The Phenion (R) Full-Thickness Skin Model for Percutaneous Absorption Testing

In recent years many efforts have been made to replace dermal
toxicity testing of chemicals in the animal by in vitro assays. As
a member of a German research consortium, we have previously
contributed to the validation of an in vitro test protocol for
percutaneous absorption studies on the basis of reconstructed human
epidermis and both human and pig skin ex vivo. Aiming to assess the
barrier properties of a newly developed reconstructed skin model,
this protocol has now been transferred to the Phenion (R)
Full-Thickness Skin Model (FT model). The permeation of
testosterone and caffeine was quantified in parallel to that of pig
skin using Franz-type diffusion cells. In addition, the permeation
of benzoic acid and nicotine was studied. As expected, the FT model
is more permeable than pig skin, yet its barrier properties are
well in accordance with those of reconstructed human epidermis when
compared to previous data. In fact, the FT model most efficiently
retards testosterone as the compound of highest lipophilicity,
which can be explained by an additional uptake by a reservoir
formed by the dermis equivalent. Thus, the structure closely
parallels human skin. In consequence, the Phenion FT model appears
to be suitable for percutaneous absorption studies in hazard
analysis and should be subjected to a catch-up validation study.
Copyright (C) 2009 S. Karger AG, Basel