclaim, delay or reduction, regardless of the effect of any such dilution or any claim that the Company may have against any Purchaser. 4.3. Furnishing of Information. As long as any Purchaser owns ------------------------- Securities, the Company covenants to timely file (or obtain extensions in respect thereof and file within the applicable grace period) all reports required to be filed by the Company after the date hereof pursuant to the Exchange Act. Upon the request of any Purchaser, the Company shall deliver to such Purchaser a written certification of a duly authorized officer as to whether it has complied with the preceding sentence. As long as any Purchaser owns Securities, if the Company is not -13-

required to file reports pursuant to such laws, it will prepare and furnish to the Purchasers and make publicly available in accordance with Rule 144(c) such information as is required for the Purchasers to sell the Securities under Rule 144. 4.4. Integration. The Company shall not, and shall use commercially ----------- reasonable efforts to ensure that no Affiliate of the Company shall, sell, offer for sale or solicit offers to buy or otherwise negotiate in respect of any security (as defined in Section 2 of the Securities Act) that would be integrated with the offer or sale of the Securities in a manner that would require the registration under the Securities Act of the sale of the Securities to the Purchasers, or that would be integrated with the offer or sale of the Securities for purposes of the rules and regulations of any Trading Market. 4.5. Reservation and Listing of Securities. The Company shall maintain ------------------------------------- a reserve from its duly authorized shares of Common Stock to comply with its conversion and exercise obligations under the Debentures and Warrants pursuant to the Transaction Documents. 4.6. Conversion and Exercise Procedures. The form of Election to ---------------------------------- Purchase included in the Warrants and the forms of Conversion Notice included in the Debentures set forth the totality of the procedures required in order to exercise the Warrants or convert the Debentures. No additional legal opinion or other information or instructions shall be necessary to enable the Purchasers to exercise their Warrants or convert their Debentures. The Company shall honor exercises of the Warrants and conversions of the Debentures and shall deliver Underlying Shares in accordance with the terms, conditions and time periods set forth in the Transaction Documents. 4.7. Subsequent Placements. --------------------- (a) From the Closing Date and for 180 days thereafter, the Company shall not, directly or indirectly, offer, sell or grant any option to purchase, or otherwise dispose of, or announce any offer, sale, grant or any option to purchase or other disposition (collectively, a "Subsequent Placement") of any of its Common Stock or other securities which entitle the holder thereof to receive Common Stock, including without limitation any debt, preferred stock or other instrument or security that is, at any time during its life and under any circumstances, convertible into or exchangeable for Common Stock. (b) The restrictions contained in Section 4.7(a) shall not apply to: (i) the granting of options to, or the purchase of shares by, employees, consultants, officers and directors of the Company pursuant to any stock option plan or employee stock purchase plan duly adopted by the Company prior to the date hereof or to the issuance of Common Stock upon exercise of such options, or (ii) issuances of shares of Common Stock pursuant to a Strategic Transaction. A "Strategic Transaction" shall mean a transaction or relationship in which the Company issues Common Stock to a Person which is, itself or through its subsidiaries, an operating company in a business related to the business of the Company and in which the Company receives material benefits in addition to the investment of funds, but shall not include a -14-

transaction in which the Company is issuing securities primarily for the purpose of raising capital or to an entity whose primary business is investing in securities. (c) The restriction contained in Section 4.7(a) shall be extended for any number of Trading Days during such period in which: (i) trading in the Common Stock is suspended by any Trading Market, or (ii) the Underlying Shares Registration Statement is not effective or (iii) the prospectus included in the Underlying Shares Registration Statement may not be used by the Purchasers for the resale of Registrable Securities thereunder. 4.8. Securities Laws Disclosure; Publicity. The Company shall, not ------------------------------------- later than the Closing Date, issue a press release reasonably acceptable to the Purchaser disclosing all material terms of the transactions contemplated hereby. The Company and the Purchaser shall consult with each other in issuing any press releases with respect to the transactions contemplated hereby. Notwithstanding the foregoing, the Company shall not publicly disclose the name of any Purchaser, or include the name of the Purchaser in any filing with the Commission or any regulatory agency or Trading Market, without the prior written consent of such Purchaser, except to the extent such disclosure is required by law or Trading Market regulations, in which case the Company shall provide the Purchaser with prior notice of such disclosure. 4.9. Non-Public Information. The Company covenants and agrees that ---------------------- neither it nor any other Person acting on its behalf has provided or will provide the Purchaser or its agents or counsel with any information that the Company believes constitutes material non-public information, unless prior thereto such Purchaser shall have executed a written agreement regarding the confidentiality and use of such information. The Company understands and confirms that each Purchaser shall be relying on the foregoing representations in effecting transactions in securities of the Company. 4.10. Use of Proceeds. The Company shall use the net proceeds from the --------------- sale of the Securities hereunder for working capital purposes and not for the satisfaction of any portion of the Company's debt (other than payment of trade payables and accrued expenses in the ordinary course of the Company's business and prior practices), to redeem any Company equity or equity-equivalent securities or to settle any outstanding litigation. 4.11. Indemnification of Purchasers. The Company will indemnify and ----------------------------- hold the Purchaser and its directors, officers, shareholders, partners, employees and agents (each, a "Purchaser Party") harmless from any and all losses, liabilities, obligations, claims, contingencies, damages, costs and expenses, including all judgments, amounts paid in settlements, court costs and reasonable attorneys' fees and costs of investigation (collectively, "Losses") that any such Purchaser Party may suffer or incur as a result of or relating to: (a) any misrepresentation, breach or inaccuracy, or any allegation by a third party that, if true, would constitute a breach or inaccuracy, of any of the representations, warranties, covenants or agreements made by the Company in this Agreement or in the other Transaction Documents; or (b) any cause of action, suit or claim brought or made against such Purchaser Party and arising -15-

solely out of or solely resulting from the execution, delivery, performance or enforcement of this Agreement or any of the other Transaction Documents and without causation by any other activity, obligation, condition or liability pertaining to such Purchaser and not to the transactions contemplated by this Agreement. The Company will reimburse such Purchaser for its reasonable legal and other expenses (including the cost of any investigation, preparation and travel in connection therewith) incurred in connection therewith, as such expenses are incurred. 4.12. Shareholders Rights Plan. In the event that a shareholders ------------------------ rights plan is adopted by the Company, no claim will be made or enforced by the Company or any other Person that any Purchaser is an "Acquiring Person" under any such plan or in any way would reasonably be expected to be deemed to trigger the provisions of such plan by virtue of receiving Securities under the Transaction Documents. ARTICLE V MISCELLANEOUS 5.1. Fees and Expenses. Each party shall pay the fees and expenses of ----------------- its advisers, counsel, accountants and other experts, if any, and all other expenses incurred by such party incident to the negotiation, preparation, execution, delivery and performance of this Agreement. The Company shall pay all transfer agent fees, stamp taxes and other taxes and duties levied in connection with the issuance of any Securities. 5.2. Entire Agreement. The Transaction Documents, together with the ---------------- Exhibits and Schedules thereto, contain the entire understanding of the parties with respect to the subject matter hereof and supersede all prior agreements and understandings, oral or written, with respect to such matters, which the parties acknowledge have been merged into such documents, exhibits and schedules. At or after the Closing, and without further consideration, the Company will execute and deliver to the Purchaser such further documents as may be reasonably requested in order to give practical effect to the intention of the parties under the Transaction Documents. 5.3. Notices. Any and all notices or other communications or ------- deliveries required or permitted to be provided hereunder shall be in writing and shall be deemed given and effective on the earliest of (a) the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section prior to 6:30 p.m. (New York City time) on a Trading Day, (b) the next Trading Day after the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section on a day that is not a Trading Day or later than 6:30 p.m. (New York City time) on any Trading Day, (c) the Trading Day following the date of mailing, if sent by U.S. nationally recognized overnight courier service, or (d) upon actual receipt by the party to whom such notice is required to be given. The addresses for such notices and communications are those set forth on the signature pages hereof, or such other address as may be designated in writing hereafter, in the same manner, by such Person. -16-

5.4. Amendments; Waivers. No provision of this Agreement may be waived ------------------- or amended except in a written instrument signed, in the case of an amendment, by the Company and the Purchaser or, in the case of a waiver, by the party against whom enforcement of any such waiver is sought. No waiver of any default with respect to any provision, condition or requirement of this Agreement shall be deemed to be a continuing waiver in the future or a waiver of any subsequent default or a waiver of any other provision, condition or requirement hereof, nor shall any delay or omission of either party to exercise any right hereunder in any manner impair the exercise of any such right. 5.5. Construction. The headings herein are for convenience only, do ------------ not constitute a part of this Agreement and shall not be deemed to limit or affect any of the provisions hereof. The language used in this Agreement will be deemed to be the language chosen by the parties to express their mutual intent, and no rules of strict construction will be applied against any party. 5.6. Successors and Assigns. This Agreement shall be binding upon and ---------------------- inure to the benefit of the parties and their successors and permitted assigns. The Company may not assign this Agreement or any rights or obligations hereunder without the prior written consent of the Purchaser. Purchaser may assign its rights under this Agreement and the Registration Rights Agreement to any Person to whom such Purchaser assigns or transfers any Securities. 5.7. No Third-Party Beneficiaries. This Agreement is intended for the ---------------------------- benefit of the parties hereto and their respective successors and permitted assigns and is not for the benefit of, nor may any provision hereof be enforced by, any other Person, except as otherwise set forth in Section 4.11. 5.8. Governing Law; Venue; Waiver of Jury Trial. All questions ------------------------------------------ concerning the construction, validity, enforcement and interpretation of this Agreement shall be governed by and construed and enforced in accordance with the internal laws of the State of New York, without regard to the principles of conflicts of law thereof. Each party hereto hereby irrevocably waives personal service of process and consents to process being served in any such Proceeding by mailing a copy thereof via registered or certified mail or overnight delivery (with evidence of delivery) to such party at the address in effect for notices to it under this Agreement and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by law. Each party hereto hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Agreement or the transactions contemplated hereby. If either party shall commence a Proceeding to enforce any provisions of a Transaction Document, then the prevailing party in such Proceeding shall be reimbursed by the other party for its reasonable attorneys fees and other costs and expenses incurred with the investigation, preparation and prosecution of such Proceeding. -17-

5.9. Survival. The representations, warranties, agreements and -------- covenants contained herein shall survive for a period of eighteen (18) months following the Closing and the delivery, exercise and/or conversion of the Securities, as applicable. 5.10. Execution. This Agreement may be executed in two or more --------- counterparts, all of which when taken together shall be considered one and the same agreement and shall become effective when counterparts have been signed by each party and delivered to the other party, it being understood that both parties need not sign the same counterpart. In the event that any signature is delivered by facsimile transmission, such signature shall create a valid and binding obligation of the party executing (or on whose behalf such signature is executed) with the same force and effect as if such facsimile signature page were an original thereof. 5.11. Severability. If any provision of this Agreement is held to be ------------ invalid or unenforceable in any respect, the validity and enforceability of the remaining terms and provisions of this Agreement shall not in any way be affected or impaired thereby and the parties will attempt to agree upon a valid and enforceable provision that is a reasonable substitute therefor, and upon so agreeing, shall incorporate such substitute provision in this Agreement. 5.12. Rescission and Withdrawal Right. Notwithstanding anything to the ------------------------------- contrary contained in (and without limiting any similar provisions of) the Transaction Documents, whenever the Purchaser exercises a right, election, demand or option under a Transaction Document and the Company does not timely perform its related obligations within the periods therein provided, then such Purchaser may rescind or withdraw, in its sole discretion from time to time upon written notice to the Company, any relevant notice, demand or election in whole or in part without prejudice to its future actions and rights. 5.13. Replacement of Securities. If any certificate or instrument ------------------------- evidencing any Securities is mutilated, lost, stolen or destroyed, the Company shall issue or cause to be issued in exchange and substitution for and upon cancellation thereof, or in lieu of and substitution therefor, a new certificate or instrument, but only upon receipt of evidence reasonably satisfactory to the Company of such loss, theft or destruction and customary and reasonable indemnity, if requested. The applicants for a new certificate or instrument under such circumstances shall also pay any reasonable third-party costs associated with the issuance of such replacement Securities. 5.14. Remedies. In addition to being entitled to exercise all rights -------- provided herein or granted by law, including recovery of damages, the Purchaser and the Company will be entitled to specific performance under the Transaction Documents. The parties agree that monetary damages may not be adequate compensation for any loss incurred by reason of any breach of obligations described in the foregoing sentence and hereby agrees to waive in any action for specific performance of any such obligation the defense that a remedy at law would be adequate. -18-

5.15. Payment Set Aside. To the extent that the Company makes a ----------------- payment or payments to the Purchaser pursuant to any Transaction Document or a Purchaser enforces or exercises its rights thereunder, and such payment or payments or the proceeds of such enforcement or exercise or any part thereof are subsequently invalidated, declared to be fraudulent or preferential, set aside, recovered from, disgorged by or are required to be refunded, repaid or otherwise restored to the Company, a trustee, receiver or any other person under any law (including, without limitation, any bankruptcy law, state or federal law, common law or equitable cause of action), then to the extent of any such restoration the obligation or part thereof originally intended to be satisfied shall be revived and continued in full force and effect as if such payment had not been made or such enforcement or setoff had not occurred. 5.16. Usury. To the extent it may lawfully do so, the Company hereby ----- agrees not to insist upon or plead or in any manner whatsoever claim, and will resist any and all efforts to be compelled to take the benefit or advantage of, usury laws wherever enacted, now or at any time hereafter in force, in connection with any claim, action or proceeding that may be brought by the Purchaser in order to enforce any right or remedy under any Transaction Document. Notwithstanding any provision to the contrary contained in any Transaction Document, it is expressly agreed and provided that the total liability of the Company under the Transaction Documents for payments in the nature of interest shall not exceed the maximum lawful rate authorized under applicable law (the "Maximum Rate"), and, without limiting the foregoing, in no event shall any rate of interest or default interest, or both of them, when aggregated with any other sums in the nature of interest that the Company may be obligated to pay under the Transaction Documents exceed such Maximum Rate. It is agreed that if the maximum contract rate of interest allowed by law and applicable to the Transaction Documents is increased or decreased by statute or any official governmental action subsequent to the date hereof, the new maximum contract rate of interest allowed by law will be the Maximum Rate of interest applicable to the Transaction Documents from the effective date forward, unless such application is precluded by applicable law. If under any circumstances whatsoever, interest in excess of the Maximum Rate is paid by the Company to the Purchaser with respect to indebtedness evidenced by the Transaction Documents, such excess shall be applied by such Purchaser to the unpaid principal balance of any such indebtedness or be refunded to the Company, the manner of handling such excess to be at such Purchaser's election. 5.17. Independent Nature of Purchaser's Obligations and Rights. -------------------------------------------------------- Nothing contained herein or in any Transaction Document, and no action taken by the Purchaser pursuant thereto shall constitute the Purchaser as a partnership, an association, a joint venture or any other kind of entity with any other party, or create a presumption that the Purchaser is in any way acting in concert with respect to such obligations or the transactions contemplated hereby. [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK SIGNATURE PAGES FOLLOWS] -19-

