A comparison of the in vitro permeability properties of human and some laboratory animal skins.

Synopsis The in vitro permeability of human and some common laboratory animals'skin has been measured to two chemicals with different physico-chemical properties: [(3)H] water, a small polar molecule and [(14)C]paraquat dichloride (the ion), a fully ionised divalent cation. All the skins examined had similar permeabilities to [(3)H]water: relative to human skin the greatest difference (x4.8) was measured through guinea pig skin. However, relative to human skin, all the animals were much more permeable to [(14)C]paraquat, with factors of difference ranging between 40 (haired rat) and 1460 (hairless mouse). The in vitro technique allows the permeability of human and animal skin to be compared, facilitating extrapolation to Man of effects seen in animals during dermal exposure studies.