Faculty of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama, 350-0295, Japan.
Pharm Res. 2010 Jan;27(1):134-42. doi: 10.1007/s11095-009-9987-y. Epub 2009 Nov 11.
To calculate the skin concentration of active ingredients in cosmetics and topical pharmaceuticals using silicone membrane permeation.
A series of parabens were used as model ingredients. Skin concentration of parabens was calculated using silicone membrane permeability. Their partition coefficient from formulations to the silicone membrane was determined by the membrane permeation profiles, and used to calculate their silicone membrane concentration, under an assumption that the membrane is one homogenous diffusion layer. The same procedure was applied for hairless rat skin.
The calculated concentration of parabens in silicone membrane was very close to their observed values. However, the skin concentration calculated by skin permeability was not similar to the observed concentration. Re-calculation was performed under the assumption that the skin consists of two diffusion layers. This modification using permeation data through full-thickness and stripped skin enabled precise prediction of the skin concentration of parabens. In addition, the partition coefficient to the silicone membrane was useful to estimate their skin concentration.
Ingredient concentration in skin can be precisely predicted using diffusion equations and partition coefficients through permeation experiments using a silicone membrane. The calculated in-skin concentration is useful for formulation studies of cosmetics and topical pharmaceuticals.
使用硅橡胶膜渗透法计算化妆品和局部用药物制剂中活性成分的皮肤浓度。
使用一系列对羟基苯甲酸酯作为模型成分。通过硅橡胶膜渗透性计算对羟基苯甲酸酯的皮肤浓度。通过膜渗透曲线确定它们从制剂到硅橡胶膜的分配系数，并假设膜为均匀扩散层，以此计算它们在硅橡胶膜中的浓度。对无毛大鼠皮肤进行了相同的程序。
计算出的硅橡胶膜中对羟基苯甲酸酯的浓度非常接近其观察值。然而，通过皮肤渗透性计算出的皮肤浓度与观察到的浓度并不相似。在假设皮肤由两个扩散层组成的情况下进行重新计算。通过全厚度和剥脱皮肤渗透数据进行的这种修正，能够精确预测对羟基苯甲酸酯的皮肤浓度。此外，分配系数对硅橡胶膜也有助于估计其皮肤浓度。
使用硅橡胶膜渗透实验的扩散方程和分配系数，可以精确预测皮肤中的成分浓度。计算出的皮肤内浓度对于化妆品和局部用药物制剂的配方研究很有用。
