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Further information
ATC Vet code: QJ01MA93
Pharmacotherapeutic group: antibacterials for systemic use, Fluoroquinolones
Pharmacodynamic properties
Marbofloxacin is a synthetic, bactericidal antimicrobial, belonging to the fluoroquinolone group, which acts by inhibition of DNA gyrase. The in vitro activity of marbofloxacin has been demonstrated towards Pasteurella multocida, Mannheimia haemolytica and Escherichia coli.
The marbofloxacin in vitro activity against pathogens isolated in 2007 from bovine respiratory diseases is good: MIC values are comprised between 0.008 and 0.5 µg/ml for M. haemolytica (MIC90 = 0.139 µg/ml; MIC50 = 0.021 µg/ml), between 0.004 and 0.5 µg/ml for P. multocida (MIC90 = 0.028 µg/ml; MIC50 = 0.012 µg/ml).
In 2008, the marbofloxacin MIC50 for E. coli isolated from bovine mastitis was 0.021 µg/ml and the MIC90 was 0.038 µg/ml.
Strains with MIC ≤ 1 µg/ml are sensitive to marbofloxacin whereas strains with MIC ≥ 4 µg/ml are resistant to marbofloxacin.
Resistance to fluoroquinolones occurs by chromosomal mutation with three mechanisms: decrease of the bacterial wall permeability, expression of efflux pump or mutation of enzymes responsible for molecule binding.
Pharmacokinetic particulars
After a single intramuscular administration in cattle at the recommended dose of 10 mg/kg body weight, the maximum plasma concentration of marbofloxacin (Cmax) is 7.915 µg/ml reached in 1.28 h (Tmax) for an exposure (AUCINF) of 52.7 µg.h/mL. Bioavailability after intramuscular injection is complete (more than 90%). Marbofloxacin is extensively distributed. Binding to plasma proteins is about 30%. After intravenous or intramuscular administration, marbofloxacin concentrations in milk increase rapidly and the AUCINF , Tmax and Cmax values obtained in plasma and milk after both administration routes are similar. Marbofloxacin is eliminated slowly (T1/2λz = 17.50 h) predominantly as the active form in urine and faeces.