Table 1.
Pharmacokinetic parameters (geometric mean ± SEM) of tildipirosin in ewes (n = 6) after intravenous, intramuscular and subcutaneous administration at a single dose of 2, 4 and 4 mg/kg, respectively.
| Parameters (Units) | Intravenous | Intramuscular | Subcutaneous |
|---|---|---|---|
| C0 (µg/L) | 5281.9 ± 799.4 | ||
| λz (h −1) | 0.040 ± 0.006 | 0.024 ± 0.010 | 0.015 ± 0.002 |
| t½λz (h) * | 17.16 ± 2.25 | 23.90 ± 6.99 | 43.19 ± 5.17 a |
| VZ (L/kg) | 5.36 ± 0.57 | ||
| Vss (L/kg) | 4.93 ± 0.58 | ||
| Cl (L/h/kg) | 0.21 ± 0.01 | ||
| AUC0–24 (µg·h/L) | 6002.0 ± 322.6 | 10452.4 ± 496.2 | 9565.5 ± 1010.7 |
| AUC0–∞ (µg·h/L) | 9395.1 ± 571.8 | 22,619.6 ± 3590.2 | 30,558.9 ± 4344.2 |
| MRT (h) | 22.68 ± 3.23 | 39.70 ± 10.07 | 65.21 ± 7.87 a |
| MAT (h) | 18.73 ± 5.49 | 38.98 ± 8.95 | |
| Cmax (µg/L) | 1264.4 ± 163.4 | 584.5 ± 75.7 b | |
| tmax (h) | 0.62 ± 0.10 | 2.67 ± 1.60 b | |
| F (%) | 79.17 ± 4.68 | 68.78 ± 7.47 |
* Harmonic mean, a: Significantly different from IV (p < 0.05). b: Significantly different from IM (p < 0.05). C0: serum drug concentration immediately after intravenous administration; λz: slowest elimination rate constant; t½λz: elimination half-life associated with the terminal slope (λz) of a semilogarithmic concentration–time curve; Vz: apparent volume of distribution calculated by the area method; Vss: apparent volume of distribution at steady state; Cl: total body clearance of drug from plasma; AUC0–24: area under the plasma concentration-time curve from zero to 24 h; AUC0–∞: area under the plasma concentration-time curve from zero to infinity; MRT: mean residence time; MAT: mean absorption time; Cmax: the peak or maximum plasma concentration following extravascular administration; tmax: time to reach peak or maximum plasma concentration following extravascular administrations; F: the fraction of the administered dose systemically available (bioavailability).