In vitro and in vivo dermal absorption assessment of acetyl aspartic acid: a compartmental study.

Abstract

The purpose of this study was to evaluate the dermal absorption of acetyl aspartic acid (A-A-A) through an in vitro and in vivo evaluation with human skin after 6 and 24 h of topical application of a cosmetic formulation containing A-A-A at 1%. The in vitro experiment was carried out using the Franz diffusion cells system with ex vivo human skin samples. The profile of diffusion of A-A-A was evaluated after 6 and 24 h. The in vivo experiment was performed on human volunteers following a tape-stripping protocol after 6 h of topical application. A-A-A was quantified in the main skin compartments, that is the skin surface, the stratum corneum, the skin and the receptor fluid using LC-MS analysis. The 24-h in vitro experiment confirmed the great penetration potential of A-A-A in all skin compartments. After 6 h of topical application, the removed tape strips from both in vitro and in vivo experiments were analysed and the profile of diffusion of A-A-A was determined, allowing also an in vitro/in vivo comparison. The diffusion profile observed on the in vitro skin penetration test is highly representative of the in vivo situation evaluated on volunteers. The combination of in vitro with in vivo data confirmed that A-A-A has the capacity to diffuse through the skin after topical application and reach the dermis as the targeted skin layer for potential anti-ageing benefits.