Chiral separation of salbutamol and bupivacaine by capillary electrophoresis using dual neutral cyclodextrins as selectors and its application to pharmaceutical preparations and rat blood samples assay

An attempt for the simultaneous separation of salbutamol (Sal) and bupivacaine (Bup) enantiomers was performed by capillary elecytrophoresis with a dual mixture of neutral cyclodextrins as chiral selector. The influence on the separation of several parameters such as buffer composition, pH, the concentration ratio of 2-hydroxypropyl-beta-cyclodextrin (HP-β-CD) to dimethyl-beta-cyclodextrin (DM-β-CD) was investigated. A better separation was obtained for Sal and Bup with the CD mixtures compared to the use of HP-β-CD or DM-β-CD alone. The best simultaneous separation of Sal and Bup enantiomers was achieved with a 20 mM HP-β-CD and 20 mM DM-β-CD at pH 2.5 in a triethanolamine (TEA)/phosphate buffer. This method-utilized chlorphenamine (Chl) as an internal standard was found to be linear in the range 0.5–100 μg/mL and 0.5–150 μg/mL for Sal and Bup enantiomers, respectively. The limits of detection for both enantiomers of Sal and Bup were 0.18 and 0.24 μg/mL, respectively. The proposed method was applied to monitor Sal and Bup enantiomers concentration change in rat blood samples obtained from a male rat after celiac doses administration 0–30 min of Sal and Bup racemate. The method could also be used to determine Sal enantiomers in a pharmaceutical aerosol.