PK-PD parameters for alfentanil in mdr1a(-/-) and mdr1a(+/+) mice
Parametera | Weighting | mdr1a(-/-) | mdr1a(+/+) |
|---|---|---|---|
| Ka (min-1) | 0.35 ± 0.03 | 0.35 ± 0.03 | |
| Cl (ml · min-1 · kg-1) | 1/y | 82 ± 3 | 82 ± 3 |
| Vc (ml · kg-1) | 1/y | 1000 ± 60 | 1000 ± 60 |
| t1/2 (min) | 12 ± 0.6b | 12 ± 0.6b | |
| Clup (ml · min-1 · kg-1) | 1/y | 7 ± 5 | 4 ± 3 |
| Clefflux (ml · min-1 · kg-1) | 1/y | 13 ± 12 | 22 ± 17 |
| Vb (ml · kg-1) | 13.4 (fixed) | 13.4 (fixed) | |
| EC50 (ng/g) | Uniform | 9.2 ± 1.7 | 11 ± 1.8 |
| γ | Uniform | 1.8 ± 0.4 | 1.8 ± 0.4 |
| K p,brain | 1/y | 0.54 ± 0.04 | 0.195 ± 0.008 |
| Keq (min-1) | 1/y | 0.46 ± 0.10 | 0.64 ± 0.09 |
| t1/2eq,brain (min) |
| 1.5 ± 0.3 | 1.08 ± 0.16 |
↵ a Parameter estimate ± S.E. from nonlinear least-squares regression analysis of pooled mdr1a(-/-) or mdr1a(+/+) mouse data. Ka, Cl, Vc, Vb, and γ were constrained to the same value for mdr1a(-/-) or mdr1a(+/+) mice. t1/2 and t1/2eq,brain were calculated from 0.693/(Vc/Cl) and 0.693/Keq,brain, respectively.
↵ b Propagation of error was used to calculated S.E.