Mass spectrometric identification of amiodarone N-monodesethyl metabolite and application of an HPLC method to a pharmacokinetic study.

Identification of an amiodarone metabolite in the plasma of patients receiving a single dose of the drug was carried out by mass-spectrometry following extraction and HPLC separation. The kinetics of the plasma concentrations of unchanged compound and its identified metabolite (N-monodesthyl-amiodarone) were studied in six patients after a single administration of amiodarone by oral or intravenous routes, using a sensitive and specific high-performance liquid chromatographic method. The observed plasma clearance rate for the drug varied from 0.