Evaluation of the role of formulation on parathion toxicity.

The influence of the vehicle on the toxicity of parathion was evaluated by determining the oral and dermal LD50 in rats. The assessment of dermal absorption was performed by measuring the inhibition of plasma cholinesterase activity. The test vehicles were arol and xylene. The data obtained indicated that the acute oral and dermal toxicities are higher in xylene than in arol, but no differences were observed on plasma cholinesterase activity.