Racial differences in the in vivo percutaneous absorption of some organic compounds: a comparison between black, Caucasian and Asian subjects.

Individual differences exist between patients, and, for topical therapy, differences in skin due to race may be a consideration. Pharmacological response depends upon the percutaneous absorption and the inherent activity of the chemical once absorbed into the biological system. Our objective was to determine the in vivo percutaneous absorption of three test chemicals in human subjects with Asian (A), black (B) and Caucasian (C) ethnic skin. Following a 30 min topical application on the upper outer arm of 1 mumol/cm2 14C-labeled chemical, percutaneous absorption was determined by both urinary excretion and the stripping technique. Amounts absorbed were: for benzoic acid 1.43 +/- 0.27% (SD) (A), 1.07 +/- 0.18% (B), 1.2 +/- 0.19% (C); for caffeine 1.06 +/- 0.17% (A), 1.01 +/- 0.19% (B) and 0.96 +/- 0.12% (C); for acetylsalicylic acid 1.8 +/- 0.31% (A), 1.59 +/- 0.31% (B) and 2.12 +/- 0.36% (C). No statistical difference (P > 0.05) was found in percutaneous absorption of benzoic acid, caffeine or acetylsalicylic acid between Asian, black and Caucasian subjects.