Chiral Chemistry and Toxicity Assessments for Pyrethroid Pesticides

摘要

Pyrethroids compose a significant and growing class of pesticides used in the United States. Their use in commercial, industrial, agricultural, and domestic settings makes study of their toxicity of general concern. These concerns extend from single exposure episodes to one pyrethroid to chronic exposure scenarios involving several pyrethroids. The toxicological fate of pyrethroids in humans is modeled by identifying exposure routes and levels, following the distribution and metabolism within the body, and tracking elimination pathways. Complex PBPK/PD models can be formulated that track exposure, absorption, distribution, reaction, and elimination over time. Traditionally, these PBPK/PD models focus on a particular pesticide, along with its various metabolites and biomarkers. Pyrethroids often contain one or more chiral centers, resulting in numerous stereoisomers in many commercial products. Each stereoisomer differs in effectiveness for its intended use, and also in its toxicity. This paper discusses the identification and tracking issues related to chiral pyrethroids that degrade the usefulness of many technical results in the published literature. It is hoped that an awareness of current practice will lead to the use of experimental studies with unambiguous utility in toxicity models.