Investigation of interaction of fluoroquinolones with aluminum, iron and magnesium ions using capillary zone eletrophoresis

The present study describes the application of capillary zone electrophoresis (CZE) to investigate interactions between ciprofloxacin, enrofloxacin, lamefloxacin, levofloxacin, ofloxacin, norfloxacin and sparfloxacin-antimicrobial drugs called fluorqlinolones, and polyvalent metal ions (Mg2+, Fe3+ and Al3+), commonly used in daily medicine practice as components of multi-mineral and antacida drugs. It was observed that polyvalent metal ions exhibit strong interactions with these drugs. The strength of these interactions depends on the metal ion, the molecular structure of the fluoroquinolone, and the pH which is very important for the investigations of complex formations. Two different pH values, 3.25 and 8.02, were utilized in this study. Addition of fluoroquinolone to background electrolyte and injection of samples consisting of different concentrations of cations allowed to observe changes in peak area depending on the concentration of the metal ion. A mathematical model for quantitative evaluation of the complex formation constant K was used. Our investigation shows new possibilities of quantitative characterization of the interactions between fluoroquinolones and metal ions using CZE. Such investigations were not described so far in the literature.