Characteristic differences in barrier and hygroscopic properties between normal and cosmetic dry skin. II. Depth profile of natural moisturizing factor and cohesivity

摘要

OBJECTIVE: In a previous paper (Lu et al, International Journal of Cosmetic Science, in press), we reported that in comparison with normal skin, cosmetic dry skin characteristically has a thicker stratum corneum (SC) with weaker barrier quality. Our goal here was to obtain a more complete picture of the difference between normal and cosmetic dry skin, by further analysing the data collected from the same clinical study to address two additional aspects of skin: the amount and depth profile of natural moisturizing factor (NMF) and the cohesivity of the SC. METHOD: The SC samples were collected by sequential tape stripping in a clinical study consisting of 64 healthy Caucasian female subjects with either normal or cosmetic dry skin. Protein and free amino acids (FAA) on tape strips were extracted and analysed using high-throughput methods. The level of pyrrolidone carboxylic acid (PCA), the prominent component of NMF, was detected using HPLC analysis.