New trends in mechanistic transdermal drug delivery modelling: Towards an accurate description of skin microstructure

Interest for in silico modelling of the absorption of xenobiotics into the skin has been growing in the last years, owing to their lower cost compared to experimental alternatives, and the desire to avoid animal experimentation. This review presents an overview of Physiologically-Based Pharmacokinetic (PBPK) models and focuses on recent, modelling approaches, such as Finite Element and Lattice Boltzmann. These methods allow for a detailed geometric representation of the skin microstructure, in contrast to classic QSPR and compartmental models. Morphological features of the skin such as the bricks and mortar description of the stratum corneum, hair follicles, and the pilosebaceous unit can therefore be represented more accurately, allowing a better description of the interaction of cosmetics with the skin. This review also highlights several perspectives to further develop these models in directions relevant to industry.