* Endorex Corp., of Chicago, signed an exclusive option agreement with British Technology Group plc (BTG), of London, to negotiate a final license agreement for peptide hepatitis B immunogens in oral treatment and prevention of hepatitis B viral infections. The agreement calls for evaluation of pre-S gene coded peptides, which will be incorporated into Endorex's Orasome polymerized liposome technology. BTG has exclusive worldwide rights to commercialize the pre-S gene coded peptides for hepatitis B as a result of an agreement with the New York Blood Center.

* Enzymed Inc., of Iowa City, Iowa, entered a five-year research agreement with Iowa State University, of Ames, focused on compounds for use in crop protection, grain handling and insect control. Enzymed will generate libraries against targets developed by Iowa State, and for lead optimization when a product is identified.

* Interferon Sciences Inc., of New Brunswick, N.J., exercised its option to repurchase $7.5 million of convertible preferred stock from an institutional investor for $7.89 million, plus accrued dividends. The company said the issuance had a negative impact on its capitalization. Buying back the stock promptly eliminated uncertainty as to whether it would be repurchased, said Lawrence Gordon, Interferon Science's CEO.