Background: The penetration of topically applied substances into the stratum corneum can non-invasively be studied using the tape stripping procedure. This method was applied to investigate in vivo the penetration of a fragrance, vanillin, applied in ethanol and a w/o emulsion.
Methods: Twenty tape strips were removed from each skin area treated with vanillin in ethanol or w/o emulsion, respectively. The concentration of vanillin was determined for each tape strip. In addition, the pseudo-absorption of the corneocytes was determined to calculate the SC profile.
Results: The vanillin concentration was correlated both with the tape number and with the stratum corneum profile. Depending on whether the tape number or the profile of the stratum corneum were correlated with the vanillin concentration, different distributions within the stratum corneum were obtained. Different amounts of stratum corneum were removed with 20 tape strips dependent on the vehicle applied previously. The application of the w/o emulsion led to the removal of nearly the half the amount of corneocytes stripped from the ethanol-treated area.
Conclusions: The results obtained underline the general necessity to correlate the amount of stratum corneum with the amount of substance in penetration studies.