TABLE 2.
Parameter Estimates of the Model-Building Data Set and the Refit and Bootstrap of the Merged Data Set
| Parameter | Model-Building Data Set [Estimate (CV%)] | Refit: Merged Data Set [Estimate (CV%)] | Bootstrap: Merged Data Set | ||
| Estimate | CI (2.5%) | CI (97.5%) | |||
| CL (L/h/70 kg) | 1.89 (5) | 1.88 (3) | 1.87 | 1.77 | 2.00 |
| Vc (L/70 kg) | 32.5 (10) | 33.2 (6) | 33.2 | 29.0 | 38.0 |
| Q (L/h/70 kg) | 2.01 (12) | 1.81 (7) | 1.83 | 1.42 | 2.21 |
| Vp (L70 kg) | 30.3 (9) | 32.2 (8) | 32.3 | 27.3 | 38.9 |
| Additive error | 0.15 (9) | 0.16 (7) | 0.16 | 0.14 | 0.19 |
| IIV on CL (%) | 26.6 (15) | 24.5 (12) | 23.7 | 17.9 | 29.4 |
| IIV on Vc (%) | 40.8 (22) | 30.1 (24) | 29.8 | 14.1 | 41.8 |
| IIV on Vp (%) | 53.3 (23) | 56.4 (20) | 55.7 | 32.7 | 84.5 |
| IIV on additive residual error (%) | 50.2 (15) | 52.3 (12) | 51.5 | 36.9 | 63.7 |
| ΘCLGA | 3.0 (16) | 2.76 (15) | 2.63 | 1.35 | 3.77 |
| ΘSD5 | 1.29 (12) | 1.36 (4) | 1.36 | 1.14 | 1.52 |
Final model: TVCL = CL × (BW/70)0.75 × θSD5 × (GA/GAmedian)θCLGA; TVVc = Vc × (BW/70)1; TVQ = Q × (BW/70)0.75; TVVp = Vp × (BW/70).1
CL, clearance; ΘCLGA, fractional change in CL with each unit of deviation from the median GA; CV, coefficient of variation; IIV, interindividual variability; ΘSD5, study day 5 (>96 h postnatal age); Q, intercompartmental clearance; Vc, volume of distribution of the central compartment; Vp, volume of distribution of the peripheral compartment.