AQUEOUS ACIDIC DEGRADATION OF THE CARBACEPHALOSPORIN LORACARBEF

The aqueous degradation of the carbacephalosporin loracarbef under mod erately acidic conditions (pH range, 2.7-4.3) is described. Structures of a total of 10 compounds isolated by preparative reversed-phase HPL C have been proposed. Five of these 10 degradation compounds arose fro m hydrolysis of the beta-lactam ring followed by structural changes in the six-membered heterocyclic ring. Four compounds form from intermol ecular reactions of loracarbef to form dimeric structures with peptide linkages. The remaining compound resulted from oxidation of the prima ry amine to a hydroxylamine. Pathways for the formation of these compo unds from the parent loracarbef are proposed.