RP-HPLC enantioseparation of β-adrenolytics using micellar mobile phase without organic solvents.

Enantioseparation of a few commonly administered racemic β-adrenolytics (namely, carvedilol, betaxolol, salbutamol and bisoprolol) has been achieved using a water micellar mobile phase containing surfactants (sodium dodecyl sulphate and Brij-35) without organic solvents as a new approach in RP-HPLC. Two chiral derivatizing reagents based on enantiomerically pure (S)-(-)-levofloxacin were synthesized using N-hydroxysuccinimide and N-hydroxybenzotriazole as the activation auxiliaries. Diastereomeric derivatives of the chosen β-adrenolytics were synthesized under microwave irradiation in a very short reaction time. The (S)-(-)-levofloxacin moiety enhanced molar absorbance of the diastereomeric derivatives resulting in very low limit of detection (1.618 and 4.902 ng/mL, respectively, for diastereomeric derivatives of (RS)-betaxolol and better resolution with lower retention times (for all the analytes), in comparison to literature reports. There was 15-20 times less consumption of mobile phase because of lower retention time.