黄原胶与HPMC的凝胶特性及释药机制

采用直接压片法，研究黄原胶与HPMC的凝胶特性。用称重法和体积测量法研究两种辅料分别在0．1mol／L盐酸和pH6．8磷酸盐缓冲液中的水合度及溶胀度，并以阿莫西林为模型药物进行体外释药研究。结果表明，在0．1mol／L盐酸中，HPMC的水合度及溶胀度均大于黄原胶，对药物释放阻滞作用较大；而在pH6．8磷酸盐缓冲液中则相反。药物在两种辅料中可通过骨架溶蚀和(或)凝胶层扩散呈零级或Higuchi型释药。

Gel Properties and Drug Release Mechanisms of Xanthan Gum and HPMC

The gel properties of xanthan gum and HPMC were investigated by direct compression method. The hydration and swelling degree of these two excipients in 0.1 mol/L HCl and pH6.8 phosphate buffer solution were determined by gravimetric and volumetric methods, respectively. Amoxicillin was selected as model drug to examine the in vitro release. The results showed that the hydration and swelling degree of HPMC were higher than those of xanthan gum in 0.1 mol/L HCl, and the former also had a stronger blocking action. However, in pH6.8 phosphate buffer solution the situation was on contrary. Both xanthan gum and HPMC acted as near zero order or Higuchi drug release by erosion and/or diffusion mechanisms.