Determination of tandospirone and its impurities in drug formulations by LC-UV and LC-MS

This work describes the determination of tandospirone in bulk drug substance and formulated products by a reversed-phase liquid chromatographic method with UV detection. Chromatographic separation was performed on a C ₁₈ column with a mobile phase of a binary mixture of methanol and water (70:30, v/v) delivered at a flow rate of 0.5 ml min^-1 and detection was performed at 243 nm. The proposed LC method is selective, precise and accurate for the determination of tandospirone in the presence of its manufacturing impurities with a limit of quantitation of 0.54 μg ml ^-1. A preliminary study for the identification of the major manufacturing impurities was made by liquid chromatography-moss spectrometry with electrospray ionization source operated in a positive ion mode.