Soppimath K S, Kulkarni A R, Aminabhavi T M
Department of Chemistry, Karnatak University, Dharwad, India.
Drug Dev Ind Pharm. 2001 Jul;27(6):507-15. doi: 10.1081/ddc-100105175.
Hollow microspheres of cellulose acetate loaded with four cardiovascular drugs (nifedipine [NFD], nicardapine hydrochloride [NCD], verapamil hydrochloride [VRP], and dipyridamole [DIP]) were prepared by a novel solvent diffusion-evaporation method. The oil-in-water emulsion prepared in an aqueous solution of 0.05% poly(vinyl alcohol) medium with ethyl acetate, a water-soluble and less toxic solvent, was used as the dispersing solvent. The yield of the microspheres was up to 80%. The microspheres had smooth surfaces, with free-flowing and good-packing properties. Scanning electron microscopy (SEM) confirmed their hollow structures, with sizes in the range 489-350 microm. The microspheres tended to float over the gastric media for more than 12 h. The drug loaded in hollow microspheres was in an amorphous state, as confirmed by differential scanning microscopy (DSC). The release of the drugs was controlled for more than 8 h. The release kinetics followed different transport mechanisms depending on the nature of the drug molecules.
采用一种新型的溶剂扩散-蒸发法制备了负载四种心血管药物（硝苯地平[NFD]、盐酸尼卡地平[NCD]、盐酸维拉帕米[VRP]和双嘧达莫[DIP]）的醋酸纤维素中空微球。以乙酸乙酯为分散溶剂，在0.05%聚乙烯醇水溶液介质中制备水包油乳液，乙酸乙酯是一种水溶性且毒性较小的溶剂。微球的产率高达80%。微球表面光滑，具有自由流动和良好的堆积性能。扫描电子显微镜（SEM）证实了它们的中空结构，尺寸范围为489 - 350微米。微球倾向于在胃介质中漂浮超过12小时。差示扫描显微镜（DSC）证实，负载在中空微球中的药物处于无定形状态。药物的释放被控制超过8小时。根据药物分子的性质，释放动力学遵循不同的转运机制。
