ABSTRACT
Cephalexin (also spelled cefalexin) is a semisynthetic first-generation cephalosporin antibiotic intended for oral administration. Cephalexin was the first oral cephalosporin introduced for clinical use in 1969. It is 7-(D-alpha-amino-alpha-phenylacetamido)-3-methyl-3-cephem-4-carboxylic acid monohydrate. Cephalexin has the molecular formula C16H17N3O4S H2O, and the molecular weight is 365.41; cephalexin’s chemical structure is illustrated in Figure 19.1.
