6700. Norfloxacin

Nomenclature

CAS number: 70458-96-7
1-Ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid; AM-715; MK-366; Baccidal (Kyorin); Barazan (Teofarma); Chibroxin (Merck & Co.); Chibroxol (Merck & Co.); Floxacin (Medix); Lexinor (Kyorin); Noflo (Merck & Co.); Nolicin (Krka); Noroxin (Merck & Co.); Sebercim (GSK); Utinor (Merck & Co.); Zoroxin (Merck & Co.).
C16H18FN3O3; mol wt 319.33.
C 60.18%, H 5.68%, F 5.95%, N 13.16%, O 15.03%.

Description and references

Fluorinated quinolone antibacterial. Prepn: T. Irikura, BE 863429; eidem, US 4146719 (1978, 1979 both to Kyorin); M. Pesson, DE 2840910; eidem, US 4292317 (1979, 1981 both to Roger Bellon/Dainippon); H. Koga et al., J. Med. Chem. 23, 1358 (1980). HPLC determn in plasma and urine: H. J. Mascher, C. Kikuta, J. Chromatogr. A 812, 381 (1998). Comparative antibacterial activity: K. Hirai et al., Antimicrob. Agents Chemother. 19, 188 (1981); M. Y. Khan et al., ibid. 265; H. H. Gadebusch et al., Infection 10, 41 (1982). Series of articles on in vivo and in vitro activity, pharmacology, pharmacokinetics, metabolism, early clinical studies, toxicology: Chemotherapy (Tokyo) 29, Suppl. 4, 1-1000 (1981). Acute toxicity data: T. Irikura et al., ibid. 783. In vitro activity vs gentamicin-resistant P. aeruginosa: J. Downs et al., Antimicrob. Agents Chemother. 21, 670 (1982). Treatment of lower urinary tract infection: H. Giamarellou et al., Eur. J. Clin. Microbiol. 2, 266 (1983); of penicillin-resistant gonorrhea: S. R. Crider et al., N. Engl. J. Med. 311, 137 (1984). Review of pharmacokinetics, antibacterial activity, clinical trials: B. Holmes et al., Drugs 30, 482-513 (1985); R. C. Rowen et al., Pharmacotherapy 7, 92-110 (1987). Symposium on clinical experience: Scand. J. Infect. Dis. Suppl. 48, 1-91 (1986). Comprehensive description: C. Mazuel, Anal. Profiles Drug Subs. 20, 557-600 (1991).

Chemical structure

Properties

White to light-yellow crystalline powder, mp 220-221°. uv max (0.1N NaOH): ≈274, 325, 336 nm (A1%1cm ≈1109, 437, 425). pKa1 6.34; pKa2 8.75. Partition coefficient (octanol/water): 0.46. Soly at 25° (mg/ml): water 0.28; methanol 0.98; ethanol 1.9; acetone 5.1; chloroform 5.5; diethyl ether 0.01; benzene 0.15; ethyl acetate 0.94; octyl alcohol 5.1; glacial acetic acid 340. Solubility in water is pH dependent, increasing sharply at pH <5 or at pH >10. Hygroscopic in air, forms a hemihydrate. LD50 in mice, rats (mg/kg): >4000 orally (both species); 1500 s.c. (both species); 470, >500 i.m.; 220, 270 i.v. (Irikura).

Therapeutic Category

Antibacterial.

Keywords

Antibacterial (Synthetic); Quinolones and Analogs