SUMMARY
Absorption rate and plasma and fat disposition of lindane after various lindane percutaneous treatments in shorn and unshorn sheep were investigated. To analyze data with a deconvolution method, iv administration was performed to determine the basic pharmacokinetic values of lindane in sheep. After iv administration, the steady state volume of distribution was very high (8.07 ± 3.60 L/kg of body weight), and the mean residence time was long (28.1 ± 11.7 hours). Deconvolution analysis indicated that lindane absorption was continuous until 33 to 41 days after spraying with a 0.025% lindane solution. Total amount of absorbed lindane in shorn (15,171 ± 4,463 μg/kg) sheep was about twice that in unshorn (7,615 ± 3,128 (μg/kg) sheep; from deconvolution analysis, it was calculated that the time required for 50% of the available dose to be absorbed was between 115 and 179 hours.
After percutaneous lindane administration, the fat concentration was compared with the available lindane dose. The apparent half-life of lindane elimination in fat was 225 ± 47.4 hours, which is similar to the value calculated for the absorption rate constant. By comparing fat and plasma concentrations, it was calculated that for a mean plasma concentration of 5 ng/ml, the fat lindane concentration was 1.65 ± 0.87 μg/g (ie, lower than the generally accepted tolerance level of 2 μg/g).
