Munday D L, Cox P J
School of Pharmacy, The Robert Gordon University, Schoolhill, AB101FR, Aberdeen, UK.
Int J Pharm. 2000 Aug 10;203(1-2):179-92. doi: 10.1016/s0378-5173(00)00444-0.
Directly compressed matrices were produced containing either xanthan gum or karaya gum as a release-controlling agent. These swellable hydrophilic natural gums were used to control the release of varying proportions of two model drugs, caffeine and diclofenac sodium, which have different solubilities in aqueous medium. Gum erosion, hydration and drug release studies were carried out using a dissolution apparatus (basket method) at two agitation speeds. Xanthan gum displayed a high degree of swelling due to water uptake and a small degree of erosion due to polymer relaxation. Neither agitation speed nor drug solubility had any significant effect on water uptake, but matrices with the lower proportion of gum produced a lesser degree of hydration. In contrast, karaya gum displayed a much lower hydration capacity and a higher rate of erosion, both markedly affected by agitation speed. Drug release from xanthan and karaya gum matrices depended on agitation speed, solubility and proportion of drug. Both xanthan and karaya gums produced near zero order drug release with the erosion mechanism playing a dominant role, especially in karaya gum matrices.
制备了直接压片的基质，其中含有黄原胶或刺梧桐树胶作为控释剂。这些可膨胀的亲水性天然胶被用于控制两种模型药物（咖啡因和双氯芬酸钠）不同比例的释放，这两种药物在水性介质中的溶解度不同。使用溶出装置（篮法）在两种搅拌速度下进行了胶侵蚀、水合作用和药物释放研究。黄原胶由于吸水而表现出高度膨胀，由于聚合物松弛而有少量侵蚀。搅拌速度和药物溶解度对吸水均无显著影响，但胶比例较低的基质水合程度较低。相比之下，刺梧桐树胶表现出低得多的水合能力和更高的侵蚀速率，两者均明显受搅拌速度影响。黄原胶和刺梧桐树胶基质中的药物释放取决于搅拌速度、溶解度和药物比例。黄原胶和刺梧桐树胶均产生接近零级的药物释放，侵蚀机制起主要作用，尤其是在刺梧桐树胶基质中。
