Barry B W, Brace A R
J Pharm Pharmacol. 1977 Jul;29(7):397-400. doi: 10.1111/j.2042-7158.1977.tb11352.x.
The permeation across cellulose acetate of three oestrogens, differing only in the number of hydroxyl groups attached to the nucleus, and a 'standard' steroid, dexamethasone, was investigated using the lag-time method for calculating diffusion parameters, between 10 and 40 degrees. Diffusion coefficients for the similarly-sized oestrogens were relatively insensitive to marked changes in polarity, but increased permeation was correlated with increased partition coefficients, decreased polarity and fewer hydroxyl groups on the nucleus. Permeation increased with temperature and energies of activation were calculated from Arrhenius-type plots. Ep values ranged from 4-84 k cal mol-1 (20 kJ mol-1) for the least polar steroid (oestrone) to 6-91 k cal mol-1 (29 kJ mol-1) for the most polar steroid (oestriol). The results implied that steroid diffusion occurred through aqueous membrane channels, but that it was impeded to various extents by both obstruction and polar interaction effects.
使用滞后时间法计算扩散参数，在10至40摄氏度之间，研究了三种仅在与核相连的羟基数量上有所不同的雌激素以及一种“标准”类固醇地塞米松在醋酸纤维素上的渗透情况。对于大小相似的雌激素，扩散系数对极性的显著变化相对不敏感，但渗透率的增加与分配系数的增加、极性的降低以及核上羟基数量的减少相关。渗透率随温度升高而增加，并根据阿伦尼乌斯型曲线计算活化能。活化能值范围从极性最小的类固醇（雌酮）的4 - 84千卡/摩尔（20千焦/摩尔）到极性最大的类固醇（雌三醇）的6 - 91千卡/摩尔（29千焦/摩尔）。结果表明，类固醇扩散通过水膜通道发生，但受到阻塞和极性相互作用效应的不同程度阻碍。
