Chiral Profiling Analysis of β‐Blockers by Capillary Electrophoresis Using Dual Chiral Selectors

Abstract

Simultaneous analysis of several β-blockers using a novel dual chiral selector system was achieved for their accurate chiral discrimination by chiral capillary electrophoresis (CE) in normal polarity mode. The CE system was operated using heptakis(2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD) dissolved in 100 mM phosphoric acid-triethanolamine buffer (pH 3) and (+)-or (−)-18-crown-6-tetracarboxylic acid (18-C-6-TA) as a co-chiral selector in DM-β-CD solution. All eight investigated analytes were resolved using (+)-18-C-6-TA as a co-chiral selector in the presence of DM-β-CD solution, whereas the other β-blockers, except propranolol, were resolved using (−)-18-C-6-TA as the second chiral selector in DM-β-CD solution. Also, DM-β-CD had a major effect on chiral discrimination compared with 18-C-6-TA as a co-chiral selector. Relative migration times to that of (S)-pindolol as an internal standard were characteristic of each enantiomer with good precision. The method showed good linearity with a correlation coefficient (r ≥ 0.993). The precision as a percentage of relative standard deviation (% RSD) and accuracy as a percentage of relative error (% RE) ranged from 0.5 to 9.6 and from −5.7 to 9.1, respectively. These were adequate for the chiral assay of the β-blockers investigated. Thus, the present chiral profiling method is expected to be useful for accurate chiral discrimination and optical purity tests of chiral β-blockers and their related drugs.

Chiral Recognition for Chromatography and Membrane-Based Separations: Recent Developments and Future Prospects

“…In addition, 18-C-6-TA can be used in CE as a single chiral selection agent, and it can also be used to form a chiral selection system with other substances for the separation of chiral compounds. Researchers such as Paik [ 98 ] dissolved heptakis (2,6-di- O -methyl)-β-CD (DM-β-CD) in 18 mM phosphate-triethanolamine buffer (pH 3) in the presence of DM-β-CD solution using 18-C-6-TA as a chiral co-selection agent for chiral resolution of eight analytes. Some other types of CSs are also used in CE chiral separation.…”

Past, present, and future developments in enantioselective analysis using capillary electromigration techniques

“…In some cases the addition of a crown ether is essential, as no enantioseparation is observed using CDs only [99,100]. The synergistic effects of employing CDs and crown ethers simultaneously were already acknowledged in early studies [101], and their combination has since been a viable strategy in chiral separations [102][103][104][105][106]. If chiral recognition would originate fully from the applied CD, less expensive achiral crown ethers can also be added for improved stability.…”

Chiral selectors in CE: Recent development and applications (mid‐2014 to mid‐2016)

“…In other reports, published in 2015, dual‐selector systems based on CDs were used for the separation of several chiral compounds. In particular, the enantiomers of H1‐histamines and β‐blockers were separated by using mixtures of SBE‐β‐CD/β‐CD and dimethyl‐β‐CD/(+)‐18‐crown‐6‐tetracarboxylic acid, respectively .…”