DEGRADABLE BIOMATERIALS WITH ELASTOMERIC CHARACTERISTICS AND DRUG-CARRIER FUNCTION

The design of drug-carrying elastomers based on poly(phosphoester-uret hanes) (PPUs) is presented. Bis(2-hydroxyethyl)phosphite and bis(6-hyd roxyhexyl)phosphite were used as the chain extenders and 1,4-butane di isocyanate was the basis of the hard segment. The labile phosphoester linkage in the backbone of the PPU confers biodegradability on the pol ymer. Using the reactive phosphite side chain in the PPUs, p-aminosali cylic acid and benzocaine were attached pendantly to the polymer with or without a spacer. In vitro release of both drugs was complete in se veral hours. In contrast, ethambutol incorporated into the backbone of the polymer was released in over 10 days. Preliminary cytotoxicity of the drug-carrier to a macrophage cell line was also assessed.