Physiologically based pharmacokinetic power

Physiologically based pharmacokinetic (PBPK) models are a special type of PK model that attempts to provide more definition to the model analysis by incorporating physiological factors into the model design, like tissue volumes, blood flow rates, and species-specific enzyme characteristics that can more accurately differentiate the dose-response relationship for a chemical or drug in one species from that of another species. The power of this approach is to be able to perform laboratory studies, both in vitro and in vivo, in common experimental species... 

While rate equations can be solved and metabolic rates can be estimated and determined easily in vitro because of the control of variables (specifically, substrate concentration), the situation is much more difficult in vivo. Here the advent of physiologically based pharmacokinetic (PBPK) models has offered a powerful tool for examining metabolic interactions that occur following exposure to chemical mixtures (see Chapter 3). 

Zhang, X., Tsang, A. M., Okino, M. S., Power, F. W., Knaak, J. B., Harrison, L. S., and Dary, C. C. (2007). A physiologically based pharmacokinetic/pharmacodynamic model for carbofuran in Sprague-Dawley rats using the exposure-related dose estimating model. Toxicol Sci 100, 345-359. 

Zhang X, Tsang AM, Okino MS, Power FW, Knaak JB, Harrison LS, Dary CC (2007) A physiologically-based pharmacokinetic harmacodynamic (PBPK/PD) model for carbofuran in Sprague-Dawley rats using the Exposure Related Dose Estimating Model (ERDEM). Toxicol Sci 100 345-359... 

Allometric scaling (allometry) is the discipline that predicts human pharmacokinetics using preclinical data [16]. This approach is based on empirical observations that various physiological parameters are functions of body size. The most widely used equation in allometry is a one-term power function ... 

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