PHARMACOKINETICS OF A SINGLE INTRAMUSCULAR DOSE OF ROBENACOXIB IN TIGERS (PANTHERA TIGRIS)

To investigate the pharmacokinetics of robenacoxib in tigers (Panthera tigris), a pilot study was performed on nine adult tigers by using four doses-2, 1, 0.5, and 0.25 mg/kg-administered as a single injection either SC or IM. A dose of 0.25 mg/kg administered IM was selected based on pilot data and ease of administration to conscious tigers. A pharmacokinetic study of robenacoxib was performed using a sparse sampling protocol with eight additional adult tigers. Blood samples were collected at time 0, 15, 30, 60, and 90 min and 2, 2.25, 8, 12, and 20 h postadministration. Plasma samples were analyzed for robenacoxib concentrations by using high-performance liquid chromatography-tandem mass spectrometry. Mean maximum observed plasma concentration was 686 ng/ml, time to maximum concentration was 1 h, and elimination half-life was 3.2 h. Plasma concentrations remained >10 ng/ml (considered therapeutic in domestic cat studies) up to 12 h after a single 0.25-mg/kg IM dose was administered to tigers. This study represents the first pharmacokinetic investigation of robenacoxib in a nondomestic felid species.