Advances in evaluation techniques for traditional Chinese medicine dermatopharmacokinetics

Evaluating the absorption of traditional Chinese medicine (TCM) formulations in skin has long been a challenge in cutaneous pharmacokinetic studies of TCM. In recent years, various new techniques, including diffusion cell, microphysiological system, matrix-assisted laser desorption/ionization mass spectrometry imaging, tape stripping, microdialysis/open-flow microperfusion, and confocal Raman microscopy technology, have been developed to characterize and predict the pharmacokinetic profiles of these formulations more accurately. This review systematically summarizes the application progress of these methods in the evaluation of cutaneous pharmacokinetics of TCM, highlights their technical features and suitable scenarios, and discusses future development trends, providing new research perspectives for further understanding the dynamic changes, spatial distribution characteristics of active ingredients in the skin, and the rationality of compatibility in topical preparations.