IN WITNESS WHEREOF, the parties hereto have caused this Securities Purchase Agreement to be duly executed by their respective authorized signatories as of the date first indicated above. QUESTCOR PHARMACEUTICALS, INC. By: /s/ Timothy E. Morris ----------------------------------- Name: Timothy E. Morris Title: Chief Financial Officer Address for Notice: Attention: President 3260 Whipple Road Union City, California 94587 Fax: 510-400-0799 With a copy to: Attention: David A. Hahn Latham & Watkins 701 B Street, Suite 2100 San Diego, California 92101 DEFIANTE FARMACEUTICA UNIPESSOAL L.D.A. By: /s/ Antonio Nicolai --------------------------------- Name: Mr. Antonio Nicolai Title: Director Address for Notice: Defiante Farmaceutica Unipessoal L.D.A. Rua dos Ferreiros, 260 Funchal- Madeira -20-

(Portogallo)9000-082 Attn: Mr.Pedro Quintas With copy to: Attn: Mr. Antonio Nicolai c/o Via Sudafrica, 20 00144 - Rome (Italy) Fax: 0039.06.54229457 -21-

EXHIBIT 4.4.2 NEITHER THIS DEBENTURE NOR THE SECURITIES ISSUABLE UPON CONVERSION OF THIS DEBENTURE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO THE TRANSFEROR TO SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY ACCEPTABLE TO THE COMPANY. THIS DEBENTURE AND THE SECURITIES ISSUABLE UPON CONVERSION OF THIS DEBENTURE MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER LOAN SECURED BY SUCH SECURITIES. Original Issue Date: March 15, 2002 $2,000,000 QUESTCOR PHARMACEUTICALS, INC. 8% CONVERTIBLE DEBENTURE THIS DEBENTURE is a duly authorized and issued debenture of Questcor Pharmaceuticals, Inc., a corporation organized under the laws of the state of California (the "Company"), designated as its 8% Convertible Debenture due March 15, 2005 or such earlier or later date as the debenture is required or permitted to be repaid as provided hereunder. FOR VALUE RECEIVED, the Company promises to pay to the order of Defiante Farmaceutica Unipessoal L.D.A., or its registered assigns (the "Holder"), the principal sum of two million dollars ($2,000,000) plus any accrued and unpaid interest thereon, on March 15, 2005, or such earlier date as the Debenture is required or permitted to be repaid as provided hereunder (the "Maturity Date). This Debenture is subject to the following additional provisions: 1. Definitions. In addition to the terms defined elsewhere in this ----------- Debenture, (a) capitalized terms that are not otherwise defined herein that are defined in the Securities Purchase Agreement, dated as of March 15, 2002 among the Company and the original Holder (the "Purchase Agreement") have the meanings given to such terms in the Purchase Agreement, and (b) the following terms have the meanings indicated in this Section 1: "Bankruptcy Event" means any of the following events: (a) the Company commences a case or other proceeding under any bankruptcy, reorganization, arrangement, adjustment of debt, relief of debtors, dissolution, insolvency or liquidation or similar law of any jurisdiction relating to the Company; (b) there is commenced

against the Company any such case or proceeding that is not dismissed within 60 days after commencement; (c) the Company is adjudicated insolvent or bankrupt or any order of relief or other order approving any such case or proceeding is entered; (d) the Company suffers any appointment of any custodian or the like for it or any substantial part of its property that is not discharged or stayed within 60 days; (e) the Company makes a general assignment for the benefit of creditors; (f) the Company fails to pay, or states that it is unable to pay, its debts generally as they become due; (g) the Company calls a meeting of its creditors with a view to arranging a composition, adjustment or restructuring of its debts; or (h) the Company, by any act or failure to act, expressly indicates its consent to, approval of or acquiescence in any of the foregoing or takes any corporate or other action for the purpose of effecting any of the foregoing. "Change of Control" means the occurrence of any of the following in one or a series of related transactions or events: (i) an acquisition after the date hereof by an individual or legal entity or "group" (as described in Rule 13d-5(b)(1) under the Exchange Act) of more than 50% of the voting rights or equity interests in the Company; (ii) during any period of two consecutive years, individuals who, at the beginning of such period constitute the Company's board of director's (the "Board"), together with any new director whose election by the Board or nomination for election by the Company's shareholders was approved by a vote of at least two-thirds (2/3) of the directors then in office either who were directors at the beginning of the two-year period, or whose election or nomination was previously so approved, cease for any reason to constitute a majority of the board; (iii) a merger, consolidation or business combination of the Company or a sale of more than 50% of the assets of the Company in connection with which the Company is not the surviving entity of or if following such transaction or series of transactions, the holders of the Company's securities prior to the first such transaction do not continue to hold at least half of the voting rights and equity interests in of the surviving entity or acquirer of such assets; (iv) a recapitalization, reorganization or other transaction involving the Company that constitutes or results in a transfer of more than 50% of the voting rights or equity interests in the Company; (v) a "Rule 13e-3 transaction" as defined in Rule 13e-3 under the Exchange Act with respect to the Company, or (vi) the execution by the Company of an agreement providing for any of the foregoing events. "Closing Price" means, for any date, the price determined by the first of the following clauses that applies: (a) if the Common Stock is then listed or quoted on an Eligible Market, the closing sale price per share of the Common Stock for such date (or the nearest preceding date) on the primary Eligible Market on which the Common Stock is then listed or quoted; (b) if the Common Stock is not then listed or quoted on an Eligible Market and if prices for the Common Stock are then quoted on the OTC Bulletin Board, the closing sale price per share of the Common Stock for such date (or the nearest preceding date) on the OTC Bulletin Board; (c) if the Common Stock is not then listed or quoted on the OTC Bulletin Board and if prices for the Common Stock are then reported in the "Pink Sheets" published by the National Quotation Bureau Incorporated (or a similar organization or agency succeeding to its functions of reporting prices), the most recent sale price per share of the Common Stock so reported; or (d) in all other cases, the -2-

fair market value of a share of Common Stock as determined by an independent appraiser selected in good faith by the Holder. "Conversion Price" means $1.58 as adjusted pursuant to the terms of this Debenture. "Eligible Market" means any of the New York Stock Exchange, the American Stock Exchange, the Nasdaq National Market or the Nasdaq Small Cap Market. "Equity Conditions" means, with respect to a specified issuance of Common Stock, that each of the following conditions is satisfied: (i) the number of authorized but unissued and otherwise unreserved shares of Common Stock is sufficient for such issuance; (ii) such shares of Common Stock are registered for resale by the Holder pursuant to an effective registration statement, and the prospectus thereunder shall be available for use by the Holder to sell such shares or all such shares may be sold without volume restrictions pursuant to Rule 144(k) under the Securities Act; (iii) the Common Stock is listed or quoted (and is not suspended from trading) on an Eligible Market and such shares of Common Stock are approved for listing upon issuance; (iv) such issuance would be permitted in full without violating Section 12 hereof or the rules or regulations of any Trading Market; (v) no Bankruptcy Event has occurred; and (vi) the Company is not in default with respect to any material obligation hereunder or under any other Transaction Document. "Interest Payment Date" means each March 31, June 30, September 30 and December 31, except if such date is not a Trading Day, in which case such interest shall be payable on the next succeeding Trading Day. "Mandatory Prepayment Amount" means the sum of: (i) 110% of the principal amount of Debentures to be prepaid, plus all accrued and unpaid interest thereon not paid or accreted to the principal amount of this Debenture under Section 2, and (ii) all other amounts, costs, expenses and liquidated damages which may be due in respect of such Debentures. "Original Issue Date" means the date of the first issuance of any Debentures, regardless of the number of transfers of any particular Debenture. "Prepayment Price" means the sum of: (i) the principal amount of Debentures to be prepaid, plus all accrued and unpaid interest thereon, and (ii) all other amounts, costs, expenses and liquidated damages which may be due in respect of such Debentures. "Trading Day" means (a) any day on which the Common Stock is traded on its primary Trading Market, or (b) if the Common Stock is not then listed or quoted for trading on an Eligible Market, then a day on which trading occurs on the New York Stock Exchange (or any successor thereto). "Trading Market" means the American Stock Exchange or any other national securities exchange, market or trading or quotation facility on which the Common Stock is then listed or quoted. -3-

"Underlying Shares" means the shares of Common Stock issuable upon conversion of principal amount and interest under the Debentures. "Underlying Shares Registration Statement" means a registration statement meeting the requirements set forth in the Registration Rights Agreement, covering the resale of the Underlying Shares and naming the Holder as a "selling stockholder" thereunder. 2. Interest. -------- (a) The Company shall pay interest to the Holder on the aggregate unconverted and then outstanding principal amount of this Debenture at the rate of 8% per annum, payable quarterly in arrears on each Interest Payment Date. Interest shall be calculated on the basis of a 360-day year and shall accrue daily commencing on the Original Issue Date. (b) If the Company is required but fails to pay interest in cash on any Interest Payment Date, the Holder may (but shall not be required to), by notice to the Company, treat such interest as if it had been added to the principal amount of this Debenture as of such Interest Payment Date. 3. Registration of Debentures. The Company shall register the -------------------------- Debentures upon records to be maintained by the Company for that purpose (the "Debenture Register") in the name of each record holder thereof from time to time. The Company may deem and treat the registered Holder of this Debenture as the absolute owner hereof for the purpose of any conversion hereof or any payment of interest hereon, and for all other purposes, absent actual notice to the contrary. 4. Registration of Transfers and Exchanges. The Company shall register --------------------------------------- the transfer of any portion of this Debenture in the Debenture Register upon surrender of this Debenture to the Company at its address for notice set forth herein. Upon any such registration or transfer, a new debenture, in substantially the form of this Debenture (any such new debenture, a "New Debenture"), evidencing the portion of this Debenture so transferred shall be issued to the transferee and a New Debenture evidencing the remaining portion of this Debenture not so transferred, if any, shall be issued to the transferring Holder. The acceptance of the New Debenture by the transferee thereof shall be deemed the acceptance by such transferee of all of the rights and obligations of a holder of a Debenture. This Debenture is exchangeable for an equal aggregate principal amount of Debentures of different authorized denominations, as requested by the Holder surrendering the same. No service charge or other fee will be imposed in connection with any such registration of transfer or exchange. Transfers of this Debenture and the shares of Common Stock issuable on conversion thereof hereby are governed by Section 4.1 of the Purchase Agreement. 5. Conversion; Payment in Shares ----------------------------- (a) Conversion Prior to Maturity Date. The Holder may, at its --------------------------------- option, convert all or any portion of this Debenture into Common Stock at the Conversion Price, at any time prior to a Maturity Date. -4-

(b) Conversion Notice. A Holder may convert principal under this ----------------- Debenture into Common Stock at any time and from time to time from and after the Original Issue Date, by delivering to the Company a completed and signed form of conversion notice attached hereto as Exhibit A (a "Conversion Notice"). The date --------- any such Conversion Notice together with a schedule in the form of Schedule 1 ---------- attached hereto (the "Conversion Schedule") is delivered to the Company (as determined in accordance with the notice provisions hereof) is a "Conversion Date." (c) Payment in Shares. At the Company's option, it may repay the ----------------- Debenture at the Maturity Date by delivering freely tradeable, registered shares of its Common Stock to Holder; provided that (i) it delivers irrevocable, written notice of such election at least twenty (20) Trading Days prior to the Maturity Date, (ii) all Equity Conditions have been satisfied, and (iii) the average of the Closing Price of Common Stock for the twenty (20) Trading Days prior to the Maturity Date is equal to or greater than the Closing Price on the Closing Date (as defined in the Securities Purchase Agreement dated the date hereof). For the purposes of repayment of the Debenture in shares of Common Stock, such shares shall be valued at 100% of the average of the Closing Price for the twenty (20) Trading Days prior to the Maturity Date. Such shares shall be delivered to Holder within at least three (3) days of the Maturity Date via the Depository Trust Corporation DWAC System. 6. Mechanics of Conversion. ----------------------- (a) The number of Underlying Shares issuable upon any conversion hereunder shall equal the outstanding principal amount of this Debenture to be converted and any interest that has been added to such principal amount in accordance with Section 2 hereof, divided by the Conversion Price. (b) Upon conversion of this Debenture, the Company shall promptly (but in no event later than three (3) Trading Days after the Conversion Date): issue or cause to be issued and cause to be delivered to or upon the written order of the Holder and in such name or names as the Holder may designate a certificate for the Underlying Shares issuable upon such conversion which, unless required by the Purchase Agreement, shall be free of any restrictive legend. The Holder, or any Person so designated by the Holder to receive Underlying Shares, shall be deemed to have become holder of record of such Underlying Shares as of the Conversion Date. If it is eligible to participate in the Depositary Trust Corporation DWAC system and no legends are required to be included on the Underlying Shares pursuant to the Purchase Agreement, the Company shall, upon request of the Holder, use commercially reasonable efforts to deliver Underlying Shares hereunder electronically through the Depository Trust Corporation or another established clearing corporation performing similar functions. (c) To effect conversions hereunder, the Holder shall be required to physically surrender this Debenture to the Company, at which time the Company shall reissue a new certificate of debenture reflecting the lowering of the outstanding principal amount of this Debenture in an amount equal to the applicable conversion. (d) The Company's obligations to issue and deliver Underlying Shares upon conversion of this Debenture in accordance with the terms hereof are absolute and -5-

unconditional, irrespective of any action or inaction by the Holder to enforce the same, any waiver or consent with respect to any provision hereof, the recovery of any judgment against any Person or any action to enforce the same, or any setoff, counterclaim, recoupment, limitation or termination, or any breach or alleged breach by the Holder or any other Person of any obligation to the Company or any violation or alleged violation of law by the Holder or any other Person, and irrespective of any other circumstance which might otherwise limit such obligation of the Company to the Holder in connection with the issuance of such Underlying Shares. (e) If by the fifth Trading Day after a Conversion Date the Company fails to deliver to the Holder such certificate or certificates in the manner required pursuant to Section 6(b), then the Holder will have the right to rescind such conversion. (f) If by the fifth Trading Day after a Conversion Date the Company fails to deliver to the Holder such certificate or certificates in the manner required pursuant to Section 6(b), and if after such seventh Trading Day the Holder purchases (in an open market transaction or otherwise) shares of Common Stock to deliver in satisfaction of a sale by such Holder of the Underlying Shares which the Holder anticipated receiving upon such conversion (a "Buy-In"), then the Company shall (A) pay in cash to the Holder (in addition to any remedies available to or elected by the Holder) the amount by which (x) the Holder's total purchase price (including brokerage commissions, if any) for the shares of Common Stock so purchased exceeds (y) the amount obtained by multiplying (1) the aggregate number of Underlying Shares that the Company was required to deliver to the Holder in connection with the conversion at issue by (2) the closing sale price of the Common Stock at the time of the obligation giving rise to such purchase obligation and (B) at the option of the Holder, either reinstate the portion of the Debenture and equivalent number of Underlying Shares for which such conversion was not honored or deliver to the Holder the number of shares of Common Stock that would have been issued had the Company timely complied with its conversion and delivery obligations hereunder. For example, if the Holder purchases Common Stock having a total purchase price of $11,000 to cover a Buy-In with respect to an attempted conversion of Debentures with a market price on the date of conversion totaling $10,000, under clause (A) of the immediately preceding sentence, the Company shall be required to pay the Holder $1,000. The Holder shall provide the Company written notice, which written notice shall include such supporting documentation as reasonably necessary to substantiate the amounts payable, indicating the amounts payable to the Holder in respect of the Buy-In. 7. Events of Default. ----------------- (a) "Event of Default" means the occurrence of any one of the following events (whatever the reason and whether it shall be voluntary or involuntary or effected by operation of law or pursuant to any judgment, decree or order of any court, or any order, rule or regulation of any administrative or governmental body): (i) any default in the payment (free of any claim of subordination) of principal, interest or liquidated damages in respect of any Debentures, as and when the same becomes due and payable (whether on a Conversion Date or the Maturity Date or by acceleration or otherwise) and such failure is not cured within ten (10) Trading Days after notice of such default is first given to the Company by the Holder; -6-

