title: Identification and characterization of potential impurities of donepezil.
abstract: Five unknown impurities ranging from 0.05 to 0.2% in donepezil were detected by a simple isocratic reversed-phase high performance liquid chromatography (HPLC). These impurities were isolated from crude sample of donepezil using isocratic reversed-phase preparative high performance liquid chromatography. Based on the spectral data (IR, NMR and MS), the structures of these impurities were characterised as 5,6-dimethoxy-2-(4-pyridylmethyl)-1-indanone (impurity I), 4-(5,6-dimethoxy-2,3-dihydro-1H-2-indenylmethyl) piperidine (impurity II), 2-(1-benzyl-4-piperdylmethyl)-5,6-dimethoxy-1-indanol (impurity III) 1-benzyl-4(5,6-dimethoxy-2,3-dihydro-1H-2-indenylmethyl) piperidine (impurity IV) and 1,1-dibenzyl-4(5,6-dimethoxy-1-oxo-2,3-dihydro-2H-2-indenylmethyl)hexahydropyridinium bromide (impurity V). The synthesis of these impurities and their formation was discussed.
authors.affiliation: Department of Analytical Research, Discover Research, Dr. Reddy's Laboratories Ltd., Bollaram Road, Miyapur, Hyderabad 500050, India.
authors.forename: K V S R
authors.initials: KV
authors.lastname: Krishna Reddy
authors.forename: J
authors.initials: J
authors.lastname: Moses Babu
authors.forename: P Anil
authors.initials: PA
authors.lastname: Kumar
authors.forename: E R R
authors.initials: ER
authors.lastname: Chandrashekar
authors.forename: Vijayavitthal T
authors.initials: VT
authors.lastname: Mathad
authors.forename: S
authors.initials: S
authors.lastname: Eswaraiah
authors.forename: M Satyanarayana
authors.initials: MS
authors.lastname: Reddy
authors.forename: K
authors.initials: K
authors.lastname: Vyas
mesh_terms: D002800:Cholinesterase Inhibitors / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D000077265:Donepezil; D007189:Indans / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D010880:Piperidines / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D002800:Cholinesterase Inhibitors; D007189:Indans; D010880:Piperidines; D000077265:Donepezil