http://repub.eur.nl/res/aut/14015/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/10880/ 2002-01-01T00:00:00Z The stratum corneum (SC) barrier typically consists of layers of corneocytes embedded in a lipid continuum that regulates barrier function. The lipid domain containing ceramides, cholesterol, and free fatty acids provides the major pathway for most drugs permeating across SC (1). Penetration enhancers diminish the SC barrier function. The classic enhancer is dimethyl sulfoxide (DMSO) (2). Its mechanisms of action remain unclear, although DMSO disrupts lipid organisation and may displace protein-bound water (3). Here we use confocal Raman spectroscopy to probe molecular interactions between a finite (depleting) dose of DMSO and SC, as functions of depth and time, providing novel information about residence time and location of DMSO in human SC in vivo. http://repub.eur.nl/res/pub/10881/ 2001-03-20T00:00:00Z Confocal Raman spectroscopy is introduced as a noninvasive in vivo optical method to measure molecular concentration profiles in the skin. It is shown how it can be applied to determine the water concentration in the stratum corneum as a function of distance to the skin surface, with a depth resolution of 5 mum. The resulting in vivo concentration profiles are in qualitative and quantitative agreement with published data, obtained by in vitro X-ray microanalysis of skin samples. Semi-quantitative concentration profiles were determined for the major constituents of natural moisturizing factor (serine, glycine, pyrrolidone-5-carboxylic acid, arginine, ornithine, citrulline, alanine, histidine, urocanic acid) and for the sweat constituents lactate and urea. A detailed description is given of the signal analysis methodology that enables the extraction of this information from the skin Raman spectra. No other noninvasive in vivo method exists that enables an analysis of skin molecular composition as a function of distance to the skin surface with similar detail and spatial resolution. Therefore, it may be expected that in vivo confocal Raman spectroscopy will find many applications in basic and applied dermatologic research.