Table 2.
Population pharmacokinetic parameters of the base model and final model
| Parameter | Base model (%CV) | Final model (%CV) | Bootstrap final model (n = 939/1000 successful runs) [mean (95% CI)] |
|---|---|---|---|
| Vc (L) | 23.3 (10.0) | ||
| Vc = Vc70kg × (TBW/70)X | |||
| Vc70kg (L) | 11.9 (8.8) | 11.9 (10.3–13.5) | |
| X | 1.25 (10.8) | 1.26 (1.06–1.46) | |
| CL (L/min) | 0.130 (5.7) | ||
| CL = CL70kg × (TBW/70)Z | |||
| CL70kg (L/min) | 0.0892 (5.6) | 0.0892 (0.0815–0.0969) | |
| Z | 0.729 (9.6) | 0.735 (0.572–0.898) | |
| Vp (L) | 7.06 (8.0) | 7.29 (5.7) | 7.33 (6.32–8.35) |
| Q (L/min) | 0.0812 (17.4) | 0.0848 (8.2) | 0.0873 (0.0541–0.121) |
| IIV (%) | |||
| Vca | 49.6 (11.6) | 19.2 (16.6) | 18.9 (7.98–25.7) |
| CLa | 32.0 (16.4) | 18.1 (5.0) | 17.6 (11.3–22.2) |
| Covariance IIV Vc–CL | 0.0316 | 0.0302 (0.00894–0.0514) | |
| Proportional errorb | 0.156 (10.8) | 0.159 (8.2) | 0.157 (0.125–0.190) |
| Additive error (mg/L)b | 0.221 (10.2) | 0.206 (8.4) | 0.204 (0.160–0.247) |
| OFV | 329.4 | 232.9 | 223.0 |
Parameter estimates are shown with standard error of estimate reported as %CV
CI confidence interval, CL clearance from the central compartment, CL70kg clearance from the central compartment for an individual weighing 70 kg, CV coefficient of variation, IIV inter-individual variation, OFV objective function value, Q intercompartmental clearance, TBW total body weight, Vc central volume of distribution, Vc70kg central volume of distribution for an individual weighing 70 kg, Vp peripheral volume of distribution, X exponent for a power function on Vc, Z exponent for a power function on CL
a Eta-shrinkage for IIV in the final model is 4% (CL) and 7% (Vc)
b Estimates of residual error terms are reported as standard deviation