Graduate School of Pharmaceutical Sciences, Josai University, Saitama, Japan; Department of Pharmacy, University of San Carlos, Cebu, Philippines.
Graduate School of Pharmaceutical Sciences, Josai University, Saitama, Japan.
Int J Pharm. 2020 Mar 30;578:119186. doi: 10.1016/j.ijpharm.2020.119186. Epub 2020 Feb 27.
Finite dose experiments represent clinical use wherein depletion of dose, evaporation of excipients, and gradual change in vehicle composition may occur. In the present study, we attempted a mathematical approach for predicting skin permeation and concentration of a cosmetic active, rhododendrol (RD), from complex vehicle-based formulations applied in finite dose. In vitro skin permeation and concentration studies of RD were conducted from formulations containing water and polyols with concentrations ranging from 10 to 100% under infinite and finite dose conditions using vertical Franz diffusion cells. Observed data for skin permeation and the viable epidermis and dermis (VED) concentration of RD were estimated by the differential equations under Fick's second law of diffusion together with water evaporation kinetics and changes in the partition coefficient from vehicles to the stratum corneum. As a result, a goodness-of-fit was observed allowing accurate estimation of skin permeation and VED concentration of RD. This mathematical approach could become a useful tool to estimate the skin permeation and concentration of actives from topical formulation applied in finite dose conditions likened in actual use.
有限剂量实验代表了临床应用，其中可能会出现剂量耗尽、赋形剂蒸发和载体组成逐渐变化的情况。在本研究中，我们尝试了一种数学方法，用于从应用于有限剂量的复杂载体配方中预测化妆品活性成分，密蒙花醇（RD）的皮肤渗透和浓度。通过垂直 Franz 扩散池，在无限和有限剂量条件下，从含有水和多元醇的配方中进行了 RD 的体外皮肤渗透和浓度研究，浓度范围为 10%至 100%。通过扩散的菲克第二定律下的微分方程，以及水蒸发动力学和从载体到角质层的分配系数的变化，估算了 RD 的皮肤渗透和活表皮和真皮（VED）浓度的观察数据。结果，观察到拟合良好，允许准确估计 RD 的皮肤渗透和 VED 浓度。这种数学方法可以成为一种有用的工具，用于从类似于实际使用的有限剂量条件下应用的局部制剂中估算活性成分的皮肤渗透和浓度。
