Endo Pharmaceuticals Holdings Inc. $345,000,000 1.75% Convertible Senior Subordinated Notes Due 2015 Purchase Agreement

Exhibit 1.1

Endo Pharmaceuticals Holdings Inc.

$345,000,000 1.75% Convertible Senior Subordinated Notes Due 2015

Purchase Agreement

New York, New York

April 9, 2008

Deutsche Bank Securities Inc.

Lazard Capital Markets LLC

c/o Deutsche Bank Securities Inc.

60 Wall Street

New York, NY 10005

Ladies and Gentlemen:

Endo Pharmaceuticals Holdings Inc., a corporation organized under the laws of Delaware (the “Company”), proposes to issue and sell to you (the “Initial Purchasers”), for whom Deutsche Bank Securities Inc. (the “Representative”) is acting as representative, $345,000,000 aggregate principal amount of its 1.75% Convertible Senior Subordinated Notes due 2015 (the “Firm Securities”). The Company also proposes to grant to the Initial Purchasers an option to purchase up to $34,500,000 aggregate principal amount of such Senior Subordinated Notes to cover over-allotments, if any (the “Option Securities” and, together with the Firm Securities, the “Securities”). The Securities are convertible into shares of Common Stock, par value $0.01 per share (the “Common Stock”), of the Company, subject to certain conditions described in the Final Memorandum (as defined below). The Securities are to be issued under an indenture (the “Indenture”), to be dated as of the Closing Date, between the Company and The Bank of New York, as trustee (the “Trustee”).

Concurrently with this Agreement, the Company is entering into a convertible note hedge transaction, a warrant transaction and an accelerated share repurchase agreement, each with Deutsche Bank AG, London Branch, and each pursuant to a confirmation letter dated the date hereof subject to an agreement in the form of the ISDA 2002 Master Agreement (collectively, together with the Indenture, the “Transaction Agreements”).

The Company acknowledges and agrees that (i) the purchase and sale of the Securities pursuant to this Agreement, including the determination of the offering price of the Securities and any related discounts and commissions, is an arm’s-length commercial transaction between the Company, on the one hand, and the Initial Purchasers, on the other hand, (ii) in connection with the offering contemplated hereby and the process leading to such transaction, the Initial Purchasers have been acting solely as principals and are not the agents or fiduciaries of the Company or its employees, (iii) the Initial Purchasers have not assumed or will not assume an advisory or fiduciary responsibility in favor of the Company with respect to the offering contemplated hereby or the process leading thereto (irrespective of whether the Initial Purchasers have advised or are currently advising the Company on other matters) and the Initial Purchasers

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have no obligation to the Company with respect to the offering contemplated hereby except the obligations expressly set forth in this Agreement and (iv) the Initial Purchasers have not provided any legal, accounting, regulatory or tax advice with respect to the offering contemplated hereby and the Company has consulted its own legal, accounting, regulatory and tax advisors to the extent it deemed appropriate.

The sale of the Securities to the Initial Purchasers will be made without registration of the Securities or the Common Stock issuable upon conversion thereof under the Act in reliance upon exemptions from the registration requirements of the Act.

In connection with the sale of the Securities, the Company has prepared a preliminary offering memorandum, dated April 9, 2008 (as amended or supplemented at the date thereof, including any and all exhibits thereto and any information incorporated by reference therein, the “Preliminary Memorandum”), and a final offering memorandum, dated April 9, 2008 (as amended or supplemented at the Execution Time, including any and all exhibits thereto and any information incorporated by reference therein, the “Final Memorandum”). Each of the Preliminary Memorandum and the Final Memorandum sets forth certain information concerning the Company, the Securities and the Common Stock issuable upon conversion thereof. The Company hereby confirms that it has authorized the use of the Disclosure Package, the Preliminary Memorandum and the Final Memorandum, and any amendments or supplements thereto, in connection with the offer and sale of the Securities by the Initial Purchasers. Unless stated to the contrary, any references herein to the terms “amend,” “amendment” or “supplement” with respect to the Final Memorandum shall be deemed to refer to and include any information filed under the Exchange Act subsequent to the Execution Time that is incorporated by reference therein.

The terms Representative and Initial Purchasers shall mean either the singular or plural as the context requires. The use of the neuter in this Agreement shall include the feminine and masculine wherever appropriate. Certain terms used herein are defined in Section 18 hereof.

1. Representations and Warranties.

The Company represents and warrants to, and agrees with, each Initial Purchaser as set forth below in this Section 1.

(a) At the Execution Time, on the Closing Date and on any settlement date, the Final Memorandum did not and will not (and any amendment or supplement thereto, at the date thereof, at the Closing Date and on any settlement date, will not) contain any untrue statement of a material fact or omit to state any material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided, however, that the Company makes no representation or warranty as to the information contained in or omitted from the Preliminary Memorandum or the Final Memorandum, or any amendment or supplement thereto, in reliance upon and in conformity with information furnished in writing to the Company by or on behalf of the Initial Purchasers through the Representative specifically for inclusion therein, it being understood and agreed that the only such information furnished by or on behalf of any Initial Purchaser consists of the information described as such in Section 8(b) hereof.

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(b) The Disclosure Package, as of the Execution Time, does not contain any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The preceding sentence does not apply to statements in or omissions from the Disclosure Package based upon and in conformity with written information furnished to the Company by any Initial Purchaser through the Representative specifically for use therein, it being understood and agreed that the only such information furnished by or on behalf of any Initial Purchaser consists of the information described as such in Section 8(b) hereof.

(c) Each of the Company’s (a) Form 10-K, for the fiscal year ended December 31, 2007, (b) Proxy Statement for the 2007 annual meeting of shareholders pursuant to Section 14(c) of the Exchange Act and (c) current reports on Form 8-K filed or furnished since December 31, 2007 (collectively, the documents listed in (a), (b) and (c) above are referred to as the “1934 Act Reports”) filed or furnished with the Commission pursuant to the Exchange Act at the time they were or hereafter are filed or furnished with the Commission complied or will comply, in either case, in all material respects with the requirements of the Exchange Act and the rules and regulations of the Commission thereunder and, when filed of furnished with the Commission, did not and will not include 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 not misleading.

(d) None of the Company, its Affiliates, or any person acting on its or their behalf has, directly or indirectly, made offers or sales of any security or solicited offers to buy any security under circumstances that would require the registration of the Securities or the Common Stock issuable upon conversion thereof under the Act.

(e) None of the Company, its Affiliates, or any person acting on its or their behalf has engaged in any form of general solicitation or general advertising (within the meaning of Regulation D) in connection with any offer or sale of the Securities or the Common Stock issuable upon conversion thereof.

(f) The Securities satisfy the eligibility requirements of Rule 144A(d)(3) under the Act.

