Chiral separation of basic drugs by capillary zone electrophoresis with cyclodextrin additives

Abstract

The enantiomers of a series of basic drugs were separated in capillary zone electrophoresis (CZE) in phosphate buffers, pH 3, containing beta-cyclodextrin or one of its derivatives as chiral selectors and uncoated fused silica capillaries thermostated at 15 degrees C. The nature of the cationic component of the background electrolyte was found to have a significant influence on achiral resolution and peak symmetry. The best results were obtained with triethanolamine, which was then used to adjust the buffer pH in all further experiments. The effects on chiral resolution of the nature and concentration of cyclodextrin, of the addition of methanol, and of capillary temperature were studied. Maximum resolution was obtained at a particular cyclodextrin concentration for each analyte, depending on the affinity of the analyte for this cyclodextrin. On the basis of the results, the effects of methanol addition and temperature on enantiomeric resolution could be explained and predicted. Numerous chiral separations are presented and suggestions for the rapid optimization of CZE enantioseparations with cyclodextrin additives are given.

Chiral recognition of verapamil by cyclodextrins studied with capillary electrophoresis, NMR spectroscopy, and electrospray ionization mass spectrometry

“…24 The enantioseparation of (±)-VP with native CDs was impossible in most of buffer systems used. 20,30 However, Bechet et al 21 achieved a partial enantioseparation of (±)-VP in a phosphoric acid-triethanolamine buffer at pH 3.0 in the presence of native ␤-CD. Our preliminary experiment confirmed the advantage of this buffer compared to sodium dihydrogenphosphate for the enantioseparation of (±)-VP (Fig.…”

“…[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] However, the migration order of the enantiomers is addressed only in few of them. Ohara et al 23 determined the migration order with TM-␤-CD to be R-(+)-before S-(−)-VP.…”

Enantiomeric Separations in Capillary Electrophoresis Using 18-Crown-6-tetracarboxylic Acid (18C6H4) as Buffer Additive

“…Characterization of the synthesized 18C6H 4 was, in the first instance, performed by 1 H-NMR and The enantioselectivity of the synthesized 18C6H 4 was tested by comparing the selectivity for some amino acid test solutes obtained on a remainder of the commercial product (Fluka). The selectivities for phenylalanine, tryptophan, and tyrosine were on both crown ethers 1.04, 1.03, and 1.04, respectively.…”

“…The synthesis of 18C6H 4 , described by Lehn and co-workers [45], starts from (R,R)-(+)-tartaric acid and is based on a modified Williamson synthesis of ethers. This is a simple S N 2 reaction of a primary alkyl halide or a sulfonate ester in which an alkoxide ion is the nucleophile [57].…”

Separation of etodolac enantiomers by capillary electrophoresis. Validation and application of the chiral method to the analysis of commercial formulations

“…For this reason, we studied the effect of the concentration of this CD from three different commercial suppliers on the resolution of etodolac enantiomers. This study was performed because the concentration of the chiral selector affects directly the chiral properties [21,24]. As can be seen in Fig.…”