8220. Rifaximin

Nomenclature

CAS number: 80621-81-4
(2S,16Z,18E,20S,21S,22R,23R,24R,25S,26R,27S,28E)-25-(Acetyloxy)-5,6,21,23-tetrahydroxy-27-methoxy-2,4,11,16,20,22,24,26-octamethyl-2,7-(epoxypentadeca[1,11,13]trienimino)benzofuro[4,5-e]pyrido[1,2-a]benzimidazole-1,15(2H)-dione; 4-deoxy-4′-methylpyrido[1′,2′-1,2]imidazo[5,4-c]rifamycin SV; rifamycin L 105; rifaxidin; L-105; Fatroximin (Fatro); Flonorm (Schering-Plough); Normix (Alfa); Rifacol (Formenti); Xifaxan (Salix).
C43H51N3O11; mol wt 785.88.
C 65.72%, H 6.54%, N 5.35%, O 22.39%.

Description and references

Nonabsorbable semisynthetic rifamycin antibiotic. Prepn: BE 888895; E. Marchi, L. Montecchi, US 4341785 (1981, 1982 both to Alfa); E. Marchi et al., J. Med. Chem. 28, 960 (1985); and NMR study: M. Brufani et al., J. Antibiot. 37, 1611 (1984). X-ray crystal structure: idem et al., ibid. 1623. In vitro and in vivo antibacterial activity: A. P. Venturini, E. Marchi, Chemioterapia 5, 257 (1986). Toxicological study: G. Borelli, D. Bertoli, ibid. 263. Clinical trial in travelers' diarrhea: R. Steffen et al., Am. J. Gastroenterol. 98, 1073 (2003). Review of activity, pharmacokinetics and clinical experience in gastrointestinal infections: J. C. Gillis, R. N. Brogden, Drugs 49, 467-484 (1995); D. B. Huang, H. L. DuPont, J. Infect. 50, 97-106 (2005).

Chemical structure

Properties

Red orange powder, mp 200-205° (dec). uv max: 232, 260, 292, 320, 370, 450 nm (E1%1cm 489, 339, 295, 216, 119, 159). Sol in alcohols, ethyl acetate, chloroform, toluene. Insol in water. LD50 orally in rats: >2000 mg/kg (Borelli, Bertoli).

Therapeutic Category

Antibacterial.

Therapeutic Category (Veterinary)

Antibacterial.

Keywords

Antibacterial (Antibiotics); Ansamycins