InVivo method for monitoring polysorbate 85 effect on epidermal permeability

An in vivo method of monitoring the rate of water desorption from human forearms, using “dry” nitrogen gas passed over approximately 1 cm² of skin was investigated with the aid of a commercial electrolytic moisture analyzer. The assembled apparatus was used to evaluate the differences in water loss rates from treated and untreated (control) forearms following surfactant application. The changes in the differences were also monitored after cessation of treatment, i.e., during the healing process. The apparatus provided an accurate, rapid, and painless method of monitoring relative water loss rates and, as such, could prove a useful tool in routine testing in experimental dermatology and cosmetology. The results confirm the earlier finding from an in vitro method with excised rabbit skin that the tested surfactant increases the permeability of the epidermis.