(ii) a Bankruptcy Event; (iii) the Common Stock is not listed or quoted, or is suspended from trading, on an Eligible Market for two (2) consecutive Trading Days or for an aggregate of five (5) Trading Days (which need not be consecutive Trading Days); (iv) the Company fails for any reason to deliver a certificate evidencing any Underlying Shares to a Holder within five Trading Days after delivery of such certificate is required pursuant to the terms hereof or the exercise or conversion rights of the Holder pursuant to the Transaction Documents are otherwise suspended (including by reason of a public document filed by the Company of its intention to no longer honor conversions of any Debentures) for any reason; (v) the Company fails to have available a sufficient number of authorized but unissued and otherwise unreserved shares of Common Stock available to issue Underlying Shares upon any conversion hereunder; (vi) the Company fails to make any cash payment required under the Transaction Documents (including, but limited to, the payment of a "Buy-In" pursuant to Section 6(f) hereunder or a Mandatory Prepayment Amount pursuant to Section 7) and such failure is not cured within ten (10) Trading Days after notice of such default is first given to the Company by the Holder; (vii) the occurrence of a Change of Control; or (viii) the Company defaults in the timely performance of any other obligation under the Transaction Documents and such default continues uncured for a period of thirty (30) days after the date on which notice of such default is first given to the Company by the Holder (it being understood that no prior notice need be given in the case of a default that cannot reasonably be cured within thirty (30) days). (b) At any time or times following the occurrence of an Event of Default, the Holder shall have the option to elect, by notice to the Company (an "Event Notice"), to accelerate the unpaid and unconverted principal and interest due hereunder and require the Company to pay an amount equal to the then outstanding principal amount of the Debenture plus any accrued and unpaid interest thereon; provided, however, if the Event Notice is a result of Section 7(a)(vii), the Company shall pay Holder the Mandatory Prepayment Amount. The Company shall pay such relevant amount to the Holder no later than the third Trading Day following the date of delivery of the Event Notice, and upon receipt thereof the Holder shall deliver the original Debenture so repurchased to the Company (to the extent such documents have been delivered to the Holder). (c) Subsequent to the delivery of an Event Notice pursuant to the terms hereof, the Company hereby waives any presentment, demand, protest or other notice of any kind, and the Holder may immediately and without expiration of any grace period enforce any and all of its rights and remedies hereunder and all other remedies available to it under applicable law. Any Event Notice may be rescinded and annulled by the Holder at any time -7-

prior to payment hereunder. No such rescission or annulment shall affect any subsequent Event of Default or impair any right consequent thereto. 8. Ranking. This Debenture ranks pari passu with all other Debentures ------- now or hereafter issued pursuant to the Transaction Documents. No indebtedness of the Company is senior to this Debenture in right of payment, whether with respect of interest, damages or upon liquidation or dissolution or otherwise. Other than that certain accounts receivable arrangement between the Company and Pacific Business Funding dated January 2, 2002, the Company will not, and will not permit any to, directly or indirectly, enter into, create, incur or assume any indebtedness of any kind, on or with respect to any of its property or assets now owned or hereafter acquired or any interest therein or any income or profits therefrom, that is senior in any respect to the Company's obligations under the Debentures, other than indebtedness secured by purchase money security interests (which will be senior only as to the underlying assets covered thereby) and indebtedness under capital lease obligations (which will be senior only as to the assets covered thereby); provided, however, the Company may grant security interests to a third party with respect to those assets acquired from such third party as part of an acquisition of a currently marketable product from such third party. 9. Charges, Taxes and Expenses. Issuance of certificates for --------------------------- Underlying Shares upon conversion of (or otherwise in respect of) this Debenture shall be made without charge to the Holder for any issue or transfer tax, withholding tax, transfer agent fee or other incidental tax or expense in respect of the issuance of such certificate, all of which taxes and expenses shall be paid by the Company; provided, however, that the Company shall not be required to pay any tax which may be payable in respect of any transfer involved in the registration of any certificates for Underlying Shares or Debentures in a name other than that of the Holder. The Holder shall be responsible for all other tax liability that may arise as a result of holding or transferring this Debenture or receiving Underlying Shares in respect hereof. 10. Reservation of Underlying Shares. The Company covenants that it -------------------------------- will at all times reserve and keep available out of the aggregate of its authorized but unissued and otherwise unreserved Common Stock, solely for the purpose of enabling it to issue Underlying Shares as required hereunder, the number of Underlying Shares which are then issuable and deliverable upon the conversion of (and otherwise in respect of) this entire Debenture (taking into account the adjustments of Section 11), free from preemptive rights or any other ---------- contingent purchase rights of persons other than the Holder. The Company covenants that all Underlying Shares so issuable and deliverable shall, upon issuance in accordance with the terms hereof, be duly and validly authorized, issued and fully paid and nonassessable. 11. Certain Adjustments. The Conversion Price is subject to adjustment ------------------- from time to time as set forth in this Section 11. ---------- (a) Stock Dividends and Splits. If the Company, at any time while -------------------------- this Debenture is outstanding, (i) pays a stock dividend on its Common Stock or otherwise makes a distribution on any class of capital stock that is payable in shares of Common Stock, (ii) subdivides outstanding shares of Common Stock into a larger number of shares, or (iii) combines outstanding shares of Common Stock into a smaller number of shares, then in each such case the Conversion Price shall be multiplied by a fraction of which the numerator shall be -8-

the number of shares of Common Stock outstanding immediately before such event and of which the denominator shall be the number of shares of Common Stock outstanding immediately after such event. (b) Pro Rata Distributions. If the Company, at any time while ---------------------- this Debenture is outstanding, distributes to all holders of Common Stock and not to the Holder (i) evidences of its indebtedness, (ii) any security (other than a distribution of Common Stock covered by the preceding paragraph), (iii) rights or warrants to subscribe for or purchase any security, or (iv) any other asset (in each case, "Distributed Property"), then upon any conversion of this Debenture that occurs after such record date, the Holder shall be entitled to receive, in addition to the Underlying Shares otherwise issuable upon such conversion, the Distributed Property that the Holder would have been entitled to receive in respect of such number of Underlying Shares had the Holder been the record holder of such Underlying Shares immediately prior to such record date. (c) Fundamental Transactions. If, at any time while this ------------------------ Debenture is outstanding: (i) the Company effects any merger or consolidation of the Company with or into another Person, (ii) the Company effects any sale of all or substantially all of its assets in one or a series of related transactions, (iii) any tender offer or exchange offer (whether by the Company or another Person) is completed pursuant to which holders of Common Stock are permitted to tender or exchange their shares for other securities, cash or property, or (iv) the Company effects any reclassification of the Common Stock or any compulsory share exchange pursuant to which the Common Stock is effectively converted into or exchanged for other securities, cash or property (in any such case, a "Fundamental Transaction"), then upon any subsequent conversion of this Debenture, the Holder shall have the right to receive, for each Underlying Share that would have been issuable upon such conversion absent such Fundamental Transaction, the same kind and amount of securities, cash or property as it would have been entitled to receive upon the occurrence of such Fundamental Transaction if it had been, immediately prior to such Fundamental Transaction, the holder of one share of Common Stock (the "Alternate Consideration"). For purposes of any such conversion, the determination of the Conversion Price shall be appropriately adjusted to apply to such Alternate Consideration based on the amount of Alternate Consideration issuable in respect of one share of Common Stock in such Fundamental Transaction, and the Company shall apportion the Conversion Price among the Alternate Consideration in a reasonable manner reflecting the relative value of any different components of the Alternate Consideration. If holders of Common Stock are given any choice as to the securities, cash or property to be received in a Fundamental Transaction, then the Holder shall be given the same choice as to the Alternate Consideration it receives upon any conversion of this Debenture following such Fundamental Transaction. To the extent necessary to effectuate the foregoing provisions, any successor to the Company or surviving entity in such Fundamental Transaction shall issue to the Holder a new debenture consistent with the foregoing provisions and evidencing the Holder's right to convert such debenture into Alternate Consideration. The terms of any agreement pursuant to which a Fundamental Transaction is effected shall include terms requiring any such successor or surviving entity to comply with the provisions of this paragraph (c) and insuring that this Debenture (or any such replacement security) will be similarly adjusted upon any subsequent transaction analogous to a Fundamental Transaction. -9-

(d) Calculations. All calculations under this Section 11 shall be ------------ ---------- made to the nearest cent or the nearest 1/100th of a share, as applicable. The number of shares of Common Stock outstanding at any given time shall not include shares owned or held by or for the account of the Company, and the disposition of any such shares shall be considered an issue or sale of Common Stock. (e) Notice of Adjustments. Upon the occurrence of each adjustment --------------------- pursuant to this Section 11, the Company at its expense will promptly compute ---------- such adjustment in accordance with the terms hereof and prepare a certificate describing in reasonable detail such adjustment and the transactions giving rise thereto, including all facts upon which such adjustment is based. Upon written request, the Company will promptly deliver a copy of each such certificate to the Holder. (f) Notice of Corporate Events. If the Company: (i) declares a -------------------------- dividend or any other distribution of cash, securities or other property in respect of its Common Stock, including without limitation any granting of rights or warrants to subscribe for or purchase any capital stock of the Company , (ii) authorizes or approves, enters into any agreement contemplating or solicits stockholder approval for any Fundamental Transaction or (iii) authorizes the voluntary dissolution, liquidation or winding up of the affairs of the Company, then the Company shall deliver to the Holder a notice describing the material terms and conditions of such transaction, at least 20 calendar days prior to the applicable record or effective date on which a Person would need to hold Common Stock in order to participate in or vote with respect to such transaction, and the Company will take all steps reasonably necessary in order to insure that the Holder is given the practical opportunity to convert this Debenture prior to such time so as to participate in or vote with respect to such transaction; provided, however, that the failure to deliver such notice or any defect therein shall not affect the validity of the corporate action required to be described in such notice. 12. Optional Prepayment. ------------------- (a) The Company shall have the right, exercisable at any time and from time to time after the first year anniversary of the Original Issue Date and upon twenty (20) Trading Days' prior written notice (which notice shall be irrevocable) to the affected Holders (an "Optional Prepayment Notice"), to prepay all of the outstanding principal amount of the Debentures for which Conversion Notices have not previously been delivered or for which an Event of Default shall not have been declared, provided, that the following conditions are satisfied: (i) the average of the closing sale price of the Common Stock for the twenty (20) consecutive Trading Days prior to the delivery of the Optional Prepayment Notice is equal to or greater than 200% of the Conversion Price, and (ii) the Equity Conditions have been satisfied as of the date that the Optional Prepayment Notice is delivered through the Optional Prepayment Date. (b) The prepayment price applicable to prepayments under Section 13(a) shall equal the Prepayment Price and shall be paid in cash on the twentieth (20th) Trading Day following the date that the Company delivers the Optional Prepayment Notice (the "Optional Prepayment Date"). Any such prepayment shall be free of any claim of subordination. The Holders shall have the right to tender, and the Company shall honor, -10-

Conversion Notices delivered prior to the expiration of the fifteenth Trading Day after delivery of an Optional Prepayment Notice for such Debentures. (c) If any portion of the Prepayment Price shall not be paid by the Company by the expiration of the Optional Prepayment Date, the Prepayment Price shall be increased by an amount equal to 18% per annum (or such lower maximum amount of interest permitted to be charged under applicable law), to accrue daily from the date such interest is due hereunder through and including the date of payment (which amount shall be paid as liquidated damages and not as a penalty). In addition, if any portion of the Prepayment Price remains unpaid by the Optional Prepayment Date, the Holder subject to such prepayment may elect by written notice to the Company to demand conversion in accordance with the formula and the time period therefor set forth in Section 5 of any portion of the principal amount of Debentures for which the Prepayment Price, plus accrued liquidated damages and accrued interest thereon, has not been paid in full (the "Unpaid Prepayment Principal Amount").If the Holder elects the option above, the Company shall, within three Trading Days after such election is deemed delivered hereunder, deliver to the Holder the shares of Common Stock issuable upon conversion of the Unpaid Prepayment Principal Amount subject to such conversion demand and otherwise perform its obligations hereunder with respect thereto. (d) Except pursuant to this Section 12, the outstanding principal amount and interest under this Debenture shall not be subject to prepayment by the Company without the prior written consent of the Holder. 13. Fractional Shares. The Company shall not be required to issue or ----------------- cause to be issued fractional Underlying Shares on conversion of this Debenture. If any fraction of an Underlying Share would, except for the provisions of this Section, be issuable upon conversion of this Debenture, the number of Underlying Shares to be issued will be rounded up to the nearest whole share. 14. Notices. Any and all notices or other communications or deliveries ------- hereunder (including without limitation any Conversion Notice) shall be in writing and shall be deemed given and effective on the earliest of (i) the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section prior to 6:30 p.m. (New York City time) on a Trading Day, (ii) the next Trading Day after the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section on a day that is not a Trading Day or later than 6:30 p.m. (New York City time) on any Trading Day, (iii) the Trading Day following the date of mailing, if sent by nationally recognized overnight courier service, or (iv) upon actual receipt by the party to whom such notice is required to be given. The addresses for such communications shall be: (i) if to the Company, to the address set forth in the Purchase Agreement, or (ii) if to the Holder, to the address or facsimile number appearing on the Company's stockholder records or such other address or facsimile number as the Holder may provide to the Company in accordance with this Section. 15. Miscellaneous. ------------- -11-

(a) This Debenture shall be binding on and inure to the benefit of the parties hereto and their respective successors and assigns. This Debenture may be amended only in writing signed by the Company and the Holder and their successors and assigns. (b) Subject to Section 16(a), above, nothing in this Debenture ------------- shall be construed to give to any person or corporation other than the Company and the Holder any legal or equitable right, remedy or cause under this Debenture. This Debenture shall inure to the sole and exclusive benefit of the Company and the Holder. (c) Governing Law; Venue; Waiver of Jury Trial. All questions ------------------------------------------ concerning the construction, validity, enforcement and interpretation of this Debenture shall be governed by and construed and enforced in accordance with the internal laws of the State of New York, without regard to the principles of conflicts of law thereof. Each party hereto hereby irrevocably waives personal service of process and consents to process being served in any such Proceeding by mailing a copy thereof via registered or certified mail or overnight delivery (with evidence of delivery) to such party at the address in effect for notices to it under this Debenture and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by law. Each party hereto hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Debenture or the transactions contemplated hereby. If either party shall commence a Proceeding to enforce any provisions of this Debenture, then the prevailing party in such Proceeding shall be reimbursed by the other party for its reasonable attorneys fees and other costs and expenses incurred with the investigation, preparation and prosecution of such Proceeding. (d) The headings herein are for convenience only, do not constitute a part of this Debenture and shall not be deemed to limit or affect any of the provisions hereof. (e) In case any one or more of the provisions of this Debenture shall be invalid or unenforceable in any respect, the validity and enforceability of the remaining terms and provisions of this Debenture shall not in any way be affected or impaired thereby and the parties will attempt in good faith to agree upon a valid and enforceable provision which shall be a commercially reasonable substitute therefor, and upon so agreeing, shall incorporate such substitute provision in this Debenture. (f) No provision of this Debenture may be waived or amended except in a written instrument signed, in the case of an amendment, by the Company and the Holder or, or, in the case of a waiver, by the Holder. No waiver of any default with respect to any provision, condition or requirement of this Debenture shall be deemed to be a continuing waiver in the future or a waiver of any subsequent default or a waiver of any other provision, condition or requirement hereof, nor shall any delay or omission of either party to exercise any right hereunder in any manner impair the exercise of any such right. (g) In addition to being entitled to exercise all rights provided herein or granted by law, including recovery of damages, each Holder will be entitled to specific performance of the obligations of the Company hereunder. The parties hereto agree that -12-

monetary damages may not be adequate compensation for any loss incurred by reason of any breach of its obligations described herein and hereby agrees to waive in any action for specific performance of any such obligation the defense that a remedy at law would be adequate. [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK SIGNATURE PAGE FOLLOWS] -13-

