Department of Polymer Materials, Shanghai University, Shanghai 201800, China.
Int J Pharm. 2012 May 10;427(2):443-51. doi: 10.1016/j.ijpharm.2012.01.025. Epub 2012 Jan 24.
Nanoporous poly(L-glutamic acid)/chitosan (PLGA/CS) multilayer microcapsules were fabricated by layer-by-layer (LbL) assembly using the porous silica particles as sacrificial templates. The LbL assembled nanoporous PLGA/CS microcapsules were characterized by Zeta-potential analyzer, FTIR, TGA, SEM, TEM and CLSM. 5-Fluorouracil (5-FU) was chosen as model drug. The drug loading content of PLGA/CS microcapsules depends on loading time, loading temperature, pH value and NaCl concentration. High loading capacity of microcapsules can be achieved by simply adjusting pH value and salt concentration. Moreover, 5-Fu loaded microcapsules take on a sustained release behavior, especially in an acid solution, in contrast to burst release of bare 5-Fu. The kinetics of 5-Fu release from PLGA/CS microcapsules conforms to Korsmeyer-Peppas and Baker-Lonsdale models, the mechanism of which can be ascribed to priority of drug diffusion and subordination of polymer degradation. The MTT cytotoxicity assay in vitro reveals the satisfactory anticancer activity of the drug-loaded PLGA/CS microcapsules. Therefore, the novel nanoporous PLGA/CS microcapsules is expected to find application in drug delivery systems.
采用层层自组装技术，以多孔硅球为牺牲模板，制备了具有纳米孔结构的聚 L-谷氨酸/壳聚糖（PLGA/CS）多层微胶囊。通过 Zeta 电位分析仪、FTIR、TGA、SEM、TEM 和 CLSM 对 LbL 组装的纳米多孔 PLGA/CS 微胶囊进行了表征。选择 5-氟尿嘧啶（5-FU）作为模型药物。PLGA/CS 微胶囊的载药量取决于装载时间、装载温度、pH 值和 NaCl 浓度。通过简单地调整 pH 值和盐浓度，可以实现微胶囊的高载药量。此外，负载 5-Fu 的微胶囊表现出持续释放行为，特别是在酸性溶液中，与裸露的 5-Fu 的爆发式释放形成对比。PLGA/CS 微胶囊中 5-Fu 的释放动力学符合 Korsmeyer-Peppas 和 Baker-Lonsdale 模型，其机制可以归因于药物扩散的优先性和聚合物降解的从属关系。体外 MTT 细胞毒性试验表明，载药 PLGA/CS 微胶囊具有良好的抗癌活性。因此，新型纳米多孔 PLGA/CS 微胶囊有望在药物传递系统中得到应用。
