Ramsey M P, Newton J M, Shaw G G, Sammon D C, Lane E S
J Pharm Pharmacol. 1987 Jan;39(1):1-4. doi: 10.1111/j.2042-7158.1987.tb07151.x.
Changing the pH of the dissolution medium has been found to affect the release of imipramine from gel-precipitated aluminium hydroxide spheres. Release from unwashed, unheated spheres into solutions of pH 1.2 was controlled by dissolution of the gel matrix, whereas that into solutions of pH 3 and pH 5 appeared to be under diffusion control. The liberation of drug from unwashed, heated spheres into the media of higher pH exhibited more complex kinetics. Washed spheres failed to release significant amounts of imipramine into the solutions of pH 3 and 5. Changing the ionic strength of the media had little effect on drug release. These phenomena have been explained with reference to model theories of the precipitation and ageing of aluminum hydroxide gels and their pH-solubility profiles.
已发现改变溶出介质的pH值会影响丙咪嗪从凝胶沉淀氢氧化铝球中的释放。未洗涤、未加热的球体在pH 1.2溶液中的释放受凝胶基质溶解的控制，而在pH 3和pH 5溶液中的释放似乎受扩散控制。未洗涤、加热的球体在较高pH介质中的药物释放表现出更复杂的动力学。洗涤后的球体在pH 3和5的溶液中未能释放出大量丙咪嗪。改变介质的离子强度对药物释放影响不大。这些现象已根据氢氧化铝凝胶沉淀和老化的模型理论及其pH-溶解度曲线进行了解释。
