Development of a Capillary Electrophoresis Method for the Separation of Fluoroquinolone Derivatives in Acidic Background Electrolyte

Introduction: Antibacterial quinolones class comprises a series of synthetic antibacterial agents, following the model of nalidixic acid. Because of their common 6-fl uorosubtituent on the quinolone ring, fluroquinolones are the most potent analogues with extended spectrum of activity and great pharmacokinetic properties. The applicability of capillary zone electrophoresis for the separation of fl uoroquinolones in acidic background electrolyte has been studied, our aim being the development of a capillary zone electrophoresis method for the simultaneous separation of six fl uoroquinolones and also to optimize the analytical conditions. The six studied fl uoroquinolones were ciprofloxacin, enoxacin, enrofloxacin, moxifloxacin, ofloxacin and sarafloxacin.

Material and methods: Preliminary, we studied the electrophoretic behavior of six fluoroquinolones in an acidic pH, which highlighted the possibility of developing a separation method in this area of pH. Electrophoretic parameters infl uencing separation performance were studied and optimized.

Results: A fast and reliable method has been developed, using a background electrolyte containing 100 mM phosphoric acid and the following conditions: applied voltage: + 25 kV, temperature: 20°C, injection pressure 30 mbar - 5 sec, UV detection at 280 nm, capillary: 60 cm (52 cm effective length) x 50 μm, analyte concentration: 167 μg/ml. The separation of the studied fl uoroquinolones was achieved in less than 8 minutes.

Conclusions: Capillary zone electrophoresis using an acidic background electrolyte proved to be an efficient tool in the separation of fluoroquinolones from different generations. Also the proposed methods are particular environment-friendly replacement and improvement of a common high performance liquid chromatography determination with rapid analysis time without using any organic solvents.