Dermal dose-cholinesterase response

Dermal Dose Cholinesterase Response and Percutaneous Absorption Studies with Several Cholinesterase Inhibitors... 

KNAAK. AND WILSON Dermal Dose-Cholinesterase Response... 

Dermal dose-ChE response and percutaneous absorption studies were conducted with parathion, carbaryl, and thiodicarb in the rat. Parathion and thiodicarb inhibited 50% of the red cell cholinesterase activity at dose levels of 3.2 and 33 mg/kg of bw. Carbaryl at the highest dose level tested (417 mg/kg of bw) produced no detectable red cell cholinesterase Inhibition. 

If the products are cholinesterase inhibitors, a dermal dose-response rate protocol ( 2) is recommended. 

The rapid inhibition of red cell cholinesterase in workers der-mally exposed to parathion suggested that parathion was rapidly absorbed from skin. In the rat dermal dose response study (J a period of 72 hr was required for a single topical dose of parathion (32 mg/kg) to inhibit 50% of the red cell cholinesterase activity. Studies by Fredriksson (18) in he c t showed that parathion was absorbed slowly (0.35 ug hr cm ) and that parathion was unsuitable as a model substance for studying percutaneous absorption. The rate of absorption was determined by serial skin stipping and by measuring the disappearance of parathion over a period of 5 hr using a GM tube. 

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