Oral delivery and pharmacokinetic models

This chapter provides a brief overview of current pharmacokinetic modeling approaches for oral absorption. Each concept is exemplified by a model introduced by means of mathematical equations and explanation of basic properties, followed by examples of drugs and absorption data it was applied to. The compartmental models and empirical models are the simplest of approaches. Physiologically based pharmacokinetic models of drug absorption are more advanced and require specialized software for model implementation. The chapter is concluded with spatiotemporal models of drug absorption that apply time and distance variables to account for longitudinal location of the drug molecule in the intestine. As the focus of this chapter is on introducing basic concepts, important aspects of modeling drug absorption such as population pharmacokinetic approaches, prediction of oral bioavailability, in vitro-in vivo correlation, drug-drug interactions, and inter-species scaling have not been discussed.