ROUTINE DETERMINATION OF A NEW 1-4 DIHYDROPYRIDINE, OXODIPINE, IN HUMAN PLASMA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH ELECTROCHEMICAL DETECTION

A rapid, specific and reproducible high-performance liquid chromatographic routine assay with electrochemical detection was developed for the determination of Oxodipine in human plasma. After extraction at alkaline pH by cyclohexane, Oxodipine and its internal standard were chromatographied on a reversed-phase column. Calibration curves were linear over a concentration range of 1–50 ng/ml with relative errors within-day or between-day not exceeding 8 % at any level. The limit of detection was 30 pg injected based on a signal-to-noise ratio of 7. However, the reliable limit of quantification was 1 ng/ml using 1 ml of human plasma. A dual-electrode coulometric detector was operated in a screening mode of oxidation, providing a greater specificity and reducing background noise. This method allowed the complete follow-up of clinical pharmacokinetic studies and drug monitoring in patients. © 1990, Taylor & Francis Group, LLC. All rights reserved.