Evaluation of percutaneous absorption promoters by means of solid fractal analysis of skin stratum corneum

点击翻译按钮获取中文摘要

Solid fractal dimension of skin stratum corneum was determined in order to evaluate the pathological damages evoked by percutaneous absorption promoters such as d-limonene and Azone in the hairless rat. As a model dermatological system, alcoholic hydrogels containing each of these promoters were applied to the hairless rat abdominal skin. The application site of the skin was excised, fixed with glutaraldehyde and osmic acid, and then lyophilized. The skin surface was scanned with a confocal laser microscope and the image data of skin surface were fed into a computer. The skin surface structure was reconstructed as a contour mapping image on the display. The solid fractal dimension was then estimated based on the extended box-counting algorithm.The solid fractal dimension of untreated skin surface was estimated to be 2.17. The fractal dimension markedly decreased when the skin was treated with hydrogels containing d-limonene. On the other hand, the degree of decrease in fractal dimension was poor when Azone was applied to the skin. The decrease of fractal dimension may be attributed to the smoothing of the skin structure, which will be caused by the hydration and/or edema formation in the shallow part of the skin.The structure change of skin surface evoked by the promoters can be quantified as a nonintegral solid fractal dimension as well as the surface fractal dimension of skin cross section. This suggests the usefulness and reliability of the fractal analysis as a novel method for evaluating the skin damage.