SYNTHESIS AND IN-VITRO BIODEGRADATION OF POLY(ETHER-ESTER) AZO POLYMERS DESIGNED FOR COLON TARGETING

A number of poly(ether-ester) azo polymers consisting of various conce ntrations of 4-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}benzoic acid (HEEE BA), 2-(2-hydroxyethoxy)ethoxy]ethoxy}phenylaozobenzoic acid (HEEEPABA ) and either 12-hydroxydodecanoic or 16-hydroxyhexadecanoic acid were synthesized. The polymers were assessed in order to determine whether they are biodegradable by the azoreductase present in the rat caecum. The polymers containing HEEEBA showed satisfactory degradation (up to 48%), while those without showed poor degradation, due to poor wettabi lity. When 1% polysorbate 80 (a wetting agent) was added to the polyme rs in the degradation medium, all polymers showed excellent degradatio n. Azo polymers with HEEEBA have the potential to be used as colon-spe cific drug release materials.