(g) No registration under the Act of the Securities or the Common Stock issuable upon conversion thereof is required for the offer and sale of the Securities to or by the Initial Purchasers in the manner contemplated herein, in the Disclosure Package and in the Final Memorandum.

(h) The Company is subject to and in full compliance, in all material respects, with the reporting requirements of Section 13 or Section 15(d) of the Exchange Act.

(i) Each of the Company and Endo Pharmaceuticals Inc., a Delaware corporation (“Endo Pharmaceuticals”), Endo Pharmaceuticals Colorado LLC, a Delaware limited liability company (“Endo Colorado”), Endo Pharma Delaware Inc., a Delaware corporation (“Endo Delaware”), Endo Pharma Canada Inc., a corporation organized under the laws of the province of New Brunswick, Canada (“Endo Canada”) and Endo Pharma Ireland Limited, a company organized under the laws of the Republic of Ireland (“Endo Ireland,” together with Endo

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Pharmaceuticals, Endo Colorado, Endo Delaware and Endo Canada, the “Subsidiaries”) has been duly incorporated and is validly existing as a corporation in good standing under the laws of the State of Delaware, or with respect to Endo Canada, the province of New Brunswick, Canada, or with respect to Endo Ireland, the Republic of Ireland, with full corporate power and authority to own or lease, as the case may be, and to operate its properties and conduct its business as described in the Disclosure Package and the Final Memorandum, and is duly qualified to do business as a foreign corporation and is in good standing under the laws of each jurisdiction which requires such qualification, except where the failure to be so qualified or in good standing in any such other jurisdiction would not have a material adverse effect on the condition (financial or otherwise), prospects, earnings, business or properties of the Company and the Subsidiaries, taken as a whole, whether or not arising from transactions in the ordinary course of business (a “Material Adverse Effect”).

(j) Other than the Subsidiaries, the Company has no subsidiaries and, except for the Company’s ownership interest in DURECT Corporation, U.S. Dermatologics, Inc. and Alpharma Inc., does not own any shares of capital stock of or interests in any other Person.

(k) All of the outstanding shares of capital stock of each Subsidiary have been duly and validly authorized and issued and are fully paid and nonassessable, and, except as otherwise set forth in the Disclosure Package, all outstanding shares of capital stock of the Subsidiaries are owned by the Company directly, free and clear of any perfected security interest or any other security interests, claims, liens or encumbrances.

(l) The Company’s authorized equity capitalization is as set forth in the Disclosure Package and the Final Memorandum. The capital stock of the Company conforms in all material respects to the description thereof contained in the Disclosure Package and the Final Memorandum. The outstanding shares of Common Stock have been duly authorized and validly issued and are fully paid and nonassessable. The shares of Common Stock initially issuable upon conversion of the Securities have been duly authorized and, when issued upon the conversion of the Securities against payment of the conversion price, will be validly issued, fully paid and nonassessable. The Board of Directors of the Company has duly and validly adopted resolutions reserving such shares of Common Stock for issuance upon conversion of the Securities. The holders of outstanding shares of capital stock of the Company are not entitled to preemptive or other rights to subscribe for the Securities or the shares of Common Stock issuable upon conversion thereof and, except as set forth in the Disclosure Package, no options, warrants or other rights to purchase, agreements or other obligations to issue, or rights to convert any obligations into or exchange any securities for, shares of capital stock of or ownership interests in the Company are outstanding.

(m) There is no franchise, contract or other document of a character required to be described in the Disclosure Package or the Final Memorandum, or to be included as an exhibit thereto, which is not described or included as required. The statements included or incorporated by reference in the Disclosure Package and the Final Memorandum under the headings “Description of the Notes,” “Description of the Capital Stock,” “Description of the Convertible Note Hedge and Warrant Transactions and the Accelerated Repurchase Program,” “Risk Factors – Our ability to protect our proprietary technology, which is vital to our business, is uncertain,” “Business – Governmental Regulation,” “Business – Patents, Trademarks, Licenses and

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Proprietary Property,” “Business – Service Agreements,” “Business – Third Party Manufacturing, Supply and Other Service Agreements,” “Business – Acquisitions, License and Collaboration Agreements,” “Business – Environmental Matters,” “Legal Proceedings” and “Certain United States Federal Income Tax Considerations,” insofar as such statements summarize legal matters, agreements, documents or proceedings discussed therein, are accurate and fair summaries of such legal matters, agreements, documents or proceedings in all material respects.

(n) This Agreement has been duly authorized, executed and delivered by the Company. Each Transaction Agreement has been duly authorized and, assuming due authorization, execution and delivery thereof by the counterparty thereto, when executed and delivered by the Company, will constitute a legal, valid and binding instrument enforceable against the Company in accordance with its terms (subject, as to the enforcement of remedies, to applicable bankruptcy, reorganization, insolvency, moratorium or other laws affecting creditors’ rights generally from time to time in effect and to general principles of equity). The Securities have been duly authorized and, when executed and authenticated in accordance with the provisions of the Indenture and delivered to and paid for by the Initial Purchasers, will have been duly executed and delivered by the Company and will constitute the legal, valid and binding obligations of the Company entitled to the benefits of the Indenture (subject, as to enforcement of remedies, to applicable bankruptcy, reorganization, insolvency, moratorium or other laws affecting creditors’ rights generally from time to time in effect and to general principles of equity) and will be convertible into Common Stock in accordance with the terms of the Indenture.

(o) The Company is not, and after giving effect to the offering and sale of the Securities and the application of the proceeds thereof as described in the Disclosure Package and the Final Memorandum will not be, an “investment company” as defined in the Investment Company Act of 1940, as amended.

(p) No consent, approval, authorization, filing with or order of any court or governmental agency or body is required in connection with the transactions contemplated herein, in the Transaction Agreements, except such as may be required under the blue sky laws of any jurisdiction in connection with the purchase and distribution of the Securities by the Initial Purchasers in the manner contemplated herein and in the Final Memorandum and such as have been obtained or made.

(q) None of the execution and delivery of the Transaction Agreements or this Agreement, the issuance and the sale of the Securities or the issuance of Common Stock upon conversion thereof, the consummation of any other of the transactions herein or therein contemplated or the fulfillment of the terms hereof or thereof will conflict with, result in a breach or violation or imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of the Subsidiaries pursuant to, (i) the charter or by-laws or comparable constituting documents of the Company or any of the Subsidiaries; (ii) the terms of any indenture, contract, lease, mortgage, deed of trust, note agreement, loan agreement or other agreement, obligation, condition, covenant or instrument to which the Company or any of the Subsidiaries is a party or bound or to which its or their property is subject; or (iii) any statute, law, rule, regulation, judgment, order or decree applicable to the Company or any of the

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Subsidiaries of any court, regulatory body, administrative agency, governmental body, arbitrator or other authority having jurisdiction over the Company or any of the Subsidiaries or any of its or their properties; except, in the case of clause (ii) or (iii), for any such conflict, breach, violation or imposition that would not have a Material Adverse Effect.

