Disposition kinetics of moxifloxacin in calves following a single intravenous bolus dose

The objective of this study was to determine the pharmacokinetics of moxifloxacin following single intravenous (IV) administration in five healthy female Sahiwal calves. Moxifloxacin was administered intravenously (5 mg.kg-1 bodyweight) and blood samples were collected prior to drug administration and up to 48 hr after injection. Plasma concentrations of moxifloxacin were examined by microbiological assay method. The disposition of plasma moxifloxacin is characterized by two compartment open model. The pharmacokinetic parameters obtained after IV administration (mean ± SE) were t½α 0.12 ± 0.00 h, t½β 8.16 ± 0.16 h, AUC 46.65 ± 1.70 µg.ml-1.h, AUMC 531.69 ± 16.72 µg.ml-1.h2, MRT 11.41 ± 0.20 h, Vdarea 1.27 ± 0.06 L.kg-1, and ClB 0.10 ± 0.00 L.kg-1.h-1. A dosage regimen of 5 mg.kg-1 bodyweight at 24 h interval following IV injection of moxifloxacin would maintain the plasma levels required to be effective against the bacterial pathogens with MIC values ≤ 0.25 μg.ml-1. The suggested dosage regimen of moxifloxacin has to be validated in the disease models before recommending for clinical use in calves.