Exhibit 10.16(a)**FIRST AMENDMENT**     This First Amendment (this “**Amendment**”) is entered into as of December 11, 2006, by and amongKENDLE INTERNATIONAL INC., an Ohio corporation (“**Borrower**”), the Guarantors listed on the signaturepages hereof, the Lenders signatory hereto, and UBS AG, STAMFORD BRANCH, as Administrative Agentfor the Lenders (in such capacity, “**Administrative Agent**”).**RECITALS**     WHEREAS, Borrower, the Guarantors, the Lenders, the Administrative Agent, UBS SECURITIESLLC, as sole lead arranger and sole bookrunner, UBS AG, STAMFORD BRANCH, as issuing bank andcollateral agent, UBS LOAN FINANCE LLC, as swingline lender, JPMORGAN CHASE BANK, N.A., assyndication agent, and KEYBANK NATIONAL ASSOCIATION, LASALLE BANK NATIONAL ASSOCIATION, andNATIONAL CITY BANK, as co-documentation agents, are parties to that certain Credit Agreement datedas of August 16, 2006 (the “**Credit Agreement**”) (capitalized terms used herein without definitionhave the meanings ascribed to such terms in the Credit Agreement);     WHEREAS, Borrower has requested certain changes to Section 5.10 of the Credit Agreement;     WHEREAS, the Administrative Agent and the Required Lenders have agreed to amend Section 5.10of the Credit Agreement on the terms and subject to the conditions set forth herein;     NOW THEREFORE, in consideration of the premises and the mutual covenants herein contained, theparties hereto hereby agree as follows:          Section 1. Section References. Unless otherwise expressly stated herein, all Sectionreferences herein shall refer to Sections of the Credit Agreement.          Section 2. Amendment of Section 5.10 (Interest Rate Protection). Section 5.10 ishereby amended by deleting the clause in its entirety and replacing it with the following:No later than the 210th day after the Closing Date, Borrower shall enter into, and for aminimum of three years thereafter maintain, Hedging Agreements with terms and conditionsreasonably acceptable to the Administrative Agent that result in at least 40% of theaggregate principal amount of Borrower’s Consolidated Indebtedness other than RevolvingLoans being effectively subject to a fixed or maximum interest rate.          Section 3. Conditions Precedent. The effectiveness of this Amendment is subject tothe satisfaction of each of the following conditions precedent:          (a) The Administrative Agent shall have received all of the following, in form and substancesatisfactory to the Administrative Agent:              (i) Amendment Documents. This Amendment, duly executed by the Borrowerand the Guarantors (the “Amendment Documents”);
 

 
              (ii) Consent of Required Lenders. The written consent of the RequiredLenders to this Amendment; and              (iii) Additional Information. Such additional documents, instrumentsand information as the Administrative Agent may reasonably request to effect thetransactions contemplated hereby.          (b) The representations and warranties contained herein and in the Credit Agreement shall betrue and correct in all material respects as of the date hereof as if made on the date hereof(except for those which by their terms specifically refer to an earlier date, in which case suchrepresentations and warranties shall be true and correct in all material respects as of suchearlier date).          (c) All corporate proceedings taken in connection with the transactions contemplated by thisAmendment and all other agreements, documents and instruments executed or delivered pursuanthereto, and all legal matters incident thereto, shall be reasonably satisfactory to theAdministrative Agent.          (d) No Default or Event of Default shall have occurred and be continuing, after giving effectto this Amendment.          Section 4. Representations and Warranties. The Borrower hereby represents andwarrants to the Administrative Agent and the Lenders that, as of the date of and after givingeffect to this Amendment, (a) the execution, delivery and performance of this Amendment and any andall other Amendment Documents executed and/or delivered in connection herewith have been authorizedby all requisite corporate action on the part of the Borrower and will not violate the Borrower’scertificate of incorporation or bylaws, (b) all representations and warranties set forth in theCredit Agreement and in any other Loan Document are true and correct in all material respects as ifmade again on and as of such date (except those, if any, which by their terms specifically relateonly to an earlier date, in which case such representations and warranties are true and correct inall material respects as of such earlier date), and (c) no Default or Event of Default has occurredand is continuing.          Section 5. Survival of Representations and Warranties. All representations andwarranties made in this Amendment or any other Loan Document shall survive the execution anddelivery of this Amendment and the other Loan Documents, and no investigation by the AdministrativeAgent or the Lenders, or any closing, shall affect the representations and warranties or the rightof the Administrative Agent and the Lenders to rely upon them.          Section 6. Certain Waivers. Each of the Borrower and the Guarantors hereby agreesthat neither the Administrative Agent nor any Lender shall be liable under a claim of, and herebywaives any claim against the Administrative Agent and the Lenders based on, lender liability(including, but not limited to, liability for breach of the implied covenant of good faith and fairdealing, fraud, negligence, conversion, misrepresentation, duress, control and interference,infliction of emotional distress and defamation and breach of fiduciary duties) as a result of theamendments contained in Section 2 above and any discussions or actions taken or not taken by theAdministrativeAgent or the Lenders on or before the date hereof or the discussions conducted in connection
 

