AUTOMATED MICROANALYSIS OF CARBAMAZEPINE AND ITS EPOXIDE AND TRANS-DIOL METABOLITES IN PLASMA BY COLUMN LIQUID-CHROMATOGRAPHY

A fully automated high-performance liquid chromatographic procedure for the simultaneous determination of carbamazepine and its main metabolites, epoxycarbamazepine and dihydroxycarbamazepine, in plasma is described. Liquid-solid extraction on disposable C18 columns and reversed-phase chromatography on a 3-mu-m particle size C18 column were combined and automated by using the Automatic Sample Preparation with Extraction Columns system. Ultraviolet detection was performed at 210 nm. 5,6-Dihydro-11-oxo-11H-dibenz[b,e]azepine-5-carboxamide was used as internal standard. A small plasma volume (100-mu-l) was required. The total run time for the assay of one sample was about 10 min. The assay demonstrated good reproducibility. The limit of quantitation was 0.1-mu-mol/l (about 25 ng/ml).