TABLE 2.
Estimated PK parameters after intratracheal (nebulized form) or i.v. administration of colistin at 0.35 mg/kg, based on simultaneous modeling
| Parametera (units) | Typical value (RSEb [%]) | % interindividual variability (RSEb [%]) |
|---|---|---|
| Vc (liters/kg) | 0.19 (7) | 11 (90) |
| Vp (liters/kg) | 0.19 (3) | |
| VELF (liters/kg) | 30 × 10−6 (fixed) | |
| Faero (%) | 69 (5) | 19 (43) |
| CLT (liters/h/kg) | 0.43 (1) | |
| Q (liters/h/kg) | 0.29 (2) | |
| QELF (liters/h/kg) | 6.7 × 10−5 (2) | |
| ka (h−1) | 1.6 (7) | 31 (42) |
| Vmax, in (mg/h/kg) | 0.33 (2) | |
| km (μg/ml) | 133 (18) | 84 (29) |
| γ | 3.9 (1) | |
| Residual errors | ||
| Plasma | ||
| Additive residual error (μg/ml) | 0.003 | |
| Proportional residual error (%) | 15 | |
| ELF | ||
| Proportional residual error (%) | 14 |
Vc, volume of distribution in central compartment; Vp, volume of distribution of peripheral compartment; VELF, volume of distribution in ELF compartment; Faero, systemic bioavailability after nebulization; CLT, total systemic clearance; Q, clearance of distribution between central and peripheral compartments; QELF, diffusion clearance between central compartment and ELF compartment; ka, first-order transfer rate constant from depot compartment toward ELF compartment; Vmax, in, maximal rate of transfer from ELF compartment toward central compartment; km, ELF concentration for which the rate of transfer from the ELF compartment toward the central compartment is Vmax/2; γ, the slope factor.
RSE, relative standard error, expressed as the coefficient of variation.