Zheng Cai-hong, Liang Wen-quan, Yu He-yong
Institute of Pharmaceutics, Zhejiang University, Hangzhou 310031, China.
Yao Xue Xue Bao. 2005 Feb;40(2):182-6.
To elevate the encapsulation efficiency, decrease the burst release and improve the release of protein entrapped in poly (lactic-co-glycolic acid) (PLGA) microspheres. The bovine serum albumin (BSA) composite microspheres of alginate-chitosan-PLGA were prepared and the release characteristics of BSA from this composite microspheres were studied.
The much smaller calcium alginate microcapsules were first prepared by a modified emulsification method in an isopropyl alcohol-washed way and coated with chitosan, then the alginate-chitosan microcapsules were further entrapped in PLGA to form the composite microspheres. The protein concentration was determined using a BCA protein assay kit. The release profiles were changed with various formulation factors.
The average diameter of the composite microcapsules was about 30 microm. Comparing with 60% to 70% of the conventional PLGA microspheres, the average encapsulation efficiency was more than 80%, and the burst releases in phosphate buffer solution of the composite microspheres decreased from 40% and 50% to 25% and further to 5% in saline solution.
The novel composite microspheres were prepared, the drug encapsulation efficiency increased and the burst release decreased. The desired release profiles could be obtained by regulating the ratios of PLG and PLA in the composite microspheres.
提高聚乳酸-乙醇酸共聚物（PLGA）微球中蛋白质的包封率，降低突释，并改善其释放性能。制备了海藻酸钠-壳聚糖-PLGA复合微球包裹牛血清白蛋白（BSA），并研究了BSA从该复合微球中的释放特性。
首先采用改良乳化法，用异丙醇洗涤制备出粒径小得多的海藻酸钙微胶囊，并用壳聚糖包衣，然后将海藻酸钠-壳聚糖微胶囊进一步包裹在PLGA中形成复合微球。使用BCA蛋白质检测试剂盒测定蛋白质浓度。通过各种配方因素改变释放曲线。
复合微胶囊的平均直径约为30微米。与传统PLGA微球60%至70%的包封率相比，平均包封率超过80%，复合微球在磷酸盐缓冲溶液中的突释率从40%和50%降至25%，在盐溶液中进一步降至5%。
制备了新型复合微球，提高了药物包封率，降低了突释。通过调节复合微球中PLG和PLA的比例可以获得所需的释放曲线。