(r) No holders of securities of the Company have rights to the registration of any such securities that have not been so registered.

(s) The consolidated historical financial statements and schedules of the Company and its consolidated subsidiaries incorporated by reference in the Disclosure Package and the Final Memorandum present fairly in all material respects the financial condition, results of operations and cash flows of the Company and its consolidated subsidiaries as of the dates and for the periods indicated, comply as to form with the applicable accounting requirements of Regulation S-X and have been prepared in conformity with generally accepted accounting principles applied on a consistent basis throughout the periods involved (except as otherwise noted therein). The summary consolidated financial data set forth under the caption “Summary Financial Information” in the Disclosure Package and the Final Memorandum fairly present, on the basis stated in the Disclosure Package and the Final Memorandum, the information incorporated by reference therein.

(t) Except as set forth in the Disclosure Package, no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator, including, without limitation, the United States Food and Drug Administration (the “FDA”) and United States Drug Enforcement Agency (the “DEA”), involving the Company or any of the Subsidiaries or its or their respective properties is pending or, to the best knowledge of the Company, threatened that (i) could have a material adverse effect on the performance of this Agreement or the Transaction Agreements or the consummation of any of the transactions contemplated hereby or thereby or (ii) could have a Material Adverse Effect.

(u) The Company and each of the Subsidiaries owns or leases all such properties as are necessary to the conduct of its operations as presently conducted.

(v) Neither the Company nor any of the Subsidiaries is in violation or default of (i) any provision of its charter or bylaws or comparable organizational documents; (ii) the terms of any indenture, contract, lease, mortgage, deed of trust, note agreement, loan agreement or other agreement, obligation, condition, covenant or instrument to which it is a party or bound or to which its property is subject; or (iii) except as set forth in the Disclosure Package, any statute, law, rule, regulation, judgment, order or decree applicable to the Company or any of the Subsidiaries of any court, regulatory body, administrative agency, governmental body, arbitrator or other authority having jurisdiction over the Company or such Subsidiary or any of its properties; except, in the case of clause (ii) or (iii), for any such violation or default that would not have a Material Adverse Effect.

(w) Deloitte & Touche LLP, who has certified certain financial statements of the Company and its consolidated subsidiaries, and delivered its report with respect to the audited consolidated financial statements and schedules incorporated by reference in the Disclosure Package and the Final Memorandum, is an independent registered public accounting firm with respect to the Company within the meaning of the Act and the Public Company Accounting Oversight Board (United States).

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(x) There are no stamp or other issuance or transfer taxes or duties or other similar fees or charges under Federal law or the laws of any state, or any political subdivision thereof, required to be paid in connection with the execution and delivery of this Agreement or the issuance or sale of the Securities or upon the issuance of Common Stock upon the conversion thereof.

(y) The Company and each of the Subsidiaries has filed all foreign, U.S. federal, state and local tax returns that are required to be filed or has requested extensions thereof (except in any case in which the failure so to file would not have a Material Adverse Effect) and has paid all taxes required to be paid by it and any other assessment, fine or penalty levied against it, to the extent that any of the foregoing is due and payable, except for any such assessment, fine or penalty that is currently being contested in good faith or as would not have a Material Adverse Effect.

(z) No labor problem or dispute with the employees of the Company or any of the Subsidiaries exists or is threatened or imminent, and the Company is not aware of any existing or imminent labor disturbance by the employees of any of its or the Subsidiaries’ principal suppliers, contractors or customers, in each case that could have a Material Adverse Effect.

(aa) The Company and each of the Subsidiaries are insured by insurers of recognized financial responsibility against such losses and risks and in such amounts as are prudent and customary in the businesses in which they are engaged; and the Company and each such Subsidiary believes that it will 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 at a cost that would not have a Material Adverse Effect, except as set forth in or contemplated in the Disclosure Package.

(bb) None of the Subsidiaries is currently prohibited, directly or indirectly, from paying any dividends to the Company, from making any other distribution on such Subsidiary’s capital stock, from repaying to the Company any loans or advances to such Subsidiary from the Company or from transferring any of such Subsidiary’s property or assets to the Company or any other Subsidiary of the Company, except as described or contemplated in the Disclosure Package and the Final Memorandum (exclusive of any amendment or supplement thereto).

(cc) Except as set forth in the Disclosure Package, (A) the Company and each of the Subsidiaries possess all permits, licenses, provider numbers, certificates, approvals, consents, orders, certifications and other authorizations (collectively, “Governmental Licenses”) issued by, and have made all declarations and filings with, the appropriate U.S. federal, state, local or foreign regulatory agencies or bodies, including without limitation, the FDA and the DEA, necessary to conduct the business now operated by the Company and the Subsidiaries except where the failure to possess such Governmental Licenses or to make such declarations and filings would not result in a Material Adverse Effect; the Company and the Subsidiaries are in compliance with the terms and conditions of all such Governmental Licenses, except where the failure so to comply would not, individually and in the aggregate, have a Material Adverse

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Effect; all of the Governmental Licenses are valid and in full force and effect, except when the invalidity of such Governmental Licenses or the failure of such Governmental Licenses to be in full force and effect would not have a Material Adverse Effect; and (B) neither the Company nor any of the Subsidiaries has received any notice of proceedings relating to the revocation or modification of any such Governmental Licenses which, individually or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would result in a Material Adverse Effect.

(dd) The Company and each of the Subsidiaries maintain a system of internal control over financial reporting 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. The Company and each of the Subsidiaries’ internal controls over financial reporting are effective and neither the Company nor any of the Subsidiaries are aware of any material weakness in their internal controls over financial reporting.

(ee) The Company and each of the Subsidiaries maintain “disclosure controls and procedures” (as such term is defined in Rule 13a-15(e) under the Exchange Act). Such disclosure controls and procedures are effective.

(ff) The Company has not paid or agreed to pay to any person any compensation for soliciting another to purchase any securities of the Company (except as contemplated in this Agreement).

(gg) The Company has not taken, directly or indirectly, any action designed to or that would constitute or that might reasonably be expected to cause or result in stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Securities in violation of the Exchange Act.

(hh) Except as set forth in the Disclosure Package, the Company, each of the Subsidiaries and each of the research and development, manufacturing and other facilities leased or operated by them (there being no such facilities owned by the Company and the Subsidiaries) (i) are in compliance with any and all applicable foreign, U.S. federal, state and local laws and regulations relating to the protection of human health and safety, the environment or hazardous or toxic substances or wastes, pollutants or contaminants (“Environmental Laws”); (ii) have received and are in compliance with all permits, licenses or other approvals required of them under applicable Environmental Laws to conduct their respective businesses; (iii) have not received notice of any actual or potential liability for the investigation or remediation of any disposal or release of hazardous or toxic substances or wastes, pollutants or contaminants; and (iv) are not subject to liabilities and costs associated with compliance by them with Environmental Laws, except where such non-compliance with Environmental Laws, failure to receive required permits, licenses or other approvals, or liabilities or costs would not, individually or in the aggregate, have a Material Adverse Effect. Neither the Company nor any Subsidiary or any such facility has received notice that it has been named as a “potentially responsible party” under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended.

