Entropin, Inc, a development stage pharmaceutical company focused on the pain therapy market, announced that its collaborators at RTI International have successfully synthesized radio labeled ENT-103. This achievement sets the stage for the company to evaluate a variety of enhanced topical formulations of ENT-103. The company intends to select the best of the topical formulations as its candidate for initial human clinical trials.

The first step in the selection of the best possible topical formulation for the human clinical trials is the use of the radio labeled ENT-103 to test the efficiency of a variety of formulations designed to deliver ENT-103 across human skin. In vitro absorption studies using human skin are scheduled to begin in late June at Dow Pharmaceutical Sciences. These studies will measure both the rate and extent of ENT-103 transport across the skin.

"Radio labeling or tagging allows us to test various formulations to evaluate the amount of ENT-103 that is absorbed. The preparation of radio labeled ENT-103 is an important step in the determination of the optimal topical formulation for use in our upcoming human clinical trials. The completion of the preparation radio labeled ENT-103 was more difficult and time consuming than anticipated.

As many steps in the development process are sequentially time-dependent, the delay in the preparation of the radio labeled ENT-103 has forced us to reschedule selected preclinical studies and our planned IND filing for ENT-103, which will postpone the commencement of our human clinical trials. Although the revised schedule will depend on the time slots available from our third party providers, we expect a four to six month delay in our previously projected timeline. To minimize the financial impact of this delay, we have developed a plan that includes reducing our expenditures to conserve our cash reserves in the formulation development of ENT-103," explained Thomas G. Tachovsky, PhD., Entropin's president and CEO.

During the first quarter of 2004, the company completed a secondary stock offering. It was expected that the approximately $3.4 million net proceeds raised in the offering would provide sufficient capital to complete the phase I clinical study with ENT-103. The recent delay in the preparation of radio labeled ENT-103 now necessitates an acceleration of Entropin's plan to raise additional capital. The company intends to expedite discussions with our funding sources while it continues to explore strategic alternatives such as a merger or joint venture.