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An updated physiologically based pharmacokinetic model for hexachlorobenzene: incorporation of pathophysiological states following partial hepatectomy and hexachlorobenzene treatment.

Lu-Y; Lohitnavy-M; Reddy-MB; Lohitnavy-O; Ashley-A; Yang-RS

Toxicol Sci 2006 May; 91(1):29-41

https://doi.org/10.1093/toxsci/kfj133

20030410

Physiologically based pharmacokinetic (PBPK) modeling is generally used for describing xenobiotic disposition in animals and humans with normal physiological conditions. We describe here an updated PBPK model for hexachlorobenzene (HCB) in male F344 rats with the incorporation of pathophysiological conditions. Two more features contribute to the distinctness of this model from the earlier published versions. This model took erythrocyte binding into account, and a particular elimination process of HCB, the plasma-to-gastrointestinal (GI) lumen passive diffusion (i.e., exsorption), was incorporated. Our PBPK model was developed using data mined from multiple pharmacokinetic studies in the literature, and then modified to simulate HCB disposition under the conditions of our integrated pharmacokinetics/liver foci bioassay. This model included plasma, erythrocytes, liver, fat, rapidly and slowly perfused compartments, and GI lumen. To account for the distinct characteristics of HCB absorption, the GI lumen was split into an upper and a lower part. HCB was eliminated through liver metabolism and the exsorption process. The pathophysiological changes after partial hepatectomy, such as alterations in the liver and body weights and fat volume, were incorporated in our model. With adjustment of the transluminal diffusion-related parameters, the model adequately described the data from the literature and our bioassay. Our PBPK model simulation suggests that HCB absorption and exsorption processes depend on exposure conditions; different exposure conditions dictate different absorption and exsorption rates. This model forms a foundation for our further exploration of the quantitative relationship between HCB exposure and development of preneoplastic liver foci.

Models; Physiology; Physiological-testing; Physiological-effects; Physiological-factors; Laboratory-animals; Animals; Animal-studies; Liver; Absorption-rates; Exposure-assessment

TOSCF2

118-74-1

20060501

Journal Article

raymond.yang@colostate.edu

Grant

2006

Grant-Number-R01-OH-007556

1

1096-6080

Research Tools and Approaches: Risk Assessment Methods

Toxicological Sciences

CO; CA

Colorado State University - Fort Collins