In attempt to improve the properties of polyanhydrides based on aliphatic anhydrides, we synthesized novel polyanhydrides containing amide groups in the main chains. In this work, N,N'-bis(L-alanine)-sebacoylamide (BSAM) was prepared from natural amino acid and sebacic acid (SA) and characterized by IR and H-1 NMR. In addition, polymers of PBSAM, P[1,6-bis(P-carboxyphenoxy) hexane (CPH)-BSAM], and P(CPH-SA), blends of P(CPH-SA)/polylactide (PLA),]P(CPH-BSAM)/PLA were also prepared and characterized by IR, gel permeation chromatography, and differential scanning calorimetry. The hydrolytic degradation of polyanhydrides and their blends with PLA (number-average molecular weight = 2.90 x 10(5)) was evaluated in 0.1 M phosphate buffer pH 7.4 at 37 degreesC. The results indicate that the existence of amide, aromatic, and ester bonds in the main chain of polymers slows down the degradation rate, and the tendency becomes clearer with the increasing amount of them, and the copolymers and their blends with PLA possess excellent physical and mechanical properties. These can make them more widely used in drug delivery and nerve regeneration. (C) 2004 Wiley Periodicals, Inc.