Vedha Hari Bn, Brahma Reddy A, Samyuktha Rani B
Department of Pharmaceutics, CARISM, SASTRA University, Thirumalaisamudram, Thanjavur - 613 401, Tamil Nadu, India.
J Young Pharm. 2010 Oct;2(4):350-5. doi: 10.4103/0975-1483.71622.
A multiple-unit floating drug delivery system based on gas formation technique was developed, in order to prolong the gastric residence time and to increase the overall bioavailability of the dosage form. The floating bead formulations were prepared by dispersing nevirapine together with calcium carbonate in a mixture of sodium alginate and hydroxypropyl methylcellulose solution and then dripping the dispersion into an acidified solution of calcium chloride. Calcium alginate beads were formed, as the alginate underwent ionotropic gelation by calcium ions, and carbon dioxide developed from the reaction of carbonate salts with acid. The obtained beads were able to float due to CO(2)-gas formation and the gas entrapment by the polymeric membrane. The prepared beads were evaluated for percent drug loading, drug entrapment efficiency, morphology, surface topography, buoyancy, in-vitro release, and release kinetics. The formulations were optimized for different weight ratios of the gas-forming agent and sodium alginate. The beads containing higher amounts of calcium carbonate demonstrated an instantaneous, complete, and excellent floating ability over a period of 24 hours. The increased amount of the gas forming agent did not affect the time to float, but increased the drug release from the floating beads, while increasing the coating level of the gas-entrapped membrane, increased the time to float, and slightly retarded the drug release. Good floating properties and sustained drug release were achieved. Finally, these floating beads seemed to be a promising gastroretentive drug delivery system.
基于气体形成技术开发了一种多单元漂浮药物递送系统，以延长胃内滞留时间并提高剂型的整体生物利用度。通过将奈韦拉平与碳酸钙分散在海藻酸钠和羟丙基甲基纤维素溶液的混合物中，然后将分散液滴入氯化钙酸化溶液中来制备漂浮微丸制剂。由于海藻酸盐通过钙离子进行离子凝胶化，并且碳酸盐与酸反应产生二氧化碳，从而形成了海藻酸钙微丸。所获得的微丸由于形成CO(2)气体并被聚合物膜截留气体而能够漂浮。对制备的微丸进行了药物载量百分比、药物包封率、形态、表面形貌、浮力、体外释放和释放动力学的评估。针对产气剂与海藻酸钠的不同重量比优化了制剂。含有较高量碳酸钙的微丸在24小时内表现出即时、完全且优异的漂浮能力。产气剂用量的增加不影响漂浮时间，但增加了漂浮微丸的药物释放，而增加气体截留膜的包衣水平，则增加了漂浮时间，并略微延迟了药物释放。实现了良好的漂浮性能和持续药物释放。最后，这些漂浮微丸似乎是一种有前途的胃滞留药物递送系统。
