法莫替丁定时释放小丸的释药机制

Drug release mechanism of famotidine time-controlled release pellets

目的研究法莫替丁定时释放小丸的释药机制,初步探索有机酸诱导型给药系统的释药机制。方法从离子交换反应、水化作用等方面分别研究了琥珀酸离子和琥珀酸分子在药物释放过程中的作用。结果琥珀酸酸根离子通过与膜材进行离子交换反应造成了新的离子环境,琥珀酸分子由于进入膜材的疏水部分而提高了膜的柔韧性。上述两种作用均可导致膜水化作用增强,从而使膜的透过性明显增加。结论定时释放小丸的时滞是由于膜材的疏水性所致;当水进入丸芯溶解有机酸后,产生的酸根离子及有机酸分子以不同的方式与膜材发生相互作用,显著提高了其透过性,从而使药物快速释放出来。

Aim To study the drug release mechanism of famotidine time-controlled release pellets and to explore the mechanism of ＂organic acid-induced type drug delivery system＂. Methods The effects of dissociated and undissociated forms of succinic acid on the drug release behavior of famotidine timecontrolled release pellets were studied from the following aspects： ion-exchange reaction, hydration, etc. Results The dissociated succinic acid created new ionic circumstances by ion-exchange reaction with Eudragit RS100. Whereas undissociated succinic acid increased the flexibility of the film by distribution in the hydrophobic segment of Eudragit RS100. Effects of both forms of the succinic acid could improve the hydration of Eudragit RS film. As a result, the permeability of the film was improved evidently. Conclusion The lag time of famotidine time-controlled release pellets is induced by the hydrophobicity of the film. After water dissolve the organic acid, the dissociated and undissociated forms of succinic acid interact with the film through different ways. These interactions can change the structure of the film. Therefore the permeability of the film will be improved markedly.