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(ii) Each of the Company and the Subsidiaries has fulfilled its obligations, if any, in all material respects, under the minimum funding standards of Section 302 of the United States Employee Retirement Income Security Act of 1974 (“ERISA”) and the regulations and published interpretations thereunder with respect to each “plan” (as defined in Section 3(3) of ERISA and such regulations and published interpretations) that is sponsored or maintained by the Company or a Subsidiary in which employees of the Company and the Subsidiaries are eligible to participate and each such plan is in compliance in all material respects with the presently applicable provisions of ERISA and such regulations and published interpretations. Neither the Company nor any Subsidiary has incurred any material unpaid liability to the Pension Benefit Guaranty Corporation (other than for the payment of premiums in the ordinary course) or to any such plan under Title IV of ERISA.

(jj) The Company and the Subsidiaries own, have rights under, license or have other rights to use, on reasonable terms, all patents, patent applications, trade and service marks, trade and service mark registrations, trade names, copyrights, licenses, inventions, trade secrets, technology, know-how and other intellectual property (collectively, the “Intellectual Property”) necessary for the conduct of their business as now conducted; and neither the Company nor any of the Subsidiaries has received any notice of infringement of or conflict with asserted rights of others with respect to any Intellectual Property, which infringement or conflict, individually or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would result in a Material Adverse Effect.

(kk) Neither the Company nor any of the Subsidiaries have failed to file with applicable regulatory authorities (including, but not limited to, the FDA and DEA) any statement, report, information or form required by any applicable law, regulation or order, except where the failure to file or to be so in compliance would not, individually and in the aggregate, have a Material Adverse Effect. No deficiencies have been asserted by any regulatory commission, agency or authority with respect to any such filings or submissions, except for any such failures to be in compliance or deficiencies which would not, individually and in the aggregate, have a Material Adverse Effect.

(ll) The Company has established a compliance program (including a written compliance policy) to assist the Company and the Subsidiaries and their respective directors, officers and employees in complying with applicable regulatory agency guidelines (including, without limitation, those regulations and guidelines published by FDA and DEA), and to provide compliance policies governing applicable areas for pharmaceutical companies.

(mm) To the knowledge of the Company, there is and has been no failure on the part of the Company and any of the Company’s directors or officers, in their capacities as such, to comply with any provision of the Sarbanes-Oxley Act of 2002, as amended (the “Sarbanes-Oxley Act”), and the rules and regulations promulgated in connection therewith.

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(nn) Except as disclosed in the Disclosure Package, the Company and the Subsidiaries do not have any material lending or other relationship with any bank or lending Affiliate of the Initial Purchasers.

Any certificate signed by any officer of the Company and delivered to the Representative or counsel for the Initial Purchasers in connection with the offering of the Securities shall be deemed a representation and warranty by the Company, as to matters covered thereby, to each Initial Purchaser.

2. Purchase and Sale.

(a) Subject to the terms and conditions and in reliance upon the representations and warranties herein set forth, the Company agrees to sell to each Initial Purchaser, and each Initial Purchaser agrees, severally and not jointly, to purchase from the Company, at a purchase price of 97.5% of the principal amount thereof, the principal amount of Firm Securities set forth opposite such Initial Purchaser’s name in Schedule I hereto.

(b) Subject to the terms and conditions and in reliance upon the representations and warranties herein set forth, the Company hereby grants an option to the several Initial Purchasers to purchase, severally and not jointly, the Option Securities at the same purchase price as the Initial Purchasers shall pay for the Firm Securities, plus accrued interest, if any, from April 15, 2008 to the settlement date for the Option Securities. The option may be exercised only to cover over-allotments in the sale of the Firm Securities by the Initial Purchasers. The option may be exercised in whole or in part at any time or from time to time during the 13-day period beginning on the date of issuance of the Firm Securities upon written or telegraphic notice by the Representative to the Company setting forth the principal amount of Option Securities as to which the several Initial Purchasers are exercising the option and the settlement date. Delivery of the Option Securities, and payment therefor, shall be made as provided in Section 3 hereof. The principal amount of Option Securities to be purchased by each Initial Purchaser shall be the same percentage of the total principal amount of Option Securities to be purchased by the several Initial Purchasers as such Initial Purchaser is purchasing of the Firm Securities, subject to such adjustments as you in your absolute discretion shall make to eliminate any fractional Securities.

3. Delivery and Payment.

(a) Delivery of and payment for the Firm Securities and the Option Securities (if the option provided for in Section 2(b) hereof shall have been exercised on or before the first Business Day immediately preceding the Closing Date) shall be made at the offices of Cleary Gottlieb Steen & Hamilton LLP, counsel for the Initial Purchasers, at One Liberty Plaza, New York, New York 10006 at 10:00 AM, New York City time, on April 15, 2008, or at such time on such later date not more than three Business Days after the foregoing date as the Representative shall designate, which date and time may be postponed by agreement between the Representative and the Company or as provided in Section 9 hereof (such date and time of delivery and payment for the Securities being herein called the “Closing Date”). Delivery of the Securities shall be made to the Representative for the respective accounts of the several Initial Purchasers against payment by the several Initial Purchasers through the Representative of the purchase price thereof to or upon the order of the Company by wire transfer payable in same-day funds to such

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account or accounts as the Company and the Representative may mutually agree. Delivery of the Securities shall be made through the facilities of The Depository Trust Company unless the Representative shall otherwise instruct.

(b) If the option provided for in Section 2(b) hereof is exercised after the first Business Day immediately preceding the Closing Date, the Company will deliver the Option Securities (at the expense of the Company) to the Representative on the date specified by the Representative (which shall be within three Business Days after exercise of said option and shall not be later than the end of the 13-day period referred to above) for the respective accounts of the several Initial Purchasers, against payment by the several Initial Purchasers through the Representative of the purchase price thereof to or upon the order of the Company by wire transfer payable in same-day funds to such account or accounts as the Company and the Representative may mutually agree. If settlement for the Option Securities occurs after the Closing Date, the Company will deliver to the Representative on the settlement date for the Option Securities, and the obligation of the Initial Purchasers to purchase the Option Securities shall be conditioned upon receipt of, supplemental opinions, certificates and letters confirming as of such date the opinions, certificates and letters delivered on the Closing Date pursuant to Section 6 hereof.

4. Offering by the Initial Purchasers. (a) Each Initial Purchaser acknowledges that the Securities and the Common Stock issuable upon conversion thereof have not been and will not be registered under the Act and may not be offered or sold within the United States or to, or for the account or benefit of, U.S. persons, except pursuant to an exemption from, or in a transaction not subject to, the registration requirements of the Act.

