Investigation on the chiral recognition mechanism between verteporfin and cholate salts by capillary electrophoresis

In this article, capillary electrophoresis was applied to investigate the chiral recognition mechanism for the enantioseparation on a well-known second-generation photodynamic therapy drug of benzoporphyrin derivative monoacid ring A, that is, verteporfin. In our previous study, cholate salts have been studied as the chiral selectors, which can realize baseline separation of the four verteporfin isomers. Aiming to reveal the chiral recognition mechanism, the separation effect of several kinds of chiral selectors was discussed. According to the results and references, the chiral separation mechanism of this system was concluded: the analytes selectively combine with the chiral micelles, that is, dynamic H-bonds interactions occur between the hydroxyl groups on the outer side of the cholate micelles and the ester/carboxy groups of the four isomers. In addition, the role of dimethyl formamide as an organic modifier was also researched, including reducing the effective mobility of the analytes and mobility of electroosmotic flow, and preventing them from adsorbing to the capillary wall and self-aggregating of verteporfin, which are pretty beneficial for separation. The method used in this article provides a direct and reliable solution to study the mechanism of chiral separation.