Zentner G M, Cardinal J R, Feijen J, Song S Z
J Pharm Sci. 1979 Aug;68(8):970-5. doi: 10.1002/jps.2600680814.
Hydrogel films were prepared from hydroxyethyl methacrylate, both with (Film II) and withouth (Film I) 5.25 mole% of ethylene glycol dimethacrylate. Permeation, diffusion, and partition coefficients for progesterone, testosterone, nandrolone, norethindrone, 17 alpha-hydroxyprogesterone, estradiol, and hydrocortisone were determined. A solute permeation model was proposed based on the separation of a domain (B) composed of "bulk-like" water and a doman (A) composed of polymer, interfacial water, and bound water present in the films. The separate contributions from the "pore" and "solution-diffusion" mechanisms to the total permeability were calculated from the model. Steroid permeabilities through Films I and II were analyzed in accordance with this model. Permeation of Film II occurred via the solution-diffusion mechanism. Permeation of Film I occurred predominately by the pore mechanism with a small contribution (approximate 20%) from the solution-diffusion mechanism. The latter contribution was dependent on the solubility of the solute within the A domains of the hydrogel film. Functional group contributions to permeation of Film II were ascribed to either steric or hydrogen bonding effects.
水凝胶薄膜由甲基丙烯酸羟乙酯制备而成，其中一种（薄膜II）含有5.25摩尔%的乙二醇二甲基丙烯酸酯，另一种（薄膜I）不含该成分。测定了孕酮、睾酮、诺龙、炔诺酮、17α-羟基孕酮、雌二醇和氢化可的松的渗透系数、扩散系数和分配系数。基于由“块状”水组成的区域（B）和由聚合物、界面水以及薄膜中存在的结合水组成的区域（A）的分离，提出了一种溶质渗透模型。根据该模型计算了“孔隙”和“溶液扩散”机制对总渗透率的单独贡献。按照此模型分析了甾体通过薄膜I和薄膜II的渗透率。薄膜II的渗透通过溶液扩散机制发生。薄膜I的渗透主要通过孔隙机制，溶液扩散机制的贡献较小（约20%）。后一种贡献取决于溶质在水凝胶薄膜A区域内的溶解度。薄膜II渗透中官能团的贡献归因于空间位阻或氢键效应。
