Aqueous acidic degradation of the carbacephalosporin loracarbef.
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.
Skibic
M J
MJ
Eli Lilly and Company, Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN 46285-0724.
Taylor
K W
KW
Occolowitz
J L
JL
Collins
M W
MW
Paschal
J W
JW
Lorenz
L J
LJ
Spangle
L A
LA
Dorman
D E
DE
Baertschi
S W
SW
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
D002511:Cephalosporins; D012996:Solutions; C054920:loracarbef; D002433:Cefaclor