Pharmacokinetics of marbofloxacin after single intravenous and repeat oral administration to cats

The pharmacokinetic properties of marbofloxacin, a third generation fluoroquinolone, were investigated in six cats after single intravenous (IV) and repeat oral (PO) administration at a daily dose of 2 mg/kg. Marbofloxacin serum concentration was analysed by microbiological assay using Klebsiella pneumoniae ATCC 10031 as micro-organism test. marbofloxacin disposition was best described by bicompartmental and mono-compartmental open models with first-order elimination after IV and oral dosing respectively. After IV administration, distribution was rapid (T1/2(d) 0.23 ± 0.24 h) and wide, as reflected by the steady-state volume of distribution of 1.01 ± 0.15 L/kg. Elimination from the body was slow with a body clearance of 0.09 ± 0.02 L/h kg and a T1/2 of 7.98 ± 0.57 h. After repeat oral administration, absorption half-life was 0.86 ± 1.59 h and Tmax of 1.94 ± 2.11 h. Bioavailability was almost complete (99 ± 29%) with a peak plasma concentration at the steady-state of 1.97 ± 0.61 μg/mL. Drug accumulation was not significant after six oral administrations. Calculation of efficacy predictors showed that marbofloxacin has good therapeutic profile against Gram-negative and Gram-positive bacteria with a MIC50 value <0.25 μg/mL.