Норфлоксацин

Описание

Norfloxacin is the first of the third generation nalidixic acid analogs to reach the marketplace. It exhibits potent in vitro and in vivo activity against Pseudomonas, enteric gram-negative rods and gram-positive cocci. Norfloxacin is orally effective in the treatment of urinary tract infections, including those due to organisms refractory to many other agents.

Химические свойства

Off-white to light yellow cryst powder

Использование

It finds it application as a fluorinated quinolone antibacterial. It is clinically used to treat urinary tract infections and prostatitis. In neutrophils from cirrhotic subjects, norfloxacin increases expression of IL-10 and heme oxygenase 1 (HO-1) and decreases expression of pro-inflammatory cytokines. Additionally, when complexed with gold(III), norfloxacin binds DNA and inhibits cellular proliferation in several cancer cell lines.

Определение

ChEBI: A quinolinemonocarboxylic acid with broad-spectrum antibacterial activity against most gram-negative and gram-positive bacteria. Norfloxacin is bactericidal and its mode of action depends on blocking of bacterial DNA replication by binding itself to an enz me called DNA gyrase.

Антимикробная активность

It is active against a wide range of Gram-negative bacteria, including Enterobacteriaceae and Campylobacter spp. Ps. aeruginosa, Acinetobacter, Serratia and Providencia spp. are weakly susceptible (and often resistant). It has no useful activity against anaerobes, Chlamydia, Mycoplasma and Mycobacterium spp.

Фармацевтические приложения

A 6-fluoro, 7-piperazinyl quinoline available for oral administration and as an ophthalmic ointment.

Фармакокине?тика

Oral absorption: 50–70%
C_max 400 mg oral :1.5 mg/L after 1–1.5 h
Plasma half-life :3–4 h
Volume of distribution: 2.5–3.1 L/kg
Plasma protein binding: 15%
absorption and distribution
Norfloxacin displays linear kinetics. There is no significant accumulation with the recommended dosage of 400 mg every 12 h. Food slightly delays but does not otherwise impair absorption. Antacids reduce absorption. It is widely distributed, but concentrations in tissues other than those of the urinary tract are low： levels in the prostate are around 2.5 mg/g.
Metabolism and excretion
Six or more inactive metabolites are produced. Around 30% of a dose appears as unchanged drug in the urine and <10% as metabolites, producing peak concentrations of microbiologically active drug of around 100–400 mg/L. Urinary recovery is halved by probenecid, with little effect on the plasma concentration. The apparent plasma elimination half-life increases with renal impairment, rising to around 8 h in the anuric patient. Some of the drug appears in the bile where concentrations three- to seven-fold greater than the simultaneous plasma levels are achieved, but this is not a significant route of elimination and hepatic impairment is without effect. Very variable quantities, averaging 30% of a dose, appear in the feces, producing concentrations of active agent of around 200–2000 mg/kg.

Клиническое использование

Complicated and uncomplicated urinary tract infections (including prophylaxis in recurrent infections), prostatitis
Uncomplicated gonorrhea
Gastroenteritis caused by Salmonella, Shigella and Campylobacter spp., Vibrio cholerae
Conjunctivitis (ophthalmic preparation)

Побочные эффекты

Untoward reactions are those common to the fluoroquinolones. Gastrointestinal tract disturbances, which are generally mild, have been reported in 2–4% of patients. CNS disturbances have largely been limited to headache, drowsiness and dizziness. Co-administration with theophylline results in increased plasma theophylline levels.

Профиль безопасности

Poison by intravenous route.Moderately toxic by other routes. Human systemic effectsby ingestion: musculoskeletal changes. An experimentalteratogen. Other experimental reproductive effects.Mutation data reported. When heated to decomposition itemits