Whitehouse Station, NJ and King of Prussia, PA, May 20, 2003

Merck & Company (Merck) and NanoSystems (NanoSystems), the NanoCrystal® technology drug delivery division of Elan Corporation, plc (NYSE: ELN) (Elan), are pleased to announce the important role for NanoCrystal® technology in developing the formulation for Emend® (aprepitant), Merck’s new product which received approval March 26, 2003. The formulation work was the result of a collaboration between NanoSystems and Merck.

“We are very pleased that Merck selected the NanoCrystal® technology for the development of this important new chemical entity, which is the first of a new class of molecules. Emend® represents a new approach to the prevention of nausea and vomiting due to highly emetogenic cancer chemotherapy. Merck had confidence in the utility of this technology for Emend® after seeing how much the bioavailability of aprepitant, especially in fasted subjects, could be improved by application of NanoCrystal® technology,” said Dr. Joe Fix, EVP and COO of NanoSystems. The agreement between NanoSystems and Merck involved R&D support, R&D milestones and royalties. Financial terms were not disclosed.

Overview of NanoCrystal Technology

NanoCrystal® technology is a valuable enabling technology which enhances the dissolution performance of molecules which exhibit poor water solubility and can be applied early in the discovery phase through scale-up and commercial manufacturing. The technology can be used on new or existing products to enhance performance. The process is also useful for moderately soluble drugs when a high concentration of drug in a low volume of fluid is desired.

NanoCrystal® technology can be presented in oral dosage presentations including:

• Tablets — fast-melt, modified-release, immediate-release
• Capsules — modified-release, immediate-release
• Liquid dispersion
• Powders
• Other presentations 

NanoCrystal® dispersions of poorly water-soluble drugs can also provide improved performance characteristics for intravenous, subcutaneous or intramuscular injection. More information on this technology is available at www.nanocrystal.com.

NanoSystems is a business unit of Elan Corporation, plc a fully-integrated biopharmaceutical company based in Dublin, Ireland. Elan is focused on the discovery, development and marketing of therapeutic products and services in neurology, autoimmune diseases and pain management. Elan shares trade on the New York, London and Dublin Stock Exchanges.

Statements contained in this press release, which are not historical facts, are forward-looking statements, as the term is defined in the Private Securities Litigation Reform Act of 1995. Such forward-looking statements are subject to risks and uncertainties which can cause actual results to differ materially from those currently anticipated, due to a number of factors, which include, but are not limited to, product demand, pricing, market acceptance, changing economic conditions, risks in product and technology development, the effect of the company's accounting policies and other risk factors discussed in documents filed by the company with the Securities and Exchange Commission from time to time.