Kinetic disposition, urinary excretion and dosage regimen of subcutaneously administered levofloxacin in cross bred calves

The present study was conducted on five healthy male cross bred calves to study the kinetic disposition and urinary excretion of levofloxacin following its single subcutaneous administration at the dose of 4 mg.kg-1. The concentration of levofloxacin in plasma and urine samples was estimated by microbiological assay. Peak plasma level of levofloxacin (2.8 ± 0.3 mg.ml-1) was observed at 45 min and the drug level above MIC90 in plasma, was detected up to 12 hrs of administration. The bioavailability of levofloxacin was 41.9 ± 3.2%. High value of AUC (9.88 ± 0.1 mg.ml-1.hr) reflected a vast area of body covered by drug concentration. Good distribution of the drug was reflected by the high value of Vdarea (0.73 ± 0.04 L.kg-1). The elimination half-life and MRT were 3.0 ± 0.2 hr and 4.79 ± 0.2 hr, respectively. A suitable subcutaneous dosage regimen for levofloxacin was calculated to be 1.25 mg.kg-1 repeated at 12-hr intervals in calves.