title: Application of liquid chromatography-two-dimensional nuclear magnetic resonance spectroscopy using pre-concentration column trapping and liquid chromatography-mass spectrometry for the identification of degradation products in stressed commercial amlodipine maleate tablets.
abstract: Application of the HPLC hyphenated techniques of LC-two-dimensional (2D) NMR using pre-concentration column trapping and LC-MS was demonstrated by the identification of two major degradation products, DP-1 and DP-2, in stressed commercial tablets of amlodipine maleate. The molecular formulas were estimated by LC-MS. Sample pre-concentration by column trapping was conducted to obtain adequate 2D-NMR signals by reducing the peak widths of the degradation products and making sure that the maximum amount of each component was inside the flow cell for NMR detection. Double-quantum filtered correlation spectroscopy (DQF-COSY) was applied to identify DP-1 as beta-N-lactosylamlodipine by suppressing the residual water signal without affecting the sample signal and by measuring the coupling constant of the lactose anomeric proton. Heteronuclear multiple bond coherence spectroscopy (HMBC) was applied to characterize DP-2 as an aspartic acid derivative of amlodipine by detecting long-range CH correlations. The chemical structures of the degradation products could be successfully elucidated unambiguously without an isolation process.
authors.affiliation: Analytical and Quality Evaluation Research Laboratories, Daiichi-Sankyo Co. Ltd., 1-12-1 Shinomiya, Hiratsuka, Kanagawa 254-0014, Japan. murakami.tomonori.a5@daiichisankyo.co.jp
authors.forename: Tomonori
authors.initials: T
authors.lastname: Murakami
authors.forename: Naoto
authors.initials: N
authors.lastname: Fukutsu
authors.forename: Junichi
authors.initials: J
authors.lastname: Kondo
authors.forename: Takao
authors.initials: T
authors.lastname: Kawasaki
authors.forename: Fumiyo
authors.initials: F
authors.lastname: Kusu
mesh_terms: D017311:Amlodipine / Q000737:chemistry*; D002853:Chromatography, Liquid / Q000379:methods*; D004340:Drug Contamination; D004355:Drug Stability; D013058:Mass Spectrometry / Q000379:methods*; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*
chemical_list: D017311:Amlodipine