New degradable poly(ester anhydride)s were prepared by the melt polycondensation of diacid oligomers of poly(sebacic acid) (PSA) transesterified with ricinoleic acid. The transesterification of PSA with ricinoleic acid to form oligomers was conducted via a melt bulk reaction between a high molecular weight PSA and ricinoleic acid. A systematic study on the synthesis, characterization, degradation in vitro, drug release, and stability of these polymers was performed. Polymers with weight-average molecular weights of 2000-60,000 and melting temperatures of 24-77degreesC were obtained for PSA containing 20-90%(w/w) ricinoleic acid. NMR and IR analyses indicated the formation of ester bonds along the polyanhydride backbone. These new degradable copolymers have potential use as drug carriers. (C) 2003 Wiley Periodicals, Inc.