硝苯地平缓释凝胶的制备工艺及其释药性能研究

目的:制备硝苯地平缓释凝胶并考察其体外释药情况。方法:采用复凝聚法制备硝苯地平缓释凝胶,以壳聚糖、海藻酸钠的浓度、搅拌速度和壳聚糖溶液与海藻酸钠溶液的体积比为因素进行正交试验;用转篮法测定所制凝胶的释放度,通过改变释放介质的pH值,考察该缓释药物对pH的敏感性。结果:最佳工艺为壳聚糖浓度0.4%、海藻酸钠浓度1.5%、搅拌速度160r.min-1、壳聚糖溶液与海藻酸钠溶液的体积比为6:1。硝苯地平缓释凝胶在pH1.5的人工胃液中4h释放度为13.43%;在pH6.8的人工肠液中4h释放度为52.30%,12h释放度为81.72%。结论:所制硝苯地平缓释凝胶具有明显的缓释作用,体外释放具有较强的pH敏感性。

Preparation Technique and Dissolution Rate of Nifedipine Sustained-release Hydrogels

OBJECTIVE： To prepare nifedipine sustained - release hydrogels and to study their drug release in vitro. METHODS： Nifedipine sustained- release hydrogels were prepared by complex coacervation. An orthogonal experiment was performed with chitosan, concentration of sodium alginate, mixing speed and the volume ratio of chitosan solution to sodium alginate solution as factors. Meanwhile, the dissolution rate of the prepared hydrogels was determined by basket - rotating method, and pH- sensitivity of the released drug in different pH medium was investigated. RESULTS： The optimal technical condition was as follows： the concentration of chitosan was 0.4% and that of sodium alginate was 1.5% ; the mixing speed was 160 r . min -1 the volume ratio of chitosan solution to sodium alginate solution was 6 ： 1. The dissolution rate of sustained- release hydrogels containing nifedipine was 13.43% in simulated gastric fluid （pH 1.5） at 4 hours, which stood at 52.30% at 4 hours and 81.72% at 12 hours in simulated intestinal fluid （pH 6.8） . CONCLUSION： The sustained-release hydrogels of nifedipine showed remarkable sustained - release properties and strong pH sensibility in vitro.