title: An innovative classification of, and a new structure-activity-relationship approach to degradation kinetics of cephalosporins: an attempt to enhance the therapeutic activity.
abstract: Degradation kinetics of cephalosporins was innovatively classified into six groups according to its mechanism that is based on the attached functional and/or substituent groups. 3-Position plays an important role in the degradation kinetics, and they are classified into three major groups; one with a 3-acetoxy group, another with a 3-deacetoxy group, and the other without a 3-acetoxy group. Each group is further subdivided depending on whether it contains 7-x-amino group or not. The order of the alkaline hydrolysis of cephalosporins coincided with the order of the degree of their antibacterial activities. This provides an evidence to support the hypothesis that the biological activity of beta-lactam antibiotics depends upon the reactivity of the beta-lactam moiety. At the same time, the compound should be stable, and the stability is often related to the reactivity of 3-position. Combination products of biodegradable cephalosporins and acid-stable cephalosporins are desired products. An example of such products produced by chemical modifications stated above will be the one with a good leaving group at the 3-position that is not hydrolyzed.
authors.affiliation: Faculty of Pharmaceutical Sciences, High Technology Research Institute, Kobe Gakuin University, Nishi-ku, Kobe 651-2180, Japan. akaho@pharm.kobegakuin.ac.jp
authors.forename: Eiichi
authors.initials: E
authors.lastname: Akaho
authors.forename: Hitomi
authors.initials: H
authors.lastname: Nakayama
mesh_terms: D000818:Animals; D002511:Cephalosporins / Q000737:chemistry / Q000145:classification* / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D013329:Structure-Activity Relationship
chemical_list: D002511:Cephalosporins