Abstract: Poly(lactic acid) (PLA) microspheres were prepared by premix membrane emulsification and compared with the results by homogenization and ultrasonification. The mean diameters of PLA microspheres prepared by homogenization and ultrasonification were 1.022 and 0.987 mm, and the corresponding polydispersities 0.133, 0.145, respectively, while the mean diameter of PLA microspheres by premix membrane emulsification was 0.906 mm and the polydispersity 0.005. Furthermore, the microspheres of paclitaxel (PTX) loaded PLA, PLGA [poly(lactic-co-glycolic acid)], PELA [poly(ethylene glycol-co-lactide acid)] with uniform size were prepared by premix membrane emulsification, and their encapsulation efficiency and cumulative release profiles in vitro were studied. The mean diameters of PTX-loaded PLA, PLGA and PELA microspheres were 0.906, 0.987 and 1.015 mm with the same polydispersity of 0.005. The corresponding drug loading efficiencies and encapsulation efficiencies were 3.89%, 4.93%, 3.18% and 63.2%, 71.6%, 51.3%, respectively. The cumulative release rates of PLA, PLGA, and PELA microspheres in vitro for 60 d were 83.87%, 50.25% and 41.27%.

Key words: premix membrane emulsification, microspheres, uniformity, loading efficiency, drug release in vitro

摘要： 采用快速膜乳化法、均质乳化法和超声法制备了聚乳酸(PLA)空白微球，比较了3种方法所制微球的均一性. 采用均质乳化法和超声法制备的PLA微球平均粒径分别为1.022和0.987 mm，多分散系数分别为0.133和0.145，而快速膜乳化法制备的PLA微球平均粒径为0.906 mm，多分散系数为0.005. 在此基础上，采用快速膜乳化法制备了聚乳酸、聚(乳酸-羟基乙酸)共聚物(PLGA)和聚(乳酸-聚乙二醇)二嵌段共聚物(PELA)载紫杉醇微球，平均粒径分别为0.906, 0.987和1.015 mm，多分散系数均为0.005，载药率分别为3.89%, 4.93%和3.18%，包埋率分别为63.2%, 71.6%和51.3%，在磷酸盐缓冲液中释放60 d后，PLGA微球的药物释放率为83.87%，PLA微球为50.25%，PELA微球为41.27%.

关键词: 快速膜乳化, 聚乳酸类微球, 均一性, 载药率, 体外释放