端羟基聚乳酸微球的制备与降解

Preparation and degradation of hydroxy-terminated polylactic acid microsphere

以1,4-丁二醇和D,L-乳酸为原料,经缩合聚合法制备了端羟基聚乳酸,并用溶剂挥发法制备了端羟基聚乳酸微球。考察了乳化剂浓度、油水相比例及聚乳酸浓度对微球平均粒径和形貌的影响,并在pH=7.4缓冲溶液中进行了微球的降解。结果表明以二氯甲烷为溶剂,PVA作为乳化剂,室温和600 r/min搅拌速度下可制得平均粒径0.5-1.0 m的较均匀的、表面平滑的端羟基聚乳酸微球。随着在pH=7.4下降解时间增加,微球表面变得粗糙。

The hydroxy-tenninated polylactic acid （HO-PDLLA-OH） is prepared with D, L-lactic acid and 1,4-butylene glycol through direct condensational polymerization. The microspheres based on HO-PDLLA-OH, which the average diameter ranges from 0.5 /ma to 1.0 μm, are prepared by the solvent evaporation method at room temperature with stirring rate of 600 r/min, with methane dichloride as organic disperse phase and water solution of polyvinyl alcohol as continuous phase. The influences of different factors, such as concentration of polylactic acid and polyvinyl alcohol, the ratio of oil phase to water phase, on average diameter and morphology of microsphere are investigated in detail. The results show that the morphology of the title microsphere is smooth, however,its surface gets rough after degradation in phosphate buffer solution （pH 7.4）.