Bioanalysis and Validation of Fesoterodine, an Antimuscarinic Agent and its Active Metabolite Using Liquid Chromatography with Tandem Mass Spectrometry

Abstract

Aim: To establish a bioanalytical method with rapid, specific and sensitiveness with tandem mass spectrometric with liquid chromatography for an anti-muscuranic agent, fesoterodine and its metabolite, 5-hydroxy methyl tolterodine in plasma of human, using their isotopic labeled compounds correspondingly, with internal standards, fesoterodine d14 and 5-hydroxy methyl tolterodine d14. Materials and Methods: The extraction of analytes is by employing tert-butyl methyl ether, divided with Kromasil 100 column C18 using the mixture of mobile phase containing methanol and 5 mM ammonium formate buffer (PH 3.5) at a rate of 1 mL/min. The outstanding linearity was shown in the range of concentrations, 0.1022 to 15.0154 and 0.1022 to 15.0211 ng/mL for fesoterodine and its metabolite simultaneously. The lower limit of quantitation values is 0.1022 and 0.1022 ng/mL respectively for fesoterodine and 5-hydroxy methyl tolterodine. Results: The accuracy and repeatability results for four different batches at five different concentration levels were discovered to be in the limits of acceptability for ICH guidelines. Conclusion: Stability tests, including benchtop, injector, freeze-thaw cycles, and -20ºC storage, confirmed fesoterodine and its metabolite stability in plasma. The chromatographic elution time of 2.5 min enabled the analysis of 300 samples rapidly in a day for the established technique. Validation results qualified the method for regular analysis and pharmacokinetic studies of fesoterodine and 5-hydroxy methyl tolterodine, its metabolite in the human biological fluid, plasma.