Table 2.
Pharmacokinetic and pharmacodynamic parameters and estimates of variability
| Parameter, unit | Definition | Population mean (% RSE) | Bootstrap median (95% CI*) | Interindividual variability (IIV) CV% | Bootstrap IIV CV% (95% CI*) |
|---|---|---|---|---|---|
| Pharmacokinetic | |||||
| CL (l h−1) | Apparent clearance | 52.6 (4.18) | 52.9 (48.5, 56.7) | 29.7 | 27.9 (26.5, 29.1) |
| V (l) | Apparent volume of distribution | 113 (56.6) | 113 (100, 126) | 22.1 | 22.2 (20.2, 24.1) |
| Ka (h−1) | Absorption rate constant | 0.41 (2.43) | 0.41 (0.39, 0.43) | –† | –† |
| Residual error (ng ml−1) | 23.0 (11.7) | 23.1 (21.7, 25.2) | |||
| Pharmacodynamic | |||||
| τ | Mean transit time | 0.50 (2.97) | 0.48 (0.48, 0.51) | –† | –† |
| Emax | Maximum simulation | 19.8 (3.17) | 20.3 (19.2, 20.4) | –† | –† |
| EC50 | Simulation constant | 3.68 (3.89) | 3.68 (3.49, 3.81) | –† | –† |
| r | Hill coefficient | 0.55 (9.05) | 0.59 (0.50, 0.60) | 4.05 | 4.07 (3.86, 4.22) |
| Residual error, % | 40.4 (1.52) | 40.4 (38.2, 42.9) |
*
CI, confidence interval calculated from 1000 bootstrap resamplings.
†
Not estimated. % RSE, relative standard error for estimate; CV, coefficient of variation.