After an equilibration period of 30 min, the integrity of the skin's
barrier was tested with [3H]–H2O (New England Nuclear, Boston, MA,
USA). However, only skin to be treated with [14C]-permethrin was
tested. The procedure for skin integritywas as follows: [3H]–H2O (1 μCi,
100 μl) was applied to the skin with a Pipetman, the pump turned on,
and the receptor fluid was collected. The [3H]–H2O was removed with
Kim Wipe® paper 5 min after it was applied to the skin. The skin was
rinsedwith a small volume of nonradioactivewater and driedwith Kim
Wipe® paper three times. Receptor fluid was collected for 1 h. The
collected receptor fluid was mixed with 10ml of scintillation fluid and
analyzed for [3H] in a PerkinElmer Model 2700 liquid scintillation
analyzer. The mean percentage of the dose of [3H]–H2O detected in the
receptor fluid for the rat skin was 0.21±0.24% and for human cadaver
skin was 0.32±0.25%.