EVALUATION OF PHOTOTOXIC AND PHOTOGENOTOXIC RISK ASSOCIATED WITH THE USE OF PHOTOSENSITIZERS IN SUNTAN PREPARATIONS - APPLICATION TO TANNING PREPARATIONS CONTAINING BERGAMOT OIL

Bases for the elaboration of a standardized protocol are proposed for studying phototoxic effects of skin tanning preparations containing ph otosensitizing agents. The experimental procedure includes in vivo pho totoxicity tests, evaluation of the photogenotoxic risk and determinat ion of the photosensitizer concentration in plasma after topical appli cation. This procedure was carried out with tanning preparations conta ining a well-known photosensitizer, 5-methoxypsoralen, as a component of bergamot oil. The whole study has been performed using topical appl ication of the commercial suntan product, i.e. containing the sunscree ns and all other components. Whereas the exposure to solar simulated r adiation never triggered any phototoxic response, a photosensitizing e ffect was observed for skin type I volunteers exposed to high doses of ultraviolet A. The transepidermal penetration resulted in a 5-methoxy psoralen concentration of 1-4 ng/ml in the suction blister fluid. The photogenotoxicity of this suction blister fluid containing 5-methoxyps oralen and also other ingredients of the tanning preparation was assay ed on yeast cells and was found to be rather low. 5-Methoxypsoralen wa s also detected in plasma after repeated applications but at low conce ntrations (about 1 ng/ml) which do not present a potential risk for sy stemic ocular effects.