Rifalazil and derivative compounds show potent efficacy in a mouse model of H. pylori colonization.

The rifamycin rifalazil (RFZ), and derivatives (NCEs) were efficacious in a mouse model of Helicobacter pylori colonization. Select NCEs were more active in vitro and showed greater efficacy than RFZ. A systemic component contributes to efficacy.

Efficacy of novel rifamycin derivatives against rifamycin-sensitive and -resistant Staphylococcus aureus isolates in murine models of infection.

Novel rifamycins (new chemical entities [NCEs]) having MICs of 0.002 to 0.03 microg/ml against Staphylococcus aureus and retaining some activity against rifampin-resistant mutants were tested for in vivo efficacy against susceptible and rifampin-resistant strains of S.