Biological Activity
Ceftibuten is an orally bioavailable broad-spectrum cephalosporin antibiotic that inhibits the growth of B. catarrhalis, H. influenzae, pathogenic Neisseria, Streptococcus, penicillin-susceptible S. pneumoniae, and eleven Enterobacteriaceae strains (MICs = 0.25, ≤0.06, ≤0.06, 0.5-1, 4, and ≤0.06-0.5 μg/ml, respectively).1,2 Ceftibuten is also active against E. coli expressing β-lactamase type I, III, and V and K. oxytoca expressing β-lactamase type IV (MICs = 8, 0.25, 0.5, and ≤0.06 μg/ml, respectively) as well as a panel of eight bacterial stains expressing plasmid-encoded extended spectrum β-lactamases, including E. coli CTX-M and K. pneumoniae SHV-2 (MICs = 1 and 0.25 μg/ml, respectively). In vivo, ceftibuten reduces the number of mice killed within 6 days of a K. pneumoniae, E. coli, S. pneumoniae, or S. aureus infection by 50% when administered subcutaneously at doses of 0.125, 2, 1,024, and >512 mg/kg, respectively.3 Formulations containing ceftibuten have been used in the treatment of bacterial infections including bronchitis, pneumonia, and enteritis.
Pharmacokinetics
Ceftibuten Dihydrate is the dihydrate form of ceftibuten, a semisynthetic, beta-lactamase-stable, third-generation cephalosporin with antibacterial activity. Ceftibuten binds to and inactivates penicillin-binding proteins (PBPs) located on the inner membrane of the bacterial cell wall. PBPs are enzymes involved in the terminal stages of assembling the bacterial cell wall and in reshaping the cell wall during growth and division. Inactivation of PBPs interferes with the cross-linkage of peptidoglycan chains necessary for bacterial cell wall strength and rigidity. This results in the weakening of the bacterial cell wall and causes cell lysis.