IN-VITRO DEGRADATION CHARACTERISTICS OF POLY(ANHYDRIDE-IMIDES) CONTAINING PYROMELLITYLIMIDOALANINE

The in vitro degradation characteristics of poly(anhydride-imides) con taining pyromellitylimidoalanine, with either 1,6-bis(carboxyphenoxy)h exane (CPH) or sebacic acid (SA) were assessed. The copolymers contain ed up to 50 mol % of the imide monomer, pyromellitylimidoalanine (PMA- ala). Degradation was pH sensitive, being enhanced under basic conditi ons. Control of degradation times from 2 days to 2 months was achieved by the selection of appropriate monomer units in the polymer backbone . Monomers were chosen based on their solubility in aqueous media, as well as how they influenced the hydrophobicity and crystallinity of th e polymer matrices. Polymer degradation was followed by ultraviolet sp ectroscopy and high-pressure liquid chromatography. Increasing the amo unt of imide monomer, PMA-ala, and the use of SA (rather than CPH) as the comonomer increased the degradation rate of the polymer matrices. (C) 1996 John Wiley & Sons, Inc.