Ciflomed Mechanism of Action

Pharmacology: Pharmacodynamics: Mechanism Of Action: Ciprofloxacin acts on the A-sub unit of the enzyme, DNA gyrase that carries out the strand-cutting function of the gyrase during DNA replication or transcription. The drug inhibits gyrase mediated DNA super coiling at concentrations that correlate well with those required to inhibit bacterial growth. Mutation of the gene that encode the A subunit polypeptide can confer resistance to it. Eukaryotic cells do not contain DNA gyrase but they contain mechanistically similar type-II DNA topoisomerase that removes positive supercoils from eukaryotic DNA to prevent its tangling during replication. The drug inhibits eukaryotic type-II isomerase only at much higher concentrations (100 to 1000 μgm/mL).
After oral administration, Ciprofloxacin is absorbed mainly from the small intestine, reaching peak serum concentrations 60-90 min later.
Since the protein binding of Ciprofloxacin is low (20-30%) and since the substance is present in plasma largely in a non-ionized form, almost the entire dose administered can diffused freely into the extravascular space. In this way, the concentrations in certain body fluids and tissues can clearly exceed the corresponding serum levels.
Ciprofloxacin is excreted essentially unchanged, the bulk being eliminated by the renal route.
Ciprofloxacin is excreted not only renally but also to a considerable extent via the intestine, only a severely impaired kidney function results in prolonged serum half-lives of up to 12 hrs.
Bioavailability: After oral administration, Ciprofloxacin is absorbed rapidly and well (bioavailability: approximately 70-80%).