The disposition of diclofenac in camels after intravenous administration

The pharmacokinetics of diclofenac was studied in camels (Camelus dromedarus) (n=6) following intravenous (i.v.) administration of a dose of 2.5 mg kg−1 body weight. The metabolism and urinary detection time were also studied. The results obtained (median and range) were as follows: the terminal elimination half-life (t1/2β) was 2.35 (1.90–2.73) h, total body clearance (ClT) was 0.17 (0.16–0.21) l h kg−1. The volume of distribution at steady state (VSS) was 0.31 (0.21–0.39) l−1 kg−1, the volume of the central compartment of the two compartment pharmacokinetic model (VC) was 0.15 (0.11–0.17) l kg−1. Five metabolites of diclofenac were tentatively identified in urine and were excreted mainly in conjugate form. The main metabolite was identified as hydroxy diclofenac. Both diclofenac and hydroxy diclofenac, appear to be the main elimination route for diclofenac when administered i.v. in camels. Diclofenac could be identified up to 4 days following i.v. administration in camels using a sensitive gas chromatography/mass spectrometry (GC/MS) method.