A Rapid High Performance Liquid Chromatographic Method for the Simultaneous Measurement of Six Tricyclic Antidepressants

Abstract

A reversed-phase high pressure liquid chromatographic procedure has been developed for the quantitation of the concentration of six different tricyclic antidepressants in the plasma of patients undergoing routine drug therapy. Plasma samples were extracted into a 97:3 hexane:isoamyl alcohol solution and then extracted back into dilute acid. A Supelcosil C-8 column with 5 micron packing was employed in combination with an acetonitrile/ phosphate buffer/diethylamine mobile phase. At an optimized mobile phase pH of 7.22, baseline separation of all six tricyclic antidepressants plus the internal standard was achieved within 8 minutes. UV detection at 254 nm resulted in limits of detection of 2.5 μg/L for each drug. The potential interferences from 13 different benzodiazepines and neuroleptics was investigated. Five of the 13 parent drugs and three metabolites were found to interfere with this tricyclic antidepressant assay.