Enantioseparation of ofloxacin in urine by capillary electrokinetic chromatography using charged cyclodextrins as chiral selectors and assessment of enantioconversion

A method was developed for the enantioseparation of ofloxacin, a member of the fluoroquinolones, using an anionic cyclodextrin-derivative with or with out combination with a neutral cyclodextrin-derivative, as the chiral selec tor (s) in an electrokinetic chromatography system. The best results were o btained with 0.35 mM sulfated beta -cyclodextrin dissolved in a 50 mM phosp hate buffer, pH 2.5, and at 15 degreesC. Under these conditions, a resoluti on of 2 was readily achieved. Furthermore, under adequate separation condit ions, studies were performed in order to assess possible in vitro and in vi vo enantioconversion of levofloxacin. The current method allows detection o f 2 mug R-(+)-ofloxacine/ml. diluted urine without the necessity of sample cleanup.