Determination of orbifloxacin in sheep plasma by high performance liquid chromatography with ultraviolet detection after intravenous and intramuscular administration

Abstract Introduction Single-dose pharmacokinetics of orbifloxacin (2.5 mg/kg body weight) were determined in clinically normal female Patanwadi sheep (n = 6) following intravenous and intramuscular administration. Methods Orbifloxacin concentrations were determined by high performance liquid chromatography with ultraviolet detection. The concentration–time data were analyzed by non-compartmental kinetic method. Results and discussion Following a single intravenous injection, an elimination half-life (t 1/2β ) of 8.31 ± 0.102 h. Steady-state volume of distribution (Vd ss ) and total body clearance (Cl B ) were 3.09 ± 0.282 L/kg and 0.158 ± 0.006 L/kg/h, respectively. Following intramuscular administration, an elimination rate constant (β), the area under the curve from zero to infinity (AUC 0 − ∞ ) and the mean absorption time (MAT) were 0.015 ± 0.001 h − 1 , 23.49 ± 1.722 μg·h/mL and 7.50 ± 0.58 h, respectively. The peak plasma concentration (C max ) of 1.81 ± 0.005 µg/mL was achieved at 1.00 ± 0.00 h. The mean residence time (MRT) was 26.25 ± 1.083 h and the absolute bioavailability was 150.8 ± 12.35%, respectively. Orbifloxacin could be useful for the treatment of bacterial infections in sheep that are sensitive to this drug.