Rifalazil

941.07

941.07

S1976TE8QK

230.66000

6.57360

1.36g/cm3

195-200° (dec)

1048.6ºC at 760mmHg

588ºC

1.634

Investigated for use/treatment in atherosclerosis, bacterial infection, and peripheral vascular disease.

Rifalazil represents a new generation of ansamycins that contain a unique four-ring structure. Originally rifalazil was developed as a therapeutic agent to replace rifampin as part of a multiple drug regimen in the treatment of tuberculosis. As a result of its superior antimicrobial activity and high intracellular levels, rifalazil has potential to treat indications caused by the intracellular pathogen, Chlamydia trachomatis, which causes non-gonococcal urethritis and cervicitis, often leading to pelvic inflammatory disease. Rifalazil also has potential to treat the related microorganism, Chlamydia pneumoniae, which may be involved in chronic inflammatory processes thought to be partly responsible for atherosclerosis. Due to its favourable antimicrobial spectrum and other positive attributes, rifalazil may also prove valuable in the treatment of gastric ulcer disease, caused by Helicobacter pylori, and antibiotic-associated colitis, the result of toxin production following the growth of Clostridium difficile in the colon. The potential value of rifalazil in the treatment of these indications will be assessed in human clinical trials.

Substances obtained from various species of microorganisms that are, alone or in combination with other agents, of use in treating various forms of tuberculosis; most of these agents are merely bacteriostatic, induce resistance in the organisms, and may be toxic. (See all compounds classified as Antibiotics, Antitubercular.)|Substances that suppress Mycobacterium leprae, ameliorate the clinical manifestations of leprosy, and/or reduce the incidence and severity of leprous reactions. (See all compounds classified as Leprostatic Agents.)

The major metabolites of rifalazil in human are 25-deacetyl-benzoxazinorifamycin and 32-hydroxy-benzoxazinorifamycin. The enzyme responsible for the benzoxazinorifamycin-25-deacetylation is a B-esterase while the enzyme responsible for the benzoxazinorifamycin-32-hydroxylation is CYP3A4.

The potent antimycobacterial activity of rifalazil is due to inhibition of bacterial RNA polymerase.

3'-hydroxy-5'-(4-isobutylpiperazinyl)benzoxazinorifamycin