Pharmacokinetic Study of Ceftriaxone Alone and With Probenecid in Febrile Goats

Abstract

Ceftriaxone (CTA), a third generation cephalosporin, is being used extensively in animal practice. CTApharmacokinetics has not been investigated with probenecid (PB) in febrile goats. In this investigation, pharmacokinetic properties and dosage regimen of CTA alone (50 mg/kg body weight) and with PB (1 g, orally) were studied in febrile goats. Blood samples were collected into heparinized tubes at predetermined time intervals after administration of the drug. Plasma concentrations of CTA were determined by the UV-detector, attached to high performance liquid chromatography. The plasma concentrations of CTA alone and with PB were detected up to 6 and 8 h, respectively. The plasma concentrations versus time data of CTA were adequately described by a two compartment open model. The pharmacokinetic properties (maximum plasma concentration-Cp max, totalbodyclearance-Cl, totalareaunderthetimeconcentrationcurve-AUC B and mean residence time-MRT) differed significantly (P<0.01) between CTA alone and with PB. The elimination of the drug tends to be faster in CTA alone treated goats. The Cp max of CTA alone and with PB in goats was 133.67±1.62 and 246.04±1.20 μg/ml, respectively. The elimination halflife (t½ β) of CTA alone was lower (0.98±0.02 h) as compared to PB (1.35±0.02 h) treated goats. A suitable intravenous dosage regimenfor CTA with PB was calculated as 1mg/kg bodyweight and repeated at 6 h intervals in febrile goats.