The<unk> s are a family of broad-spectrum antibiotics. The parent of the group is nalidixic acid. The majority of<unk> s in clinical use belong to the subset of fluoroquinolones, which have a fluoro group attached the central ring system, typically at the 6-position.
Quinolone
Anthracycline
Tetracycline 
Metacycline
Minocycline
Enoxolone
Quinbolone
Penicillin