In vitro dermal penetration study of carbofuran, carbosulfan, and furathiocarb

In this study, the dermal penetration rate of carbofuran, carbosulfan, and furathiocarb has been measured with rat abdominal skin using the static diffusion cell. The technical grades of three compounds were applied at different doses on skin surface mounted in static diffusion cell and incubated at 32°C for 48 h with shaking. The same procedures were carried out with furathiocarb EC (emulsifiable concentrate) and WP (wettable powder). At regular intervals, the receptor fluid in cell was sampled and analyzed by HPLC. Only carbofuran was found in carbosulfan- or furathiocarbtreated samples, suggesting they converted into carbofuran while passing through the skin layer. The quantity of insecticide penetrating skin increased with time and applied dose. The skin penetration rate increased with the water solubility of insecticides. The dermal penetration rates of carbofuran, furathiocarb, and carbosulfan were determined as 1.05 μg/cm² per h (r² = 0.991), 0.46 μg/cm² per h (r² = 0.984) and 0.14 μg/cm² per h (r² = 0.967), respectively. There was no significant difference in rate of skin penetration between furathiocarb EC (1.42 μg/cm² per h, r² = 0.988) and WP (1.35 μg/cm² per h, r² = 0.982), while furathiocarb technical grade showed a lower skin penetration rate. In vitro models may be used to predict percutaneous absorption and are useful in selecting safer formulations for field application of pesticide.