In vitro method to evaluate the barrier properties of medical devices for cutaneous use
Barrier creams (BC) are marketed as cosmetic products or locally-applied medical devices to protect skin against damages induced by chemical agents or physical insults. However, the determination of the BC effectiveness is still a matter of discussion at both the clinical and the regulatory level. In this context, this work aimed at the development of a reliable, reproducible and easy-to-perform experimental protocol for the evaluation of BC performances. Preliminarily, an in vivo method based on the measurement of trans-epidermal water loss had been matter of investigation and was discarded: it required too much time and was not robust and sensitive enough. In vitro, reduction of the permeation of caffeine (used as a model of irritant), through an epidermal membrane mounted on a Franz cell or through a reconstructed 3D human epidermis model, was evaluated. Six BC among oil in water (O/W) or water in oil (W/O) creams were investigated with respect to the petrolatum, which is an efficient impermeable barrier against hydrophilic molecules. Despite minor differences, both methods could rate the effectiveness of the tested products in preventing caffeine exposure. Both methods enable to evaluate and quantify the BC effectiveness in a simple and fast manner. Their application may help regulatory agencies to prevent the marketing of ineffective products for the benefit of consumers.