Enhanced LC-MS/MS analysis of alogliptin and pioglitazone in human plasma: Applied to a preliminary pharmacokinetic study

A new fast LC-MS/MS method was developed for determination of alogliptin and pioglitazone in human plasma. Linearity ranges of 10-400 ng mL(-1) for alogliptin and 25-2000 ng mL(-1) for pioglitazone, were found to be suitable for their bioanalysis covering the C-min and C-max values of the drugs. Direct precipitation technique was used for simultaneous extraction of the drugs successfully from human plasma samples. Chromatographic separation was achieved on a BEH C-18 column (50 mm x 2.1 mm, 1.7 mu m) with 0.1% aqueous formic acid: acetonitrile (40:60, v/v) at a flow rate of 0.3 mL min(-1). The validated method was applied to a preliminary pharmacokinetic study on human volunteers. Monitoring the transition pairs of m/z 340.18 to 116.08 for alogliptin and m/z 356.99 to 133.92 for pioglitazone, using triple quadrupole mass spectrometer with multiple reaction monitoring, was achieved in the positive mode. The validated method is accurate and suitable for further clinical applications and possible bioequivalence studies.