Carboxymethyl-β-cyclodextrin-based nanomicelles as chiral selector and pseudostationary phase for enantioseparation in capillary electrophoresis

This study integrated a chiral selector with micelle pseudostationary phase to develop a novel chiral separation method in capillary electrophoresis. A new type of nanomicelles materials was prepared via amidation reaction using the carboxymethyl-β-cyclodextrin (CM-β-CD) as the hydrophilic group and long chain fatty amines as the hydrophobic group. This novel amide compound self-assembled into nanomicelles in a buffer solution, acting as both a chiral selector and pseudostationary phase. The separations of model drugs were notably improved when compared to the single CM-β-CD system and CM-β-CD/sodium dodecyl sulfate micellar electrokinetic capillary chromatograph system. This study optimized several separation parameters and comprehensively characterized the nanomicelles through several methods such as infrared spectroscopy, nuclear magnetic resonance spectroscopy, particle size determination, and transmission electron microscopy (TEM). Additionally, amlodipine was chosen as the model analyte to determine drug loading in both the single CM-β-CD system and the nanomicelles system using high performance liquid chromatography. The findings indicated that nanomicelles exhibited superior drug loading capacity. The particle size and TEM analysis visually confirmed the distribution of enantiomers in the hydrophobic core of nanomicelles. The proposed nanomicelles showed promise in chiral separation and this strategy opened up new pathways for the development of functional chiral materials.