Norfloxacin
[CAS# 70458-96-7]

Identification

• Classification: API >> Synthetic anti-infective drugs >> Quinolone
• Name: Norfloxacin
• Synonyms: Noroxin; Baccidal; Chibroxin; Floxacin 400; Noroxin; Norphloxacine; N-Desmethylpefloxacin; 1-Ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid
• Molecular Formula: C₁₆H₁₈FN₃O₃
• Molecular Weight: 319.33
• CAS Registry Number: 70458-96-7
• EC Number: 274-614-4
• SMILES: CCN1C=C(C(=O)C2=CC(=C(C=C21)N3CCNCC3)F)C(=O)O

Properties

• Melting point: 220 °C

Safety Data

• Hazard Symbols: GHS05;GHS07;GHS08 Danger
• Risk Statements: H318-H319-H361
• Safety Statements: P203-P264+P265-P280-P305+P351+P338-P305+P354+P338-P317-P318-P337+P317-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Serious eye damage	Eye Dam.	1	H318
Reproductive toxicity	Repr.	2	H361
Skin irritation	Skin Irrit.	2	H315
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Acute toxicity	Acute Tox.	4	H332

Discovery and Applications

Norfloxacin is a synthetic antibiotic belonging to the fluoroquinolone class, widely used to treat bacterial infections. Discovered in the late 1970s and approved for medical use in the 1980s, norfloxacin has been particularly effective in treating urinary tract infections (UTIs), gastrointestinal infections, and certain types of sexually transmitted infections.

Norfloxacin works by inhibiting bacterial DNA gyrase and topoisomerase IV, enzymes essential for DNA replication, transcription, repair, and recombination in bacteria. By interfering with these processes, norfloxacin prevents bacterial cells from multiplying and ultimately leads to their death. This mechanism of action makes norfloxacin effective against a broad spectrum of Gram-negative and some Gram-positive bacteria.

The discovery of norfloxacin was a result of extensive research aimed at developing new antibiotics that could overcome the limitations of existing treatments. The fluoroquinolone class, to which norfloxacin belongs, was developed to enhance the antibacterial activity and broaden the spectrum of older quinolones. Norfloxacin was one of the first fluoroquinolones to be introduced, marking a significant advancement in the treatment of bacterial infections.

Norfloxacin is primarily used to treat infections of the urinary tract, including cystitis and prostatitis. Its efficacy in treating these infections has made it a common choice for patients with recurrent UTIs. Additionally, norfloxacin is used to treat gastrointestinal infections, such as traveler’s diarrhea caused by susceptible strains of bacteria. It has also been employed in the treatment of certain sexually transmitted infections, like gonorrhea, although its use for this purpose has decreased due to rising antibiotic resistance.

The drug is usually administered orally, in tablet form, with the dosage and duration of treatment depending on the type and severity of the infection. Norfloxacin is generally well-tolerated, but like other fluoroquinolones, it can cause side effects. The most common side effects include nausea, headache, dizziness, and gastrointestinal discomfort. In rare cases, more serious side effects such as tendonitis, tendon rupture, and nerve damage have been reported, leading to increased caution in its use.

One of the challenges associated with norfloxacin, as with other antibiotics, is the development of bacterial resistance. Over time, some bacteria have developed mechanisms to evade the effects of norfloxacin, reducing its efficacy. This has led to more restricted use of the drug and the development of guidelines to minimize the risk of resistance.

Despite these challenges, norfloxacin remains an important antibiotic, especially in regions where it is still effective against prevalent bacterial strains. Its role in the treatment of urinary tract infections and other bacterial diseases underscores its continued relevance in clinical practice.

References

1983. In vitro antibacterial activity of norfloxacin (MK-0366, AM-715) and other agents against gastrointestinal tract pathogens. Antimicrobial Agents and Chemotherapy, 23(1).
DOI: 10.1128/aac.23.1.86

1991. (Acyloxy)alkyl carbamate prodrugs of norfloxacin. Journal of Medicinal Chemistry, 34(1).
DOI: 10.1021/jm00105a013

2005. Norfloxacin and cisapride combination decreases the incidence of spontaneous bacterial peritonitis in cirrhotic ascites. Journal of Gastroenterology and Hepatology, 20(3).
DOI: 10.1111/j.1440-1746.2005.03796.x