5Ajioka M, Suizu C, Higuchi C, et al. Aliphatic polyesters and their copolymers synthesized through direct condensation polymerization[J]. Polymer Degradation and Stability, 1998,59 : 137 - 143.
6Wang N, Wu X S, Lujan-Upton H, et al. Synthesis and characterization of lactic/glycolic acid oligomem[J]. Polymeric Materials Science and Engineering, Proceedings of the ACS Division of Polymeric Materials Science and Engineering, 1997,76:373 - 374.
7Kricheldorf H R. Syntheses and application of polylactides [J].Chemophere,2001,43 :49 - 54.
8Moon S I, Lee C W, Miyamoto M, et al. Melt polycondensation of L-lactic acid with Sn (Ⅱ) catalysts activated by various proton acids:a direct manufacturing route to high weight poly (L-lactic acid) [J]. Polym Sci,Part A: Polym Chem,2000,38(9) : 1673- 1679.
9Wang N,Wu X S. Stabilization of aspirin by using a lactic/glycolic acid oligomer [J]. Polymer Preprints, 1997,38 ( 2 ) : 568 - 569.
10Li J K, Wang N, Wu X S. Novel approach to stabilization of protein drugs in poly ( lactic-co-glycolic acid ) microspheres [J].Polymer Preprints, 1997,38 (2) :604 - 605.
