First liquid chromatographic method for the simultaneous determination of amiodarone and desethylamiodarone in human plasma using microextraction by packed sorbent (MEPS) as sample preparation procedure.

For the first time a simple and fast high-performance liquid chromatography (HPLC) method using a novel sample preparation procedure based on microextraction by packed sorbent (MEPS) was developed and validated for the determination of amiodarone (AM) and its main metabolite desethylamiodarone (DEA) in human plasma. Chromatographic separation of the analytes (AM and DEA) and tamoxifen, used as internal standard (IS), was achieved within less than 5min on a LiChroCART Purospher(®) Star C(18) column (55mm×4mm, 3μm). The mobile phase consisting of 50mM phosphate buffer with 0.1% formic acid (pH 3.1)/methanol/acetonitrile (45:5:50, v/v/v) was pumped isocratically at a flow rate of 1.2mL/min. The detection was carried out at 254nm. Calibration curves were linear (r(2)≥0.9976) in the ranges of 0.1-10μg/mL for AM and DEA. The limits of quantification were established at 0.1μg/mL for AM and DEA. The overall imprecision did not exceed 6.67% and inaccuracy was within ±9.84%. The overall mean recovery of AM and DEA ranged from 58.6% to 68.2%. Neither endogenous nor tested exogenous compounds were found to interfere at retention times of the analytes (AM and DEA) and IS. This new MEPS/HPLC method was also applied to real samples obtained from polymedicated patients receiving AM therapy. Thus, this bioanalytical method seems to be a useful tool for therapeutic drug monitoring of patients under AM treatment and also to support other clinical pharmacokinetic-based studies involving this drug, such as bioavailability/bioequivalence studies.