quinolone Flashcards
What are synthetic antibacterial agents?
Organic compounds obtained by chemical synthesis with antibacterial activity for treating infections
Includes local, systemic, and urinary tract infections.
Name three chemical classes of synthetic antibacterial agents.
- Sulfonamide
- Nitroheterocyclic compounds (e.g. nitrofurans, metronidazole)
- Quinolones
What are the advantages of quinolone antimicrobial agents?
- Effective against many organisms
- Well-absorbed orally
- Well-distributed in tissues
- Relatively long serum half-lives
- Minimal toxicity
What infections are quinolones useful for?
- Urinary tract infections
- Prostatitis
- Infections of the skin and bones
- Penicillin-resistant sexually transmitted diseases
What common structure do quinolone antimicrobials share?
An N-alkylated-3-carboxypyrid-4-one ring
When was Nalidixic acid discovered, and what significance does it hold?
Discovered in 1962, it was the first quinolone and was commercialized for urinary tract infections in 1964.
What major advance in quinolones occurred between 1978 and 1982?
Preparation and patenting of many new fluoroquinolones classified as second-generation quinolones.
What is a key characteristic of third-generation fluoroquinolones?
Significantly improved activity against gram-positive bacteria, notably Streptococcus pneumonia.
How do quinolones inhibit bacterial DNA synthesis?
By interfering with DNA gyrase and topoisomerases, inhibiting replication and transcription.
What is the mechanism of action for quinolones?
They form a ternary complex involving the drug, the enzyme, and bound DNA after the enzyme has nicked DNA strands.
What is the primary metabolic pathway for quinolones?
Most metabolic reactions occur at the piperazine rings.
What structural feature is essential for the antibacterial activity of quinolones?
The 1,4-dihydro-4-oxo-3-pyridinecarboxylic acid moiety.
True or False: The effective antibacterial spectrum of nalidixic acid is limited to Gram-positive bacteria.
False
What is a significant incompatibility associated with quinolones?
They have excellent chelating properties, leading to incompatibility with antacids and mineral supplements.
What is the chemical name of Norfloxacin?
1-Ethyl-6-fluoro-4-oxo-1,4-dihydro-7-(piperazin-1-yl)quinoline-3-carboxylic acid
What distinguishes Ciprofloxacin from Norfloxacin?
Ciprofloxacin has lower MIC values against certain bacteria and is more potent.
What is Levofloxacin, and when was it marketed?
Optical isomer of Ofloxacin, marketed in 1991, with double the antibacterial activity of Ofloxacin.
What unique property does Delafloxacin have compared to other fluoroquinolones?
It is anionic, leading to increased accumulation in cells at acidic pH.
Fill in the blank: The first commercially available quinolone was _______.
Nalidixic acid
Which quinolone was approved in 2014 and shows good activity at acidic pH?
Finafloxacin