IN WITNESS WHEREOF, the Company has caused this Debenture to be duly executed by a duly authorized officer as of the date first above indicated. QUESTCOR PHARMACEUTICALS, INC. By: /s/ Timothy E. Morris --------------------------- Name: Timothy E. Morris Title: Chief Financial Officer -14-

EXHIBIT A CONVERSION NOTICE The undersigned hereby elects to convert the principal amount of Debenture set forth below into shares of common stock, no par value per share (the "Common Stock"), of Questcor Pharmaceuticals, Inc. (the "Company") according to the conditions hereof, as of the date written below. If shares are to be issued in the name of a person other than the undersigned, the undersigned will pay all transfer taxes payable with respect thereto and is delivering herewith such certificates and opinions as reasonably requested by the Company in accordance therewith. No fee will be charged to the holder for any conversion, except for such transfer taxes, if any. Conversion calculations: ------------------------------------------------ Date to Effect Conversion ------------------------------------------------ Principal amount of Debentures owned prior to conversion ------------------------------------------------ Principal amount of Debentures to be Converted (including of interest added under Section 2(b) --------------- of the Debenture) ------------------------------------------------- Number of shares of Common Stock to be issued -------------------------------------------------- Applicable Conversion Price -------------------------------------------------- Principal amount of Debentures owned subsequent to Conversion -------------------------------------------------- Name of Holder By: ------------------------------------------------- Name: Title: [ ] By the delivery of this Notice of Conversion the undersigned represents and warrants to the Company that its ownership of the Common Stock does not exceed the amounts determined in accordance with Section 13(d) of the Exchange Act, specified under Section 12 of the Debenture.

Schedule 1 CONVERSION SCHEDULE ------------------- 8% Convertible Debentures in the aggregate principal amount of $2,000,000 issued by Questcor Pharmaceuticals, Inc. This Conversion Schedule reflects conversions made under the above referenced Debentures. Dated: - -------------------------------------------------------------------------------- Date of Conversion Aggregate Principal Aggregate Applicable Conversion Amount of Principal Price with Respect to Converted Amount of Debentures Debentures Debentures Remaining Subsequent to Conversion - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- -2-

EXHIBIT 4.4.3 REGISTRATION RIGHTS AGREEMENT This Registration Rights Agreement (this "Agreement") is made and --------- entered into as of March 15, 2002, by and between Questcor Pharmaceuticals, Inc. a California corporation (the "Company"), and Defiante Farmaceutica Unipessoal ------- L.D.A., a Portuguese company (the "Purchaser"). --------- This Agreement is made pursuant to the Securities Purchase Agreement, dated as of the date hereof among the Company and the Purchaser (the "Purchase -------- Agreement"). - --------- The Company and the Purchaser hereby agree as follows: 1. Definitions. Capitalized terms used and not otherwise defined ----------- herein that are defined in the Purchase Agreement shall have the meanings given such terms in the Purchase Agreement. As used in this Agreement, the following terms shall have the following meanings: "Debentures" means the 8% Convertible Debentures issued to the ---------- Purchaser in accordance with the Purchase Agreement. "Effectiveness Date" means the earlier of (a) the 90th day following ------------------ the Closing Date (or the 120th day if the Commission notifies the Company that it will be subject to a second comment letter) and (b) the fifth Trading Day following the date on which the Company is notified by the Commission that such Registration Statement will not be reviewed or is no longer subject to further review and comments. "Effectiveness Period" shall have the meaning set forth in Section -------------------- 2(a). "Filing Date" means, with respect to the initial Registration ----------- Statement required to be filed hereunder, the 30th day following the Closing Date. "Holder" or "Holders" means the holder or holders, as the case may be, ------ ------- from time to time of Registrable Securities. "Indemnified Party" shall have the meaning set forth in Section 5(c). ----------------- "Indemnifying Party" shall have the meaning set forth in Section 5(c). ------------------ "Losses" shall have the meaning set forth in Section 5(a). ------ "Proceeding" means an action, claim, suit, investigation or proceeding ---------- (including, without limitation, an investigation or partial proceeding, such as a deposition), whether commenced or threatened. "Prospectus" means the prospectus included in a Registration Statement ---------- (including, without limitation, a prospectus that includes any information previously omitted from a prospectus filed as part of an effective registration statement in reliance upon Rule 430A promulgated under the Securities Act), as amended or supplemented by any prospectus

supplement, with respect to the terms of the offering of any portion of the Registrable Securities covered by the Registration Statement, and all other amendments and supplements to the Prospectus, including post-effective amendments, and all material incorporated by reference or deemed to be incorporated by reference in such Prospectus. "Registrable Securities" means the shares of Common Stock issuable ---------------------- upon: (i) conversion of the Debentures and (ii) exercise of the Warrants. "Registration Statement" means the initial registration statement ---------------------- required to be filed hereunder and any additional registration statements contemplated by Section 2(d), including (in each case) the Prospectus, ------------ amendments and supplements to such registration statement or Prospectus, including pre- and post-effective amendments, all exhibits thereto, and all material incorporated by reference or deemed to be incorporated by reference in such registration statement. "Rule 144" means Rule 144 promulgated by the Commission pursuant to -------- the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. "Rule 415" means Rule 415 promulgated by the Commission pursuant to -------- the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. "Rule 424" means Rule 424 promulgated by the Commission pursuant to -------- the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule. "Warrants" means the Common Stock purchase warrants issued under the -------- Purchase Agreement. 2. Registration. ------------ (a) On or prior to the Filing Date, the Company shall prepare and file with the Commission a Registration Statement covering the resale of not less than 2,025,316 Registrable Securities for an offering to be made on a continuous basis pursuant to Rule 415. The Registration Statement shall be on Form S-3 (except if the Company is not then eligible to register for resale the Registrable Securities on Form S-3, in which case such registration shall be on another appropriate form in accordance herewith) and shall contain (except if otherwise required by the Commission) the "Plan of Distribution" attached hereto -------------------- as Annex A. The Company shall use commercially reasonable efforts to cause the ------- Registration Statement to become effective and remain effective as provided herein. The Company shall use commercially reasonable efforts to cause the Registration Statement to be declared effective under the Securities Act as promptly as possible after the filing thereof, but in any event prior to its Effectiveness Date, and shall use commercially reasonable efforts to keep the Registration Statement continuously effective under the Securities Act until the date which is the earlier date when all Registrable Securities covered by such Registration Statement have been sold or may be sold without volume restrictions pursuant to Rule 144(k) as determined by the counsel to the -2-

Company pursuant to a written opinion letter to such effect, addressed and acceptable to the Company's transfer agent and the affected Holders (the "Effectiveness Period"). - --------------------- (b) The Company shall give written notice to the Holders of the Registrable Securities (which notice pursuant to clauses (ii)-(v) hereof shall be accompanied by an instruction to suspend the use of the Prospectus pursuant to the terms of Section 2(b)(v) and is referred to herein as a "Deferral Notice"): (i) when the Registration Statement or any amendment thereto has been filed with the Commission and when the Registration Statement or any post-effective amendment thereto has become effective; (ii) of any request by the Commission for amendments or supplements to the Registration Statement or the prospectus included therein or for additional information; (iii) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or the initiation of any proceedings for that purpose; (iv) of the receipt by the Company or its legal counsel of any notification with respect to the suspension of the qualification of the Registrable Securities for sale in any jurisdiction; and (v) of (A) the happening of any event that requires the Company to make changes in the Registration Statement or the Prospectus in order that the Registration Statement or the Prospectus does not contain an untrue statement of a material fact nor omit to state a material fact required to be stated therein or necessary to make the statements therein (in the case of the Prospectus, in light of the circumstances under which they were made) not misleading, or (B) the occurrence or existence of any pending corporate development, public filing with the Commission or other similar event with respect to the Company that, in the reasonable discretion of the Company, makes it necessary to suspend the availability of a Registration Statement and the related Prospectus. The Company shall be entitled to exercise its right to deliver a Deferral Notice under this Section 2(b) to suspend the availability of the Registration Statement or any prospectus, without incurring or accruing any obligation to pay liquidated damages pursuant to Section 2(c) (except for a Deferral Notice pursuant to Section 2(b)(v)(B) for which the Company shall remain obligated to pay liquidated damages), for one or more periods not to exceed ten (10) consecutive days in any 120-day period, and not to exceed, in the aggregate, thirty (30) days in any 365-day period (such period during which the availability of the Registration Statement and any prospectus is suspended being a "Deferral Period"). (c) If: (a) any Registration Statement is not filed on or prior to the Filing Date or (b) a Registration Statement filed hereunder is not declared effective by the Commission by the Effectiveness Date, or (c) after a Registration Statement is filed with and -3-

declared effective by the Commission, such Registration Statement ceases to be effective as to all Registrable Securities to which it is required to relate at any time prior to the expiration of the Effectiveness Period without being succeeded within fifteen Trading Days by an amendment to such Registration Statement or by a subsequent Registration Statement filed with and declared effective by the Commission or (d) the Common Stock is not listed or quoted, or is suspended from trading on the American Stock Exchange for a period of two consecutive Trading Days (any such failure or breach being referred to as an "Event," and for purposes of clause (a) or (b) the date on which such Event ----- occurs, or for purposes of clause (c) the date which such fifteen Trading Day-period is exceeded, being referred to as "Event Date"), then beginning on ---------- each such Event Date the Company shall pay to each Holder an amount in cash, as liquidated damages and not as a penalty, equal to 1.00% per 30 day period of the aggregate principal amount of the Debenture held by such Holder pursuant to the Purchase Agreement, which shall accrue on a daily basis until the applicable Event shall have been cured, during the first 90 day period, and increasing to 2.00% per 30 day period thereafter, of the aggregate principal amount of the Debenture held by such Holder pursuant to the Purchase Agreement, which shall accrue on a daily basis until the applicable Event shall have been cured. Notwithstanding the foregoing, an Event Date shall be deemed not to have occurred and be continuing in relation to the Registration Statement or the related Prospectus if the Company has delivered a Deferral Notice pursuant to Section 2(b) of this Agreement and the Deferral Period shall not have extended past the periods permitted by Section 2(b)(v). If the Company fails to pay any liquidated damages pursuant to this Section in full within seven days after the date payable, the Company will pay interest thereon at a rate of 18% per annum (or such lesser maximum amount that is permitted to be paid by applicable law) to the Holder, accruing daily from the date such liquidated damages are due until such amounts, plus all such interest thereon, are paid in full. 3. Registration Procedures ----------------------- In connection with the Company's registration obligations hereunder, the Company shall: (a) Not less than two Trading Days prior to the filing of the Registration Statement or any related Prospectus or any amendment or supplement thereto, the Company shall, (i) furnish to the Holders copies of all such documents proposed to be filed (including documents incorporated or deemed incorporated by reference) which documents will be subject to the review of such Holders, and (ii) cause its officers and directors, counsel and independent certified public accountants to respond to such inquiries from Holders as shall be necessary, in the reasonable opinion of respective counsel to enable the Holder to conduct a reasonable investigation within the meaning of the Securities Act. (b) (i) Prepare and file with the Commission such amendments, including post-effective amendments, to the Registration Statement and the Prospectus used in connection therewith as may be necessary to keep the Registration Statement continuously effective as to the applicable Registrable Securities for the Effectiveness Period and prepare and file with the Commission such additional Registration Statements in order to register for resale under the Securities Act all of the Registrable Securities; (ii) cause the related Prospectus to be amended or supplemented by any required Prospectus supplement, and as so supplemented or amended to be filed pursuant to Rule 424; (iii) respond as promptly as reasonably possible, and -4-

under the Securities Act) or their then equivalents relating to equity securities to be issued solely in connection with any acquisition of any entity or business or equity securities issuable in connection with stock option or other employee benefit plans, then the Company shall send to each Holder written notice of such determination and, if within fifteen days after receipt of such notice, any such Holder shall so request in writing, the Company shall include in such registration statement all or any part of such Registrable Securities such holder requests to be registered, subject to customary underwriter cutbacks applicable to all holders of registration rights. (f) Amendments and Waivers. The provisions of this Agreement, ---------------------- including the provisions of this sentence, may not be amended, modified or supplemented, and waivers or consents to departures from the provisions hereof may not be given, unless the same shall be in writing and signed by the Company and a majority of the Holders of the then outstanding Registrable Securities. Notwithstanding the foregoing, a waiver or consent to depart from the provisions hereof with respect to a matter that relates exclusively to the rights of certain Holders and that does not directly or indirectly affect the rights of other Holders may be given by Holders of at least a majority of the Registrable Securities to which such waiver or consent relates; provided, however, that the -------- ------- provisions of this sentence may not be amended, modified, or supplemented except in accordance with the provisions of the immediately preceding sentence. (g) Notices. Any and all notices or other communications or ------- deliveries required or permitted to be provided hereunder shall be in writing and shall be deemed given and effective on the earliest of (i) the date of transmission, if such notice or communication is delivered via facsimile at the facsimile telephone number specified in this Section prior to 6:30 p.m. (New York City time) on a Trading Day, (ii) the Trading Day after the date of transmission, if such notice or communication is delivered via facsimile at the facsimile telephone number specified in this Agreement later than 6:30 p.m. (New York City time) on any date and earlier than 11:59 p.m. (New York City time) on such date, (iii) the Trading Day following the date of mailing, if sent by nationally recognized overnight courier service, or (iv) upon actual receipt by the party to whom such notice is required to be given. The address for such notices and communications shall be as follows: If to the Company: Questcor Pharmaceuticals, Inc. Attention: President 3620 Whipple Road Union City, California 94587 Fax: 510-400-0799 If to the Purchaser: Defiante Farmaceutica Unipessoal L.D.A. Rua dos Ferreiros, 260 Funchal- Madeira (Portogallo) 9000-082 Attn: Mr. Pedro Quintas With copy to: -11-

Attn: Mr. Antonio Nicolai c/o Via Sudafrica, 20 00144 - Rome (Italy) Fax: 0039.06.54229457 If to any other Person who is then the registered Holder: To the address of such Holder as it appears in the stock transfer books of the Company or such other address as may be designated in writing hereafter, in the same manner, by such Person. (h) Successors and Assigns. This Agreement shall inure to the ---------------------- benefit of and be binding upon the successors and permitted assigns of each of the parties and shall inure to the benefit of each Holder. The Company may not assign its rights or obligations hereunder without the prior written consent of each Holder. Each Holder may assign their respective rights hereunder in the manner and to the Persons as permitted under the Purchase Agreement. (i) Execution and Counterparts. This Agreement may be executed in -------------------------- any number of counterparts, each of which when so executed shall be deemed to be an original and, all of which taken together shall constitute one and the same Agreement. In the event that any signature is delivered by facsimile transmission, such signature shall create a valid binding obligation of the party executing (or on whose behalf such signature is executed) the same with the same force and effect as if such facsimile signature were the original thereof. (j) Governing Law. All questions concerning the construction, ------------- validity, enforcement and interpretation of this Agreement shall be governed by and construed and enforced in accordance with the internal laws of the State of New York, without regard to the principles of conflicts of law thereof. Each party hereto hereby irrevocably waives personal service of process and consents to process being served in any such Proceeding by mailing a copy thereof via registered or certified mail or overnight delivery (with evidence of delivery) to such party at the address in effect for notices to it under this Agreement and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by law. Each party hereto hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Agreement or the transactions contemplated hereby. If either party shall commence a Proceeding to enforce any provisions of a Transaction Document, then the prevailing party in such Proceeding shall be reimbursed by the other party for its reasonable attorneys fees and other costs and expenses incurred with the investigation, preparation and prosecution of such Proceeding. (k) Cumulative Remedies. The remedies provided herein are ------------------- cumulative and not exclusive of any remedies provided by law. -12-