(b) Each Initial Purchaser, severally and not jointly, represents and warrants to and agrees with the Company that:

(a) The Company will furnish to each Initial Purchaser and to counsel for the Initial Purchasers, without charge, during the period referred to in Section 5(c) below, as many copies of the materials contained in the Disclosure Package and the Final Memorandum and any amendments and supplements thereto as they may reasonably request.

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(b) The Company will not amend or supplement the Disclosure Package or the Final Memorandum, other than by filing documents under the Exchange Act that are incorporated by reference therein, without the prior written consent of the Representative; provided, however, that prior to the completion of the distribution of the Securities by the Initial Purchasers (as determined by the Initial Purchasers), the Company will not file any document under the Exchange Act that is incorporated by reference in the Disclosure Package or the Final Memorandum unless, prior to such proposed filing, the Company has furnished the Representative with a copy of such document for their review and the Representative has not reasonably objected to the filing of such document. The Company will promptly advise the Representative when any document filed under the Exchange Act that is incorporated by reference in the Disclosure Package or the Final Memorandum shall have been filed with the Commission.

(c) If at any time prior to the completion of the sale of the Securities by the Initial Purchasers (as determined by the Representative), any event occurs as a result of which the Disclosure Package or the Final Memorandum, as then amended or supplemented, would include any untrue statement of a material fact or omit to state any material fact necessary to make the statements therein, in the light of the circumstances under which they were made or the circumstances then prevailing, not misleading, or if it should be necessary to amend or supplement the Disclosure Package or the Final Memorandum to comply with applicable law, the Company will promptly (i) notify the Representative of any such event; (ii) subject to the requirements of Section 5(b), prepare an amendment or supplement that will correct such statement or omission or effect such compliance; and (iii) supply any supplemented or amended Disclosure Package or Final Memorandum to the several Initial Purchasers and counsel for the Initial Purchasers without charge in such quantities as they may reasonably request.

(d) Without the prior written consent of the Representative, the Company has not given and will not give to any prospective purchaser of the Securities any written information concerning the offering of the Securities other than materials contained in the Disclosure Package, the Final Memorandum or any other offering materials prepared by or with the prior written consent of the Representative.

(e) The Company will arrange, if necessary, for the qualification of the Securities for sale by the Initial Purchasers under the laws of such jurisdictions as the Representative may reasonably designate in writing and will maintain such qualifications in effect so long as required for the sale of the Securities; provided that in no event shall the Company be obligated to qualify as a foreign corporation or to do business in any jurisdiction where it is not now so qualified, to execute or file a general consent to service of process in any jurisdiction or to subject itself to taxation in any jurisdiction in which it is otherwise not so subject. The Company will promptly advise the Representative of the receipt by the Company of any notification with respect to the suspension of the qualification of the Securities for sale in any jurisdiction or the initiation or threatening of any proceeding for such purpose.

(f) Prior to removal of the restrictive legend from the Securities (or, if any Securities are converted while bearing a restrictive legend any Shares of Common Stock issued on such conversions), the Company will not, and will not permit any of its Affiliates to, resell any Securities or Shares of Common Stock issued upon conversion thereof that are acquired by any of them.

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(g) None of the Company, its Affiliates, or any person acting on its or their behalf will, directly or indirectly, make offers or sales of any security, or solicit offers to buy any security, under circumstances that would require the registration of the Securities or Common Stock issuable upon conversion thereof under the Act.

(h) None of the Company, its Affiliates, or any person acting on its or their behalf will engage in any form of general solicitation or general advertising (within the meaning of Regulation D) in connection with any offer or sale of the Securities in the United States.

(i) For so long as any of the Securities or the Common Stock issuable upon the conversion thereof are “restricted securities” within the meaning of Rule 144(a)(3) under the Act, the Company will, during any period in which it is not subject to and in compliance with Section 13 or 15(d) of the Exchange Act, provide to each holder of such restricted securities and to each prospective purchaser (as designated by such holder) of such restricted securities, upon the request of such holder or prospective purchaser, any information required to be provided by Rule 144A(d)(4) under the Act. This covenant is intended to be for the benefit of the holders, and the prospective purchasers designated by such holders, from time to time of such restricted securities.

(j) The Company will cooperate with the Representative and use its reasonable best efforts to permit the Securities to be eligible for clearance and settlement through The Depository Trust Company and to permit the Securities to be eligible for trading in PORTAL.

(k) The Company will reserve and keep available at all times, free of pre-emptive rights, the full number of shares of Common Stock issuable upon conversion of the Securities.

(l) Each of the Securities and the shares of Common Stock issuable upon conversion thereof will bear, to the extent applicable, the legend contained in “Notice to Investors; Transfer Restrictions” in the Preliminary Memorandum and the Final Offering Memorandum for the time period and upon the other terms stated therein.

(m) The Company will not, without the prior written consent of the Representative, offer, sell, contract to sell, pledge, or otherwise dispose of (or enter into any transaction which is designed to, or might reasonably be expected to, result in the disposition (whether by actual disposition or effective economic disposition due to cash settlement or otherwise) by the Company or any Affiliate of the Company or any person in privity with the Company or any Affiliate of the Company), directly or indirectly, including through the filing (or participation in the filing) of a registration statement (other than a registration statement on Form S-8) with the Commission in respect of, or establish or increase a put equivalent position or liquidate or decrease a call equivalent position within the meaning of Section 16 of the Exchange Act, any other shares of Common Stock or any securities convertible into, or exercisable, or exchangeable for, shares of Common Stock; or publicly announce an intention to effect any such transaction, for a period of 90 days after the date of this Agreement, provided, however, that the Company may (i) issue and sell the Securities pursuant to this Agreement, (ii) issue and/or sell Common

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Stock and grant stock options, restricted stock units or restricted stock pursuant to any employee stock incentive plan, stock ownership plan or dividend reinvestment plan of the Company in effect at the Execution Time and (iii) issue Common Stock issuable upon the conversion of securities outstanding at the Execution Time.

(n) The Company will not take, directly or indirectly, any action designed to or that would constitute or that might reasonably be expected to cause or result in stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Securities in violation of the Exchange Act.

(o) Between the date hereof and the Closing Date, the Company will not do or authorize any act or thing that would result in an adjustment of the conversion price of the Securities.

(p) The Company will, for a period of twelve months following the Execution Time, furnish to the Representative all reports or other communications (financial or other) generally made available to stockholders, and deliver such reports and communications to the Representative as soon as they are available, unless such documents are furnished to or filed with the Commission or any securities exchange on which any class of securities of the Company is listed and generally made available to the public.

(q) The Company will prepare a final term sheet, containing solely a description of the Securities and the offering thereof, in the form approved by you and attached as Schedule II hereto.

