Use of various models for in vitro percutaneous absorption studies of ultraviolet filters.

BACKGROUND: The percutaneous absorption test aims to estimate the passage of a substance across the skin. The absorption process can be described in three steps: (a) penetration of a substance into the skin layer, followed by (b) penetration from one layer into another (permeation) and finally (c) resorption into the vascular system. In vivo and in vitro models are available but owing to ethical reasons as well as the latter providing greater feasibility, in vitro models are preferred. AIMS: This present study reviews the natural membranes (human skin and animal models: pig, rabbit, rat, hairless mouse, guinea-pig and mouse), artificial skin equivalents and synthetic membranes that are currently being used for in vitro percutaneous absorption studies of UV filters, in order to provide the researcher with a greater insight when selecting membrane models for given experimental conditions.