Metabolism of (14C) cefaclor, a cephalosporin antibiotic, in three species of laboratory animals.

The metabolic fate of the orally effective cephalosporin antibiotic cefaclor (Lilly 99638) has been studied in rats, mice, and dogs. Cefaclor is efficiently absorbed from the gastrointestinal tract as the intact antibiotic. In rats and mice, cefaclor, for the most part, escapes metabolism in the body and is eliminated unchanged as unaltered antibiotic, primarily by renal excretion. In dogs, however, cefaclor is more labile to metabolism and only a portion of the administered antibiotic is eliminated unchanged via the kidney.