Comparison of the penetration of 14 pesticides through the skin of young and adult rats

Abstract

In vivo percutaneous absorption of 14 pesticides was studied in young (33‐d‐old) and adult (82‐d‐old) female Fischer 344 rats, at three different dose levels. Carbon‐14‐labeled pesticides in acetone were applied to previously clipped middorsal skin. The treatment area was 2–3% of the body surface area. Penetration of the pesticides during a 72‐h period ranged from approximately 1%‐90%, depending on compound, dose, and age of animal. No clear age‐related pattern of dermal absorption among compounds was found. Only chlordecone, folpet, and permethrin did not show significant age‐dependent differences in skin penetration. Atrazine, carbaryl, chlorpyrifos, and hexachloro‐biphenyl had greater absorption in the young, while carbofuran, captan, dinoseb, DSMA, MSMA nicotine, and parathion displayed greater absorption in the adult. The majority of the compounds showed dose‐dependent penetration. The dose‐response curves for penetration were not parallel for 8 of the 14 compounds studied.