Abstract:

Based on laser confocal Raman spectroscopy technology, a real-time in vivo testing method for the depth distribution and transdermal penetration of sunscreen in the stratum corneum of the skin was established using a skin component analyzer combined with multivariate linear regression analysis. Using volunteers’ arms as the experimental subject, the consistency of transdermal penetration ability of three common sunscreen agents, OMC, DBHB, and EHT, was tested and analyzed in different skin regions of the arm. And the transdermal penetration of the sunscreen agents in sunscreen lotions with different formulation was compared. The results indicate that the relative standard deviation of the skin penetration of sunscreen in different areas on the inner side of the arm is less than 15%, indicating that the method is suitable for comparison of the skin penetration of different sunscreen products. After one hour of skin penetration, it is found that the transdermal penetration of the three sunscreen agents in the skin is reduced by about 60%, and the penetration depth of EHT is relatively shallow, when the in oil-in-water sunscreen compared to the nano emulsion sunscreen. This method has been effectively applied in the study of transdermal penetration of sunscreen agents, and can provide methodological references for transdermal absorption of cosmetics.

Key words: Raman spectra, in vivo, sunscreen, transdermal penetration