(l) Severability. If any term, provision, covenant or restriction ------------ of this Agreement is held by a court of competent jurisdiction to be invalid, illegal, void or unenforceable, the remainder of the terms, provisions, covenants and restrictions set forth herein shall remain in full force and effect and shall in no way be affected, impaired or invalidated, and the parties hereto shall use their reasonable efforts to find and employ an alternative means to achieve the same or substantially the same result as that contemplated by such term, provision, covenant or restriction. It is hereby stipulated and declared to be the intention of the parties that they would have executed the remaining terms, provisions, covenants and restrictions without including any of such that may be hereafter declared invalid, illegal, void or unenforceable. (m) Headings. The headings in this Agreement are for convenience -------- of reference only and shall not limit or otherwise affect the meaning hereof. (n) Independent Nature of Purchaser's Obligations and Rights. -------------------------------------------------------- Nothing contained herein or in any other agreement or document delivered at any closing, and no action taken by the Purchaser pursuant hereto or thereto, shall be deemed to constitute the Purchasers as a partnership, an association, a joint venture or any other kind of entity with any other party, or create a presumption that the Purchaser is in any way acting in concert with any third party with respect to such obligations or the transactions contemplated by this Agreement. [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK SIGNATURE PAGE TO FOLLOW] -13-

IN WITNESS WHEREOF, the parties have executed this Registration Rights Agreement as of the date first written above. QUESTCOR PHARMACEUTICALS, INC. By: /s/ Timothy E. Morris --------------------------------- Name: Timothy E. Morris Title: Chief Financial Officer DEFIANTE FARMACEUTICA UNIPESSOAL L.D.A. By: /s/ Antonio Nicolai --------------------------------- Name: Mr. Antonio Nicolai Title: Director -14-

Annex A - ------- Plan of Distribution - -------------------- The selling stockholders and any of their pledgees, assignees and successors-in-interest may, from time to time, sell any or all of their shares of common stock on any stock exchange, market or trading facility on which the shares are traded or in private transactions. These sales may be at fixed or negotiated prices. The selling stockholders may use any one or more of the following methods when selling shares: . ordinary brokerage transactions and transactions in which the broker-dealer solicits purchasers; . block trades in which the broker-dealer will attempt to sell the shares as agent but may position and resell a portion of the block as principal to facilitate the transaction; . purchases by a broker-dealer as principal and resale by the broker-dealer for its account; . an exchange distribution in accordance with the rules of the applicable exchange; . privately negotiated transactions; . short sales . broker-dealers may agree with the selling stockholders to sell a specified number of such shares at a stipulated price per share; . a combination of any such methods of sale; and . any other method permitted pursuant to applicable law. The selling stockholders may also sell shares under Rule 144 under the Securities Act, if available, rather than under this prospectus. Broker-dealers engaged by the selling stockholders may arrange for other brokers-dealers to participate in sales. Broker-dealers may receive commissions or discounts from the selling stockholders (or, if any broker-dealer acts as agent for the purchaser of shares, from the purchaser) in amounts to be negotiated. The selling stockholders do not expect these commissions and discounts to exceed what is customary in the types of transactions involved. The selling stockholders may from time to time pledge or grant a security interest in some or all of the shares of common stock or Warrants owned by them and, if they default in the performance of their secured obligations, the pledgees or secured parties may offer and sell the shares of common stock from time to time under this prospectus, or under an amendment to this prospectus under Rule 424(b)(3) or other applicable provision of the Securities Act of 1933 amending the list of selling stockholders to include the pledgee, transferee or other successors in interest as selling stockholders under this prospectus.

EXHIBIT 4.4.4 NEITHER THESE SECURITIES NOR THE SECURITIES INTO WHICH THESE SECURITIES ARE EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO THE TRANSFEROR TO SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY ACCEPTABLE TO THE COMPANY. THESE SECURITIES AND THE SECURITIES ISSUABLE UPON EXERCISE OF THESE SECURITIES MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER LOAN SECURED BY SUCH SECURITIES. QUESTCOR PHARMACEUTICALS, INC. WARRANT ------- Warrant No. 1 Date of Original Issuance: March 15, 2002 Questcor Pharmaceuticals, Inc., a California corporation (the "Company"), hereby certifies that, for value received, Defiante Farmaceutica Unipessoal L.D.A., or its registered assigns (the "Holder"), is entitled to purchase from the Company up to a total of 759,493 shares of common stock, no par value per share (the "Common Stock"), of the Company (each such share, a "Warrant Share" and all such shares, the "Warrant Shares") at an exercise price (as adjusted from time to time as provided in Section 9, the "Exercise Price") per Warrant Share equal to $1.70, at any time and from time to time from and after the date hereof and through and including March 15, 2006 (the "Expiration Date"), and subject to the following terms and conditions: 1. Definitions. In addition to the terms defined elsewhere in this Warrant, ----------- capitalized terms that are not otherwise defined herein and that are defined in the Securities Purchase Agreement, dated as of March 15, 2002, between the Company and the original Holder (the "Purchase Agreement"), shall have the meanings given to such terms in the Purchase Agreement. 2. Registration of Warrant. The Company shall register this Warrant, upon ----------------------- records to be maintained by the Company for that purpose (the "Warrant Register"), in the name of the record Holder hereof from time to time. The Company may deem and treat the registered Holder of this Warrant as the absolute owner hereof for the purpose of any exercise hereof or any distribution to the Holder, and for all other purposes, absent actual notice to the contrary.

3. Registration of Transfers. The Company shall register the transfer of ------------------------- any portion of this Warrant in the Warrant Register, upon surrender of this Warrant, with the Form of Assignment attached hereto duly completed and signed, to the Transfer Agent or to the Company at its address specified herein. Upon any such registration or transfer, a new warrant to purchase Common Stock, in substantially the form of this Warrant (any such new warrant, a "New Warrant"), evidencing the portion of this Warrant so transferred shall be issued to the transferee and a New Warrant evidencing the remaining portion of this Warrant not so transferred, if any, shall be issued to the transferring Holder. The acceptance of the New Warrant by the transferee thereof shall be deemed the acceptance by such transferee of all of the rights and obligations of a holder of a Warrant. 4. Exercise and Duration. This Warrant shall be exercisable by the --------------------- registered Holder at any time and from time to time on or after the date hereof to and including the Expiration Date. At 6:30 p.m., New York City time on the Expiration Date, the portion of this Warrant available for exercise and not exercised prior thereto shall be and become void and of no value. 5. Delivery of Warrant Shares. -------------------------- (a) Upon delivery of the Form of Election to Purchase to the Company (with the attached Warrant Shares Exercise Log) at its address for notice set forth in Section 13 and upon payment of the Exercise Price multiplied by the number of Warrant Shares that the Holder intends to purchase hereunder, the Company shall promptly (but in no event later than three Trading Days after the Date of Exercise (as defined herein)) issue and deliver to the Holder, a certificate for the Warrant Shares issuable upon such exercise free of restrictive legends unless otherwise required by the Purchase Agreement. The Company shall, upon request of the Holder, if available, use its best efforts to deliver Warrant Shares hereunder electronically through the Depository Trust Corporation or another established clearing corporation performing similar functions, provided, that, the Company may, but will not be required to change its transfer agent if its current transfer agent cannot deliver Warrant Shares electronically through the Depository Trust Corporation. A "Date of Exercise" means the date on which the Holder shall have delivered to the Company (i) the Form of Election to Purchase attached hereto (with the Warrant Exercise Log attached to it), appropriately completed and duly signed and (ii) payment of the Exercise Price for the number of Warrant Shares so indicated by the Holder to be purchased. (b) If by the fifth Trading Day after a Date of Exercise the Company fails to deliver the required number of Warrant Shares in the manner required pursuant to Section 5(a), then the Holder will have the right to rescind such exercise. (c) If by the fifth Trading Day after a Date of Exercise the Company fails to deliver the required number of Warrant Shares in the manner required pursuant to Section 5(a), and if after such fifth Trading Day the Holder purchases (in an open market transaction or otherwise) shares of Common Stock to deliver in satisfaction of a sale by the Holder of the Warrant Shares which the Holder anticipated receiving upon such exercise (a "Buy-In"), then the Company shall (1) pay in cash to the Holder the amount by which (x) the Holder's total purchase -2-

without limitation any granting of rights or warrants to subscribe for or purchase any capital stock of the Company or any Subsidiary, (ii) authorizes or approves, enters into any agreement contemplating or solicits stockholder approval for any Fundamental Transaction or (iii) authorizes the voluntary dissolution, liquidation or winding up of the affairs of the Company, then the Company shall deliver to the Holder a notice describing the material terms and conditions of such transaction, at least twenty (20) calendar days prior to the applicable record or effective date on which a Person would need to hold Common Stock in order to participate in or vote with respect to such transaction, and the Company will take all steps reasonably necessary in order to insure that the Holder is given the practical opportunity to exercise this Warrant prior to such time so as to participate in or vote with respect to such transaction; provided, however, that the failure to deliver such notice or any defect therein shall not affect the validity of the corporate action required to be described in such notice. 10. Payment of Exercise Price. The Holder shall pay the Exercise Price in ------------------------- one of the following manners: (a) Cash Exercise. The Holder may deliver immediately available funds; ------------- or (b) Cashless Exercise. The Holder may satisfy its obligation to pay ----------------- the Exercise Price through a "cashless exercise" in which event the Company shall issue to the Holder the number of Warrant Shares determined as follows: X = Y [(A-B)/A] where: X = the number of Warrant Shares to be issued to the Holder. Y = the number of Warrant Shares with respect to which this Warrant is being exercised. A = the average of the Closing Prices for the five Trading Days immediately prior to (but not including) the Exercise Date. B = the Exercise Price. For purposes of Rule 144 promulgated under the Securities Act, it is intended, understood and acknowledged that the Warrant Shares issued in a cashless exercise transaction shall be deemed to have been acquired by the Holder, and the holding period for the Warrant Shares shall be deemed to have commenced, on the date this Warrant was originally issued pursuant to the Purchase Agreement. 11. No Fractional Shares. No fractional shares of Warrant Shares will be -------------------- issued in connection with any exercise of this Warrant. In lieu of any fractional shares which would, otherwise be issuable, the Company shall pay cash equal to the product of such fraction multiplied by the Closing Price of one Warrant Share as reported on the Eligible Market on the date of exercise. 12. Notices. Any and all notices or other communications or deliveries ------- hereunder (including without limitation any Exercise Notice) shall be in writing and shall be deemed given -6-

and effective on the earliest of (i) the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section prior to 6:30 p.m. (New York City time) on a Trading Day, (ii) the next Trading Day after the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section on a day that is not a Trading Day or later than 6:30 p.m. (New York City time) on any Trading Day, (iii) the Trading Day following the date of mailing, if sent by nationally recognized overnight courier service, or (iv) upon actual receipt by the party to whom such notice is required to be given. The addresses for such communications shall be: (i) if to the Company, to Questcor Pharmaceuticals, Inc., Attention: President, 3620 Whipple Road, Union City, California 94587 or (ii) if to the Holder, to the address or facsimile number appearing on the Warrant Register or such other address or facsimile number as the Holder may provide to the Company in accordance with this Section. 13. Warrant Agent. The Company shall serve as warrant agent under this ------------- Warrant. Upon 30 days' notice to the Holder, the Company may appoint a new warrant agent. Any corporation into which the Company or any new warrant agent may be merged or any corporation resulting from any consolidation to which the Company or any new warrant agent shall be a party or any corporation to which the Company or any new warrant agent transfers substantially all of its corporate trust or shareholders services business shall be a successor warrant agent under this Warrant without any further act. Any such successor warrant agent shall promptly cause notice of its succession as warrant agent to be mailed (by first class mail, postage prepaid) to the Holder at the Holder's last address as shown on the Warrant Register. 14. Miscellaneous. ------------- (a) This Warrant shall be binding on and inure to the benefit of the parties hereto and their respective successors and assigns. Subject to the preceding sentence, nothing in this Warrant shall be construed to give to any Person other than the Company and the Holder any legal or equitable right, remedy or cause of action under this Warrant. This Warrant may be amended only in writing signed by the Company and the Holder and their successors and assigns. (b) All questions concerning the construction, validity, enforcement and interpretation of this Warrant shall be governed by and construed and enforced in accordance with the internal laws of the State of New York, without regard to the principles of conflicts of law thereof. Each party hereto hereby irrevocably waives personal service of process and consents to process being served in any such suit, action or proceeding by mailing a copy thereof via registered or certified mail or overnight delivery (with evidence of delivery) to such party at the address in effect for notices to it under this Warrant and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by law. Each party hereto (including its affiliates, agents, officers, directors and employees) hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Warrant or the transactions contemplated hereby. If either party shall commence an action or proceeding to enforce any provisions of this Warrant, then the prevailing party in such action or proceeding shall be -7-

reimbursed by the other party for its reasonable attorneys fees and other costs and expenses incurred with the investigation, preparation and prosecution of such action or proceeding. (c) The headings herein are for convenience only, do not constitute a part of this Warrant and shall not be deemed to limit or affect any of the provisions hereof. (d) In case any one or more of the provisions of this Warrant shall be invalid or unenforceable in any respect, the validity and enforceability of the remaining terms and provisions of this Warrant shall not in any way be affected or impaired thereby and the parties will attempt in good faith to agree upon a valid and enforceable provision which shall be a commercially reasonable substitute therefor, and upon so agreeing, shall incorporate such substitute provision in this Warrant. [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK, SIGNATURE PAGE FOLLOWS] -8-

FORM OF ELECTION TO PURCHASE To Questcor Pharmaceuticals, Inc.: In accordance with Warrant No. [ ] issued to the undersigned, the undersigned hereby elects to purchase shares of common stock ------------- ("Common Stock"), no par value per share, of Questcor Pharmaceuticals, Inc. and, if such Holder is not utilizing the cashless exercise provisions set forth in this Warrant, encloses herewith $ in cash, certified or official bank -------- check or checks, which sum represents the aggregate Exercise Price (as defined in the Warrant) for the number of shares of Common Stock to which this Form of Election to Purchase relates. By its delivery of this Form of Election To Purchase, the Holder represents and warrants to the Company that in giving effect to the exercise evidenced hereby the Holder will not beneficially own in excess of the number of shares of Common Stock (determined in accordance with Section 13(d) of the Securities Exchange Act of 1934) permitted to be owned under Section 11of this Warrant to which this notice relates. The undersigned requests that certificates for the shares of Common Stock issuable upon this exercise be issued in the name of SOCIAL SECURITY OR TAX IDENTIFICATION NUMBER: --------------------------- NAME AND ADDRESS: ------------------------ ------------------------------- -------------------------------

