title: Structural identification and characterization of potential impurities of pantoprazole sodium.
abstract: Six impurities in pantoprazole sodium bulk drug substance were detected by a simple high performance liquid chromatographic method (HPLC) whose area percentage ranged from approximately 0.05 to 0.34%. Liquid chromatography-mass spectrometry (LC-MS) was performed to identify the molecular weight of the impurities. A thorough study was undertaken to characterize these impurities. These impurities were synthesized, subsequently characterized and were co-injected with the sample containing impurities and found the retention time match of the spiked impurities. Based on their spectral data (IR, NMR and MS), these impurities were characterized as; 5-(difluoromethoxy)-2-[[(3,4-dimethoxy-2-pyridinyl)methyl]thio]-1H-benzimidazole (Impurity-I); 5-(difluoromethoxy)-2-[[(3,4-dimethoxy-2-pyridinyl)methyl]sulfonyl]-1H-benzimidazole (Impurity-II); 5-(difluoromethoxy)-2-[[(3,4-dimethoxy-1-oxide-2-pyridinyl)methyl]sulfonyl]-1H-benzimidazole (Impurity-III); 5-(difluoromethoxy)-2-[[(3,4-dimethoxy-2-pyridinyl)methyl]thio]-1-((3,4-dimethoxy-2-pyridinyl)methyl)-1H-benzimidazole (Impurity-IV); 5-(difluoromethoxy)-2-[[(3,4-dimethoxy-2-pyridinyl)methyl]sulfinyl]-1-((3,4-dimethoxy-2-pyridinyl)methyl)-1H-benzimidazole (Impurity-V); 5-(difluoromethoxy)-2-[[(3,4-dimethoxy-1-oxide-2-pyridinyl)methyl]sulfinyl]-1H-benzimidazole (Impurity-VI). The formation of these impurities was proposed. The structure of the Impurity-II was unambiguously confirmed by single crystal X-ray diffraction (XRD) studies.
authors.affiliation: Research and Development, Active Pharmaceutical Ingredients-IV, Dr. Reddy's Laboratories Ltd., IDA Jeedimetla, Hyderabad 500055, A.P., India.
authors.forename: Ganta Madhusudhan
authors.initials: GM
authors.lastname: Reddy
authors.forename: B Vijaya
authors.initials: BV
authors.lastname: Bhaskar
authors.forename: P Pratap
authors.initials: PP
authors.lastname: Reddy
authors.forename: S
authors.initials: S
authors.lastname: Ashok
authors.forename: P
authors.initials: P
authors.lastname: Sudhakar
authors.forename: J Moses
authors.initials: JM
authors.lastname: Babu
authors.forename: K
authors.initials: K
authors.lastname: Vyas
authors.forename: K
authors.initials: K
authors.lastname: Mukkanti
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles / Q000032:analysis* / Q000737:chemistry; D000897:Anti-Ulcer Agents / Q000032:analysis* / Q000737:chemistry; D002853:Chromatography, Liquid; D004340:Drug Contamination; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D008970:Molecular Weight; D000077402:Pantoprazole; D013055:Spectrophotometry, Infrared; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000897:Anti-Ulcer Agents; D000077402:Pantoprazole