What is/are Ofloxacin Ophthalmic?
The 2- and 4-quinolones are a class of bicyclic molecules, organic chemical structures that are related to the heteroaromatic coal tar isolate quinoline, see image at right. Specific quinoline molecules substituted with an hydroxyl functional group at carbons 2 and 4 (C-2 and C-4, see image) are most often observed in isomeric forms termed 2- and 4-quinolones, respectively (tautomers, relationships explained further below). The relative importance of 4-quinolones has increased with the discovery that such structures that also bear a carboxylic acid (-COOH) and other functional groups at particular sites on the ring have very potent bacteriocidal activities, inhibiting of a broad spectrum of Gram negative and Gram positive DNA gyrase and topoisomerase enzymes. Hence, they are very useful in antibacterial therapy. An example of such a 4-quinolone is "cipro" (ciprofloxacin, image at right), where the atoms of quinoline can be traced within this related structure. Ciprofloxacin is a "second-generation" fluoroquinolone antibacterial (see below), introduced by Bayer AG and still in wide use as the second decade of the new millennium begins.
The quinolones have been widely used in animal husbandry, and several agents have veterinary-specific applications.
- Danofloxacin (Advocin, Advocid) (for veterinary use)
- Difloxacin (Dicural, Vetequinon) (for veterinary use)
- Enrofloxacin (Baytril) (for veterinary use)
- Ibafloxacin (Ibaflin) (for veterinary use)
- Marbofloxacin (Marbocyl, Zenequin) (for veterinary use)
- Orbifloxacin (Orbax, Victas) (for veterinary use)
- Sarafloxacin (Floxasol, Saraflox, Sarafin) (for veterinary use)
More commonly, some eye burning, stinging, irritation, itching, redness, blurred vision, eyelid itching, eyelid swelling or crusting, a bad taste in your mouth, tearing, or sensitivity to light may occur.
Mechanism of action
Quinolones and fluoroquinolones are chemotherapeutic bactericidal drugs, eradicating bacteria by interfering with DNA replication. Quinolones inhibit the bacterial DNA gyrase or the topoisomerase II enzyme, thereby inhibiting DNA replication and transcription. Recent evidence has shown topoisomerase II is also a target for a variety of quinolone-based drugs. Thus far, most of the compounds that show high activity against the eukaryotic type II enzyme contain aromatic substituents at their C-7 positions.
Quinolones can enter cells easily and, therefore, are often used to treat intracellular pathogens such as Legionella pneumophila and Mycoplasma pneumoniae. For many Gram-negative bacteria, DNA gyrase is the target, whereas topoisomerase IV is the target for many Gram-positive bacteria. It is believed eukaryotic cells do not contain DNA gyrase or topoisomerase IV. However, there is debate concerning whether the quinolones still have such an adverse effect on the DNA of healthy cells
This article uses material from the Wikipedia article Ofloxacin Ophthalmic, which is released under the Creative Commons Attribution-Share-Alike License 3.0.