Urinary metabolites and disposition of the antiarrhythmic agent 2′-[2-(diisopropylamino) ethoxy] propylbenzyl alcohol hydrochloride in the rat

An oral dose of 10 mg/kg of the antiarrhythmic drug14C-2′-[2-(diisopropylamino)ethoxy]propylbenzyl alcohol to rats was mainly eliminated within 2 days. During 5 days, means of 62% and 30% of the dose were excreted in the urine and faeces respectively, and less than 1% remained in the carcass. Mean plasma concentrations of radioactivity reached a maximum (0.12% dose/ml) at about 30 min, and parent drug represented less than 15% of the plasma radioactivity at 30 min and could not be detected after 4 hr. After an oral dose, radioactivity was mainly confined to the gastrointestinal tract, liver and kidneys and was not detected in any tissues at 96 hr. After an intravenous dose of 10 mg/kg concentrations were highest in the brain, brown fat, lungs, adrenals, kidneys, liver and salivary glands, and at 4 hr radioactivity could only be detected in the large intestine. Five major radioactive components were detected in rat urine and three metabolites have been identified by mass spectrometry as the products of dealkylation (loss of N-isopropyl and O-diisopropylaminoethyl) and oxidation in the butyl side-chain.