Table 2.
PK model parameter estimates
| Base model* | Covariate model | ||||
|---|---|---|---|---|---|
| Model 1 (free allometric scaling parameters) | Model 2 (fixed allometric scaling parameters) | ||||
| Parameters | Estimates (SE) | Parameters | Estimates (SE) | Parameters | Estimates (SE) |
| (Obj = ‐2197) | (Obj = ‐2321) | (Obj = ‐2285) | |||
| CL | CL = θ1 (wgt/70)θ2 | CL = θ1 (wgt/70)θ2 | |||
| 8.4 (0.9) [4.7, 9.9]† | θ1 | 49.0 (8.2) [19.3, 79.2] | θ1 | 39.6 (2.2) [33.2, 46.1] | |
| θ2 | 0.9 (0.1) [0.4, 1.1] | θ2 = 0.75 | |||
| V 1 | V 1 = θ3 (wgt/70)θ4 | V 1 = θ3 (wgt/70)θ4 | |||
| 86.5 (13.9) [14.8, 145.2] | θ3 | 198.8 (107.8) [28.1, 659.4] | θ3 | 529.1 (72.1) [255.8, 893.3] | |
| θ4 | 0.7 (0.2) [0.001, 1.1] | θ4 = 1 | |||
| Q | 0.5 (0.2) [0.1, 3.5] | Q = θ5 (wgt/70)θ6 | Q = θ5 (wgt/70)θ6 | ||
| θ5 | 35.3 (17.0) [3.9, 332.5] | θ5 | 7.8 (2.9) [2.0, 26.5] | ||
| θ6 | 1.3 (0.2) [0.5, 2.5] | θ6 = 0.75 | |||
| V 2 | 9.0 (2.9) [4.8, 67.8] | V 2 = θ7 (wgt/70)θ8 | V 2 = θ7 (wgt/70)θ8 | ||
| θ7 | 520.9 (181.3) [87.4, 2323.1] | θ7 | 227.3 (56.8) [140.0, 554.1] | ||
| θ8 | 1.2 (0.2) [0.1, 1.8] | θ8 = 1 | |||
| Ω2 CL (%CV) | 103 (13) [56, 133] | Ω2 CL (%CV) | 70 (13) [43, 130] | Ω2 CL (%CV) | 64 (13) [38, 97] |
| Ω2 V1 (%CV) | 118 (12) [47, 176] | Ω2 V1 (%CV) | 64 (19) [40, 178] | Ω2 V1 (%CV) | 73 (16) [35, 165] |
| σ2 proportional (%CV ) | 48 (5) [40, 90] | σ2 proportional (%CV) | 52 (5) [40, 104] | σ2 proportional (%CV) | 49 (5) [40, 80] |
| σ2 additive (ng ml–1) | 0.01 (0.01) [0.00, 0.02] | σ2 additive (ng ml–1) | 0.01 (0.01) [0.00, 0.02] | σ2 additive (ng ml–1) | 0.01 (0.01) [0.00, 0.02] |
*
The estimates from the base model using the entire cohort are presented.
†
The 95% bootstrap confidence intervals (CIs) are presented in square brackets.
SE, the standard error; Obj, the objective function value; CL, total clearance (l h–1); Q, intercompartmental clearance (l h–1); V 1, volume of distribution for the central compartment (l); V 2, volume of distribution for the peripheral compartment (l); CV, coefficient of variation; wgt, body weight in kg; Ω2 CL and Ω2 V1, the variance for ηi CL and ηi V1, respectively; σ2 proportional and σ2 additive, the proportional and additive residual error variance, respectively.