克林霉素-PLGA微球的制备及其体外抑菌活性评价

Preparation of clindamycin-loaded PLGA microspheres and evaluation on its in vitro antibacterial activity

目的：制备出一种具有生物可降解性的搭载克林霉素的聚乳酸-羟基乙酸共聚物（PLGA）缓释微球,并对其相关性质进行研究。方法：采用乳化-溶剂挥发法制备搭载克林霉素的PLGA微球,检测克林霉素-PLGA微球表面形貌和粒径分布,观察PLGA/二氯甲烷（P/D）与PLGA/克林霉素（P/C）不同投药比对微球包封率的影响;用适量的释放介质分散缓释微球后,37℃震荡,取各时间点的药液,采用K-B纸片琼脂扩散法检测不同时间点的抑菌环直径大小评价微球体外缓释抑菌能力。结果：微球的形体圆整、表面光滑、无明显黏连,且粒径大小主要集中在700nm左右。当投药比为P/D=80/1、P/C=5/1时包封率最佳,为45.02%,包覆效果良好。微球在第1-2天时体外抑菌效果最为明显,第3-19天呈现持续稳定的抑菌效果,在第20天时降至药物的最小抑菌浓度（MIC）。结论：克林霉素-PLGA微球的制备工艺良好,其体外抑菌效果表现出明显的缓释性。

Objective To prepare the clindamycin-loaded sustained release microspheres with poly（lactic-co-glycolic acid）（PLGA）which have good biodegradability,and to investigate its related properties.Methods The clindamycin-loaded PLGA microsheres were prepared by emulsion-solvent evaporation method.Then the morphology and particle size distribution of clindamylin-PLGA microsheres were detected.And two factors affecting entrapment rate of microspheres,including the rate of PLGA/dichloromethane（P/D）and PLGA/clindamycin（P/C）,were investigated.In addition,the clindamycin-PLGA was dispersed in dissolve medium and oscillated at37℃.Then the solution at different time was taken.Kirby-Bauer method was used to observe the ability of bacteriostasis by measuring the bacteriostatic ring size at different time.Results The acquired PLGA microspheres containing drugs exhibited well-defined properties,with the even and uniform sphere in appearance,general particles without adhesion,at the mean diameter of 700 nm mostly.The optimal ratio of P/D was 80/1and P/C was 5/1,and the entrapment rate obtained was 45.02%.Moreover the antibacterial effect was very obvious on the initial release,followed by aprolonged release from days 3to 19.The minimum inhibitory concentration（MIC）was reached on day 20.Conclusion Clindamycin-PLGA microspheres with good morphology and high encapsulation efficiency can be obtained using optimized formulation.The microspheres have a good antimicrobial effect in vivo through a long period of sustained release of drugs.