Determination of a novel calmodulin antagonist, 3-{2-[4-(3-chloro-2-methylphenyl)-1-piperazinyl] ethyl}-5, 6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate, DY-9760e, in human plasma using solid-phase extraction and high-performance liquid chromatography with fluorescence detection

A high-performance Liquid chromatographic method for the determination of a novel calmodulin antagonist, 3-{2-[4-(3-chloro-2-methylphenyl)-1-piperazin yl]ethyl}-5,6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate, DY-9760e and its major metabolite, 3-{2-[4-(3-chloro-2-methylp henyl)-1-piperazinyl]ethyl}-5,6-dimethoxyindazole, DY-9836 in human plasma has been developed. DY-9760e, DY-9836 and the internal standard (I.S.) were extracted from plasma by means of an Isolute C-18 (EC) column. The extract s were chromatographed on a reversed-phase TSK-gel ODS-80Ts column using 0. 1 M acetate buffer (pH 5)-CH3CN (65:35, v/v) as the mobile phase at a flow- rate of 1.0 ml/min. Fluorescence detection at an excitation wavelength of 3 03 nm and an emission wavelength of 347 nm resulted in a limit of quantitat ion of 1.000 ng/ml for plasma. The method showed satisfactory sensitivity, precision, accuracy, recovery and selectivity. Stability studies showed tha t DY-9760 and DY-9836 were stable in plasma up to at least eight weeks at - 80 degrees C. (C) 1999 Elsevier Science B.V. All rights reserved.