Azithromycin as a new chiral selector in capillary electrophoresis

In capillary electrophoresis (CE), separation of enantiomers of a chiral compound can be achieved through the chiral interactions and/or complex formation between the chiral selector and the enantiomeric analytes on leaving their diastereomeric forms with different stability constants and hence different mobilities. A great number of chiral selectors have been employed in CE and among them macrocyclic antibiotics exhibited excellent enantioselective properties towards a wide number of racemic compounds. The use of azithromycin (AZM) as a chiral selector has not been reported previously. This work reports the use of AZM as a chiral selector for the enantiomeric separations of five chiral drugs and one amino acid (tryptophan) in CE. The enantioseparation is carried out using polar organic mixtures of acetonitrile (ACN), methanol (MeOH), acetic acid and triethylamine as run buffer. The influences of the chiral selector concentration, ACN/MeOH ratio, applied voltage and capillary temperature on enantioseparation are investigated. The results show that AZM is a viable chiral selector in CE for the enantioseparation of the type of chiral drugs investigated.