Determination of the Antiallergic Agent KB-2413 in Plasma by Means of Capillary Gas Chromatography with a Nitrogen-Sensitive Detector

Abstract

A gas chromatographic method for the quantitative determination of the new antiallergic agent, 1-(2-ethoxyethyl)-2-(4-methyl-1-homopiperazinyl)benzimidazole difumarate (KB-2413), in plasma has been developed. This method, which was based on solvent extraction and flexible fusedsilica capillary gas chromatography with a nitrogen-sensitive detector and a moving needle solvent cut sample injector, is simple, sensitive and selective.The detection limit was about 1 ng (as free base)/ml and the calibration curve was linear over the range of 2 to 100 ng/ml. Moreover, the intra- and inter-assay coefficients of variation for the determination of KB-2413 were 3.1-4.0% and 1.5-6.7%, respectively. This assay was applied to the determination of the plasma concentration of KB-2413 base after oral administration to dogs.