Merck, R9904-5G, Rifaximin

General description
Chemical structure: macrolide
Application
Rifaximin is a semisynthetic analog of rifamycin with poor absorptivity. It selectively inhibits (E. coli, B subtilis) bacterial DNA-dependent RNA polymerase by a mechanism similar to rifabutin, β subunit binding. It is effective against aerobic and anaerobic Gram-positive and Gram-negative bacteria. It is active against species of Staphylococcus, Streptococcus and Enterococcus. It is less active against species of Enterobacteriaceae. Rifaximin is a non-systemic, gastrointestinal site-specific antibiotic. It has a pyridoimidazole ring, making it non-absorbable. Rifaximin is a pregnane X receptor (PXR) activator.
Biochem/physiol Actions
Rifaximin is a semisynthetic analog of rifamycin with poor absorptivity. Mode of action: selectively inhibits (E. coli, B subtilis) bacterial DNA-dependent RNA polymerase by mechanism similar to rifabutin, β subunit binding.
Antimicrobial spectrum: Aerobic and anaerobic Gram-positive and Gram-negative bacteria. Active against species of Staphylococcus, Streptococcus and Enterococcus; less active against species of Enterobacteriaceae.†
Preparation Note
Practically insoluble in water, soluble in acetone and methanol.
Other Notes
Keep container tightly closed in a dry and well-ventilated place.