Determination of mephenoxalone in human plasma sample by high-performance liquid chromatography–fluorescence detection

A simple and sensitive high-performance liquid chromatographic method involving fluorescence detection was developed for the determination of mephenoxalone in human plasma. A Cosmosil 5C18-MS column (250 mm×4.6 mm I.D., 5 μm) was used as stationary phase and the mobile phase consisted of water–acetic acid–acetonitrile (200:1:300) at a flow-rate of 1.0 ml/min. The fluorescence absorbance was monitored at 280 nm for excitation wavelength and 310 nm for emission wavelength. Temperature control was kept at 40°C for the column. The limit of quantitation achieved was 10 ng/ml, and the standard curve was found to be linear in the concentration range of 10–10 000 ng/ml. Under these analytical conditions, a sufficient mephenoxalone plasma concentration profile could be obtained for pharmacokinetic study.