Rapid determination of granisetron in human plasma by liquid chromatography coupled to tandem mass spectrometry and its application to bioequivalence study

A simple, sensitive and rapid method for analysis of granisetron in human plasma, utilizing liquid chromatography tandem mass spectrometry (LC-MS/MS), has been developed and validated to satisfy FDA guidelines for bioanalytical methods. The analyte and internal standard (IS) were isolated from 100 μl plasma samples by liquid–liquid extraction (LLE). A Varian 1200 l tandem mass spectrometer equipped with an electrospray ionization source was operated in selected reaction monitoring (SRM) mode with the precursor-to-product ion transitions m/z 313.4/138 for granisetron and m/z 270/201 for the IS used for quantitation. The assay exhibited a linear dynamic range of 0.02–20 ng/ml for granisetron in human plasma. The lower limit of quantification (LLOQ) was 0.02 ng/ml with a relative standard deviation of less than 15%. The mean extraction recovery from spiked plasma samples was 97.9%. The intra-day accuracy of the assay was within 10% of nominal and intra-day precision was better than 15% C.V. A run time of 2.0 min for each sample made it possible for high-throughput bioanalysis. The method was employed in a bioequivalence study of two formulations of granisetron hydrochloride 1 mg rapidly disintegrating tablets/1 mg capsules.