 
therewith, or any course of action taken by the Administrative Agent or any Lender in responsethereto or arising therefrom; provided, that the foregoing waiver shall not include thewaiver of any claims which are based on the gross negligence or willful misconduct of theAdministrative Agent or any Lender or any of their respective agents. This Section 6 shall survivethe execution and delivery of this Amendment and the other Loan Documents and the termination ofthe Credit Agreement.          Section 7. Reference to Agreement. Each of the Loan Documents, including the CreditAgreement, and any and all other agreements, documents or instruments now or hereafter executedand/or delivered pursuant to the terms hereof or pursuant to the terms of the Credit Agreement asamended hereby, are hereby amended so that any reference in such Loan Documents to the CreditAgreement, whether direct or indirect, shall mean a reference to the Credit Agreement as amendedhereby.          Section 8. Costs and Expenses. The Borrower shall pay on demand all reasonableout-of-pocket costs and expenses of the Administrative Agent (including the reasonable fees, costsand expenses of counsel to the Administrative Agent) incurred in connection with the preparation,execution and delivery of this Amendment.          Section 9. Governing Law. THIS AMENDMENT SHALL BE GOVERNED BY, AND CONSTRUED INACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.          Section 10. Headings. Section Headings in this Amendment are included herein forconvenience of reference only and shall not constitute a part of this Amendment for any otherpurposes.          Section 11. Execution. This Amendment may be executed in any number of counterpartsand by different parties hereto in separate counterparts, each of which when so executed shall bedeemed to be an original and all of which taken together shall constitute one and the sameagreement. Delivery of an executed counterpart of a signature page to this Amendment by telecopiershall be effective as delivery of a manually executed counterpart of this Amendment.          Section 12. Limited Effect. This Amendment relates only to the specific matterscovered herein, shall not be considered to be a waiver of any rights any Lender may have under theCredit Agreement (other than as expressly set forth herein), and shall not be considered to createa course of dealing or to otherwise obligate any Lender to execute similar amendments under thesame or similar circumstances in the future.          Section 13. Ratification By Guarantors. Each Guarantor hereby agrees to thisAmendment, and each Guarantor acknowledges that such Guarantor’s Guarantee shall remain in fullforce and effect without modification thereto.[*signature pages follow*]
 

 
     IN WITNESS WHEREOF, the parties hereto have caused this amendment to be executed by theirrespective officers thereunto duly authorized, as of the date first above written.         KENDLE INTERNATIONAL INC.           By:         Name:      Title:           KENDLE U.K. INC.           By:         Name:      Title:           ACER/EXCEL INC.           By:         Name:      Title:           AAC CONSULTING GROUP, INC.           By:         Name:      Title:           KENDLE INTERNATIONAL CPU LLC           By:         Name:      Title:           KENDLE AMERICAS HOLDING INC.           By:         Name:      Title:  
 

 
         KENDLE AMERICAS INVESTMENT INC.           By:         Name:      Title:           KENDLE AMERICAS MANAGEMENT INC.           By:         Name:      Title:           KENDLE DELAWARE INC.           By:         Name:      Title:           KENDLE NC INC.           By:         Name:      Title:           KENDLE CLINICAL DEVELOPMENT SERVICES LIMITED (formerly known as Charles River Laboratories Clinical Services International Ltd.)           By:         Name:      Title:           UBS AG, STAMFORD BRANCH,    as Administrative Agent           By:         Name:      Title:           By:         Name:      Title:           LENDERS:                         By:         Name:      Title: