Citropten and bergapten suction blister fluid concentrations after solar product application in man

Citropten (5,7-dimethoxycoumarin) and bergapten (5-methoxypsoralen) are present in bergamot oil which is used as a cosmetic tanning product. The aim of this study was to quantify, using HPLC, the amount of citropten and bergapten in the skin after the application of suntan products (emulsion and oil formulations). A suction blister technique, performed on the volar aspect of the forearm, permitted the collection of these two molecules. The blister fluid concentrations were 37 and 51 ng/ml (emulsion) and 26 and 23 ng/ml (oil), respectively, for citropten and bergapten. Our results show that the suction blister technique could be used for comparing transepidermal penetration of several compounds in vivo in man.