title: Liquid chromatography-mass spectrometry and proton nuclear magnetic resonance characterization of trace level condensation products formed between lactose and the amine-containing diuretic hydrochlorothiazide.
abstract: Trace levels of condensation products between lactose and the amine-containing diuretic hydrochlorothiazide are formed when a mixture of the two solids containing 30% weight water is heated at 60 degrees C for 2 weeks. The two most abundant condensation products were characterized by liquid chromatography-mass spectrometry (LC-MS) and proton nuclear magnetic resonance ((1)H NMR) spectroscopy. Under these relatively mild conditions of formation, the amine-lactose reaction products are limited to those involving the elimination of only a single molecule of water, rather than the multiple-water eliminations associated with later stages of the Maillard reaction. The spectroscopic data clearly show that the primary condensation products are cyclic N-substituted glycosylamines rather than Schiff base, 1,2-enolic forms, or Amadori rearrangement products of identical mass. In solution, the two most abundant N-substituted glycosylamines are shown to be in a kinetically slow equilibrium with each other, most likely through a mutarotation involving the intermediate formation of the acyclic Schiff base.
authors.affiliation: Merck & Company, Inc., West Point, PA 19486, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Harmon
authors.forename: W
authors.initials: W
authors.lastname: Yin
authors.forename: W E
authors.initials: WE
authors.lastname: Bowen
authors.forename: R J
authors.initials: RJ
authors.lastname: Tyrrell
authors.forename: R A
authors.initials: RA
authors.lastname: Reed
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002851:Chromatography, High Pressure Liquid; D004232:Diuretics; D006852:Hydrochlorothiazide / Q000737:chemistry*; D006868:Hydrolysis; D007202:Indicators and Reagents; D007785:Lactose / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D049993:Sodium Chloride Symporter Inhibitors / Q000737:chemistry*; D012995:Solubility; D013056:Spectrophotometry, Ultraviolet
chemical_list: D004232:Diuretics; D007202:Indicators and Reagents; D049993:Sodium Chloride Symporter Inhibitors; D006852:Hydrochlorothiazide; D007785:Lactose