The in vitro percutaneous absorption of diquat: A species comparison.

The in vitro absorption of diquat ion from aqueous solution has been measured through human, rat, mouse, rabbit and guinea-pig skin. Diquat was absorbed poorly through human skin, which was the least permeable. At the lowest concentration applied (1 mg diquat ion/ml) rat skin had the most similar permeability to human skin but was four times more permeable. This similarity in permeability was studied further using a range of concentrations (up to 50 mg/ml). As the concentration increased, so did the factor of difference between human and rat skin. Thus, whilst animal skin might appear to be a good model for human skin at a particular applied concentration, the similarity might decrease when the skin samples are examined with a range of concentrations and formulations.