Vestar Inc. said Tuesday that it has filed a suit in the U.S.District Court in Delaware challenging the validity of a secondlyophilization patent (U.S. Patent 4,880,635) held by TheLiposome Company Inc. (TLC).

TLC (NASDAQ:LIPO) of Princeton, N.J., in June 1992 filed suitagainst Vestar Inc., alleging that Vestar infringed its patent byselling a liposomal from of amphotericin B in Europe. TLC saidit believed that Vestar's AmBisome violates TLC's patent forthe dehydration of colloidal dispersions of liposomes.

Vestar (NASDAQ:VSTR) of San Dimas, Calif., said Tuesday thatits objective is to resolve the entire disputed area of liposomelyophilization technology as rapidly as possible.

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