title: Identification and characterization of new impurities in rivastigmine.
abstract: Rivastigmine is a drug against Alzheimer's disease, and is a non-pharmacopoeial compound. During the preparation of rivastigmine in our laboratory, two impurities were detected and identified with a simple and sensitive reversed-phase liquid chromatography coupled with electrospray-mass spectrometry. The same impurities were also observed in commercial batches. These impurities were isolated by preparative HPLC and co-injected with rivastigmine sample to confirm the retention times in HPLC. These impurities were characterized as N,N-dimethyl-3-[1-dimethylaminoethyl]phenylcarboxylate (dimethyl-rivastigmine) and N,N-diethyl-3-[1-dimethylaminoethyl]phenylcarboxamide (diethyl-rivastigmine). Structural elucidation of these impurities by spectral data (1H NMR, 13C NMR and MS) is discussed.
authors.affiliation: APL Research Centre, Hyderabad, India.
authors.forename: M
authors.initials: M
authors.lastname: Srinivasa Rao
authors.forename: Sumathi V
authors.initials: SV
authors.lastname: Rao
authors.forename: D V N
authors.initials: DV
authors.lastname: Srinivasa Rao
authors.forename: Ch
authors.initials: Ch
authors.lastname: Bharathi
authors.forename: Pradeep
authors.initials: P
authors.lastname: Rajput
authors.forename: Hemant Kumar
authors.initials: HK
authors.lastname: Sharma
mesh_terms: D002800:Cholinesterase Inhibitors / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D004340:Drug Contamination; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D048448:Phenylcarbamates / Q000032:analysis*; D000068836:Rivastigmine; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D002800:Cholinesterase Inhibitors; D048448:Phenylcarbamates; D000068836:Rivastigmine