High-performance liquid chromatographic assay of amiodarone in rat plasma

Purpose. A high-performance liquid chromatographic method is described for the determination of amiodarone in rat plasma. Methods. After liquid-liquid extraction, the separation of amiodarone from internal standard and endoge nous components was accomplished using reversed phase chromatography. The m obile phase, a combination of monobasic potassium phosphate, methanol and a cetonitrile, was run isocratically through a C-8 analytical column. The UV detection was at 254 nm for ethopropazine, the internal standard, and subse quently changed to 242 nm for amiodarone detection. Results. Analytical run time was less than 13 min. Mean recovery was 75% and 82% for lower (0.5 mu g/ml) and higher concentrations (5 mug/ml), respectively. The assay exhibit ed excellent linear relationships between peak height ratios and plasma con centrations; quantitation limit was at least 0.035 mug/ml, based on 100 mul of rat plasma. Accuracy and precision were <17% over the concentration ran ge of 0.035 to 5 <mu>g/ml. Conclusion. The assay was applied successfully t o the measurement of amiodarone plasma concentrations in rats given the dru g orally.