A recent comparison of non-compartmental analysis through the prediction of VDSS and CL was outperformed by PBPK modeling approaches, as well as direct prediction of the concentration-time curve and prediction of input parameters to a 2-compartment model. To improve the applicability of the QSP model for quantitative predictions, through the use of a physiology-based (PB) PK model, we may be able to more accurately simulate the concentration-time profile. This may also enable us to use more "low-level" PK parameters which could be tested in vitro (such as intrinsic CL).