IMPAX ANDA Filing for Generic Version of Adderall XR Accepted by FDA.

Business Editors/Health/Medical Writers

HAYWARD, Calif.--(BUSINESS WIRE)--Nov. 19, 2003

IMPAX Laboratories, Inc. (Nasdaq:IPXL) today announced that the United States Food and Drug Administration (FDA) has accepted the Company's filing of an Abbreviated New Drug Application (ANDA) for a generic version of Adderall XR(R) 30mg Capsules. Adderall XR is a once daily extended-release, mixed salts of a single-entity amphetamine product. Shire Pharmaceuticals Group plc (Nasdaq:SHPGY) (TSX:SHQ) (LSE:SHP) markets the product for the treatment of Attention Deficit and Hyperactivity Disorder (ADHD). According to NDCHealth, U.S. sales of Adderall XR Capsules were approximately $540 million in the twelve months ended September 30, 2003. Shire received initial FDA approval of this product in October of 2001.

IMPAX's application includes a certification under Paragraph IV of the Hatch-Waxman Amendments stating the Company's belief that its generic version of Adderall XR Capsules does not infringe certain Shire listed patents on Adderall XR Capsules. FDA's acceptance of the IMPAX ANDA for filing means that the Agency has made a threshold determination that the application is sufficiently complete to permit a substantive review.

IMPAX has 18 applications pending at the FDA, including three tentatively approved that address approximately $7 billion in U.S. branded product sales for the 12 months ended September 30, 2003. Fourteen 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: www.impaxlabs.com.

"Safe Harbor" statement under the Private Securities Litigation Reform Act of 1995:

To the extent any statements made in this news release contain information that is not historical, these statements are forward-looking in nature and express the beliefs and expectations of management. Such statements are based on current expectations and involve a number of known and unknown risks and uncertainties that could cause Impax's future results, performance or achievements to differ significantly from the results, performance or achievements expressed or implied by such forward-looking statements. Such risks and uncertainties include, but are not limited to, Impax's ability to obtain sufficient capital to fund its operations, the difficulty of predicting FDA filings and approvals, consumer acceptance and demand for new pharmaceutical products, the impact of competitive products and pricing, Impax's ability to successfully develop and commercialize pharmaceutical products, Impax's reliance on key strategic alliances, the uncertainty of patent litigation, the availability of raw materials, the regulatory environment, dependence on patent and other protection for innovative products, exposure to product liability claims, fluctuations in operating results and other risks detailed from time to time in Impax's filings with the Securities and Exchange Commission. Forward-looking statements speak only as to the date on which they are made, and Impax undertakes no obligation to update publicly or revise any forward-looking statement, regardless of whether new information becomes available, future developments occur or otherwise.