Physiologically Based Pharmacokinetic Model for Developmental Exposures

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent devel-opmental toxicant in rodents, and these effects occur at exposures similar tobackgroundhumanbodyburdens.Aphysiologicallybased pharmacokinetic (PBPK)model canaid inquantitativelydescribing the relationship between exposure, dose, and response. The aim of this work was the development a PBPK model to describe the rela-tionship between maternal TCDD exposure and fetal TCDD con-centrations during critical windows of susceptibility in the rat. This PBPKmodel is a modification of an eight-compartment model that describes the adult female rat. The modified model reduces the compartments from eight to four maternal compartments (liver, fat, placenta and rest of the body). Activation of the placental com-partment anda separate fetal compartment occurs duringgestation. The systemic circulation connects thematernal compartments. The physiological and biochemical parameters were obtained fro