Table 4.
Pharmacokinetic constants for carfentanil and norcarfentanil after s.c. administration of 1, 3, or 10 μg/kg carfentanil in male rats.
| Analyte | Carfentanil dose (μg/kg) |
Cmax (pg/mL) |
AUC0-8 h (min*ng/mL) |
Ke (min−1) |
t1/2 (min) |
|---|---|---|---|---|---|
| Carfentanil | 1 (N=6) | 613 ± 49 | 29 ± 3 | 0.020 ± 0.002 | 35.4 ± 2.5 |
| 3 (N=6) | 1902 ± 418 | 148 ± 25 | 0.013 ± 0.001* | 55.1 ± 6.3 | |
| 10 (N=5) | 7862 ± 804*# | 696 ± 184*# | 0.012 ± 0.002* | 64.4 ± 8.4* | |
| Norcarfentanil | 1 (N=6) | 40 ± 4 | 7 ± 1 | 0.004 ± 0.001 | 176 ± 10 |
| 3 (N=6) | 211 ± 38 | 38 ± 5 | 0.004 ± 0.001 | 350 ± 215 | |
| 10 (N=5) | 601 ± 116*# | 128 ± 18*# | 0.002 ± 0.001 | 537 ± 200 |
Data are mean ± SEM for group size given.
Abbreviations are: maximal concentration (Cmax), area-under-the-curve from 0-8 h (AUC0-8 h); elimination rate constant (Ke), and half-life (t1/2)
*
= significant difference compared to 1 μg/kg dose (Tukey’s p<0.05)
#
= significant difference compared to 3 μg/kg dose (Tukey’s, p<0.05)