(r) The Company agrees to pay the costs and expenses relating to the following matters: (i) the preparation of the Transaction Agreements, the issuance of the Securities, the fees of the Trustee and the issuance of Common Stock upon conversion of the Securities; (ii) the preparation, printing or reproduction of the materials contained in the Disclosure Package and the Final Memorandum and each amendment or supplement to either of them; (iii) the printing (or reproduction) and delivery (including postage, air freight charges and charges for counting and packaging) of such copies of the materials contained in the Disclosure Package and the Final Memorandum and all amendments or supplements to either of them, as may, in each case, be reasonably requested for use in connection with the offering and sale of the Securities; (iv) the preparation, printing, authentication, issuance and delivery of the Securities; (v) any stamp or transfer taxes in connection with the original issuance and sale of the Securities; (vi) the printing (or reproduction) and delivery of this Agreement, any blue sky memorandum and all other agreements or documents printed (or reproduced) and delivered in connection with the offering of the Securities; (vii) any registration or qualification of the Securities for offer and sale under the securities or blue sky laws of the several states (including filing fees and the reasonable fees and expenses of counsel for the Initial Purchasers relating to such registration and qualification); (viii) admitting the Securities for trading in the PORTAL Market; (ix) transportation and other expenses incurred by or on behalf of Company representatives in connection with presentations to prospective purchasers of the Securities; (x) the fees and expenses of the Company’s accountants and the fees and expenses of counsel (including local and special counsel) for the Company; and (xi) all other costs and expenses incident to the performance by the Company of its obligations hereunder.

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6. Conditions to the Obligations of the Initial Purchasers. The obligations of the Initial Purchasers to purchase the Firm Securities and the Option Securities, as the case may be, shall be subject to the accuracy of the representations and warranties of the Company contained herein at the Execution Time, the Closing Date and any settlement date pursuant to Section 3 hereof, to the accuracy of the statements of the Company made in any certificates pursuant to the provisions hereof, to the performance by the Company of its obligations hereunder and to the following additional conditions:

(a) The Company shall have requested and caused Skadden, Arps, Slate, Meagher & Flom LLP, counsel for the Company, to furnish to the Representative its opinion and letter, dated the Closing Date and addressed to the Initial Purchasers, substantially in the forms attached hereto as Exhibits B and C, and Caroline B. Manogue, Esq., Chief Legal Officer of the Company, and Guy T. Donatiello, Esq., Vice President, Intellectual Property, to have furnished to the Representative their opinions, dated the Closing Date and addressed to the Initial Purchasers, substantially in the forms attached hereto as Exhibits D and E.

(b) The Company shall have requested and caused Wiley Rein LLP, special regulatory counsel for the Company, to furnish to the Representative their opinion, dated the Closing Date and addressed to the Initial Purchasers, substantially in the form attached hereto as Exhibit F.

(c) The Representative shall have received from Cleary Gottlieb Steen & Hamilton, LLP, counsel for the Initial Purchasers, such opinion or opinions, dated the Closing Date and addressed to the Initial Purchasers, with respect to the issuance and sale of the Securities, the Transaction Documents, the Disclosure Package, the Final Memorandum (as amended or supplemented at the Closing Date) and other related matters as the Representative may reasonably require, and the Company shall have furnished to such counsel such documents as they request for the purpose of enabling them to pass upon such matters.

(d) The Company shall have furnished to the Representative a certificate of the Company, signed by the Chief Executive Officer and the Chief Financial Officer of the Company, dated the Closing Date, to the effect that the signers of such certificate have carefully examined the Disclosure Package and the Final Memorandum, and any amendments or supplements thereto, and this Agreement and that:

(e) At the Execution Time and at the Closing Date, the Company shall have requested and caused Deloitte & Touche LLP to furnish to the Representative letters, dated respectively as

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of the Execution Time and as of the Closing Date, in form and substance satisfactory to the Representative and confirming that they are independent accountants within the meaning of the Exchange Act and which should cover, among other customary matters, the Preliminary Memorandum and the Final Memorandum (and any amendments or supplements thereto at the date of the applicable letter).

(f) Subsequent to the Execution Time or, if earlier, the dates as of which information is given in the Disclosure Package (exclusive of any amendment or supplement thereto) and the Final Memorandum (exclusive of any amendment or supplement thereto), there shall not have been (i) any change or decrease specified in the letters referred to in paragraph (e) of this Section 6 or (ii) any change, or any development involving a prospective change, in or affecting the condition (financial or otherwise), earnings, business or properties of the Company and the Subsidiaries, taken as a whole, whether or not arising from transactions in the ordinary course of business, except as set forth in or contemplated in the Disclosure Package and the Final Memorandum (exclusive of any amendment or supplement thereto), the effect of which, in any case referred to in clause (i) or (ii) above, is, in the sole judgment of the Representative, so material and adverse as to make it impractical or inadvisable to proceed with the offering or delivery of the Securities as contemplated in the Disclosure Package and the Final Memorandum (exclusive of any amendment or supplement thereto).

(g) Prior to the Closing Date, the Company shall have furnished to the Underwriter such further information, customary closing and secretary certificates and documents as the Underwriter may reasonably request.

(h) The Securities have been designated as PORTAL-eligible securities in accordance with the rules and regulations of the Nasdaq and the Securities shall be eligible for clearance and settlement through The Depository Trust Company.

(i) The Company shall have taken the steps required for listing of the shares of Common Stock initially issuable upon conversion of the Securities, subject to notice of issuance, on The Nasdaq Global Select Market.

(j) Prior to the Execution Time, the Company shall have furnished to the Representative a letter substantially in the form of Exhibit A hereto from each executive officer and director of the Company, addressed to the Initial Purchasers.

If any of the conditions specified in this Section 6 shall not have been fulfilled when and as provided in this Agreement, or if any of the opinions and certificates mentioned above or elsewhere in this Agreement shall not be reasonably satisfactory in form and substance to the Representative and counsel for the Initial Purchasers, this Agreement and all obligations of the Initial Purchasers hereunder may be cancelled at, or at any time prior to, the Closing Date by the Representative. Notice of such cancellation shall be given to the Company in writing or by telephone or facsimile confirmed in writing.

The documents required to be delivered by this Section 6 shall be delivered at the offices of Cleary Gottlieb Steen & Hamilton LLP on the Closing Date.

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7. Reimbursement of the Initial Purchasers’ Expenses. If the sale of the Securities provided for herein is not consummated because any condition to the obligations of the Initial Purchasers set forth in Section 6 hereof is not satisfied, because of any termination pursuant to Section 10 hereof or because of any refusal, inability or failure on the part of the Company to perform any agreement herein or comply with any provision hereof other than by reason of a default by the Initial Purchasers, the Company will reimburse the Initial Purchasers severally through the Representative on demand for all out-of-pocket expenses (including reasonable fees and disbursements of counsel) that shall have been reasonably incurred by them in connection with the proposed purchase and sale of the Securities.

