Pharmacokinetics, urinary excretion and plasma protein binding of ofloxacin in water buffalo calves (<i>Bubalus bubalis</i>)

Abstract

Pharmacokinetics and urinary excretion of an intravenous dose of 5 mg.kg-1 ofloxacin were investigated in water buffalo calves. Plasma concentrations of ofloxacin were determined by high-performance liquid chromatography. Ofloxacin was rapidly distributed from the central to the peripheral compartment as evidenced by a short distribution half-life (0.09 h ± 0.003 h) and high K12 (4.7 h(-1) ± 0.1 h(-1)), and was detected in plasma for 8 h. The large volume of distribution (2.48 L.kg(-1) ± 0.18 L.kg(-1)) obtained in this study indicated high distribution of ofloxacin in water buffalo calves. The elimination half-life, the area under the plasma drug concentration-time curve and total body clearance were 2.11 h ± 0.13 h, 6.20 µg.mL(-1) ± 0.23 µg.mL(-1).h and 0.81 mL.kg(-1).h(-1) ± 0.03 mL.kg(-1).h(-1), respectively. About 18.7% of administered drug was bound to plasma proteins and approximately 32.5% of the administered dose was recovered in urine within 48 h. The results of the study indicated a favourable pharmacokinetic profile of ofloxacin in water buffalo calves, which suggests that ofloxacin may be effective against urinary pathogens in this species.

Unique Pharmacokinetic and Pharmacodynamic Parameters of Antimicrobials in Goats

“…Human equivalent dose HED ðÞ ¼ animal dose  animal Km human Km (27) Metabolism constant Km ðÞ ¼ body surface area body weight (28) But human body surface area BSA ðÞ ¼ H 0:528  W 0:528  K (29) whereas H = height, W = weight and K = constant. But goat's BSA = W O.67  10 À3 and dosimetric adjustment factor (DAF) is body weight of goat over body weight of humans and can be scaled up to 0.25, 0.33 and 0.58.…”