FLUORESCENCE PHOTOMETRIC DETERMINATION OF DISOPYRAMIDE AND MONO-N-DEALKYLATED DISOPYRAMIDE IN PLASMA AFTER SEPARATION BY THIN-LAYER CHROMATOGRAPHY

A thin-layer chromatographic method for the estimation of disopyramide and its metabolite, mono-N-dealkylated disopyramide is described. The method involves a simple extraction of 200 μL of plasma at alkaline pH with benzene. An aliquot of the extract is quantitatively spotted on a TLC plate. The plate is developed in the solvent (ethyl acetate:metha-nol:ammonia, 40:30:0.5) which allows good separation of the two compounds from one another, from plasma constituents, from other drugs which are prescribed along with disopyramide. The plate is dipped in 20 % sulfuric acid in methanol to make these compounds fluorescent. Densltometric scanning of the separated compounds provides a precise quantitative estimation. The procedure is linear up to 10 mg/L and the calibration curve passes through the origin. © 1979, American Chemical Society. All rights reserved.