8. Indemnification and Contribution.

(a) The Company agrees to indemnify and hold harmless each Initial Purchaser, the directors, officers, employees, Affiliates and agents of each Initial Purchaser and each person who controls any Initial Purchaser within the meaning of either the Act or the Exchange Act against any and all losses, claims, damages or liabilities, joint or several, to which they or any of them may become subject under the Act, the Exchange Act or other U.S. federal or state statutory law or regulation, at common law or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon any untrue statement or alleged untrue statement of a material fact contained in the Disclosure Package, the Final Memorandum, or in any amendment or supplement thereto, or arise out of or are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading, and agrees to reimburse each such indemnified party, as incurred, for any legal or other expenses reasonably incurred by it in connection with investigating or defending any such loss, claim, damage, liability or action; provided, however, that the Company will not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon any such untrue statement or alleged untrue statement or omission or alleged omission made in the Disclosure Package, the Final Memorandum, or in any amendment or supplement thereto, in reliance upon and in conformity with written information furnished to the Company by or on behalf of any Initial Purchaser through the Representative specifically for inclusion therein. This indemnity agreement will be in addition to any liability that the Company may otherwise have.

(b) Each Initial Purchaser severally, and not jointly, agrees to indemnify and hold harmless the Company, each of its directors, each of its officers and each person who controls the Company within the meaning of either the Act or the Exchange Act, to the same extent as the foregoing indemnity to each Initial Purchaser, but only with reference to written information relating to such Initial Purchaser furnished to the Company by or on behalf of such Initial Purchaser through the Representative specifically for inclusion in the Disclosure Package, the Final Memorandum or in any amendment or supplement thereto. This indemnity agreement will be in addition to any liability that any Initial Purchaser may otherwise have. The Company acknowledges that the following statements constitute the only information furnished in writing by or on behalf of such Initial Purchaser through the Representative for inclusion in the Disclosure Package, the Final Memorandum or in any amendment or supplement thereto: the last paragraph on the cover page of the Preliminary Memorandum and Final Memorandum regarding delivery of the Securities, the names of the Initial Purchasers set forth on the cover page and in

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the “Plan of Distribution” thereof and, under the heading “Plan of Distribution” thereof the ninth paragraph, relating stabilization, syndicate covering transactions and penalty bids, and the twelfth paragraph relating to one of the Initial Purchasers.

(c) Promptly after receipt by an indemnified party under this Section 8 of notice of the commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against the indemnifying party under this Section 8, notify the indemnifying party in writing of the commencement thereof; but the failure so to notify the indemnifying party (i) will not relieve it from liability under paragraph (a) or (b) above unless and to the extent it did not otherwise learn of such action and such failure results in the forfeiture by the indemnifying party of substantial rights and defenses and (ii) will not, in any event, relieve the indemnifying party from any obligations to any indemnified party other than the indemnification obligation provided in paragraph (a) or (b) above. The indemnifying party shall be entitled to appoint counsel (including local counsel) of the indemnifying party’s choice at the indemnifying party’s expense to represent the indemnified party in any action for which indemnification is sought (in which case the indemnifying party shall not thereafter be responsible for the fees and expenses of any separate counsel, other than local counsel if not appointed by the indemnifying party, retained by the indemnified party or parties except as set forth below); provided, however, that such counsel shall be satisfactory to the indemnified party. Notwithstanding the indemnifying party’s election to appoint counsel (including local counsel) to represent the indemnified party in an action, the indemnified party shall have the right to employ separate counsel (including local counsel), and the indemnifying party shall bear the reasonable fees, costs and expenses of such separate counsel if (i) the use of counsel chosen by the indemnifying party to represent the indemnified party would present such counsel with a conflict of interest; (ii) the actual or potential defendants in, or targets of, any such action include both the indemnified party and the indemnifying party and the indemnified party shall have reasonably concluded that there may be legal defenses available to it and/or other indemnified parties that are different from or additional to those available to the indemnifying party; (iii) the indemnifying party shall not have employed counsel satisfactory to the indemnified party to represent the indemnified party within a reasonable time after notice of the institution of such action; or (iv) the indemnifying party shall authorize the indemnified party to employ separate counsel at the expense of the indemnifying party. An indemnifying party will not, without the prior written consent of the indemnified parties, settle or compromise or consent to the entry of any judgment with respect to any pending or threatened claim, action, suit or proceeding in respect of which indemnification or contribution may be sought hereunder (whether or not the indemnified parties are actual or potential parties to such claim or action) unless such settlement, compromise or consent includes an unconditional release of each indemnified party from all liability arising out of such claim, action, suit or proceeding.

(d) In the event that the indemnity provided in paragraph (a) or (b) of this Section 8 is unavailable to or insufficient to hold harmless an indemnified party for any reason, the Company and the Initial Purchasers severally agree to contribute to the aggregate losses, claims, damages and liabilities (including legal or other expenses reasonably incurred in connection with investigating or defending any loss, claim, damage, liability or action) (collectively “Losses”) to which the Company and one or more of the Initial Purchasers may be subject in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and by the Initial Purchasers on the other from the offering of the Securities; provided, however, that in no case shall any Initial Purchaser be responsible for any amount in excess of the purchase

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discount or commission applicable to the Securities purchased by such Initial Purchaser hereunder. If the allocation provided by the immediately preceding sentence is unavailable for any reason, the Company and the Initial Purchasers severally shall contribute in such proportion as is appropriate to reflect not only such relative benefits but also the relative fault of the Company on the one hand and the Initial Purchasers on the other in connection with the statements or omissions that resulted in such Losses, as well as any other relevant equitable considerations. Benefits received by the Company on the one hand shall be deemed to be equal to the total net proceeds from the offering (before deducting expenses) received by it, and benefits received by the Initial Purchasers on the other shall be deemed to be equal to the total purchase discounts and commissions. Relative fault shall be determined by reference to, among other things, whether any untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information provided by the Company on the one hand or the Initial Purchasers on the other, the intent of the parties and their relative knowledge, access to information and opportunity to correct or prevent such untrue statement or omission. The Company and the Initial Purchasers agree that it would not be just and equitable if contribution were determined by pro rata allocation or any other method of allocation that does not take account of the equitable considerations referred to above. Notwithstanding the provisions of this paragraph (d), no person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. For purposes of this Section 8, each person who controls an Initial Purchaser within the meaning of either the Act or the Exchange Act and each director, officer, employee, Affiliate and agent of an Initial Purchaser shall have the same rights to contribution as such Initial Purchaser, and each person who controls the Company within the meaning of either the Act or the Exchange Act and each officer and director of the Company shall have the same rights to contribution as the Company, subject in each case to the applicable terms and conditions of this paragraph (d).

