title: Aqueous acidic degradation of the carbacephalosporin loracarbef.
abstract: The aqueous degradation of the carbacephalosporin loracarbef under moderately acidic conditions (pH range, 2.7-4.3) is described. Structures of a total of 10 compounds isolated by preparative reversed-phase HPLC have been proposed. Five of these 10 degradation compounds arose from hydrolysis of the beta-lactam ring followed by structural changes in the six-membered heterocyclic ring. Four compounds form from intermolecular reactions of loracarbef to form dimeric structures with peptide linkages. The remaining compound resulted from oxidation of the primary amine to a hydroxylamine. Pathways for the formation of these compounds from the parent loracarbef are proposed.
authors.affiliation: Eli Lilly and Company, Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN 46285-0724.
authors.forename: M J
authors.initials: MJ
authors.lastname: Skibic
authors.forename: K W
authors.initials: KW
authors.lastname: Taylor
authors.forename: J L
authors.initials: JL
authors.lastname: Occolowitz
authors.forename: M W
authors.initials: MW
authors.lastname: Collins
authors.forename: J W
authors.initials: JW
authors.lastname: Paschal
authors.forename: L J
authors.initials: LJ
authors.lastname: Lorenz
authors.forename: L A
authors.initials: LA
authors.lastname: Spangle
authors.forename: D E
authors.initials: DE
authors.lastname: Dorman
authors.forename: S W
authors.initials: SW
authors.lastname: Baertschi
mesh_terms: D002433:Cefaclor / Q000737:chemistry; D002511:Cephalosporins / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D012996:Solutions / Q000737:chemistry
chemical_list: D002511:Cephalosporins; D012996:Solutions; C054920:loracarbef; D002433:Cefaclor