Glycol modified poly(sebacic anhydride) (PSA), a biodegradable poly(ester anhydride) copolymer, was prepared by melt bulk reaction of PSA and glycol. The structure of PSAG was characterized by FTIR, 1H NMR, and GPC. The results indicate the formation of ester bonds along the polyanhydride backbone. The thermal properties and crystallinity changes of the polyanhydrides were investigated using DSC and XRD. In vitro degradation experiments show that the degradation rate of PSAG is slower than that of PSA because of the introduction of the glycol. Using dexamethasone as a model drug, the in vitro release rate of a drug from PSAG discs was shown to be slower than that from PSA discs, and no initial burst releases were observed for 13 days. PSAG is therefore a promising candidate, which control the release of an incorporated drug over a sustained period of time. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013