Development and validation of a stability indicating assay of doxofylline by RP-HPLC: ESI-MS/MS, 1H and 13C NMR spectroscopic characterization of degradation products and process related impurities

► Separation and determination of doxofylline from its process related substances by RPLC. ► Isolation and characterization of two major degradants of doxofylline by 1H,13C NMR and mass spectrometry. ► Till now, there is no validated LC method reported for determination of process related substances of DFL in literature.