A liquid chromatography–mass spectrometry assay method for simultaneous determination of amiodarone and desethylamiodarone in rat specimens

Abstract

A liquid chromatographic-mass spectrometry (LC/MS) assay method was developed for the determination of amiodarone and desethylamiodarone in rat specimens. Analytes were extracted using liquid-liquid extraction in hexane. The LC/MS system consisted of a Waters Micromass ZQtrade mark 4000 spectrometer with an autosampler and pump. A C(18) 3.5 microm (2.1 x 50 mm) column heated to 45 degrees C was used for separation. The mobile phase consisted of methanol and 0.2% aqueous formic acid pumped at 0.2 mL/min as a linear gradient. Components eluted within 12 min. The concentrations of ethopropazine (internal standard), desethylamiodarone and amiodarone were monitored for m/z of 313.10, combination of 546.9 and 617.73, and 645.83, respectively. In plasma (0.1 mL), linearity was achieved between the peak area ratios and concentrations over the range of 2.5-1000 ng/mL for both amiodarone and desethylamiodarone (r(2) > 0.999). The intraday and interday CV were equal or less than 18%, and mean error was <12%. Similarly, in homogenates containing 0.1 g of rat tissue, linearity was observed in standards ranging from 5 to 5000 ng/g. The method was successfully used to measure tissue and plasma concentrations of drug. The validated lower limit of quantitation was 2.5 ng/mL for drug and metabolite, based on 0.1 mL of plasma.

The Influence of Hyperlipoproteinemia on in Vitro Distribution of Amiodarone and Desethylamiodarone in Human and Rat Plasma

“…The assay had a validated lower limit of quantification of 2.5 ng/ml for both AM and DEA in 100 ml of rat plasma (15). Measurements of AM and DEA were made in 100 ml of each lipoprotein fractions.…”

“…The mixture of standard compounds and internal standard were analyzed on the mass spectrometer using flow injection in scan mode to determine optimal fragmentation for each compound and establishment of the m/z values of the molecular ions (15).…”

“…The organic layer was transferred to new glass tubes and evaporated to dryness in vacuo. The residues were reconstituted using 1 ml of methanol and aliquots of 5Y10 ml were injected into the LC/MS system (15).…”

Pharmacokinetics of desethylamiodarone in the rat after its administration as the preformed metabolite, and after administration of amiodarone

“…Measurements of AM and DEA were accomplished in each plasma sample by LC/MS as described previously [22]. The validated lower limit of quantitation was 2.5 ng/ml for both AM and DEA, based on 0.1 ml of plasma.…”

Cyclodextrin‐based nonaqueous electrokinetic chromatography with UV and mass spectrometric detection: Application to the impurity profiling of amiodarone

“…Amiodarone is an antiarrhytmic agent used in the treatment of ventricular and supraventicular tachycardia. Most reported analytical methods for amiodarone are directed towards the determination of the drug in biological matrices using LC [13][14][15]. Only few LC studies have dealt with purity analysis of the drug substance.…”