Determination of deracoxib in feline plasma samples using high performance liquid chromatography

A new HPLC procedure for the determination of deracoxib, a selective cyclooxygenase-2 inhibitor, has been developed and validated. Following a liquid–liquid extraction using isopropyl alcohol and chloroform, samples were separated by isocratic reversed-phase HPLC on an Atlantis C18 column and quantified using UV detection at 252 nm. The mobile phase was a mixture of 10 mM potassium phosphate (pH 4.5) and acetonitrile, with a flow-rate of 1.0 ml/min. The procedure produced a linear curve over the concentration range 10–1500 ng/ml. The development of the assay allowed the determination of pharmacokinetic parameters after oral administration of deracoxib in cats and would be suitable for other pharmacokinetic studies.