Warrant Shares Exercise Log --------------------------- - ----------------------------------------------------------------------------------------------------------------- Date Number of Warrant Shares Number of Warrant Shares Number of Warrant Shares Available to be Exercised Exercised Remaining to be Exercised - ----------------------------------------------------------------------------------------------------------------- - -----------------------------------------------------------------------------------------------------------------

FORM OF ASSIGNMENT [To be completed and signed only upon transfer of Warrant] FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers unto the right represented by the -------------------------------- within Warrant to purchase shares of Common Stock of Questcor ------------ Pharmaceuticals, Inc. to which the within Warrant relates and appoints attorney to transfer said right on the books of Questcor - ---------------- Pharmaceuticals, Inc. with full power of substitution in the premises. Dated: , --------------- ---- ------------------------------------------- (Signature must conform in all respects to name of holder as specified on the face of the Warrant) ------------------------------------------- Address of Transferee ------------------------------------------- ------------------------------------------- In the presence of: - ---------------------------------

EXHIBIT 4.5 NEITHER THESE SECURITIES NOR THE SECURITIES INTO WHICH THESE SECURITIES ARE EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO THE TRANSFEROR TO SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY ACCEPTABLE TO THE COMPANY. THESE SECURITIES AND THE SECURITIES ISSUABLE UPON EXERCISE OF THESE SECURITIES MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER LOAN SECURED BY SUCH SECURITIES. QUESTCOR PHARMACEUTICALS, INC. WARRANT ------- Warrant No. Date of Original Issuance: March 15, 2002 --- Questcor Pharmaceuticals, Inc., a California corporation (the "Company"), hereby certifies that, for value received, Robert Schacter or his registered assigns (the "Holder"), is entitled to purchase from the Company up to a total of 57,000 shares of common stock, no par value per share (the "Common Stock"), of the Company (each such share, a "Warrant Share" and all such shares, the "Warrant Shares") at an exercise price (as adjusted from time to time as provided in Section 9, the "Exercise Price") per Warrant Share equal to $1.70, at any time and from time to time from and after the date hereof and through and including March 15, 2006 (the "Expiration Date"), and subject to the following terms and conditions: 1. Definitions. In addition to the terms defined elsewhere in this Warrant, ----------- capitalized terms that are not otherwise defined herein and that are defined in that certain Securities Purchase Agreement, dated as of March 15, 2002, between the Company and SF Capital Partners Ltd. (the "Purchase Agreement"), shall have the meanings given to such terms in the Purchase Agreement. 2. Registration of Warrant. The Company shall register this Warrant, upon ----------------------- records to be maintained by the Company for that purpose (the "Warrant Register"), in the name of the record Holder hereof from time to time. The Company may deem and treat the registered Holder of this Warrant as the absolute owner hereof for the purpose of any exercise hereof or any distribution to the Holder, and for all other purposes, absent actual notice to the contrary.

price (including brokerage commissions, if any) for the shares of Common Stock so purchased exceeds (y) the amount obtained by multiplying (A) the number of Warrant Shares that the Company was required to deliver to the Holder in connection with the exercise at issue by (B) the Closing Price of the Common Stock at the time of the obligation giving rise to such purchase obligation and (2) at the option of the Holder, either reinstate the portion of the Warrant and equivalent number of Warrant Shares for which such exercise was not honored or deliver to the Holder the number of shares of Common Stock that would have been issued had the Company timely complied with its exercise and delivery obligations hereunder. For example, if the Holder purchases Common Stock having a total purchase price of $11,000 to cover a Buy-In with respect to an attempted exercise of shares of Common Stock with a market price on the date of exercise totaled $10,000, under clause (1) of the immediately preceding sentence the Company shall be required to pay the Holder $1,000. The Holder shall provide the Company written notice, which written notice shall include such supporting documentation as reasonably necessary to substantiate the amounts payable, indicating the amounts payable to the Holder in respect of the Buy-In. (d) The Company's obligations to issue and deliver Warrant Shares in accordance with the terms hereof are absolute and unconditional, irrespective of any action or inaction by the Holder to enforce the same, any waiver or consent with respect to any provision hereof, the recovery of any judgment against any Person or any action to enforce the same, or any setoff, counterclaim, recoupment, limitation or termination, or any breach or alleged breach by the Holder or any other Person of any obligation to the Company or any violation or alleged violation of law by the Holder or any other Person, and irrespective of any other circumstance which might otherwise limit such obligation of the Company to the Holder in connection with the issuance of Warrant Shares. Nothing herein shall limit a Holder's right to pursue any other remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific performance and/or injunctive relief with respect to the Company's failure to timely deliver certificates representing shares of Common Stock upon exercise of the Warrant as required pursuant to the terms hereof. 6. Charges, Taxes and Expenses. Issuance and delivery of certificates for ---------------------------- shares of Common Stock upon exercise of this Warrant shall be made without charge to the Holder for any issue or transfer tax, withholding tax, transfer agent fee or other incidental tax or expense in respect of the issuance of such certificates, all of which taxes and expenses shall be paid by the Company; provided, however, that the Company shall not be required to pay any tax which may be payable in respect of any transfer involved in the registration of any certificates for Warrant Shares or Warrants in a name other than that of the Holder. The Holder shall be responsible for all other tax liability that may arise as a result of holding or transferring this Warrant or receiving Warrant Shares upon exercise hereof. 7. Replacement of Warrant. If this Warrant is mutilated, lost, stolen or ---------------------- destroyed, the Company shall issue or cause to be issued in exchange and substitution for and upon cancellation hereof, or in lieu of and substitution for this Warrant, a New Warrant, but only upon receipt of evidence reasonably satisfactory to the Company of such loss, theft or destruction and customary and reasonable indemnity, if requested. Applicants for a New Warrant under such circumstances shall also comply with such other reasonable regulations and procedures and pay such other reasonable third-party costs as the Company may prescribe. -3-

8. Reservation of Warrant Shares. The Company covenants that it will at all ----------------------------- times reserve and keep available out of the aggregate of its authorized but unissued and otherwise unreserved Common Stock, solely for the purpose of enabling it to issue Warrant Shares upon exercise of this Warrant as herein provided, the number of Warrant Shares which are then issuable and deliverable upon the exercise of this entire Warrant. The Company covenants that all Warrant Shares so issuable and deliverable shall, upon issuance and the payment of the applicable Exercise Price in accordance with the terms hereof, be duly and validly authorized, issued and fully paid and nonassessable. 9. Certain Adjustments. The Exercise Price and number of Warrant Shares ------------------ issuable upon exercise of this Warrant are subject to adjustment from time to time as set forth in this Section 9. (a) Stock Dividends and Splits. If the Company, at any time while this -------------------------- Warrant is outstanding, (i) pays a stock dividend on its Common Stock or otherwise makes a distribution on any class of capital stock that is payable in shares of Common Stock, (ii) subdivides outstanding shares of Common Stock into a larger number of shares, or (iii) combines outstanding shares of Common Stock into a smaller number of shares, then in each such case the Exercise Price shall be multiplied by a fraction of which the numerator shall be the number of shares of Common Stock outstanding immediately before such event and of which the denominator shall be the number of shares of Common Stock outstanding immediately after such event. (b) Pro Rata Distributions. If the Company, at any time while this ---------------------- Warrant is outstanding, distributes to all holders of Common Stock (i) evidences of its indebtedness, (ii) any security (other than a distribution of Common Stock covered by the preceding paragraph), (iii) rights or warrants to subscribe for or purchase any security, or (iv) any other asset (in each case, "Distributed Property"), then, at the request of any Holder delivered before the 90th day after the record date fixed for determination of stockholders entitled to receive such distribution, the Company will deliver to such Holder, within five Trading Days after such request (or, if later, on the effective date of such distribution), the Distributed Property that such Holder would have been entitled to receive in respect of the Warrant Shares for which such Holder's Warrant could have been exercised immediately prior to such record date. If such Distributed Property is not delivered to a Holder pursuant to the preceding sentence, then upon any exercise of the Warrant that occurs after such record date, such Holder shall be entitled to receive, in addition to the Warrant Shares otherwise issuable upon such conversion, the Distributed Property that such Holder would have been entitled to receive in respect of such number of Warrant Shares had the Holder been the record holder of such Warrant Shares immediately prior to such record date. (c) Fundamental Transactions. If, at any time while this Warrant is ------------------------ outstanding: (i) the Company effects any merger or consolidation of the Company with or into another Person, (ii) the Company effects any sale of all or substantially all of its assets in one or a series of related transactions, (iii) any tender offer or exchange offer (whether by the Company or another Person) is completed pursuant to which holders of Common Stock are permitted to tender or exchange their shares for other securities, cash or property, or (iv) the Company effects any reclassification of the Common Stock or any compulsory share exchange pursuant to which the Common Stock is effectively converted into or exchanged for other securities, cash or -4-

without limitation any granting of rights or warrants to subscribe for or purchase any capital stock of the Company or any Subsidiary, (ii) authorizes or approves, enters into any agreement contemplating or solicits stockholder approval for any Fundamental Transaction or (iii) authorizes the voluntary dissolution, liquidation or winding up of the affairs of the Company, then the Company shall deliver to the Holder a notice describing the material terms and conditions of such transaction, at least twenty (20) calendar days prior to the applicable record or effective date on which a Person would need to hold Common Stock in order to participate in or vote with respect to such transaction, and the Company will take all steps reasonably necessary in order to insure that the Holder is given the practical opportunity to exercise this Warrant prior to such time so as to participate in or vote with respect to such transaction; provided, however, that the failure to deliver such notice or any defect therein shall not affect the validity of the corporate action required to be described in such notice. 10. Payment of Exercise Price. The Holder shall pay the Exercise Price in ------------------------- one of the following manners: (a) Cash Exercise. The Holder may deliver immediately available funds; ------------- or (b) Cashless Exercise. The Holder may satisfy its obligation to pay ----------------- the Exercise Price through a "cashless exercise" in which event the Company shall issue to the Holder the number of Warrant Shares determined as follows: X = Y [(A-B)/A] where: X = the number of Warrant Shares to be issued to the Holder. Y = the number of Warrant Shares with respect to which this Warrant is being exercised. A = the average of the Closing Prices for the five Trading Days immediately prior to (but not including) the Exercise Date. B = the Exercise Price. For purposes of Rule 144 promulgated under the Securities Act, it is intended, understood and acknowledged that the Warrant Shares issued in a cashless exercise transaction shall be deemed to have been acquired by the Holder, and the holding period for the Warrant Shares shall be deemed to have commenced, on the date this Warrant was originally issued pursuant to the Purchase Agreement. 11. Limitation on Exercise. (a) Notwithstanding anything to the contrary ---------------------- contained herein, the number of shares of Common Stock that may be acquired by the Holder upon any exercise of this Warrant (or otherwise in respect hereof) shall be limited to the extent necessary to insure that, following such exercise (or other issuance), the total number of shares of Common Stock then beneficially owned by such Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act, does not exceed 4.999% of the total number of issued and outstanding shares of Common Stock (including for such purpose the shares of Common Stock -6-

issuable upon such exercise). For such purposes, beneficial ownership shall be determined in accordance with Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder. Each delivery of an Exercise Notice hereunder will constitute a representation by the Holder that it has evaluated the limitation set forth in this paragraph and determined that issuance of the full number of Warrant Shares requested in such Exercise Notice is permitted under this paragraph. By written notice to the Company, the Holder may waive the provisions of this Section but (i) any such waiver will not be effective until the 61st day after such notice is delivered to the Company, and (ii) any such waiver will apply only to the Holder and not to any other holder of Warrants. (b) Notwithstanding anything to the contrary contained herein, the number of shares of Common Stock that may be acquired by the Holder upon any exercise of this Warrant (or otherwise in respect hereof) shall be limited to the extent necessary to insure that, following such exercise (or other issuance), the total number of shares of Common Stock then beneficially owned by such Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act, does not exceed 9.999% of the total number of issued and outstanding shares of Common Stock (including for such purpose the shares of Common Stock issuable upon such exercise). For such purposes, beneficial ownership shall be determined in accordance with Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder. Each delivery of an Exercise Notice hereunder will constitute a representation by the Holder that it has evaluated the limitation set forth in this paragraph and determined that issuance of the full number of Warrant Shares requested in such Exercise Notice is permitted under this paragraph. By written notice to the Company, the Holder may waive the provisions of this Section but (i) any such waiver will not be effective until the 61st day after such notice is delivered to the Company, and (ii) any such waiver will apply only to the Holder and not to any other holder of Warrants. 12. No Fractional Shares. No fractional shares of Warrant Shares will be -------------------- issued in connection with any exercise of this Warrant. In lieu of any fractional shares which would, otherwise be issuable, the Company shall pay cash equal to the product of such fraction multiplied by the Closing Price of one Warrant Share as reported on the Eligible Market on the date of exercise. 13. Notices. Any and all notices or other communications or deliveries ------- hereunder (including without limitation any Exercise Notice) shall be in writing and shall be deemed given and effective on the earliest of (i) the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section prior to 6:30 p.m. (New York City time) on a Trading Day, (ii) the next Trading Day after the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section on a day that is not a Trading Day or later than 6:30 p.m. (New York City time) on any Trading Day, (iii) the Trading Day following the date of mailing, if sent by nationally recognized overnight courier service, or (iv) upon actual receipt by the party to whom such notice is required to be given. The addresses for such communications shall be: (i) if to the Company, to Questcor Pharmaceuticals, Inc., Attention: President, 3620 Whipple Road, Union City, California 94587 or (ii) if to the Holder, to the address or facsimile number appearing on the Warrant Register or -7-

such other address or facsimile number as the Holder may provide to the Company in accordance with this Section. 14. Warrant Agent. The Company shall serve as warrant agent under this ------------- Warrant. Upon thirty (30) days' notice to the Holder, the Company may appoint a new warrant agent. Any corporation into which the Company or any new warrant agent may be merged or any corporation resulting from any consolidation to which the Company or any new warrant agent shall be a party or any corporation to which the Company or any new warrant agent transfers substantially all of its corporate trust or shareholders services business shall be a successor warrant agent under this Warrant without any further act. Any such successor warrant agent shall promptly cause notice of its succession as warrant agent to be mailed (by first class mail, postage prepaid) to the Holder at the Holder's last address as shown on the Warrant Register. 15. Miscellaneous. ------------- (a) This Warrant shall be binding on and inure to the benefit of the parties hereto and their respective successors and assigns. Subject to the preceding sentence, nothing in this Warrant shall be construed to give to any Person other than the Company and the Holder any legal or equitable right, remedy or cause of action under this Warrant. This Warrant may be amended only in writing signed by the Company and the Holder and their successors and assigns. (b) All questions concerning the construction, validity, enforcement and interpretation of this Warrant shall be governed by and construed and enforced in accordance with the internal laws of the State of New York, without regard to the principles of conflicts of law thereof. Each party hereto hereby irrevocably waives personal service of process and consents to process being served in any such suit, action or proceeding by mailing a copy thereof via registered or certified mail or overnight delivery (with evidence of delivery) to such party at the address in effect for notices to it under this Warrant and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by law. Each party hereto (including its affiliates, agents, officers, directors and employees) hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Warrant or the transactions contemplated hereby. If either party shall commence an action or proceeding to enforce any provisions of this Warrant, then the prevailing party in such action or proceeding shall be reimbursed by the other party for its reasonable attorneys fees and other costs and expenses incurred with the investigation, preparation and prosecution of such action or proceeding. (c) The headings herein are for convenience only, do not constitute a part of this Warrant and shall not be deemed to limit or affect any of the provisions hereof. (d) In case any one or more of the provisions of this Warrant shall be invalid or unenforceable in any respect, the validity and enforceability of the remaining terms and provisions of this Warrant shall not in any way be affected or impaired thereby and the parties will attempt in good faith to agree upon a valid and enforceable provision which shall be a -8-

commercially reasonable substitute therefor, and upon so agreeing, shall incorporate such substitute provision in this Warrant. [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK, SIGNATURE PAGE FOLLOWS] -9-

