Determination of meloxicam in human plasma using a HPLC method with UV detection and its application to a pharmacokinetic study

A simple and sensitive high performance liquid chromatography method using UV detection (HPLC-UV) for the determination of meloxicam in human plasma was developed and validated. After extraction with diethyl ether, the chromatographic separation of meloxicam was carried out using a reverse phase Sunfire C18 column (150 mm × 4.6 mm, 5 μm) with a mobile phase of acetonitrile–20 mM potassium hydrogen phosphate (40:60, v/v, pH 3.5) and UV detection at a wavelength of 355 nm. The flow rate of mobile phase was 1.2 ml/min and the retention time of meloxicam and internal standard, piroxicam, was found to be 11.6 and 6.3 min, respectively. The calibration curve was linear within the concentration range, 10–2400 ng/ml (r2 > 0.9999). The lower limit of quantification was 10 ng/ml. This method improved the sensitivity for the quantification of meloxicam in plasma using a HPLC-UV. The mean accuracy was 98–114%. The coefficient of variation (precision) in the intra- and inter-day validation was 1.6–4.3 and 2.4–7.3%, respectively. The pharmacokinetics of meloxicam was evaluated after administering an oral dose of 15 mg to 11 healthy Korean subjects. The AUCinf, Cmax, tmax and t1/2 were 42.4 ± 13.2 μg h/ml, 1445.7 ± 305.5 ng/ml, 4.1 ± 0.3 h and 22.0 ± 4.9 h, respectively.