“…Blood concentrations versus time data sets after oral administration in rats (Kamiya et al, 2021a(Kamiya et al, , 2021b of the previously analyzed 323 primary and 10 secondary chemicals (Kamiya et al, 2021b) obtained by a literature survey underwent machine learning, along with 39 new additional chemicals, including medicines from a Japanese drug database (Supplemental Table S1). The variety of compounds in the chemical space (Kamiya et al, 2021b(Kamiya et al, , 2021c(Kamiya et al, , 2021a(Kamiya et al, , 2019 was previously evaluated for the examined chemicals in studies on intestinal permeability (Kamiya et al, 2021c, Shimizu et al, 2022 and rat pharmacokinetics (Kamiya et al, 2019(Kamiya et al, , 2021b(Kamiya et al, , 2021a. Traditionally, the necessary input parameters for PBPK models, i.e., F a •F g , k a , volume of the systemic circulation (V 1 ), and hepatic intrinsic clearance (CL h,int ), have been computed to give the best fit to reported/measured plasma concentrations using nonlinear regression analyses (Kamiya et al, 2021a(Kamiya et al, , 2021b, as briefly outlined in the Supplemental materials and methods.…”