OPTISON Recommended for European Approval; New Ultrasound Imaging Agent Will Aid in the Detection of Cardiac Disease.

ST. LOUIS and SAN DIEGO--(BW HealthWire)--Jan 29, 1998-- Mallinckrodt Inc. (NYSE:MKG) and Molecular Biosystems, Inc. (NYSE:MB)(MBI) today announced that the European Union's Committee for Proprietary Medicinal Products (CPMP) of the European Medicines Evaluation Agency (EMEA) has recommended the approval of OPTISON(TM), a new ultrasound imaging agent developed to aid in the detection of cardiac disease.

Bobba Venkatadri, president and chief executive officer of Molecular Biosystems, said: "We are pleased that OPTISON(TM) is once again the first of the next generation ultrasound contrast agents recommended for approval. We believe that OPTISON(TM)'s clearance in the United States and now this recommendation in the European Union reinforces the product's safety and efficacy profile. Our management team has worked hard to obtain approval for OPTISON(TM) in these two territories and has succeeded in being first in this approval process."

C. Ray Holman, chairman and chief executive officer of Mallinckrodt, said: "OPTISON(TM) is meeting with good early success in the United States. Clinicians are finding that it enhances suboptimal cardiac ultrasound images. We are looking forward to marketing the product in Europe as well."

The regulatory file was submitted to the European Medicines Evaluation Agency (EMEA) under the centralized procedure in which a single license is granted for 15 member states of the European Union. The marketing authorization is expected to be granted by the European Commission within three to four months. Upon EMEA approval, OPTISON(TM) will be launched by Mallinckrodt. OPTISON(TM) also received marketing clearance from the U.S. Food and Drug Administration on December 31, 1997 and is being distributed by Mallinckrodt in the United States.

MBI, based in San Diego, CA., is a world leader in the development and manufacture of ultrasound contrast agents for medical imaging. MBI shares are listed on the New York Stock Exchange under the symbol "MB." OPTISON(TM), MBI's second generation ultrasound imaging agent cleared for marketing by the FDA, is currently marketed in the United States by Mallinckrodt.

Based in St. Louis, MO, and operating globally in more than 100 countries, Mallinckrodt Inc. had fiscal 1997 net sales of $1.9 billion. The Mallinckrodt web site address is www.mallinckrodt.com.

NOTE: MOLECULAR BIOSYSTEMS NEWS RELEASES ARE AVAILABLE VIA FAX BY CALLING 888-329-4007 TOLL FREE. MBI's new web site at http://www.mobi.com provides an informative overview of the Company and its products. The web site includes information about MBI's products and development programs, corporate partner and research pipeline. The site also contains investor information, including links to the Company's financial information and current stock price.

This news release contains forward-looking statements that involve risk and uncertainties. The commercialization of OPTISON(TM) may differ materially from the Company's expectations. Among the factors that could result in a materially different outcome are the following: the failure of OPTISON(TM) to gain sufficient market acceptance either in the United States or other markets, to generate profits for the company.nt market to develop consistently with the Company's expectations, the failure of ultrasound contrast agents to penetrate expanded markets; an adverse result in MBI's and Mallinckrodt's pending patent lawsuit against, or future litigation with, Sonus Pharmaceutical, Inc.; Nycomed Imaging AS; ImaRx Pharmaceutical Corp. and marketing partner DuPont Merck; and Bracco International B.V., including potential injunctive relief delaying or prohibiting the sale of OPTISON(TM); an adverse ruling by the PTO in the pending patent reexaminations; unfavorable results in clinical trials, the ability of the Company to obtain FDA approval for the use of OPTISON(TM); to detect myocardial perfusion; the inherent uncertainty involved in the development of any new product; and other risk factors reported from time to time in MBI's filing with the Securities Exchange Commission.

CONTACT: Molecular Biosystems, Inc.

Gerard A. Wills, Chief Financial Officer, 619/824-2219

Stephen F. Keane, Investor Relations, 619/824-2212

Patricia Sullivan, Corporate Communications, 619/824-2262

or

Mallinckrodt Inc.

Media Contacts:

Peter Faur, 314/654-5234

Barbara Abbett, 314/654-5230

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Investor Contacts:

Doug McKinney, 314/654-5264

Scott Johnsen, 314/654-5295

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