9. Default by an Initial Purchaser. If any one or more Initial Purchasers shall fail to purchase and pay for any of the Securities agreed to be purchased by such Initial Purchaser hereunder and such failure to purchase shall constitute a default in the performance of its or their obligations under this Agreement, the remaining Initial Purchasers shall be obligated severally to take up and pay for (in the respective proportions which the principal amount of Securities set forth opposite their names in Schedule I hereto bears to the aggregate principal amount of Securities set forth opposite the names of all the remaining Initial Purchasers) the Securities which the defaulting Initial Purchaser or Initial Purchasers agreed but failed to purchase; provided, however, that in the event that the aggregate principal amount of Securities which the defaulting Initial Purchaser or Initial Purchasers agreed but failed to purchase shall exceed 10% of the aggregate principal amount of Securities set forth in Schedule I hereto, the remaining Initial Purchasers shall have the right to purchase all, but shall not be under any obligation to purchase any, of the Securities, and if such nondefaulting Initial Purchasers do not purchase all the Securities, this Agreement will terminate without liability to any nondefaulting Initial Purchaser or the Company. In the event of a default by any Initial Purchaser as set forth in this Section 9, the Closing Date shall be postponed for such period, not exceeding five Business Days, as the Representative shall determine in order that the required changes in the Final Memorandum or in any other documents or arrangements may be effected. Nothing contained in this Agreement shall relieve any defaulting Initial Purchaser of its liability, if any, to the Company or any nondefaulting Initial Purchaser for damages occasioned by its default hereunder.

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10. Termination. This Agreement shall be subject to termination in the absolute discretion of the Representative by notice given to the Company by the Representative, prior to delivery of and payment for the Securities, if at any time prior to such time (i) trading in the Company’s Common Stock shall have been suspended by the Commission or The Nasdaq Global Select Market or trading in securities generally on the New York Stock Exchange or The Nasdaq Global Select Market shall have been suspended or limited or minimum prices shall have been established on such Exchange or The Nasdaq Global Select Market, (ii) a banking moratorium shall have been declared either by U.S. federal or New York State authorities or (iii) there shall have occurred any outbreak or escalation of hostilities, declaration by the United States of a national emergency or war or other calamity or crisis the effect of which on financial markets is such as to make it, in the sole judgment of the Representative, impractical or inadvisable to proceed with the offering or delivery of the Securities as contemplated in the Disclosure Package and the Final Memorandum (exclusive of any amendment or supplement thereto).

11. Representations and Indemnities to Survive. The respective agreements, representations, warranties, indemnities and other statements of the Company or its officers and of the Initial Purchasers set forth in or made pursuant to this Agreement will remain in full force and effect, regardless of any investigation made by or on behalf of the Initial Purchasers, the Company or any indemnified persons referred to in Section 8 hereof, and will survive delivery of and payment for the Securities. The provisions of Sections 7 and 8 hereof shall survive the termination or cancellation of this Agreement.

12. Notices. All communications hereunder will be in writing and effective only on receipt, and, if sent to the Representative, will be mailed, delivered or telefaxed to Deutsche Bank Securities Inc., 60 Wall Street, 4th Floor, New York, New York 10005; Attention: Syndicate Manager, fax number: (212)  ###-###-####, with a copy to Deutsche Bank Securities Inc., 60 Wall Street, New York, New York 10005, Attention: General Counsel, fax number (212)  ###-###-####, and copied to Cleary Gottlieb Steen & Hamilton, LLP, One Liberty Plaza, New York, NY 10006, Attention: Leslie N. Silverman, Esq. (fax no. (212)  ###-###-####), or, if sent to the Company, will be mailed, delivered or telefaxed to Endo Pharmaceuticals Holdings Inc. (fax no.: (610)  ###-###-####) and confirmed to the Chief Legal Officer, Endo Pharmaceuticals Holdings Inc. at 100 Endo Boulevard, Chadds Ford, PA 19317, Attention: Caroline B. Manogue, Esq., and copied to Skadden, Arps, Slate, Meagher & Flom LLP, 4 Times Square, New York, NY 10036, Attention: Stacy J. Kanter, Esq. (fax no.: (917)  ###-###-####).

13. Successors. This Agreement will inure to the benefit of and be binding upon the parties hereto and their respective successors and the indemnified persons referred to in Section 8 hereof, and their respective successors, and, except as expressly set forth in Section 5(j) hereof, no other person will have any right or obligation hereunder.

14. Applicable Law. This Agreement will be governed by and construed in accordance with the laws of the State of New York applicable to contracts made and to be performed within the State of New York.

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15. Waiver of Jury Trial. The Company 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.

16. Counterparts. This Agreement may be signed in one or more counterparts, each of which shall constitute an original and all of which together shall constitute one and the same agreement.

17. Headings. The section headings used herein are for convenience only and shall not affect the construction hereof.

18. Definitions. The terms that follow, when used in this Agreement, shall have the meanings indicated.

“Act” shall mean the Securities Act of 1933, as amended, and the rules and regulations of the Commission promulgated thereunder.

“Affiliate” shall have the meaning specified in Rule 501(b) of Regulation D.

“Business Day” shall mean any day other than a Saturday, a Sunday or a legal holiday or a day on which banking institutions or trust companies are authorized or obligated by law to close in The City of New York.

“Commission” shall mean the Securities and Exchange Commission.

“Disclosure Package” shall mean (i) the Preliminary Memorandum, as amended or supplemented at the Execution Time, (ii) the final term sheet prepared pursuant to Section 5(t) hereof and in the form attached as Schedule II hereto and (iii) any Issuer Written Information.

“Exchange Act” shall mean the Securities Exchange Act of 1934, as amended, and the rules and regulations of the Commission promulgated thereunder.

“Execution Time” shall mean the date and time that this Agreement is executed and delivered by the parties hereto, which shall be deemed to be 11:30 p.m. (New York City time) on the date hereof.

“Issuer Written Information” shall mean any writings in addition to the Preliminary Memorandum that the parties expressly agree in writing to treat as part of the Disclosure Package.

“Nasdaq” shall mean The NASDAQ OMX Group, Inc.

“Person” shall mean any natural person, corporation, limited liability company, trust, joint venture, association, company, partnership, governmental authority or other entity.

“PORTAL” shall mean the Private Offerings, Resales and Trading through Automated Linkages system of the Nasdaq.

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“Regulation D” shall mean Regulation D under the Act.

“Regulation S-X” shall mean Regulation S-X under the Act.

19. Integration. This Agreement supersedes all prior agreements and understandings (whether written or oral) between the Company and the Initial Purchasers, or any of them, with respect to the offering of Securities hereunder.

If the foregoing is in accordance with your understanding of our agreement, please sign and return to us the enclosed duplicate hereof, whereupon this letter and your acceptance shall represent a binding agreement between the Company and the several Initial Purchasers.

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SCHEDULE I

1