Pharmacokinetic‐pharmacodynamic integration of enrofloxacin and its metabolite ciprofloxacin in buffalo calves

The present study was planned with an objective to test the pharmacokinetics of a new formulation of enrofloxacin (Flobac(®) SA) in buffalo calves. The drug was administered at the dose rate of 7.5 mg kg(−1) body weight through the intravenous (i.v.) and intramuscular (i.m.) route followed by plasma collection and analysis at different time intervals. After analysis, using High Performance Liquid Chromatography – Ultraviolet, various pharmacokinetic parameters were calculated using visual fit for compartmental analysis, followed by integration with pharmacodynamic parameters against Escherichia coli and Pasteurella multocida. Although total area under plasma drug concentration time curve was higher through the i.v. route, mean residence time and metabolic conversion ratio was higher following administration by the i.m. route indicating longer persistence of the drug in body. Overall i.m. bioavailability of the parent compound with its metabolite was found to be 91%. Upon, Pharmacokinetic–Pharmacodynamic integration, all the parameters indicated significant antibacterial activity. It can be concluded that the dose of enrofloxacin used in the present study can be administered to contain infections caused by P. multocida and E. coli in buffalo calves.