1. Degradation Kinetics and Isomerization of Cefdinir, a New Oral Cephalosporin, in Aqueous Solution. 1
- Author
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Yoshihiro Namiki, Junichi Matsushita, Mamoru Fujioka, Yoshihiko Okamoto, Kuniko Kiriyama, and Tsutomu Yasuda
- Subjects
Cefdinir ,Aqueous solution ,Chemistry ,Hydrolysis ,Kinetics ,Molecular Conformation ,Administration, Oral ,Pharmaceutical Science ,Hydrogen-Ion Concentration ,Cephalosporins ,Solutions ,medicine ,Degradation (geology) ,Organic chemistry ,Epimer ,Isomerization ,Antibacterial agent ,medicine.drug - Abstract
Hydrolytic degradation products of cefdinir were studied in acidic (pH 1), neutral (pH 6), and basic (pH 9) solutions. Seven major degradation products were isolated by preparative and/or high-performance liquid chromatography and characterized by UV, IR, 1H-NMR, and mass spectra. To clarify degradation pathways in each pH solution, kinetic and product analyses during hydrolysis of cefdinir were carried out along with the followup reaction of representative degradation products. Cefdinir was shown to degrade via two major degradation routes: beta-lactam ring-opening and pH-dependent isomerizations (lactonization, epimerization at C-6 or C-7, syn-anti isomerization of N-oxime function).
- Published
- 1996