Enantioseperation of chiral phenothiazine derivatives in capillary electrophoresis using cyclodextrin type chiral selectors

Abstract

SummaryThe enantioseparation of chiral phenothiazine derivatives has been studied in capillary electrophoresis (CE) using various cyclodextrins (CD) such as native 0~,/?, and y-CD and some of their neutral and charged derivatives. Comparative binding studies were performed using nuclear magnetic resonance (NMR) spectrometry. The advantages and disadvantages of the binding parameters obtained in both techniques (NMR and CE) from the viewpoint of separation optimization are discussed.ques seem to be a promising approach for mechanistic studies and the optimization of enantioseparations in CE.However, before applying the data obtained with one technique for the optimization in another technique the question must be answered how transferable are the data from one technique to another. Previous studies [2, 4, 18 20] described good correlation's between CE and NMR spectrometric data. Both techniques are liquid-phase techniques with a comparable degree of freedom of the chiral selector and the selectand.In this work the interaction between the enantiomers of promethazine (PMZ) and native 13-CD was studied with CE and N M R spectrometry. The data obtained in both techniques were compared from the viewpoint of enantioseparation optimization in CE.

Enantioseparation of phenothiazines in cyclodextrin-modified capillary zone electrophoresis using sulfated cyclodextrins as chiral selectors

“…6 and 8, the effective electrophoretic mobility of the enantiomer of promethazine (designated as 1a) varies only to a small extent, while the electrophoretic mobility of the other enantiomer (designated as 1b) decreases to a slightly greater extent when increasing the concentration of b-CD or g-CD. According to the findings of previous studies [35,55], the binding constant and limiting mobility of the (1)-enantiomer are greater than those of the (2)-enantiomer and the interactions of phenothiazines to g-CD in a buffer electrolyte should not be too strong to observe the phenomena of migration reversal in a suitable concentration range of g-CD. Therefore, it seems reasonable to assign the enantiomers designated as 1a and 1b to the (2)-and (1)-enantiomers, respectively.…”

“…Enantioseparations of seven chiral phenothiazines in CZE using various native CDs and some of neutral and charged CD derivatives as chiral selectors in 100 mM triethanolamine phosphate buffer at pH 3.0 were investigated [44]. The migration order of the enantiomers of promethazine was (2)-promethazine before (1)-promethazine in the presence of a-, b-, g-CD and heptakis-(6-sulfato)-b-CD, while the migration reversal of the enantiomers occurred in the presence of heptakis-(2, 3, 6-tri-O-methlyl)-b-CD (TM-b-CD) and heptakis-(2, 3-diacetyl-6-sulfato)-b-CD (HDASb-CD) [35]. The enantioselective binding constants between the enantiomers of promethazine and b-CD were also determined.…”

“…The enantioselective binding constants between the enantiomers of promethazine and b-CD were also determined. (1)-Promethazine was found to have a greater binding strength than (2)-promethazine with b-CD [35]. The enantiomers of trimeprazine were effectively separated with addition of hydroxypropyl-b-CD (HP-b-CD) in a phosphate buffer at pH 2.5 [49].…”

“…Phenothiazines, and the enantiomers as well, have previously been separated by CE [35,[44][45][46][47][48][49][50][51][52][53][54][55], mostly by CZE [44-52, 54, 55]. Several articles have appeared in the literature regarding the applications of the CE technique to the enantioseparation of phenothiazines using CDs as chiral selectors [35,44,49,50,[52][53][54][55]. Enantioseparations of seven chiral phenothiazines in CZE using various native CDs and some of neutral and charged CD derivatives as chiral selectors in 100 mM triethanolamine phosphate buffer at pH 3.0 were investigated [44].…”

Enantioseparation of phenothiazines in CD‐modified CZE using single isomer sulfated CD as a chiral selector

“…Phenothiazines and the enantiomers as well have previously been separated by CE [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58], mostly by CZE [41,[43][44][45][46][47][48][49][50][52][53][54][55][56][57]. The applications of the CE technique to the enantioseparations of phenothiazines using CDs as chiral selectors have been reported [41,42,47,48,[50][51][52][53][54]. (1)-Promethazine was found to have a greater binding strength than (2)-promethazine with b-CD [42].…”