Relative bioavailability of salicylic acid following dermal application of a 30% salicylic acid skin peel preparation

A single‐center, single‐sequence, two‐period crossover study was performed to compare the systemic exposure to salicylic acid (SA) following facial application of a 30% SA cosmetic skin peel formulation applied for 5 min and an oral dose of 650 mg aspirin in nine healthy male and female subjects. The mean (SD) maximum SA concentration (Cmax) was 0.81 (0.32) µg/mL and 56.4 (14.2) µg/mL. The AUC‐based safety margin ratio was 50:1. A depot effect was observed during topical application of the skin peel solution as the absorption of SA continued beyond the 5‐min application period. Plasma SA Cmax values were achieved from 1.4 to 3.5 h after topical application and from 0.5 to 1.5 h after oral aspirin. The plasma concentrations in the present study (30%; 5 min) were similar to that of a low concentration (2%) applied in a leave‐on product to the same body surface area. In conclusion, our results suggest that the use of this SA facial peel should not pose any significant systemic health risks. © 2007 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:1325-1328, 2008