P. 389-395The pharmacokinetics of doxycycline were investigated in sheep after oral (PO) and intravenous (IV) administration. The IV data were
best described using a 2- (n = 5) or 3- (n = 6) compartmental open model. Mean pharmacokinetic parameters obtained using a 2-compartmental
model included a volume of distribution at steady-state (Vss) of 1.759 ± 0.3149 L/kg, a total clearance (Cl) of 3.045 ± 0.5264 mL/
kg/min and an elimination half-life (t1/2b) of 7.027 ± 1.128 h. Comparative values obtained from the 3-compartmental mean values were:
Vss of 1.801 ± 0.3429 L/kg, a Cl of 2.634 ± 0.6376 mL/kg/min and a t1/2b of 12.11 ± 2.060 h. Mean residence time (MRT0_1) was
11.18 ± 3.152 h. After PO administration, the data were best described by a 2-compartment open model. The pharmacokinetic parameter
mean values were: maximum plasma concentration (Cmax), 2.130 ± 0.950 lg/mL; time to reach Cmax (tmax), 3.595 ± 3.348 h, and absorption
half-life (t1=2k01 ), 36.28 ± 14.57 h. Non-compartmental parameter values were: Cmax, 2.182 ± 0.9117 lg/mL; tmax, 3.432 ± 3.307 h;
F, 35.77 ± 10.20%, and mean absorption time (MAT0–∞), 25.55 ± 15.27 h. These results suggest that PO administration of doxycycline
could be useful as an antimicrobial drug in sheep.S
