Determination of ambenonium in biological samples by reversed-phase ion-pair liquid chromatography

A sensitive and selective analytical method for the determination of ambenonium ion in biological samples is described. The procedure involves ion-pair extraction of the drug, followed by reversed-phase ion-pair chromatographic analysis with ultraviolet detection at 217 nm. The detection limits at a signal-to-noise ratio of 5 were 100 pmol/ml using 0.2 ml of plasma and bile, 250 pmol/ml using 0.2 ml of urine and 200 pmol/g using 1 ml of tissue homogenates containing 0.1 g/ml of each tissue. This assay procedure was used to study the pharmacokinetics of ambenonium ion after intravenous administration in rats.