Takka S, Ocak O H, Acartürk F
Department of Pharmaceutical Technology, Faculty of Pharmacy, Gazi University, 06330 Etiler Ankara, Turkey.
Eur J Pharm Sci. 1998 Jul;6(3):241-6. doi: 10.1016/s0928-0987(97)10005-7.
The release rate of nicardipine HCl from various alginate gel bead formulations was investigated. The formulations were prepared by utilizing 23 factorial design. The effect of drug:polymer weight ratio, CaCl2 and sodium-alginate concentration on the time for 50% of the drug to be released (t50%) and the drug entrapment efficiency were evaluated with analysis of variance. The mean particle size and the swelling ratio of the beads were determined. The in vitro release studies were carried out by flow-through cell apparatus in different media (pH 1.2, 2.5, 4.5, 7 and 7.5 buffer solutions). Drug:polymer weight ratio and the interaction of drug:polymer weight ratio and CaCl2 concentration had a significant effect on the drug entrapment efficiency. The release of nicardipine was extended with the alginate gel beads, which were prepared in a ratio of 1:1 (drug:polymer). The release of drug from alginate gel beads took place both by diffusion through the swollen matrix and relaxation of the polymer at pH 1.2-4.5. However, the release was due to the diffusion and erosion mechanism at pH 7-7.5.
研究了不同海藻酸钠凝胶珠制剂中盐酸尼卡地平的释放速率。这些制剂采用23析因设计制备。通过方差分析评估药物与聚合物重量比、氯化钙和海藻酸钠浓度对50%药物释放时间（t50%）和药物包封率的影响。测定了珠子的平均粒径和溶胀率。在不同介质（pH 1.2、2.5、4.5、7和7.5缓冲溶液）中，通过流通池装置进行体外释放研究。药物与聚合物重量比以及药物与聚合物重量比和氯化钙浓度的相互作用对药物包封率有显著影响。以1:1（药物:聚合物）比例制备的海藻酸钠凝胶珠可延长尼卡地平的释放。在pH 1.2 - 4.5时，海藻酸钠凝胶珠中药物的释放通过扩散穿过溶胀基质和聚合物松弛两种方式进行。然而，在pH 7 - 7.5时，释放是由于扩散和侵蚀机制。
