Improved high performance liquid chromatographic analysis of omeprazole inhuman plasma

A simple high-performance liquid chromatographic method was developed for t he determination of omeprazole in human plasma. Omeprazole and the internal standard, chloramphenicol, were extracted from alkalinized plasma samples using dichloromethane. The mobile phase was 0.05 M Na2HPO4-ACN (65:35, v/v) adjusted to pH 6.5. Analysis was run at a flow rate of 1.0 ml/min at a det ection wavelength of 302 nm. The method was specific and sensitive with a d etection limit of 2.5 ng/ml at a signal-to-noise ratio of 4:1. The limit of quantification was set at 5 ng/ml. The calibration curve was linear over a concentration range of 5-1280 ng/ml. Mean recovery value of the extraction procedure was about 96%, while the within and between day coefficient of v ariation and percent error values of the assay method were all less than 14 %. (C) 2001 Elsevier Science B.V. All rights reserved.