Percutaneous Permeability to Paraqut: In Vitro Experiments with Human Skin

Abstract

Percutaneous permeability to paraquat through intact and mechanically damaged human skin was measured in vitro from diluted solutions (1 mg/ ml). In intact human skin under occlusion, a permeability to paraquat of 3 × 10⁻⁵ cdhr was measured at steady state. The binding of paraquat to skin was determined and found to be negligible. The measured permeabilities were used in a pharmacokinetic model to predict paraquat levels in blood and lungs. The model predicts that for intact human skin and diluted paraquat solutions systemic toxicity is unlikely. However, the risk increased significantly when damaged skin or concentration paraquat solutions are involved.