克拉霉素漂浮-生物粘附微囊的制备及漂浮性能研究

Preparation and in vitro floating characteristics of floating-bioadhesive microcapsules containing clarithromycin

以克拉霉素为模型药物，采用乳化-溶剂挥发法制备乙基纤维素载药微球（EM），并通过内部凝胶化法进行包衣制得海藻酸钠-乙基纤维素载药微囊（AEM），最后通过离子交联法进一步包衣制得壳聚糖-海藻酸钠-乙基纤维素微囊（CAEM）。考察了制备条件对微囊中药物包封率及载药量的影响，并进一步评价了微囊的体外释放及漂浮性能。结果表明，EM及CAEM球形度均较好，药物包封率分别为80．9％～97．3％及72．3％～78．2％；载药量分别为16．2％～49．8％及7．1％～12．7％。CAEM在pH为5的醋酸缓冲液中，6h的累积释放率为56．6％～76．9％，漂浮率〉70％，具有较好的缓释效果及良好的体外漂浮性能。CAEM有望延长药物在胃内的滞留时间，提高胃粘膜药物浓度，从而提高幽门螺旋杆菌的根除率。

Ethylcellulose microspheres containing clarithromycin （EM） which were capable of floating in acid environment were prepared by emulsion solvent diffusion method. EM were coated with alginate by internal gelation process to get alginate-ethylcellulose microcapsules （AEM）, then AEM were dispersed into chitosan solution, and chitosan-alginate-ethylcellulose microcapsules （CAEM） were prepared by ion gelation for the enhancement of bioadhesive properties. The drug efficiency and drug content of EM were 80.9%～97.3% and 16. 2%～49. 8% respectively, the drug efficiency and drug content of CAEM was 67.3%～71.2% and 7.0%～11.5% respectively. The in vitro accumulative drug-release percent of CAEM at 6h was 56.6%～76.9%. More than 70% of CAEM has floated in Acetate Buffer Solution for 8h. These results suggest that floating-bioadhesive microparticles might be a promising drug delivery system for the treatment of Helicobacter pylori infection.