Enantioseparation of Ofloxacin Enantiomers by Mixed Extractants in Biphasic System

Abstract

The distribution behavior of ofloxacin enantiomers was examined in a biphasic system containing β-cyclodextrin in aqueous phase and a complex formation of O'O-dibenzoyl-(2R,3R)-tartaric acid (L-DBTA) and di(2-ethylhexyl)phosphoric acid in organic phase as the mixed extractants. The influences of pH, initial concentration of ofloxacin, phase ratio, and concentration of extractants were studied. The experimental results showed that both the distribution ratio and enantioselectivities of ofloxacin enantiomers were greatly improved. A higher enantioseparation efficiency with a maximum separation factor of 2.48 and enantiomeric excess of 40.4% can be obtained under the optimal experimental conditions. It could be very helpful to achieve high effective enantioseparation using the mixed extractants, which would be the guidelines for industrial amplification of chiral extraction separation.

Keywords:

• biphasic system
• enantioseparation
• mixed extractants
• ofloxacin enantiomers

ACKNOWLEDGEMENTS

We wish to acknowledge the support of the National Science Foundation of China (NO. 21176263 and NO. 20805058) and the Provincial Natural Science Foundation of Hunan (No.09JJ3026) and the Open-End Fund for the Valuable and Precision Instruments of Central South University on this work gratefully.