Parenteral cephalosporin classification

Abstract

β-lactam antibiotics can be divided into four groups of compounds: penams, penems, cephems and monolactams. Within the cephems, it is possible to distinguish according to the nature of the cephem ring: cephalosporins (1-sulfur), 1-oxacephems, carbacephems, miscellaneous analogues, such as isocephems and 7-α-substituted cephems such as cephamycins and cephabacins. Among the cephalosporins, the compounds were split up according to the nature of the α-carbon of the C-7 side chain. Cephalosporins can be divided into six groups. The early cephalosporins (for example, cephalothin) are in Group I. Group II is subdivided into Group IIA (cefuroxime and others) and Group IIB (cephamycins). Group III is subdivided into five subgroups; Group IIIB is composed of cefotaxime and derivatives; 1-oxacephems are gathered in Group IIIC. Group IIID is composed of carbacephem derivatives. Group IV covers the quaternary ammonium cephems (such as, cefpirome) and is subdivided into Group IV-1 and Group IV-2 according to the position (C-3 or C-7) of the quaternary ammonium moiety. Within Group IV-2, the compounds are divided into two subgroups according to the aryl substituent at C-7: 2-amino-5-thiazolyl and 5-amino-2-thiadiazolyl moieties. All the catechol-containing cephems are in Group V. Group VI is devoted to narrow spectrum cephalosporins such as cefsulodin.