IN WITNESS WHEREOF, the Company has caused this Warrant to be duly executed by its authorized officer as of the date first indicated above. QUESTCOR PHARMACEUTICALS, INC. By: /s/ Timothy E. Morris --------------------------- Name: Timothy E. Morris ------------------------- Title: Chief Financial Officer ------------------------ -10-

FORM OF ELECTION TO PURCHASE To Questcor Pharmaceuticals, Inc.: In accordance with Warrant No. issued to the undersigned, the ---- undersigned hereby elects to purchase shares of common stock ------------- ("Common Stock"), no par value per share, of Questcor Pharmaceuticals, Inc. and, if such Holder is not utilizing the cashless exercise provisions set forth in this Warrant, encloses herewith $ in cash, certified or official bank -------- check or checks, which sum represents the aggregate Exercise Price (as defined in the Warrant) for the number of shares of Common Stock to which this Form of Election to Purchase relates. By its delivery of this Form of Election To Purchase, the Holder represents and warrants to the Company that in giving effect to the exercise evidenced hereby the Holder will not beneficially own in excess of the number of shares of Common Stock (determined in accordance with Section 13(d) of the Securities Exchange Act of 1934) permitted to be owned under Section 11of this Warrant to which this notice relates. The undersigned requests that certificates for the shares of Common Stock issuable upon this exercise be issued in the name of SOCIAL SECURITY OR TAX IDENTIFICATION NUMBER: -------------------------------------------- NAME AND ADDRESS: -------------------------------------------- -------------------------------------------- --------------------------------------------

FORM OF ASSIGNMENT [To be completed and signed only upon transfer of Warrant] FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers unto the right represented by the -------------------------------- within Warrant to purchase shares of Common Stock of Questcor ------------ Pharmaceuticals, Inc. to which the within Warrant relates and appoints attorney to transfer said right on the books of Questcor - ---------------- Pharmaceuticals, Inc. with full power of substitution in the premises. Dated: , ------------------ --- ------------------------------------------ (Signature must conform in all respects to name of holder as specified on the face of the Warrant) ------------------------------------------ Address of Transferee ------------------------------------------ ------------------------------------------ In the presence of: - -----------------------------

EXHIBIT 4.6 NEITHER THESE SECURITIES NOR THE SECURITIES INTO WHICH THESE SECURITIES ARE EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO THE TRANSFEROR TO SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY ACCEPTABLE TO THE COMPANY. THESE SECURITIES AND THE SECURITIES ISSUABLE UPON EXERCISE OF THESE SECURITIES MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER LOAN SECURED BY SUCH SECURITIES. QUESTCOR PHARMACEUTICALS, INC. WARRANT ------- Warrant No. Date of Original Issuance: March 15, 2002 ----- Questcor Pharmaceuticals, Inc., a California corporation (the "Company"), hereby certifies that, for value received, Eric Sloane or his registered assigns (the "Holder"), is entitled to purchase from the Company up to a total of 23,750 shares of common stock, no par value per share (the "Common Stock"), of the Company (each such share, a "Warrant Share" and all such shares, the "Warrant Shares") at an exercise price (as adjusted from time to time as provided in Section 9, the "Exercise Price") per Warrant Share equal to $1.70, at any time and from time to time from and after the date hereof and through and including March 15, 2006 (the "Expiration Date"), and subject to the following terms and conditions: 1. Definitions. In addition to the terms defined elsewhere in this Warrant, ----------- capitalized terms that are not otherwise defined herein and that are defined in that certain Securities Purchase Agreement, dated as of March 15, 2002, between the Company and SF Capital Partners Ltd. (the "Purchase Agreement"), shall have the meanings given to such terms in the Purchase Agreement. 2. Registration of Warrant. The Company shall register this Warrant, upon ----------------------- records to be maintained by the Company for that purpose (the "Warrant Register"), in the name of the record Holder hereof from time to time. The Company may deem and treat the registered Holder of this Warrant as the absolute owner hereof for the purpose of any exercise hereof or any distribution to the Holder, and for all other purposes, absent actual notice to the contrary.

without limitation any granting of rights or warrants to subscribe for or purchase any capital stock of the Company or any Subsidiary, (ii) authorizes or approves, enters into any agreement contemplating or solicits stockholder approval for any Fundamental Transaction or (iii) authorizes the voluntary dissolution, liquidation or winding up of the affairs of the Company, then the Company shall deliver to the Holder a notice describing the material terms and conditions of such transaction, at least twenty (20) calendar days prior to the applicable record or effective date on which a Person would need to hold Common Stock in order to participate in or vote with respect to such transaction, and the Company will take all steps reasonably necessary in order to insure that the Holder is given the practical opportunity to exercise this Warrant prior to such time so as to participate in or vote with respect to such transaction; provided, however, that the failure to deliver such notice or any defect therein shall not affect the validity of the corporate action required to be described in such notice. 10. Payment of Exercise Price. The Holder shall pay the Exercise Price in ------------------------- one of the following manners: (a) Cash Exercise. The Holder may deliver immediately available funds; or ------------- (b) Cashless Exercise. The Holder may satisfy its obligation to pay ----------------- the Exercise Price through a "cashless exercise" in which event the Company shall issue to the Holder the number of Warrant Shares determined as follows: X = Y [(A-B)/A] where: X = the number of Warrant Shares to be issued to the Holder. Y = the number of Warrant Shares with respect to which this Warrant is being exercised. A = the average of the Closing Prices for the five Trading Days immediately prior to (but not including) the Exercise Date. B = the Exercise Price. For purposes of Rule 144 promulgated under the Securities Act, it is intended, understood and acknowledged that the Warrant Shares issued in a cashless exercise transaction shall be deemed to have been acquired by the Holder, and the holding period for the Warrant Shares shall be deemed to have commenced, on the date this Warrant was originally issued pursuant to the Purchase Agreement. 11. Limitation on Exercise. (a) Notwithstanding anything to the contrary ---------------------- contained herein, the number of shares of Common Stock that may be acquired by the Holder upon any exercise of this Warrant (or otherwise in respect hereof) shall be limited to the extent necessary to insure that, following such exercise (or other issuance), the total number of shares of Common Stock then beneficially owned by such Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act, does not exceed 4.999% of the total number of issued and outstanding shares of Common Stock (including for such purpose the shares of Common Stock -6-

issuable upon such exercise). For such purposes, beneficial ownership shall be determined in accordance with Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder. Each delivery of an Exercise Notice hereunder will constitute a representation by the Holder that it has evaluated the limitation set forth in this paragraph and determined that issuance of the full number of Warrant Shares requested in such Exercise Notice is permitted under this paragraph. By written notice to the Company, the Holder may waive the provisions of this Section but (i) any such waiver will not be effective until the 61st day after such notice is delivered to the Company, and (ii) any such waiver will apply only to the Holder and not to any other holder of Warrants. (b) Notwithstanding anything to the contrary contained herein, the number of shares of Common Stock that may be acquired by the Holder upon any exercise of this Warrant (or otherwise in respect hereof) shall be limited to the extent necessary to insure that, following such exercise (or other issuance), the total number of shares of Common Stock then beneficially owned by such Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act, does not exceed 9.999% of the total number of issued and outstanding shares of Common Stock (including for such purpose the shares of Common Stock issuable upon such exercise). For such purposes, beneficial ownership shall be determined in accordance with Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder. Each delivery of an Exercise Notice hereunder will constitute a representation by the Holder that it has evaluated the limitation set forth in this paragraph and determined that issuance of the full number of Warrant Shares requested in such Exercise Notice is permitted under this paragraph. By written notice to the Company, the Holder may waive the provisions of this Section but (i) any such waiver will not be effective until the 61st day after such notice is delivered to the Company, and (ii) any such waiver will apply only to the Holder and not to any other holder of Warrants. 12. No Fractional Shares. No fractional shares of Warrant Shares will be -------------------- issued in connection with any exercise of this Warrant. In lieu of any fractional shares which would, otherwise be issuable, the Company shall pay cash equal to the product of such fraction multiplied by the Closing Price of one Warrant Share as reported on the Eligible Market on the date of exercise. 13. Notices. Any and all notices or other communications or deliveries ------- hereunder (including without limitation any Exercise Notice) shall be in writing and shall be deemed given and effective on the earliest of (i) the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section prior to 6:30 p.m. (New York City time) on a Trading Day, (ii) the next Trading Day after the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section on a day that is not a Trading Day or later than 6:30 p.m. (New York City time) on any Trading Day, (iii) the Trading Day following the date of mailing, if sent by nationally recognized overnight courier service, or (iv) upon actual receipt by the party to whom such notice is required to be given. The addresses for such communications shall be: (i) if to the Company, to Questcor Pharmaceuticals, Inc., Attention: President, 3620 Whipple Road, Union City, California 94587 or (ii) if to the Holder, to the address or facsimile number appearing on the Warrant Register or -7-

IN WITNESS WHEREOF, the Company has caused this Warrant to be duly executed by its authorized officer as of the date first indicated above. QUESTCOR PHARMACEUTICALS, INC. By: /s/ Timothy E. Morris ------------------------------------- Name: Timothy E. Morris ----------------------------------- Title: Chief Financial Officer ---------------------------------- -10-

FORM OF ELECTION TO PURCHASE To Questcor Pharmaceuticals, Inc.: In accordance with Warrant No. issued to the undersigned, the --- undersigned hereby elects to purchase shares of common stock ------------- ("Common Stock"), no par value per share, of Questcor Pharmaceuticals, Inc. and, if such Holder is not utilizing the cashless exercise provisions set forth in this Warrant, encloses herewith $ in cash, certified or official bank -------- check or checks, which sum represents the aggregate Exercise Price (as defined in the Warrant) for the number of shares of Common Stock to which this Form of Election to Purchase relates. By its delivery of this Form of Election To Purchase, the Holder represents and warrants to the Company that in giving effect to the exercise evidenced hereby the Holder will not beneficially own in excess of the number of shares of Common Stock (determined in accordance with Section 13(d) of the Securities Exchange Act of 1934) permitted to be owned under Section 11of this Warrant to which this notice relates. The undersigned requests that certificates for the shares of Common Stock issuable upon this exercise be issued in the name of SOCIAL SECURITY OR TAX IDENTIFICATION NUMBER: ------------------------ NAME AND ADDRESS: ------------------------ ------------------------ ------------------------

Warrant Shares Exercise Log --------------------------- - ----------------------------------------------------------------------------------- Date Number of Warrant Number of Warrant Number of Warrant Shares Available to Shares Exercised Shares Remaining to be Exercised be Exercised - ----------------------------------------------------------------------------------- - -----------------------------------------------------------------------------------

FORM OF ASSIGNMENT [To be completed and signed only upon transfer of Warrant] FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers unto the right represented by the -------------------------------- within Warrant to purchase shares of Common Stock of Questcor ------------ Pharmaceuticals, Inc. to which the within Warrant relates and appoints attorney to transfer said right on the books of Questcor - ---------------- Pharmaceuticals, Inc. with full power of substitution in the premises. Dated: , --------------- ---- ------------------------------------ (Signature must conform in all respects to name ofholder as specified on the face of the Warrant) ----------------------------------- Address of Transferee ------------------------------------ ------------------------------------ In the presence of: - ------------------------

EXHIBIT 4.7 NEITHER THESE SECURITIES NOR THE SECURITIES INTO WHICH THESE SECURITIES ARE EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO THE TRANSFEROR TO SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY ACCEPTABLE TO THE COMPANY. THESE SECURITIES AND THE SECURITIES ISSUABLE UPON EXERCISE OF THESE SECURITIES MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER LOAN SECURED BY SUCH SECURITIES. QUESTCOR PHARMACEUTICALS, INC. WARRANT ------- Warrant No. Date of Original Issuance: March 15, 2002 --- Questcor Pharmaceuticals, Inc., a California corporation (the "Company"), hereby certifies that, for value received, Thomas J. Griesel or his registered assigns (the "Holder"), is entitled to purchase from the Company up to a total of 14,250 shares of common stock, no par value per share (the "Common Stock"), of the Company (each such share, a "Warrant Share" and all such shares, the "Warrant Shares") at an exercise price (as adjusted from time to time as provided in Section 9, the "Exercise Price") per Warrant Share equal to $1.70, at any time and from time to time from and after the date hereof and through and including March 15, 2006 (the "Expiration Date"), and subject to the following terms and conditions: 1. Definitions. In addition to the terms defined elsewhere in this Warrant, ----------- capitalized terms that are not otherwise defined herein and that are defined in that certain Securities Purchase Agreement, dated as of March 15, 2002, between the Company and SF Capital Partners Ltd. (the "Purchase Agreement"), shall have the meanings given to such terms in the Purchase Agreement. 2. Registration of Warrant. The Company shall register this Warrant, upon ----------------------- records to be maintained by the Company for that purpose (the "Warrant Register"), in the name of the record Holder hereof from time to time. The Company may deem and treat the registered Holder of this Warrant as the absolute owner hereof for the purpose of any exercise hereof or any distribution to the Holder, and for all other purposes, absent actual notice to the contrary.

