Rapid LC-ESI-MS-MS Method for the Simultaneous Determination of Sitagliptin and Pioglitazone in Rat Plasma and Its Application to Pharmacokinetic Study

Abstract

A liquid chromatography tandem mass spectrometry (LC-MS/MS) based method was developed for the simultaneous monitoring plasma levels of Sitagliptin (STG) and Pioglitazone (PIO) for applicability to pharmacokinetic studies. The method was based on HPLC separation on the reversed phase Phenomenex Synergy C 18 column (30 mm length, 4.6 mm internal diameter, and 4.0 μm particle size) at a temperature of 40˚C using a binary gradient mobile phase consisting of methanol and 2 mM ammonium acetate buffer pH adjusted to 4.5 with acetic acid, at a flow rate of 1 mL·min −1 . Tolbu-tamide was used as an internal standard. Detection of analytes was achieved with LC-MS/MS system in Multiple Reac-tion Monitoring (MRM) mode. The method was validated over concentration range of 10.98 -2091.77 ng·mL −1 for SIT and 8.25 -1571.63 ng·mL −1 for PIO and lower limit of quantification was 10.98 ng·mL −1 and 8.25 ng·mL −1 for STG and PIO respectively. Recoveries from spiked controls were within acceptance criteria for all the analytes and internal stan-dard at all QC levels. Within batch and between batch accuracy for STG was found within 96.9% -100.3% and for PIO was found within 100.0% -104.3%. Within batch and between batch precision for STG was less than 3.1% CV (coeffi-cient of variation) and for PIO was less than 5.3% CV at all concentrations levels. This method was successfully applied to monitor pharmacokinetics profile of both STG and PIO on simultaneous oral administration to rats. This method can be applicable for pharmacokinetic drug-drug interaction studies.