Plasma Concentrations, Pharmacokinetics and Urinary Excretion of Gatifloxacin after Single Intravenous Injection in Buffalo Calves

Abstract

The pharmacokinetics and urinary excretion of gatifloxacin were investigated after a single intravenous injection of 4 mg/kg body weight in buffalo calves. The therapeutic plasma drug concentration was maintained for up to 12 h. Gatifloxacin rapidly distributed from blood to tissue compartments, which was evident from the high values of the distribution rate constant, alpha1 (11.1 +/- 1.06 h(-1)) and the rate constant of transfer of drug from central to peripheral compartment, k12 (6.29 +/- 0.46 h(-1)). The area under the plasma drug concentration-time curve and apparent volume of distribution were 17.1 +/- 0.63 (microg.h)/ml and 3.56 +/- 0.95 L/kg, respectively. The elimination half-life (t (1/2 beta)), total body clearance (ClB) and the ratio of drug present in tissues and plasma (T/P) were 10.4 +/- 2.47 h, 235.1 +/- 8.47 ml/(kg.h) and 10.1 +/- 2.25, respectively. About 19.7% of the administered drug was excreted in urine within 24 h. A satisfactory intravenous dosage regimen for gatifloxacin in buffalo calves would be 5.3 mg/kg at 24 h intervals.

Os níveis plasmáticos, farmacocinética e regime de dosagem de gatifloxacina administrado por via intravenosa em bezerros búfalos (Bubalus bubalis) na administração concomitante com meloxicam

“…Similar values have also been reported for the half-life of other fluoroquinolones, marbofloxacin (5.7 h) in cattle 20 and pefloxacin (6.88 h) in sheep 21 . The total body clearance of gatifloxacin in buffalo calves in the present study (337.6 ± 19.9 ml.kg -1 .h -1 ) was higher than the values of Cl B reported after single intravenous injection of gatifloxacin in human beings (182-206 ml.kg -1 .h -1 ) and buffalo calves (235.1 ml.kg -1 .h -1 ) 10,17,22 .…”

“…497/01/a/CPCSEA). The doses of gatifloxacin and meloxicam employed in the present study were similar to the doses of these drugs in buffalo calves and calves in previous disposition studies 10,12 .…”

Scientific Opinion on the public health hazards to be covered by inspection of meat (bovine animals)

“…The CONTAM Panel noted the emerging literature indicating that significant differences between cattle and buffalo exist in areas such as pharmaco-and toxicokinetics of several compounds and related physiological parameters (Knox et al, 1994;Raipuria et al, 2007;Motawee et al, 2009;Genualdo et al, 2011). Although variations in the excretion profiles of a number of chemical substances in milk and milk products between the two species have been reported, the available data do not allow for any conclusion as to the practical importance of such differences for residues and contaminants in buffalo meat.…”