In Vitro SPF/UVA Protocol for use with VITRO-SKIN® Substrate

The quantity of water absorbed by human stratum corneum during product application, rub-out and dry-down impacts on how various emulsions spread and de-emulsify on skin. Our research indicates that water absorption by substrate (either human skin or VITRO-SKIN) can have a significant effect on measured SPF and UVA protection factors. Dramatic improvements in the correlation with in vivo testing can be achieved by reproducibly hydrating the substrate prior to product application.