Ranbezolid (RBx7644 free base) is an orally active oxazolidinone antibiotic effective against both Gram-positive and Gram-negative anaerobic bacteria, including Staphylococcus aureus, Staphylococcus epidermidis, and Bacteroides fragilis. It inhibits the 50s ribosomal subunit, with an IC50 value of 17 μM for bacterial ribosomes, and disrupts cell wall and lipid synthesis. Ranbezolid acts as a rapid bactericidal agent, significantly reducing bacterial load, and demonstrates improved cardiovascular safety. It is applicable in the study of antibiotics targeting anaerobic bacteria.

Ranbezolid (1 μg/mL) effectively inhibits protein synthesis in Staphylococcus aureus and Staphylococcus epidermidis, while also impeding cell wall and lipid synthesis in Staphylococcus epidermidis. At concentrations between 1-8 μg/mL, Ranbezolid causes concentration-dependent membrane damage to Staphylococcus epidermidis. The compound's IC50 for bacterial ribosomes is 17 μM, with a safety index of 865. Its minimum inhibitory concentrations (MIC) against the bacteria Bacteroides fragilis, Bacteroides vulgatus, Bacteroides thetaiotaomicron, Clostridium perfringens, Clostridioides difficile, and Peptoniphilus magnus are 0.06, 0.015, 0.06, 0.06, 0.03, and 0.015 μg/mL, respectively.

Ranbezoild (100 mg/kg, p.o., administered twice daily for 5 days) demonstrates excellent in vivo activity against Bacteroides fragilis in a mouse infection model. In a rat spontaneous hypertension model, Ranbezoild (≤ 50 mg/kg, p.o., single dose) does not significantly enhance the pressor response induced by Tyramine.