以硫酸庆大霉素为囊心物质,采用复乳法制备了硫酸庆大霉素-聚乳酸微球(gentamycin su lfate-polylactic acid-m icrospheres,GTMS-PLA-MS),比较了不同制备条件下所得微球的差异.扫描电镜(SEM)测试表明微球外观呈球形并且多孔,两种条件下制备的微球平均粒径分别为6.67μm和11.70μm,药物包封率分别为37.52%和49.19%.用差热分析法(DTA)分析微球得知,硫酸庆大霉素与聚乳酸两种物质相互融为一体.以pH=7.4的磷酸盐缓冲溶液为释药介质,用紫外分光光度法(UV)对载药微球的体外释药过程进行了试验.结果表明,微球在最初20 m in有突释效应,此后是缓慢释药,最终累积释药量达95%以上.
Gd2O3∶Tb3+ luminescent nanoparticles were prepared by the thermal decomposition of the nanosized oxlate prepared in the reverse microemulsions based on triton X-100/n-hexyl alcohol, n-octane, and water. From TG-DTA, XRD and FTIR analyses, the mechanism of thermal decomposition of the nanosized oxalate precursor is suggested as follows: Gd2(C2O4)3·10H2O → Gd2(C2O4)3 + 10H2O, Gd2(C2O4)3 → Gd2O2(CO3) + 3CO +2CO2, Gd2O2(CO3) → Gd2O3 + CO2. The kinetic parameters of thermal decomposition reaction-activation energy E of stage 2 and 3 are 194.6 kJ·mol-1, 110.9 kJ·mol-1, respectively, using Ozawa method. And the reaction order n is 2.9 and 0.43, respectively, according to the TG curves.
