Karth M G, Ho N F, Higuchi W I
J Pharm Sci. 1985 Jun;74(6):618-20. doi: 10.1002/jps.2600740607.
The transport of cholesterol solubilized in polyoxyethylene(10)-nonylphenol ether with benzyldimethyltetradecylammonium chloride additive (4:1, w/w) was studied in a diffusion cell separated by a silicone rubber membrane. Overall kinetics revealed the presence of an interfacial barrier. Additions of NaCl or Na2SO4 abolished the barrier to the extent that total cholesterol flux was essentially limited by membrane diffusion considerations. The results are consistent with the concept of micelles diffusing in an electrical field followed by a collision-complex transfer of cholesterol in the aqueous-membrane interfacial region. The electrostatic force of repulsion arises from the overlap of diffuse electrical double layers emanating from the charged mixed micelle and the cationic surfactant adsorbed on the membrane. The influence of surfactant concentration on cholesterol transport kinetics was consistent with electrostatic phenomena. The derived physical model focused on interfacial electrical properties in the donor chamber by maintaining a high concentration (greater than or equal to 0.1 M) of strong electrolyte in the receiver. A linear regression of the logarithm of theoretical transport resistance, total resistance less membrane and receiver boundary layer resistances, versus (ionic strength)1/2 in the donor resulted in a reasonable estimate of the total surface potential of the micelle and membrane surfaces as well as the net dispersion attraction constant.
在由硅橡胶膜隔开的扩散池中，研究了溶解于聚氧乙烯（10）-壬基酚醚并添加苄基二甲基十四烷基氯化铵（4:1，重量比）的胆固醇的传输。整体动力学显示存在界面屏障。添加氯化钠或硫酸钠消除了该屏障，以至于总胆固醇通量基本上受膜扩散因素限制。结果与胶束在电场中扩散，随后胆固醇在水-膜界面区域进行碰撞-络合物转移的概念一致。排斥静电力源于带电混合胶束和吸附在膜上的阳离子表面活性剂产生的扩散双电层的重叠。表面活性剂浓度对胆固醇传输动力学的影响与静电现象一致。通过在接受室中保持高浓度（大于或等于0.1 M）的强电解质，所推导的物理模型聚焦于供体室中的界面电学性质。理论传输阻力（总阻力减去膜和接受边界层阻力）的对数与供体中（离子强度）的1/2的线性回归，合理估计了胶束和膜表面的总表面电位以及净分散吸引常数。
