Blog Date 29 March, 2023


CAT.ID - C050000A

CAS No- 85721-33-1

 Ciprofloxacin, a bactericidal antibiotic of the fluoroquinolone class is chemically described as 1-cyclopropyl-6-fluoro-4-oxo-7-piperazin-1-ylquinoline-3-carboxylic acid. Its molecular formula is C17H18FN3O3, and its molecular weight is 331.34 g/mol. Structure of Ciprofloxacin is a quinolone that is quinolin-4(1H)-one bearing cyclopropyl, carboxylic acid, fluoro and piperazin-1-yl substituents at positions 1, 3, 6 and 7 position.

 Ciprofloxacin is a second-generation fluoroquinolone antibiotic with an expanded spectrum of activity against gram-positive and gram-negative bacteria through its inhibition of DNA gyrase, an enzyme responsible for bacterial DNA replication. Due to its high activity and comparatively low toxicity, Ciprofloxacin is used worldwide to treat bacterial infections in humans and animals.

Ciprofloxacin was patented in 1983 by Bayer A.G. and approved in 1987 by the United States Food and Drug Administration (USFDA). Ciprofloxacin suspension gel is FDA approved for pediatric otitis media. Ciprofloxacin otic solution is approved for treating acute otitis externa caused by susceptible strains of Pseudomonas aeruginosa or Staphylococcus aureus.

Ciprofloxacin is used for treatment of urinary tract infections, sexually transmitted infections (gonorrhea), pneumonia, typhoid fever, gastrointestinal infections, lower respiratory tract infections, acute bacterial exacerbation of chronic bronchitis. It should be recognized that Neisseria gonorrhea has high rates of resistance to ciprofloxacin.

Ciprofloxacin eye drop is used for bacterial corneal ulcers and conjunctivitis and ciprofloxacin eye ointment is used for bacterial conjunctivitis.


Ciprofloxacin (fluoroquinolones) act by inhibiting two enzymes involved in bacterial DNA synthesis.

  1. DNA topoisomerases
  2. DNA gyrase

DNA topoisomerases are responsible for separating the strands of duplex bacterial DNA, Topoisomerase IV is composed of four homologous monomeric subunits, two ParC (GrlA in S.aureus) subunits and two ParE (Grl B in S.aureus) subunits encoded by the parC and parE genes, respectively.

DNA gyrase introduces negative super helical twists in the bacterial DNA double helix ahead of the replication fork, thereby catalyzing the separation of daughter chromosomes. This activity is essential for initiation of DNA replication and allows for binding of initiation proteins. DNA gyrase is composed of two GyrA and two GyrB monomeric subunits, which are encoded by the gyrA and gyrB genes, respectively.

Ciprofloxacin interact with the enzyme-bound DNA complex (i.e., DNA gyrase with bacterial DNA or topoisomerase IV with bacterial DNA) to create conformational changes that result in the inhibition of normal enzyme activity. As a result, the Ciprofloxacin – enzyme–DNA complex blocks progression of the replication fork, thereby inhibiting normal bacterial DNA synthesis and ultimately resulting in rapid bacterial cell death.

DNA gyrase tends to be the primary target for ciprofloxacin in Gram-negative organisms whereas topoisomerase IV is typically the primary target in Gram-positive bacteria.

Some of the impurities of Ciprofloxacin are tabulated below:

Catalogue No,

Product Name

Cas Number


Ciprofloxacin EP Impurity A



Ciprofloxacin Lactate



Ciprofloxacin Ethyl Ester



Ciprofloxacin intermediate -1






Formyl Ciprofloxacin



Ciprofloxacin EP Impurity C


 To enquire for many more impurities of Ciprofloxacin follow the link given below:

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