THE INFLUENCE OF DIETHYL-M-TOLUAMIDE (DEET) ON THE PERCUTANEOUS-ABSORPTION OF PERMETHRIN AND CARBARYL

Simultaneous exposure to DEFT and permethrin was recently proposed to be associated with the ''Gulf War Syndrome.'' However, no studies have reported the percutaneous absorption of DEET and permethrin when appl ied simultaneously to the skin as a mixture, the relevant route of exp osure in the Persian Gulf, The present study quantitates percutaneous absorption of DEET and permethrin after coadministration to rodent and pig skin in vitro, Dosing solutions were also prepared with either ac etone. dimethyl sulfoxide (DMSO), or ethanol to compare vehicle effect s on percutaneous absorption of permethrin and DEET, The influence of DEET on carbaryl absorption and dermal disposition was also assessed i n pig studies to statistically demonstrate DEET effects in acetone or DMSO and different solvent concentrations, Topical application of perm ethrin + DEET resulted in absorption of DEET (1-20% dose), but no perm ethrin, Permethrin (1.2-1.7% dose) was detected only when mouse skin w as dosed solely with permethrin, a finding suggesting that DEET decrea sed permethrin absorption, DEET also inhibited carbaryl absorption in acetone mixtures, but had no effect on DMSO mixtures, Irrespective of solvent, DEET did not enhance carbaryl penetration into skin, For DEET I absorption was greater in mouse skin (10.7-20.6% dose) than in rat s kin (1.1-5.2% dose) and pig skin (2.8% dose), The extent of DEET absor ption was greater with DMSO and acetone than with ethanol in rat and m ouse skin. These studies support DEET, but not permethrin or carbaryl, as hating sufficient systemic exposure to potentially cause signs of toxicity when simultaneously applied with pesticides, Furthermore, the se studies demonstrated that DEET does not necessarily enhance dermal absorption of all toxicants as was originally hypothesized. (C) 1997 A cademic Press.