the pyrethroids bifenthrin, deltamethrin and permethrin
were absorbed in vitro into rat and human skin. The
absorption was greater in rat than in human skin. For both skin
types, more than 50% of the applied dose of the pyrethroids was
removed by a soap and water wash at 24 h. A higher percentage of the
dose was detected in rat and human skin than in the receptor fluid. For
rat and human skin, about 50% and 80% of the dose in the skin,
respectively, was removed by tape-stripping. A low percentage of the
dose in skin was able to diffuse into the receptor fluid during the first
24 h post-exposure and the 24–48 h collection period following the wash. Only the parent chemical was detected in extracts of rat skins
treated with the pyrethroids. Because the exposure of pyrethroids to
skin is potentially high, examination of the dermal absorption of this
class of insecticides is important so that the risk of their exposure can
be adequately assessed.