Confocal Raman microscopy and multivariate statistical analysis for determination of different penetration abilities of caffeine and propylene glycol applied simultaneously in a mixture on porcine skin ex vivo

摘要: Propylene glycol is one of the known substances added in cosmetic formulations as a penetration enhancer. Recently, nanocrystals have been employed also to increase skin active components. Caffeine component with many applications and its into epidermis controversially discussed literature. In present study, ability two components - caffeine propylene glycol, applied topically on porcine ear form gel, was investigated ex vivo using confocal Raman microscopes operated at different excitation wavelengths (785nm 633nm). Several depth profiles were acquired fingerprint region spectral ranges, i.e., 526-600cm(-1) 810-880cm(-1) chosen for independent analysis skin, respectively. Multivariate statistical methods such principal (PCA) linear discriminant (LDA) combined Student's t-test calculate maximum depths each substance (caffeine glycol). The results show that penetrates significantly deeper than (20.7-22.0μm versus 12.3-13.0μm) without any enhancement effect caffeine. confirm substances, even if onto mixture, can penetrate differently. obtained are comparable showing both types well suited investigations multivariate PCA-LDA very useful analyzing skin.