Investigation of enantioselective ofloxacin-albumin binding and displacement interactions using capillary affinity zone electrophoresis.

The direct chiral separation of ofloxacin by capillary affinity zone electrophoresis using serum albumins from different animal sources as chiral selector in the supporting electrolyte is described. In addition, the effects of displacers on the mobility and enantioselectivity of ofloxacin were studied. Firstly, the separation behaviour of the enantiomers of the ofloxacin (OFLX) and tryptophan (Trp) was compared. The influence of albumin types, including chemically modified bovine serum albumins (BSAs), and buffer types on the migration behaviour of enantiomers was investigated. The results showed that stereoselectivity of Trp is independent of the type of albumin used. However, chiral separation of OFLX depends on the biological species of albumin. Use of chemically modified BSA led to poorer resolution of enantiomers. Only with acetylated BSA could chiral separation of Trp be achieved. Using Good's buffer solutions (DIPSO and HEPES) as a supporting electrolyte affected the migration times of OFLX enantiomers. Finally, a variety of displacers were added to the buffer along with the protein, and the effects on separation behaviour were observed. The displacers included warfarin, ketoproten, diazepam, propranolol, benzoinphenylbutazone, digitoxin and octanoic acid. From the results obtained, it is concluded that capillary affinity zone electrophoresis using albumin as a chiral selector may allow screening of OFLX-displacer interactions.