TABLE 4

Summary of input parameters used to build the PBPK model for E7766

ParameterScenario 1Scenario 2Source
PhysChem and blood binding
 Mol. wt. (g/mol)746746Calculated
 Log P1.311.31Measured
 Compound typeMonoprotic acidMonoprotic acid
 pKa3.413.41Calculated
 B/P0.550.55Measured
fu0.500.50Measured
 Distribution modelFull PBPK modelFull PBPK model
 Vss (l/kg)0.6370.637SimCYP predicted (method 2, the Rodgers-Rowland method)
Kp scalar4.04.0Fitted based on preclinical data, see Materials and Methods for details
 CLrenal (l/h)3.03.0Estimate as fu × glomerular filtration rate
Hepatic transport (permeability-limited liver module)
 Passive diffusion CLPD (ml/min per 106 cells)0.000130.00013Obtained from E7766 uptake measured at 0.3 µmol/l at 4 °C with SCHH model (Table 1)
 fuIW1.001.00SimCYP predicted
 fuEW0.6570.657SimCYP predicted
Jmax (pmol/min per 106 cells) for OATP1B18.34Vmax in the unit of pmol/min/mg protein (Fig. 3) was converted to Jmax in the unit picomoles per minute per 106 cells by incorporating measured protein abundance data of HEK293 cells (0.3 mg protein per 106 HEK293 cells)
Km (µmol/l) for OATP1B12.20Obtained from transporter kinetic assays (Fig. 3)
fuinc for OATP1B11.00SimCYP predicted
 REF for OATP1B10.10Calculated by eq. 4, see Supplemental Table 2 for details of transporter protein expression.
Jmax (pmol/min per 106 cells) for OATP1B324.39Fig. 3. Units were converted as shown above for OATP1B1
Km (µmol/l) for OATP1B33.97Obtained from transporter kinetic assays (Fig. 3)
fuinc for OATP1B31.001.00SimCYP predicted
 REF for OATP1B32.80Calculated by eq. 5, see Supplemental Table 2 for details of transporter protein expression.
 Uptake CLint,T (µl/min per 106 cells)7.7For scenario 2, the uptake CLint,T for E7766 measured at 0.3 µmol/l after 1 min incubation at 37 °C (Table 1) was assigned as input value for uptake CLint,T in SCHH, as early time point and lower conc. can better represent the initial linear uptake phase.
 REFSCHH1The REFSCHH is assumed to be one based on literature reported data shown that OATP1B1 and OATP1B3 expression levels are comparable between SCHH and primary hepatocyte if from the same lot (Kimoto, 2012)
 Efflux CLint,T (µl/min per 106 cells)2.12.1For both scenarios 1 and 2, SCHH efflux CLint,T for E7766 measured at 0.3 µmol/l after 20-min incubation at 37 °C (Table 1) was used as input value for efflux CLint,T.
  • B/P, blood-to-plasma partition ratio; CLPD, passive diffusion clearance; fu, unbound drug fraction in plasma; fuIW, unbound drug fraction in intracellular water; fuEW, unbound drug fraction in extracellular water; fuinc, unbound drug fraction in in vitro incubation system; Kp, tissue-to-plasma partition coefficient; uptake CLint,T, intrinsic uptake clearance obtained from SCHH assay; efflux CLint,T, intrinsic biliary efflux clearance obtained from SCHH assay. For scenario 1, hepatic uptake clearance was assigned from the transporter kinetics measured in HEK293 cells and for scenario 2, intrinsic active uptake clearance measured in from SCHH was assigned to OATP1B3.