al-Helw A A, Al-Angary A A, Mahrous G M, al-Dardari M M
Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia.
J Microencapsul. 1998 May-Jun;15(3):373-82. doi: 10.3109/02652049809006864.
Chitosan microspheres containing phenobarbitone were successfully prepared by glutaraldehyde cross-linking of an aqueous acetic acid dispersion of chitosan in light liquid paraffin containing sorbitan mono-oleate as a stabilizing agent. Uniform and spherical microspheres, with a loading efficiency up to 57.2%, could be prepared depending on the preparation conditions. The main parameters affecting the preparation and the performance of the prepared microspheres were the molecular weight and concentration of chitosan as well as the concentration of the used stabilizing agent. The incorporation of citric acid into the microspheres was found to increase the formation of a water-soluble gel when the microspheres come in contact with the dissolution medium increasing the rate of drug release. The particle size was shifted towards smaller diameters with increased concentration of sorbitan mono-oleate, up to 4.0% v/v, by use of a lower concentration of chitosan (1.0% w/v) and chitosan with low molecular weight. Rapid initial drug release (20-30% of the incorporated drug) was exhibited in all the prepared microspheres followed by slow release of the remaining amount of the drug. The release rate of the drug from the microspheres prepared from high molecular weight chitosan was slow in comparison with that prepared from medium and low molecular weight chitosan. High concentrations of sorbitan mono-oleate increased the rate of drug release.
以山梨醇单油酸酯为稳定剂，在轻质液体石蜡中，通过壳聚糖的醋酸水溶液分散体的戊二醛交联成功制备了含苯巴比妥的壳聚糖微球。根据制备条件，可以制备出均匀的球形微球，载药效率高达57.2%。影响微球制备及性能的主要参数是壳聚糖的分子量和浓度以及所用稳定剂的浓度。当微球与溶出介质接触时，发现将柠檬酸掺入微球中会增加水溶性凝胶的形成，从而提高药物释放速率。通过使用较低浓度的壳聚糖（1.0% w/v）和低分子量壳聚糖，随着山梨醇单油酸酯浓度增加至4.0% v/v，粒径向较小直径方向移动。所有制备的微球均表现出快速的初始药物释放（占掺入药物的20 - 30%），随后是剩余药物的缓慢释放。与由中、低分子量壳聚糖制备的微球相比，由高分子量壳聚糖制备的微球中药物的释放速率较慢。高浓度的山梨醇单油酸酯提高了药物释放速率。
