Four process-related potential new impurities in ticagrelor: Identification, isolation, characterization using HPLC, LC/ESI-MSⁿ, NMR and their synthesis

Five process-related impurities were detected in the range of 0.08-0.22% in ticagrelor laboratory batches by HPLC and LC-MS methods. These impurities were named as TIC Imp-I, -II, -III, -IV and -V. Four of these impurities, TIC Imp-I to -IV were unknown and have not been reported previously. Based on LC-ESI/MSⁿ study, the chemical structures of new impurities were presumed as (1S,2S,3S,5S)-3-(2-hydroxyethoxy)-5-(7-amino-5-(propylthio)-3H-[1,2,3]triazolo[4,5-d] pyrimidin-3-yl)cyclopentane-1,2-diol (TIC Imp-I), (1S,2S,3S,5S)-3-(7-((1R,2S)-2-(3,4-difluorophenyl)cyclopropylamino)-5-(propylsulfinyl)-3H-[1,2,3]triazolo [4,5-d]pyrimidin-3-yl)-5-(2-hydroxyethoxy)cyclopentane-1,2-diol (TIC Imp-II), (1S,2R,3S,4S)-4-(7-((1R,2S)-2-(3,4-difluorophenyl)cyclopropylamino)-5-(propylthio)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl)cyclopentane-1,2,3-triol (TIC Imp-III) and (3S,5S)-3-(7-((1R,2S)-2-(3,4-difluorophenyl)cyclopropylamino)-5-(propylthio)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl)-5-(2-hydroxyethoxy)cyclopentane-1,2-diol (TIC Imp-IV). The unknown impurities were isolated from enriched crude sample by column chromatography and preparative HPLC. The complete spectral analysis, MS, 1D NMR (¹H, ¹³C and DEPT), 2D NMR (HSQC and HMBC) and IR confirmed the proposed chemical structures of impurities. Identification, isolation, structural characterization, prospects for the formation of impurities and their synthesis were first reported in this paper.