Spectral Characterization of Degradation Impurities of Paroxetine Hydrochloride Hemihydrate

Two unknown impurities were detected in stressed samples (by hydrochloric acid and hydrogen peroxide) of paroxetine hydrochloride hemihydrate (an active pharmaceutical ingredient – API) using a gradient reversed-phase high performance liquid chromatography (HPLC). These impurities were enriched and were present up to 30% in the degraded sample. The impurities were isolated from the degraded sample by column purification. Spectral data of the isolated impurities were collected. Based on the spectral data of two dimensional nuclear magnetic spectroscopy (2D-NMR) and mass spectrometry (MS) Impurity-1 and Impurity-2 were characterized as (3S,4R)-3-{[(6-chloro-1,3-benzodioxol-5-yl)oxy]methyl}-4-(4-fluorophenyl)piperidine and [(3S,4R)-4-(4-fluorophenyl)piperidin-3-yl]methanol respectively