New degradable poly(ester-anhydride)s were prepared by melt polycondensation of poly(sebacic acid) (PSA), transesterified by different amounts (30-90%) of lithocholic acid (LCA), a natural hydroxy bile acid. Transes-terification of PSA is a one-pot reaction that starts with a high-molecular-weight polymer based on anhydride bonds and yields polymer based on random anhydride-ester bonds. A systematic study of the synthesis, characterization, degradation in vitro, drug release, and stability of these polymers was performed. Polymers with molecular weights (Mw) in the range of 12 000-115 000 and melting points in the range of 55-112 °C were obtained for 30-90% of lithocholic acid content. NMR and IR spectroscopic analyses indicate the formation of ester bonds in the polyanhydride backbone. The experimental results fit the calculated molecular weight, with the highest Mw, obtained for a 4:6 PSA-LCA ratio. The study shows that some of these new degradable copolymers can be potentially used as carriers for the controlled release of drugs.
- Drug delivery systems