Physiologically based pharmacokinetic components

Physiologically based pharmacokinetic (PBPK) modelling sometimes constitutes a basis for replacement of default components of uncertainty for toxicokinetics and a portion of toxicodynamics. Where data are sufficient, a full biologically based dose-response model addresses additional uncertainties with respect to both interspecies differences and interindividual variability in both kinetics and dynamics. 

Figure 5.5 Flowchart showing various human risk assessment options for chemical mixtures based on component data. PBPK model = Physiologically Based Pharmacokinetic model. 

Dennison JE. Physiologically-based pharmacokinetic modeling of simple and complex mixtures of gasoline and the gasohne components n-hexane, benzene, toluene, ethylbenzene, and xylene. Ph.D. dissertation. 2004, Colorado State University. 

Physiologically based pharmacokinetic (PB-PK) models for some JP-8 components have been developed to understand the relationship between vapor concentrations and accumulation in tissue and blood compartments. When appropriately developed and validated, PB-PK models can provide a time course of distribution of a chemical or its metabolites in tissues and show the effect of changingphysiologic characteristics on plasma and tissue concentrations. PB-PK models have been applied to predict toxicokinetic parameters and to scale dose in different species. 

---