A Y AL-Taher
Department of Physiology, Biochemistry and Pharmacology, College of Veterinary Medicine and
Animal Resources, King Faisal University, Kingdom of Saudi Arabia
The aim of this study was to compare the pharmacokinetics of the non steroidal anti-inflammatory drug meloxicam in heifers and camels following intravenous administration at a dose of 0.5 mg/kg body weight. Jugular blood samples were collected serially for 48 hours and the plasma concentrations of meloxicam were determined by reverse phase high performance liquid chromatography. The plasma concentrations versus time curve were adequately described by a two-compartment open model. The plasma concentrations of meloxicam were significantly higher in camels than in heifers along all the sampling period and the drug was detected for 36 hours and 48 hours in both species, respectively. There was no significant difference in the distribution half life and steady state volume of distribution between heifers and camels. The elimination half life (t1/2β) and mean residence time (MRT) were significantly longer in camels (12.8 h; 17.6 h) than in heifers (7.9 h; 10.3 h). Value of total body clearance (CLB) was significantly lower in camels (0.013 l h-1 kg-1) than in heifers (0.029 l h-1 kg-1). The area under the curve (AUC0-∞) were significantly higher in camels (36.6 μg h mL-1) than in heifers (17.6 μg h mL-1). The results indicate that elimination kinetics of meloxicam differ significantly between heifers and camels and the elimination of the drug tend to be faster in heifers compared to camels.
Key words: Bioavailability, camels, heifers, HPLC, meloxicam, NSAID, pharmacokinetics