Simultaneous enantioselective determination and quantification of dimethindene and its metabolite N-demethyl-dimethindene in human urine using cyclodextrins as chiral additives in capillary electrophoresis

Abstract

Capillary electrophoresis (CE) has been used for the chiral resolution of the basic racemic drug dimethindene (Fenistil) and its metabolite N-demethyl-dimethindene. After oral administration of 4 mg dimethindene maleate the enantioselective excretion in human urine was determined by capillary electrophoresis using a 50 mM phosphate run buffer (pH 3.3) containing 30 mM hydroxypropyl-beta-cyclodextrin. The determination of very low concentrations of dimethindene and N-demethyl-dimethindene in human urine was possible using sample stacking conditions to increase the amount of analyte in the capillary with good peak forms and resolutions. The detection limit of the method was approximately 1 ng ml-1 urine for each compound.