Importance of Skin Penetration and Permeation in Development of Cosmetics

Abstract

The skin permeation can explain with Fick's diffusion model. Skin concentration depends on partition coefficient between skin and vehicle and concentration in vehicle. However it is changed with various factors, activity of ingredient in vehicle, effect of other ingredients on skin, the change of formulation after application and so on. Thus, if the same concentration of active ingredient is in the formulation, the skin concentration or skin absorption is not always the same. It is important to know the skin penetration and permeation of cosmetic ingredient for the assessment of not only toxicity but also efficacy.