ABSTRACT
The skin of the back of the ASR hairless miniature swine shows a rough and scaly fissured appearance. Clinically it resembles that of ichthyosis vulgaris or senile xerosis in humans. By using the skin of this animal, we developed an assay system to evaluate the efficacy of different moisturizers. The study was carried out in winter months from January to March. To establish this system, we studied various topical agents including such ordinary emollients as petrolatum and 10% salicylic acid in petrolatum as well as those available as pseudodrugs from cosmetic companies or prescription drugs from pharmaceutical companies such as heparinoid- containing creams (w/o and o/w) and 10% urea creams. Applying 0.01 g of each agent to 7 randomly selected skin areas (2x2 cm(2)) on the back of a 6-month-old swine once daily for various periods of time, we measured high-frequency conductance, the parameter for the hydration state of the skin surface. As a result, we have established a simple assay system. It consists of applications of topical agents once daily for 5 days from Monday to Friday in the first week and of subsequent measurement of the skin surface hydration state once every week. Evaluation measurements were performed from day 14 to day 21 depending upon their moisturizing effects. We found that heparinoid-containing creams exerted highly effective moisturizing effects on the dry pig skin that lasted even over 3 weeks after discontinuation of the treatments that were carried out for the first 5 days.
