聚乳酸微球体外降解研究(英文)

本文研究了聚乳酸微球降解的规律及机理。用五种方法研究聚乳酸微球降解过程：扫描电子显微镜观察微球表面形态；测定失重；凝胶渗透色谱法测定聚合物的平均相对分子质量；测定pH；紫外分光光度法测定乳酸含量。聚乳酸微球的降解过程有两个阶段，初期主要发生聚合物分子链断裂和相对分子质量减小，后期主要发生聚合物片段溶蚀和重量减少。其降解速度随平均相对分子质量增加而减慢。聚乳酸是可生物降解材料，降解有规律，是优良的药物控制释放材料。

Study on the Degradation of Polylactide Microsphere In Vitro

This report concentrated on the rules and mechanism of the degradation of polylactide and the microspheres. The rate of degradation was assessed with five methods: observation of microsphere surface morphology by SEM, determination of the weight loss of the microspheres, determination of the molecular mass of the polymers by GPC, determination of pH and determination of the contents of lactic acid by UV spectrophotometry. The degradation of polylactide microspheres showed two-phase characteristics. At the early stage of the degradation, the high molecular mass polymers were cleaved into lower molecular mass fractions and at the late stage, there was a period of erosion and weight loss of the microspheres. The degradation was much slower for polymers with a higher molecular mass. The polylactide degradation showed good regularity.