Simultaneous determination of metabolic stability and identification of buspirone metabolites using multiple column fast liquid chromatography time-of-flight mass spectrometry.

A recent trend in the drug discovery and development process is to shift the starting point of drug metabolism and pharmacokinetic (DMPK) studies to a time as early as possible in the development chain to address potential issues in parallel with the optimization of the drug's lead structure. Therefore, it is necessary to develop assay methods to determine early adsorption, distribution, metabolism and excretion (ADME) parameters like metabolic stability and metabolite identification. For metabolite identification it is of crucial importance to work with fast liquid chromatography/mass spectrometry (LC/MS) systems, which provide the necessary high throughput functionalities to handle a large number of samples in combination with high speed and high resolution chromatography as well as mass accuracy. In this study a fast two-column liquid chromatography (LC) method will be used to simultaneously determine metabolic stability and to identify metabolites of buspirone using highly accurate mass measurement by means of an electrospray time-of-flight (ESI-TOF) mass spectrometer. Whereby, the metabolic stability will be determined on a short sub-two micron column, the main metabolites will be identified in the same experiment by the automated use of a long sub-two micron column, which provides the necessary high resolution.