Simple and rapid liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for estimation of Ondansetron HCl in dog plasma

A simple and rapid liquid chromatography/tandem mass spectrometry (LC-MS/MS) method has been developed and applied for estimation of Ondansetron concentration levels in dog plasma after administration of Ondansetron tablets. The drug and Internal standard, ISTD (Trospium HCl) were extracted from plasma by protein precipitation technique. The analytes were separated using a mobile phase of ammonium formate (10 mM) and organic mixture containing Acetonitrile and Methanol (20:80, v/v) on Zorbax SB C18, 75 x 2.1 mm, 3.5µm with guard column at a flow rate of 0.3 mL/min and analyzed by a triple-quadrupole mass spectrometer in positive ion multiple reaction monitoring (MRM) mode at transitions (m/z) of 294.0 ® 170.1 for Ondansetron and 392.2®182 for ISTD, respectively. The total chromatographic run time was 3.5 min and the assay exhibited a linear dynamic range of 0.5 - 100 ng/mL for Ondansetron in dog plasma. The developed method was successfully employed to support the bioavailability / pharmacokinetic study of Ondansetron formulations in dogs.