Liquid-liquid extraction and high-performance liquid chromatography for the determination of a novel antidysrhythmic agent (UK-68,798) in human urine.

A routine method for the determination of a novel class III antidysrhythmic agent, 1-(4-methanesulphonamidophenoxy)-2-[N-(4-methanesulponamidophen ethyl)- N-methylamino]ethane, in human urine has been developed. The method involves solvent extraction followed by high-performance liquid chromatography on an unmodified silica column with ultraviolet detection. Despite a low recovery of drug through the three-stage extraction procedure a reliable assay with high precision (coefficient of variation less than 6%) and a limit of determination of 2.5 ng/ml was achieved. The method has been applied to the analysis of samples following single oral and intravenous doses of 1-12.5 micrograms/kg of the drug to human volunteers.