Comparing Surfactant Penetration into Human Skin and Resulting Skin Dryness Using In Vivo and Ex Vivo Methods

Numerous tests have been developed to estimate a surfactant's mildness in rinse-off formulations. In this study, mixed surfactant systems were examined for their impact on surfactant penetration into the skin and skin hydration using and methods. A forearm controlled application test (FCAT) was conducted, and skin hydration was evaluated using corneometry and visual dryness grading. Tape strip and cup scrub extractions were completed within the FCAT to examine the penetration of five individual surfactants into the skin . The ratio of surfactant mass extracted by five pooled tape strips to surfactant mass extracted by cup scrubs was found to be in the range of 40-59%. Furthermore, cup scrub collection and analysis was less time-consuming and less expensive to conduct than tape stripping. Thus, we recommend cup scrub extraction as a suitable substitute for tape stripping in future surfactant skin penetration analyses. results were compared with C-sodium dodecyl sulfate ( C-SDS) penetration into human cadaver skin from the same surfactant systems. measurements conducted in the FCAT, including corneometer reading, visual dryness score, and individual surfactant (sodium laureth (1) ether sulfate and cocamidopropyl betaine) extracted from the skin, were found to correlate well with C-SDS penetration into the skin for anion-based surfactant systems. Thus, C-SDS skin penetration may be a useful preclinical test for skin dryness induced by rinse-off products containing anionic surfactants.