Table 2.
Population pharmacokinetic parameters of abacavir and bootstrap validation
| Parameter | Final model | Bootstrap (n = 1000) | ||
|---|---|---|---|---|
| Final estimate | Relative standard error (%) | Median | 5th–95th confidence interval | |
| Absorption rate constant, Ka (h−1) | 0.913 | 4.1 | 0.909 | 0.842–0.985 |
| Apparent systemic clearance, CL/F (l h−1) | ||||
| CL/F = CL/Fref × (WTi/17.6)θ1 | ||||
| CL/Fref | 20.1 | 3.8 | 20.1 | 18.7–21.4 |
| θ1 | 0.802 | 11.6 | 0.796 | 0.651–0.954 |
| Apparent central volume of distribution, V1/F (l) | ||||
| V1/F = V1/Fref × (WTi/17.6)θ2 | ||||
| V1/Fref | 13.0 | 11.7 | 12.8 | 9.3–15.5 |
| θ2 | 0.810 | 23.3 | 0.793 | 0.330–1.090 |
| Apparent peripheral volume of distribution, V2/F (l) | 13.5 | 10.7 | 13.4 | 11.0–16.0 |
| Intercompartment clearance, Q/F (l h–1) | 2.0 | 9.9 | 2.0 | 1.7–2.4 |
| Interindividual variability (%) | ||||
| Q/F | 42.5 | 41.7 | 41.0 | 27.5–62.1 |
| V1/F | 47.7 | 33.6 | 46.2 | 29.7–66.4 |
| V2/F | 57.5 | 40.5 | 55.8 | 38.3–76.4 |
| CL/F | 21.9 | 38.4 | 21.0 | 13.7–28.6 |
| Interoccasion variability (%) | ||||
| CL/F | 20.4 | 25.3 | 20.2 | 15.7–24.8 |
| Residual proportional (%) | 38.2 | 8.2 | 38.1 | 35.7–40.9 |
CL/F, apparent systematic clerance; Q/F, intercompartment clearance; V1/F, apparent central volume of distribution; V2/F, apparent peripheral volume of distribution; WTi, individual weight.