Identification and characterization of new impurities in rivastigmine.
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.
Srinivasa Rao
M
M
APL Research Centre, Hyderabad, India.
Rao
Sumathi V
SV
Srinivasa Rao
D V N
DV
Bharathi
Ch
Ch
Rajput
Pradeep
P
Sharma
Hemant Kumar
HK
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
D002800:Cholinesterase Inhibitors; D048448:Phenylcarbamates; D000068836:Rivastigmine