Impax Laboratories Confirms Patent Suit Relating to Generic Detrol(R) Immediate-Release 1 mg and 2 mg Tablets

Impax Laboratories, Inc. (NASDAQ:IPXL) today confirms that Pfizer Inc., Pharmacia & Upjohn Company LLC and Pfizer Health AB (collectively, "Pfizer") have filed suit for patent infringement against Impax in the United States District Court for the District of New Jersey in connection with Detrol® (tolterodine tartrate) immediate-release, 1 mg and 2 mg tablets. Impax filed its Abbreviated New Drug Application (ANDA) containing a paragraph IV certification for a generic version of Detrol® with the U.S. Food & Drug Administration (FDA).Following receipt of the notice from the FDA that Impax's ANDA had been accepted for filing, Impax notified the New Drug Application holder and patent owner of its paragraph IV certification. On May 31, Pfizer filed suit for patent infringement against Impax formally initiating the patent challenge process under the Hatch-Waxman Act. Detrol® is indicated for the treatment of overactive bladder and urinary incontinence. According to Wolters Kluwer Health, U.S. sales of Detrol® immediate-release, 1 mg and 2 mg tablets were approximately $62 million for the 12 months ended March 2011.

About Impax Laboratories, Inc.  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 markets its branded products through the Impax Pharmaceuticals division. Additionally, where strategically appropriate, Impax has developed marketing partnerships to fully leverage its technology platform. Impax is headquartered in Hayward, California, and has a full range of capabilities in its Hayward, Philadelphia and Taiwan 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 the Company'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 the effect of current economic conditions on the Company's industry, business, financial position, results of operations and market value of its common stock, the ability to maintain an effective system of internal control over financial reporting, fluctuations in revenues and operating income, reductions or loss of business with any significant customer, the impact of competitive pricing and products and regulatory actions on the Company's products, the ability to sustain profitability and positive cash flows, the ability to maintain sufficient capital to fund operations, the ability to successfully develop and commercialize pharmaceutical products, the uncertainty of patent litigation, consumer acceptance and demand for new pharmaceutical products, the difficulty of predicting FDA filings and approvals, the inexperience of the Company in conducting clinical trials and submitting New Drug Applications, reliance on key alliance and collaboration agreements, the availability of raw materials, the ability to comply with legal and regulatory requirements governing the healthcare industry, the regulatory environment, exposure to product liability claims and other risks described in the Company's periodic reports filed with the SEC. 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.