OCT monitoring of cosmetic creams in human skin in vivo

Optical coherence tomography (OCT) is a tool currently used for noninvasive diagnosis of human disease as well as for monitoring treatment during or after therapy. In this study, OCT was used to examine penetration and accumulation of cosmetic creams on human hand skin. The samples varied in collagen content with one formulation containing soluble collagen as its primary active ingredient. Collagen is a major connective tissue protein that is essential in maintaining health vitality and strength of many organs. The penetration and localization of collagen in cosmetic creams is thought to be the main determinant of the efficacy of new collagen synthesis. Detection and quantification of collagen in cosmetic creams applied to skin may thus help predict the eventual efficacy of the product in skin collagen regeneration. We hypothesize that the topically applied collagen may be detectable by OCT through its modulation of skin scattering properties. To test this hypothesis, we used a FDML swept-source optical coherence tomography (SS-OCT) system. A particular location on the skin of two male adult volunteers was used to investigate 4 different cosmetic creams. The duration of OCT monitoring of cosmetic penetration into skin ranged from 5 minutes to 2 hours following topical application. The results showed that OCT can discriminate between a cream with collagen and other collagen-free formulations. Thus it seems feasible that OCT intensity can monitor the in vivo effects of topical application of collagen contained in cosmetic formulations.