Doripenem monohydrate (S 4661 monohydrate) is a broad-spectrum injectable antibiotic, used for Gram-positive, Gram-negative and anaerobic pathogens.

Doripenem is a broad-spectrum carbapenem antibiotic effective against both Gram-negative and Gram-positive bacteria, such as S. aureus, S. pneumoniae, E. coli, and K. pneumoniae, with minimum inhibitory concentrations (MICs) ranging from less than 0.015 to 0.3 µg/ml. It has been proven to reduce the viable bacteria count in mouse lung models of chronic P. aeruginosa respiratory tract infection at a dosage of 100 mg/kg per day. Doripenem operates by inhibiting bacterial cell wall synthesis through the formation of stable acyl-enzyme complexes with penicillin-binding proteins, leading to their inactivation. This compound has been utilized in various formulations for the treatment of bacterial infections.

Doripenem is a new parenteral carbapenem antibiotic with broad-spectrum activity against gram-negative and gram-positive pathogens.