Ertapenem sodium was introduced in the US as a once daily intravenous or
intramuscular injection for the treatment of adult patients with moderate to severe bacterial
infections. This new I-β-methyl carbapenem can be assembled from commercially
available 4-nitrobenzyl protected β-methyl carbapenem enolphosphate and the appropriate
thiol derivative. The last intermediate can be synthesized from a suitably N-protected 4-
hydroxy proline derivative in a one pot operation involving bis activation of the carboxy and
hydroxy groups, reaction with sodium sulfide yielding the corresponding thiolactone,
aminolysis with 2-aminobenzoic acid and Kdeprotection. This bacterial cell wall synthesis
inhibitor has broad spectrum antimicrobial activity including common Gram-positive and
Gram-negative aerobic pathogens and restricted activity against nosocomial pathogens
such as Pseudomonas aeruginosa, Acinetobacfer species, methicillin-resistant
staphylococci and enterococci. Ertapenem is resistant to a broad and extended spectrum
of β-lactamases (excluding metallo-beta-lactamase) and is also more resistant than
imipenem to human renal dehydroxypeptidase-I-inactivation (DHP-I). In drug-resistant
strains of P. aeruginosa, resistance to ertapenem and imipenem was common but almost
all strains remain susceptible to at least one antipseudomal agent. In phase III studies,
ertapenem showed efficacy in the treatment of obstetric and gyneacological infections,
skin and soft tissues infections, community-acquired pneumonia, urinary tract infections
and in intra abdominal infections. Ertapenem has improved pharmacokinetics over
currently available carbapenems and cephalosporins with an extended serum half-life of 4h. The overall safety and tolerability profile of ertapenem was comparable to that seen with
comparator antibacterials.
