Abstract
A new, simple and precise method using ion-pair high-performance liquid chromatography was developed for the determination of piroxicam in ointment and plasma. A reversed-phase system was used, consisting of a 5-μm NOVA-PAK C18 column with acetunitrile-water (42:58 v/v) containing 0.01M tetrabutylammoniium phosphate and adjusted to pH 7.5 by phosphoric acid as the mobile phase. The flow rate was 0.8 ml/min and the effluent was monitored at 355 nm. The sensitivities of this method were 2 ng/ml levels of piroxicam in ointment and plasma samples using indomethacin as internal standard.