Nalidixic acid *
a
 typical chemical features of
   fluoroquinolones (a, b, c)
   BUT a naphthridone
    (N at position 8:    )
 limited usefulness as drug
 narrow antibacterial spectrum
   (Enterobacteriaceae only)
 short half-life (1.5h)
 high protein binding (90%)
O
O
C
-
b
C
N
N
5
c
* Belg.  pat. 612,258 to Sterling Drugs, 1962
10