In the pharmaceutical industry, Nalidixic Acid 500 mg is recognized as the first of the quinolone class of antibiotics. As a pharmacist and manufacturer, I view Nalidixic Acid as a “urinary antiseptic.” While it has largely been superseded by newer fluoroquinolones (like Ciprofloxacin) in urban centers, it remains a vital, cost-effective treatment in international markets for specific bacterial infections.

Primary Clinical Uses

• Urinary Tract Infections (UTIs): It is primarily indicated for the treatment of uncomplicated UTIs caused by Gram-negative bacteria, such as E. coli, Proteus, Klebsiella, and Enterobacter species.

• Shigellosis (Bacillary Dysentery): Used in certain regions to treat intestinal infections caused by Shigella species, particularly where resistance to other antibiotics is a factor.

• Gram-Negative Infections: Because it achieves high concentrations in the urine rather than the blood, its use is almost exclusively confined to the urinary tract.

Mechanism of Action: Inhibiting DNA Gyrase

Nalidixic Acid is a bactericidal agent that interferes with the bacterial reproductive cycle.

Targeting DNA Gyrase: It inhibits the A-subunit of the bacterial enzyme DNA gyrase (Topoisomerase II).

Supercoiling Interference: DNA gyrase is responsible for the negative supercoiling of DNA, which is essential for bacterial DNA replication and transcription.

DNA Fragmentation: By blocking this enzyme, Nalidixic Acid causes the DNA strands to break, leading to the rapid death of the bacterial cell.

The Manufacturer’s Perspective: Formulation & Export

From a manufacturing and global trade standpoint, Nalidixic Acid 500 mg requires specific technical attention:

• Photosensitivity (Critical Warning): Nalidixic Acid is highly photosensitive. As a firm owner, you must ensure your Product Information Leaflet (PIL) warns patients to avoid excessive sunlight, as it can cause severe phototoxic reactions.

• Packaging Requirements: At our WHO-GMP facility in Mumbai, we utilize Amber-colored PVC or Alu-Alu blister packaging to protect the 500 mg tablets from light degradation, ensuring a 36-month shelf life for export to Zone IVb regions.

• Pediatric Considerations: While the 500 mg is for adults, the molecule is generally avoided in young children due to its potential effect on cartilage and the risk of increased intracranial pressure.

• B2B & Dossier Support: This product is often requested for government tenders in emerging markets. We provide full CTD/eCTD Dossiers to support your firm in international registration and supply.