Modeling Transdermal Absorption

Abstract

The human skin has long since been realized as a possible pathway for drug molecules to enter the human body. The skin, however, impedes drug absorption quite effectively, since one of its main purposes, like in all epithelial tissues, is the protection of the organism by sealing off the body from the environment. While several laboratory techniques exist to assess the migration of drug molecules into and through the skin, computational models able to predict such experimental results in a reliable manner hold obvious advantages. The interest in such models has given rise to numerous and quite different approaches, which makes it virtually impossible to list all of them. Here, a selection of computational models—divided into different classes according to their underlying concept—is presented. The chapter starts with the fundamentals outlining the properties of the skin barrier and the experimental assessment of permeability. In the next sections, the theoretical framework for each class is presented followed by a description of representative models. The chapter concludes with an outlook illustrating current and possible future trends.