Methods for measuring in-vivo percutaneous absorption in humans

Abstract

<jats:p> In-vivo human data on percutaneous absorption are scarce, although they are indispensable for health risk assessment of dermal exposure. In addition, they are considered to be the gold standard for the evaluation of in-vitro systems as well as predictive mathematical models. Dermal absorption in vivo can be assessed using different approaches. The most used methods for determination of in-vivo dermal absorption are the measurement of the parent chemical and/or its metabolite level in biological material, the microdialysis technique and stratum corneum tape stripping. Recently, the non-invasive spectrophotometric methods based on infrared and Raman spectroscopy showed themselves as promising tools for studying percutaneous absorption though these approaches are still in their developmental stages and requires further optimization and validation. The aim of this article is to review different methods for determination of percutaneous absorption in vivo in humans. The advantages and limitations are discussed with respect to generating data for comparison with in-vitro or predictive mathematical models or health risk assessment of chemicals. Furthermore, the importance of the volunteer experiments in generating relevant data for human risk assessment as well as for the development and implementation of biological monitoring in occupational settings will be addressed. </jats:p>

Assessment of Drug Delivery Kinetics to Epidermal Targets In Vivo

“…While local drug concentrations in the skin can be measured using spectroscopic techniques (e.g. Raman/IR) or by microdialysis/microperfusion (2)(3)(4)(5), these approaches are limited by sensitivity issues, on the one hand, and by considerable technical demands, on the other.…”

Raman spectroscopy analysis of the skin of patients with melasma before standard treatment with topical corticosteroids, retinoic acid, and hydroquinone mixture

“…The application of Raman spectroscopy in the field of dermatology dates back to 1992, when the first Raman spectrum of human skin was published . Since then, the use of Raman spectroscopy in the skin has been diversified from characterization of skin components to many other uses such as percutaneous skin absorption of drugs and metabolism of active ingredients interaction of water with other skin cell compounds and medical diagnosis .…”

Bioequivalence for Topical Products—An Update

“…Raman spectroscopy and Near Infra-Red (Near IR) spectroscopy represent advanced non-invasive in vivo techniques for real-time determination of diffusion of drugs and chemicals into human skin (14,85,86). The prerequisite for the spectroscopic technique is that the molecule of interest should possess distinct spectral features of sufficient intensity to be able to differentiate from the skin spectrum, thus limiting its universal use.…”