Selective, sensitive and rapid liquid chromatography–tandem mass spectrometry method for the determination of alfuzosin in human plasma

A selective, sensitive and rapid liquid chromatography–tandem mass spectrometry method for the determination of alfuzosin in plasma was developed. A PE Sciex API 2000 triple quadrupole mass spectrometer in multiple reaction monitoring (MRM) mode, using TurboIonSpray with positive ionisation was used. Using prazosin as an internal standard, liquid–liquid extraction was followed by C 18 reversed-phase liquid chromatography and tandem mass spectrometry. The mean recovery for alfuzosin was 82.9% with a lower limit of quantification set at 0.298 ng/ml, the calibration range being between 0.298 and 38.1 ng/ml. This assay method makes use of the increased sensitivity and selectivity of tandem mass spectrometric (MS–MS) detection to allow for a more rapid (extraction and chromatography) and selective method for the determination of alfuzosin in human plasma than has previously been described. The assay method was used to quantify alfuzosin in human plasma samples generated in a multiple-dose (5 mg bd.) study at steady state.