ASSIGNMENT, ASSUMPTION AND CONSENT

EXHIBIT 10.45

ASSIGNMENT, ASSUMPTION AND CONSENT

THIS ASSIGNMENT, ASSUMPTION AND CONSENT (this “Agreement”) is dated as of January 31, 2007 (the “Effective Date”), by and among Jazz Pharmaceuticals, Inc., a Delaware corporation (“Assignee”), Solvay Pharmaceuticals, Inc., a Georgia corporation (“Assignor”) and Elan Pharma International Limited, a company incorporated in Ireland (“Elan”).

WITNESSETH

(A) WHEREAS, Assignor and Elan Corporation, plc entered into a license agreement dated December 22, 1997 as amended by Amendment No. 1 to the License Agreement dated March 1, 1999, Amendment No. 2 to the License Agreement dated April 13, 2000 and Amendment No. 3 to the License Agreement dated November 7, 2006 (collectively, the “Elan Agreement”);

(B) WHEREAS, Solvay and Solvay Pharmaceuticals Marketing & Licensing AG of Binningerstrasse 94, 4123 Allschwil, Switzerland (“SPML”) entered into an Assignment and Assumption Agreement of the Elan Agreement dated 4 August 2000 (the “Assignment Agreement”) which was subsequently re-assigned back by SPML to Solvay through a letter agreement for reassignment and re-assumption dated 13 December 2001, (the “Re-assignment Agreement”), and said Assignment Agreement and Re-assignment Agreement were consented to by Elan Corporation plc.;

(C) WHEREAS, on December 31, 2006, Elan Corporation, plc assigned all of its rights and obligations under the Elan Agreement to its Affiliate, Elan, and Elan has assumed said rights and obligations, as Assignor and Assignee hereby acknowledge;

(D) WHEREAS, Assignor desires to assign all of its right, title and interest in and to the Elan Agreement to Assignee, and Assignee desires to assume all of Assignors’ right, title and interest in and to the Elan Agreement;

(E) WHEREAS, in accordance with Article XII, Section 2 of the Elan Agreement, Elan is willing to consent to such assignment and assumption on the terms set out below;

(F) WHEREAS all parties have agreed to the terms of this Agreement setting out how their respective future contractual relationship shall be governed; and

(G) WHEREAS the parties also wish to clarify that monies currently held on account by Elan for Assignor as of the date of this Agreement may be applied by Elan to cover the costs of on-going engineering and other work that is conducted by Elan under the Agreement before, on or after the Effective Date.

NOW, THEREFORE, the parties agree as follows:

Unless otherwise mutually agreed in writing by the parties:

If to Assignor to:

Solvay Pharmaceuticals, Inc.

901 Sawyer Road

Marietta, Georgia 30062

Attention: Office of the President

cc: General Counsel

Facsimile: 770 ###-###-####

If to Assignee to:

Jazz Pharmaceuticals, Inc.

3180 Porter Drive

Palo Alto, California 94304

United States of America

Fax: 650 ###-###-####

Attention: General Counsel

With a copy to:

Jazz Pharmaceuticals, Inc.

3180 Porter Drive

Palo Alto, California 94304

United States of America

Fax: 650 ###-###-####

Attention: Executive Vice President, Chief Business Officer

If to Elan:

Elan Pharma International Limited

Monksland

Athlone

Co Westmeath

Ireland

Fax: +353 90 ###-###-####

Attention: Vice President and Legal Counsel

With a copy to:

Elan Pharma International Limited

Treasury Building

Lower Grand Canal Street

Dublin 2

Ireland

Fax: +353 1 ###-###-####

Attention: Vice President, Commercial Management

“IND” means Investigational New Drug Application as set forth in the 21 C.F.R. Section 312 in the United States and/or its equivalent in the other countries of the Territory.

“NDA” means a New Drug Application in the United States made in accordance with applicable regulations and requirements of the FDA as from time to time in effect and/or its equivalent in the other countries of the Territory.

{Reminder of Page Intentionally Left Blank; Signature Page Follows}

IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be duly executed as of the Effective Date.