PHYSIOLOGICALLY BASED PHARMACOKINETIC (PBPK) MODELS
What they are
Based on known physiological processes (blood flow rates, absorption rates, breathing rates, etc.), chemical-specific processes (metabolic constants, molecular weight, etc.) and species-dependent processes.
Describe the path of a compound through the body, including how it enters, how it is broken down, and how it exits.
Tissues, organs, etc. considered as "compartments"
(Differential) equations describe the processes in the body (flows between compartments)
How they are used
Predict "target tissues" of toxins; base risk on tissue does rather than external exposure.
Identify most important parameters for sensitivity analysis
Give guidance to extrapolation (high- to low-dose, interspecies, route to route, acute to chronic, continuous to intermittent, single chemical to mixture, between subpopulations)
Identify data gaps
Perform analysis on individual basis or accounting for variability in populations
Medical diagnostics, occupational exposure assessment, regulation, basic research.