Determination of amiodarone and its N-deethylated metabolite in serum by high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) method utilizing hexane extraction and a normal bonded phase column (NH2-alkylamine) was developed to measure serum concentrations of amiodarone and its N-deethylated metabolite. A single analysis requires 8 min. The one-step extraction efficiencies of amiodarone and the internal standard are greater than 90%. The method is linear between 0.05 and 20.0 micrograms/ml. The average relative standard deviation of the slope of the standard curve is 4% and the single day coefficient of variation is 3.2%. The use of hexane extraction for sample cleanup and a bonded phase column for chromatography result in a sensitive and reproducible system well suited to laboratories monitoring serum concentrations of multiple drugs by HPLC. A preliminary study has shown the assay to be useful for the investigation of the pharmacokinetics of this agent.