Prakongpan S, Higuchi W I, Kwan K H, Molokhia A M
J Pharm Sci. 1976 May;65(5):685-9. doi: 10.1002/jps.2600650514.
A physical model approach was used to investigate cholesterol gallstone dissolution kinetics in simulated bile. Critical experimental and theoretical investigations simulating in vivo conditions showed that, in the bile acid-lecithin solutions, there is a significant interfacial barrier for both cholesterol gallstone and cholesterol monohydrate pellet dissolution. In the present study, the rotating-disk dissolution method and the accompanying Levich theory were applied to assess the contributions of the diffusion convection mass transfer resistance and of the interfacial barrier to the overall kinetics. Cholesterol dissolution rates in bile acid solutions were about 2-20 times slower than diffusion-controlled rates depending upon the degree of agitation. As found in previous studies, these rates in the presence of sufficient concentrations of dissolution accelerators approached the theoretical diffusion-convection-controlled rates. To account for the much slower dissolution rates in bile acid-lecithin solutions, two possible kinetic interpretations were investigated. The first is based upon slow crystal-micellar solution interfacial kinetics, and the second is based upon a slow rate of cholesterol solubilization in the aqueous diffusion layer. For the latter, an analytical mathematical solution was obtained.
采用物理模型方法研究模拟胆汁中胆固醇胆结石的溶解动力学。模拟体内条件的关键实验和理论研究表明，在胆汁酸 - 卵磷脂溶液中，胆固醇胆结石和胆固醇一水合物颗粒的溶解均存在显著的界面屏障。在本研究中，应用旋转圆盘溶解法及相关的列维奇理论来评估扩散对流传质阻力和界面屏障对整体动力学的贡献。胆汁酸溶液中胆固醇的溶解速率比扩散控制速率慢约2 - 20倍，这取决于搅拌程度。如先前研究中所发现的，在存在足够浓度的溶解促进剂时，这些速率接近理论扩散对流控制速率。为了解释胆汁酸 - 卵磷脂溶液中慢得多的溶解速率，研究了两种可能的动力学解释。第一种基于缓慢的晶体 - 胶束溶液界面动力学，第二种基于胆固醇在水扩散层中的缓慢溶解速率。对于后者，获得了一个解析数学解。
