Spring Valley, New York, September 5, 2002 — Par Pharmaceutical, a subsidiary of Pharmaceutical Resources, Inc. (NYSE:PRX), announced today that it has entered into a licensing agreement with Advancis Pharmaceutical Corp. for Clarithromycin XL. The product, anticipated to be filed with the FDA in the near future, is being developed as a generic equivalent to Abbott's Biaxin XL®.

Clarithromycin is an antibiotic that is indicated for the treatment of a broad range of infections. Sales of Biaxin XL® were approximately $300 million in the past twelve months.

Clarithromycin, since it is an antibiotic, is excluded from Waxman-Hatch. Accordingly, no generic drug company is eligible to receive FDA exclusivity for being the first-to-file an ANDA for this drug but it also means that the brand company will not be awarded a 30-month stay. Therefore, it is possible, barring other legal actions, that the drug can be marketed upon approval.

Advancis Pharmaceutical Corporation is a privately held specialty pharmaceutical company focused on the development and commercialization of anti-infective therapeutics.

Pharmaceutical Resources, Inc., a holding company, develops, manufactures, and distributes generic pharmaceuticals through its wholly owned subsidiary, Par Pharmaceutical. Through its FineTech unit, PRX also develops and utilizes synthetic chemical processes to design and develop intermediate ingredients used in the production of finished products for the pharmaceutical industry. PRX currently manufactures and distributes over 173 products representing various dosage strengths of 64 drugs. For press release and other Company information, visit http://www.parpharm.com.

Certain statements in this press release constitute "forward-looking statements" within the meaning of 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 essentially forward-looking and are subject to risks and uncertainties, including the difficulty of predicting FDA filings and approvals, acceptance and demand for new pharmaceutical products, the impact of competitive products and pricing, new product development and launch, reliance on key strategic alliances, uncertainty of patent litigation filed against us, availability of raw materials, the regulatory environment, fluctuations in operating results and other risks and uncertainties detailed from time to time in the Company's filings with the Securities and Exchange Commission, such as the Company's Form 10-K, Form 10-Q, and Form 8-K reports.