Methods for cutaneous penetration assessment of organic UV filters - a review

Sunscreens are currently considered cosmetic assets and their use has considerably increased since consumers have become greatly aware of the damages induced by ultraviolet (UV) radiation on the skin, such as premature aging and cancer. However, concerns have arisen over the percutaneous absorption of UV filters. In order to ensure both efficacy and safety, sunscreens need to remain in the outermost layers of the stratum corneum, because their penetration into the dermis can cause systemic effects. Herein, a review was conducted of specialized literature published between 2000 to 2020, clustering studies focused on the skin penetration of UV filters. In this context, different in vitro and in vivo methodologies employed to assess the penetration of such compounds are highlighted, such as those based on tape stripping and diffusion cells. When combined with analytical methods, such as high-performance liquid chromatography, it is possible to trace a profile of the penetration of UV filters and elucidate factors that interfere with this phenomenon. Moreover, studies have been carried out on dissemination strategies that aim to encapsulate the molecules of UV filters, and/or change their physicochemical characteristics, in effort to increase the efficacy and safety of these formulations. Keywords: Franz cell; sunscreens; percutaneous penetration; tape stripping