IMPAX Comments on Merck's Lawsuit Related to Generic Version of Sinemet CR

February 24, 2003

Feb. 24, 2003--IMPAX Laboratories, Inc. (NASDAQ:IPXL) today announced that Merck & Co. Inc. has filed a lawsuit against the Company in the federal district court in Delaware alleging patent infringement related to IMPAX's filing of an Abbreviated New Drug Application (ANDA) for a generic version of Sinemet® CR tablets.

Sinemet CR is used to treat patients with Parkinsonism, and is exclusively distributed in the U.S. by Bristol-Myers Squibb Company. U.S. sales of Sinemet CR and the currently marketed generic equivalent were approximately $154 million in the 12 months ended December 31, 2002, according to IMS Health data. The FDA accepted for review IMPAX's application to market a generic version of Merck's Sinemet CR in December 2002. IMPAX's submission includes a Paragraph IV certification stating the Company believes its product does not infringe upon Merck's listed Sinemet CR patents.

Barry R. Edwards, Co-Chief Executive Officer of IMPAX Laboratories, commented, "This type of lawsuit is standard practice in the industry and we are not surprised by Merck's action. It has become part of the process in getting these complex generic products to market. We believe our product as formulated does not infringe upon Merck's patents and will provide a safe, effective and economical alternative in the marketplace. We will proceed accordingly to defend our application."

IMPAX has 19 applications pending at the FDA, including three tentatively approved, that address more than $5.8 billion in U.S. branded product sales for the 12 months ended December 31, 2002. Thirteen of these filings were made under Paragraph IV of the Hatch-Waxman Amendments.

IMPAX Laboratories, Inc. is a technology based specialty pharmaceutical company applying its formulation expertise and drug delivery technology to the development of controlled-release and specialty generics in addition to the development of branded products. IMPAX markets its generic products through its Global Pharmaceuticals division and intends to market its branded products through the IMPAX Pharmaceuticals division. Additionally, where strategically appropriate, IMPAX has developed marketing partnerships to fully leverage its technology platform. IMPAX Laboratories is headquartered in Hayward, California, and has a full range of capabilities in its Hayward and Philadelphia facilities. For more information, please visit the Company's Web site at: