Studies on percutaneous penetration of chemicals - Impact of storage conditions for excised human skin

According to international guidelines skin penetration experiments can be carried out using freshly excised or frozen stored skin. However, this recommendation refers to data obtained in experiments with human cadaver skin. In our study, the percutaneous penetration of the occupationally relevant chemicals anisole, cyclohexanone and 1,4-dioxane was investigated for freshly excised as well as for 4 and 30 days at −20 °C stored human skin using the diffusion cell technique. As indicator for the impairment of skin barrier by freezing cholesterol dissolution was determined in the solvents in exposure chambers of diffusion cells. Considering the percutaneously penetrated amounts, the following ranking was determined: 1,4-dioxane > anisole > cyclohexanone (decline to a factor of 5.9). The differences of fluxes between freshly excised and frozen stored skin (4 and 30 days) were not significant (p > 0.05). Cholesterol dissolved from the skin indicates no significant differences between freshly excised and frozen stored skin. This study shows that freezing of human skin for up to 30 days does not alter the skin barrier function and the permeability of chemicals.

► Freezing for up to 30 days does not alter skin barrier function. ► Cholesterol extraction by solvents does not differ in fresh and frozen stored skin. ► Recommendations for skin storage (OECD Guidance No. 28) are valid.