Enantioseparation of phenothiazines in cyclodextrin-modified capillary zone electrophoresis using sulfated cyclodextrins as chiral selectors.
In this study, enantioseparations of five phenothiazines, including promethazine, ethopropazine, trimeprazine, methotrimeprazine, and thioridazine, in CD-modified CZE using dual CD systems consisting of randomly sulfate-substituted CD (MI-S-beta-CD) and a neutral CD as chiral selectors in a citrate buffer (100 mM) at pH 3.0 were investigated. The results indicate that MI-S-beta-CD is an excellent chiral selector for enantioseparation of ethopropazine. The enantiomers of promethazine can also be baseline-resolved with MI-S-beta-CD at concentrations in the range of 0.5-1.0% w/v. On the other hand, thioridazine and trimeprazine interact strongly with neutral CDs. As a result, the enantioselectivity of these two phenothiazines is remarkably and synergistically enhanced with increasing the concentration of neutral CDs in the presence of MI-S-beta-CD and simultaneous enantioseparations of these phenothiazines, except for methotrimeprazine, could favorably be achieved with the use of dual CD systems. Moreover, by varying the concentration of beta-CD or gamma-CD at a fixed concentration of MI-S-beta-CD (0.75% w/v) reversal of the enantiomer migration order of promethazine occurred. This may be attributable to the opposite effects of charged and neutral CDs on the mobility of the enantiomers of promethazine.
Lin
Ching-Erh
CE
Department of Chemistry, National Taiwan University, Taipei, Taiwan. celin@ntu.edu.tw
Liao
Wei-Ssu
WS
Cheng
Hsu-Tun
HT
Kuo
Chia-Ming
CM
Liu
Yu-Chih
YC
D003505:Cyclodextrins; D019075:Electrophoresis, Capillary / Q000379:methods*; D010640:Phenothiazines / Q000302:isolation & purification*; D013237:Stereoisomerism; D013431:Sulfates
D003505:Cyclodextrins; D010640:Phenothiazines; D013431:Sulfates