without limitation any granting of rights or warrants to subscribe for or purchase any capital stock of the Company or any Subsidiary, (ii) authorizes or approves, enters into any agreement contemplating or solicits stockholder approval for any Fundamental Transaction or (iii) authorizes the voluntary dissolution, liquidation or winding up of the affairs of the Company, then the Company shall deliver to the Holder a notice describing the material terms and conditions of such transaction, at least twenty (20) calendar days prior to the applicable record or effective date on which a Person would need to hold Common Stock in order to participate in or vote with respect to such transaction, and the Company will take all steps reasonably necessary in order to insure that the Holder is given the practical opportunity to exercise this Warrant prior to such time so as to participate in or vote with respect to such transaction; provided, however, that the failure to deliver such notice or any defect therein shall not affect the validity of the corporate action required to be described in such notice. 10. Payment of Exercise Price. The Holder shall pay the Exercise Price in ------------------------- one of the following manners: (a) Cash Exercise. The Holder may deliver immediately available funds; ------------- or (b) Cashless Exercise. The Holder may satisfy its obligation to pay ------------------ the Exercise Price through a "cashless exercise" in which event the Company shall issue to the Holder the number of Warrant Shares determined as follows: X = Y [(A-B)/A] where: X = the number of Warrant Shares to be issued to the Holder. Y = the number of Warrant Shares with respect to which this Warrant is being exercised. A = the average of the Closing Prices for the five Trading Days immediately prior to (but not including) the Exercise Date. B = the Exercise Price. For purposes of Rule 144 promulgated under the Securities Act, it is intended, understood and acknowledged that the Warrant Shares issued in a cashless exercise transaction shall be deemed to have been acquired by the Holder, and the holding period for the Warrant Shares shall be deemed to have commenced, on the date this Warrant was originally issued pursuant to the Purchase Agreement. 11. Limitation on Exercise. (a) Notwithstanding anything to the contrary ---------------------- contained herein, the number of shares of Common Stock that may be acquired by the Holder upon any exercise of this Warrant (or otherwise in respect hereof) shall be limited to the extent necessary to insure that, following such exercise (or other issuance), the total number of shares of Common Stock then beneficially owned by such Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act, does not exceed 4.999% of the total number of issued and outstanding shares of Common Stock (including for such purpose the shares of Common Stock -6-

issuable upon such exercise). For such purposes, beneficial ownership shall be determined in accordance with Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder. Each delivery of an Exercise Notice hereunder will constitute a representation by the Holder that it has evaluated the limitation set forth in this paragraph and determined that issuance of the full number of Warrant Shares requested in such Exercise Notice is permitted under this paragraph. By written notice to the Company, the Holder may waive the provisions of this Section but (i) any such waiver will not be effective until the 61st day after such notice is delivered to the Company, and (ii) any such waiver will apply only to the Holder and not to any other holder of Warrants. (b) Notwithstanding anything to the contrary contained herein, the number of shares of Common Stock that may be acquired by the Holder upon any exercise of this Warrant (or otherwise in respect hereof) shall be limited to the extent necessary to insure that, following such exercise (or other issuance), the total number of shares of Common Stock then beneficially owned by such Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act, does not exceed 9.999% of the total number of issued and outstanding shares of Common Stock (including for such purpose the shares of Common Stock issuable upon such exercise). For such purposes, beneficial ownership shall be determined in accordance with Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder. Each delivery of an Exercise Notice hereunder will constitute a representation by the Holder that it has evaluated the limitation set forth in this paragraph and determined that issuance of the full number of Warrant Shares requested in such Exercise Notice is permitted under this paragraph. By written notice to the Company, the Holder may waive the provisions of this Section but (i) any such waiver will not be effective until the 61st day after such notice is delivered to the Company, and (ii) any such waiver will apply only to the Holder and not to any other holder of Warrants. 12. No Fractional Shares. No fractional shares of Warrant Shares will be -------------------- issued in connection with any exercise of this Warrant. In lieu of any fractional shares which would, otherwise be issuable, the Company shall pay cash equal to the product of such fraction multiplied by the Closing Price of one Warrant Share as reported on the Eligible Market on the date of exercise. 13. Notices. Any and all notices or other communications or deliveries ------- hereunder (including without limitation any Exercise Notice) shall be in writing and shall be deemed given and effective on the earliest of (i) the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section prior to 6:30 p.m. (New York City time) on a Trading Day, (ii) the next Trading Day after the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section on a day that is not a Trading Day or later than 6:30 p.m. (New York City time) on any Trading Day, (iii) the Trading Day following the date of mailing, if sent by nationally recognized overnight courier service, or (iv) upon actual receipt by the party to whom such notice is required to be given. The addresses for such communications shall be: (i) if to the Company, to Questcor Pharmaceuticals, Inc., Attention: President, 3620 Whipple Road, Union City, California 94587 or (ii) if to the Holder, to the address or facsimile number appearing on the Warrant Register or -7-

IN WITNESS WHEREOF, the Company has caused this Warrant to be duly executed by its authorized officer as of the date first indicated above. QUESTCOR PHARMACEUTICALS, INC. By: /s/ Timothy E. Morris ------------------------------- Name: Timothy E. Morris ----------------------------- Title: Chief Financial Officer ---------------------------- -10-

FORM OF ASSIGNMENT [To be completed and signed only upon transfer of Warrant] FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers unto the right represented by the -------------------------------- within Warrant to purchase shares of Common Stock of Questcor ------------ Pharmaceuticals, Inc. to which the within Warrant relates and appoints attorney to transfer said right on the books of Questcor - ---------------- Pharmaceuticals, Inc. with full power of substitution in the premises. Dated: , --------------- ---- ------------------------------------ (Signature must conform in all respects to name of holder as specified on the face of the Warrant) ----------------------------------- Address of Transferee ------------------------------------ ------------------------------------ In the presence of: - -------------------

EXHIBIT 4.8 NEITHER THESE SECURITIES NOR THE SECURITIES INTO WHICH THESE SECURITIES ARE EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO THE TRANSFEROR TO SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY ACCEPTABLE TO THE COMPANY. THESE SECURITIES AND THE SECURITIES ISSUABLE UPON EXERCISE OF THESE SECURITIES MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER LOAN SECURED BY SUCH SECURITIES. QUESTCOR PHARMACEUTICALS, INC. WARRANT ------- Warrant No. Date of Original Issuance: March 15, 2002 --- Questcor Pharmaceuticals, Inc., a California corporation (the "Company"), hereby certifies that, for value received, Financial West Group or its registered assigns (the "Holder"), is entitled to purchase from the Company up to a total of 5,000 shares of common stock, no par value per share (the "Common Stock"), of the Company (each such share, a "Warrant Share" and all such shares, the "Warrant Shares") at an exercise price (as adjusted from time to time as provided in Section 9, the "Exercise Price") per Warrant Share equal to $1.70, at any time and from time to time from and after the date hereof and through and including March 15, 2006 (the "Expiration Date"), and subject to the following terms and conditions: 1. Definitions. In addition to the terms defined elsewhere in this Warrant, ----------- capitalized terms that are not otherwise defined herein and that are defined in that certain Securities Purchase Agreement, dated as of March 15, 2002, between the Company and SF Capital Partners Ltd. (the "Purchase Agreement"), shall have the meanings given to such terms in the Purchase Agreement. 2. Registration of Warrant. The Company shall register this Warrant, upon ----------------------- records to be maintained by the Company for that purpose (the "Warrant Register"), in the name of the record Holder hereof from time to time. The Company may deem and treat the registered Holder of this Warrant as the absolute owner hereof for the purpose of any exercise hereof or any distribution to the Holder, and for all other purposes, absent actual notice to the contrary.

without limitation any granting of rights or warrants to subscribe for or purchase any capital stock of the Company or any Subsidiary, (ii) authorizes or approves, enters into any agreement contemplating or solicits stockholder approval for any Fundamental Transaction or (iii) authorizes the voluntary dissolution, liquidation or winding up of the affairs of the Company, then the Company shall deliver to the Holder a notice describing the material terms and conditions of such transaction, at least twenty (20) calendar days prior to the applicable record or effective date on which a Person would need to hold Common Stock in order to participate in or vote with respect to such transaction, and the Company will take all steps reasonably necessary in order to insure that the Holder is given the practical opportunity to exercise this Warrant prior to such time so as to participate in or vote with respect to such transaction; provided, however, that the failure to deliver such notice or any defect therein shall not affect the validity of the corporate action required to be described in such notice. 10. Payment of Exercise Price. The Holder shall pay the Exercise Price in ------------------------- one of the following manners: (a) Cash Exercise. The Holder may deliver immediately available funds; ------------- or (b) Cashless Exercise. The Holder may satisfy its obligation to pay ----------------- the Exercise Price through a "cashless exercise" in which event the Company shall issue to the Holder the number of Warrant Shares determined as follows: X = Y [(A-B)/A] where: X = the number of Warrant Shares to be issued to the Holder. Y = the number of Warrant Shares with respect to which this Warrant is being exercised. A = the average of the Closing Prices for the five Trading Days immediately prior to (but not including) the Exercise Date. B = the Exercise Price. For purposes of Rule 144 promulgated under the Securities Act, it is intended, understood and acknowledged that the Warrant Shares issued in a cashless exercise transaction shall be deemed to have been acquired by the Holder, and the holding period for the Warrant Shares shall be deemed to have commenced, on the date this Warrant was originally issued pursuant to the Purchase Agreement. 11. Limitation on Exercise. (a) Notwithstanding anything to the contrary ---------------------- contained herein, the number of shares of Common Stock that may be acquired by the Holder upon any exercise of this Warrant (or otherwise in respect hereof) shall be limited to the extent necessary to insure that, following such exercise (or other issuance), the total number of shares of Common Stock then beneficially owned by such Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act, does not exceed 4.999% of the total number of issued and outstanding shares of Common Stock (including for such purpose the shares of Common Stock -6-

issuable upon such exercise). For such purposes, beneficial ownership shall be determined in accordance with Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder. Each delivery of an Exercise Notice hereunder will constitute a representation by the Holder that it has evaluated the limitation set forth in this paragraph and determined that issuance of the full number of Warrant Shares requested in such Exercise Notice is permitted under this paragraph. By written notice to the Company, the Holder may waive the provisions of this Section but (i) any such waiver will not be effective until the 61st day after such notice is delivered to the Company, and (ii) any such waiver will apply only to the Holder and not to any other holder of Warrants. (b) Notwithstanding anything to the contrary contained herein, the number of shares of Common Stock that may be acquired by the Holder upon any exercise of this Warrant (or otherwise in respect hereof) shall be limited to the extent necessary to insure that, following such exercise (or other issuance), the total number of shares of Common Stock then beneficially owned by such Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act, does not exceed 9.999% of the total number of issued and outstanding shares of Common Stock (including for such purpose the shares of Common Stock issuable upon such exercise). For such purposes, beneficial ownership shall be determined in accordance with Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder. Each delivery of an Exercise Notice hereunder will constitute a representation by the Holder that it has evaluated the limitation set forth in this paragraph and determined that issuance of the full number of Warrant Shares requested in such Exercise Notice is permitted under this paragraph. By written notice to the Company, the Holder may waive the provisions of this Section but (i) any such waiver will not be effective until the 61st day after such notice is delivered to the Company, and (ii) any such waiver will apply only to the Holder and not to any other holder of Warrants. 12. No Fractional Shares. No fractional shares of Warrant Shares will be -------------------- issued in connection with any exercise of this Warrant. In lieu of any fractional shares which would, otherwise be issuable, the Company shall pay cash equal to the product of such fraction multiplied by the Closing Price of one Warrant Share as reported on the Eligible Market on the date of exercise. 13. Notices. Any and all notices or other communications or deliveries ------- hereunder (including without limitation any Exercise Notice) shall be in writing and shall be deemed given and effective on the earliest of (i) the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section prior to 6:30 p.m. (New York City time) on a Trading Day, (ii) the next Trading Day after the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number specified in this Section on a day that is not a Trading Day or later than 6:30 p.m. (New York City time) on any Trading Day, (iii) the Trading Day following the date of mailing, if sent by nationally recognized overnight courier service, or (iv) upon actual receipt by the party to whom such notice is required to be given. The addresses for such communications shall be: (i) if to the Company, to Questcor Pharmaceuticals, Inc., Attention: President, 3620 Whipple Road, Union City, California 94587 or (ii) if to the Holder, to the address or facsimile number appearing on the Warrant Register or -7-

IN WITNESS WHEREOF, the Company has caused this Warrant to be duly executed by its authorized officer as of the date first indicated above. QUESTCOR PHARMACEUTICALS, INC. By: /s/ Timothy E. Morris --------------------------- Name: Timothy E. Morris ------------------------- Title: Chief Financial Officer ------------------------ -10-

Warrant Shares Exercise Log --------------------------- - ----------------------------------------------------------------------------------------------- Date Number of Warrant Shares Number of Warrant Shares Number of Warrant Shares Available to be Exercised Exercised Remaining to be Exercised - ----------------------------------------------------------------------------------------------- - -----------------------------------------------------------------------------------------------

FORM OF ASSIGNMENT [To be completed and signed only upon transfer of Warrant] FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers unto the right represented by the -------------------------------- within Warrant to purchase shares of Common Stock of Questcor ------------ Pharmaceuticals, Inc. to which the within Warrant relates and appoints attorney to transfer said right on the books of Questcor - ---------------- Pharmaceuticals, Inc. with full power of substitution in the premises. Dated: , --------------- ---- ------------------------------------ (Signature must conform in all respects to name of holder as specified on the face of the Warrant) ----------------------------------- Address of Transferee ------------------------------------ ------------------------------------ In the presence of: - -------------------------

Exhibit 5.1 BOSTON Latham & Watkins NEW YORK BRUSSELS ATTORNEYS AT LAW NORTHERN VIRGINIA CHICAGO www.lw.com ORANGE COUNTY FRANKFURT PARIS HAMBURG ____________________ SAN DIEGO NORTH COUNTY HONG KONG SAN FRANCISCO LONDON SILICON VALLEY LOS ANGELES SINGAPORE MOSCOW TOKYO NEW JERSEY WASHINGTON, D.C. March 28, 2002 FILE NO. 029924-0006 Questcor Pharmaceuticals, Inc. 3260 Whipple Road Union City, California 94587 Re: Registration Statement on Form S-3; 4,467,087 Shares of Common Stock, no par value per share -------------------------------------------------------- Ladies and Gentlemen: In connection with the registration under the Securities Act of 1933, as amended, of 4,467,087 shares (the "Shares") of common stock, no par value per share, of Questcor Pharmaceuticals, Inc., a California corporation (the "Company"), including a total of 2,848,100 Shares which may be issued in the future upon conversion or redemption of certain debentures (the "Debenture Shares") and a total of 1,618,987 Shares which may be issued in the future upon exercise of certain warrants (the "Warrant Shares"), on a registration statement on Form S-3 filed with the Securities and Exchange Commission on March 28, 2002 (the "Registration Statement") to register certain resales of the Shares by the selling stockholders named in the Registration Statement, you have requested our opinion with respect to the matters set forth below. In our capacity as your counsel in connection with such registration, we are familiar with the proceedings taken and proposed to be taken by the Company in connection with the authorization, issuance and sale of the Shares, and for the purposes of this opinion, have assumed such proceedings will be timely completed in the manner presently proposed. In addition, we have made such legal and factual examinations and inquiries, including an examination of originals or copies certified or otherwise identified to our satisfaction of such documents, corporate records and instruments, as we have deemed necessary or appropriate for purposes of this opinion. In our examination, we have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, and the conformity to authentic original documents of all documents submitted to us as copies. We are opining herein as to the effect on the subject transaction only of the internal laws of the State of California, and we express no opinion with respect to the applicability thereto, or the effect thereon, of the laws of any other jurisdiction or as to any matters of municipal law or the laws of any local agencies within any state. - -------------------------------------------------------------------------------- 701 B Street, Suite 2100 . San Diego, California 92101-8197 TELEPHONE: (619) 236-1234 . FAX: (6I9) 696-7419

LATHAM & WATKINS Questor Pharmaceuticals, Inc. March 28, 2002 Page 2 Subject to the foregoing, it is our opinion that (i) upon the conversion or redemption of the debentures in accordance with the terms set forth in the respective debentures under which such Debenture Shares will be issued, the Debenture Shares will be, legally and validly issued, fully paid and nonassessable, and (ii) upon exercise of the warrants and payment for the Warrant Shares in accordance with the terms set forth in the respective warrants under which such Warrant Shares will be issued, the Warrant Shares will be, legally and validly issued, fully paid and nonassessable. We consent to your filing this opinion as an exhibit to the Registration Statement and to the reference to our firm contained under the heading "Legal Matters." Very truly yours, /s/ LATHAM & WATKINS

Exhibit 23.2 CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS We consent to the reference to our firm under the caption "Experts" in the Registration Statement (Form S-3) and related Prospectus of Questcor Pharmaceuticals, Inc. for the registration of 4,467,087 shares of its common stock and to the incorporation by reference therein of our report dated February 12, 2002, except for Note 1, paragraph 4, and Note 17, as to which the date is March 15, 2002, with respect to the consolidated financial statements and schedule of Questcor Pharmaceuticals, Inc. included in its Annual Report (Form 10-K) for the year ended December 31, 2001, filed with the Securities and Exchange Commission. Palo Alto, California March 26, 2002

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents

Table of Contents