is divided into first, second, third, and fourth generations according to the order of invention and its antibacterial properties.
The first-generation quinolones only have antibacterial effects on Escherichia coli, Shigella, Klebsiella, and a few Proteus. Because of the poor efficacy, it has rarely been used.
The second-generation quinolones have expanded their antibacterial spectrum, and have certain antibacterial effects against Enterobacter, Citrobacter, Pseudomonas aeruginosa, and Serratia.
The antibacterial spectrum of the third-generation quinolones has been further expanded. It also has antibacterial effects on gram-positive bacteria such as staphylococcus, and further strengthens antibacterial effects on some gram-negative bacteria. This generation of drugs have fluorine atoms in the molecules. Therefore, called fluoroquinolone.
The fourth-generation quinolones are structurally modified compared to the previous three-generation drugs. The introduction of 8-methoxy group in the structure helps to strengthen the anti-anaerobic bacteria activity, while the azadioxane structure at the C-7 position strengthens the anti-gram positive Bacteria activity and maintain the original activity against Gram-negative bacteria, adverse reactions are smaller, but the price is more expensive. Increased antibacterial activity against Gram-positive bacteria, increased effects on anaerobic bacteria including Bacteroides fragilis, and enhanced effects on typical pathogens such as Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella and Mycobacterium tuberculosis.
Quinolone drugs have the following contents: nalidixic acid, pipemidic acid, norfloxacin, ciprofloxacin, enoxacin, ofloxacin, levofloxacin, fleroxacin, lomefloxacin, pefloxacin, toxa Ofloxacin, Sifloxacin, etc.