DISSOCIATION AND COMPLEXATION OF FLUOROQUINOLONE ANALOGS

The dissociation and the complexation behaviours of four fluoroquinolo ne antibiotics have been studied. The acid dissociation constants of c iprofloxacin, enoxacin, norfloxacin and ofloxacin were determined by c onventional potentiometric and conductometric techniques. Increasing t he Hammett substituent constant, the pK(a) values were decreased. The absorption of fluoroquinolones in the intestinal tract are probably tr ansported by pH-dependent mechanisms. Formation constants of the iron( III) complexes (1:1) of the fluoroquinolone analogues were determined by spectrophotometry. The optimum pH for complexation was 3.80.