Over the past few decades, drug research programs have used a variety of computer models. Drug disposition modeling and simulation have emerged as essential tools in drug research, clinical study design, and regulatory assessment. Publications and regulatory filings related to physiologically based pharmacokinetic (PBPK) modeling have increased significantly in recent years [1]. To provide a mechanistic representation of the drug in biological systems, PBPK models integrate data on the drug with separate previous knowledge on the biology and physiology at the organism level. This enables the a priori modeling of drug concentration–time profile.