Mechanistic study on the opposite migration order of clenbuterol enantiomers in capillary electrophoresis with β-cyclodextrin and single-isomer heptakis(2,3-diacetyl-6-sulfo)-β-cyclodextrin

Chankvetadze, Bezhan; Lomsadze, Ketevan; Bergenthal, Dieter; Breitkreutz, Jörg; Bergander, Klaus; Blaschke, Gottfried

doi:10.1002/1522-2683(200109)22:15<3178::aid-elps3178>3.0.co;2-f

Cited by 42 publications

(27 citation statements)

References 47 publications

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“…There are different ways to change the enantiomeric migration order by CE when CDs are used as chiral selectors [4,[10][11][12][13]: (i) modifying the CD cavity size [14]; (ii) changing the nature of CD substituents [15,16]; (iii) varying the location of substituents on the CD rim [17]; (iv) employing charged CDs in the BGE and changing the polarity of the applied voltage [18,19]; (v) modifying the pH of the BGE [18,20]; (vi) changing the EOF, i.e., eliminating or reversing it [19,20]; (vii) using achiral additives (i.e., micelles or ligandexchange compounds as metals) in chiral systems [21,22], and finally, (viii) varying the concentration of the CD in the separation buffer. However, this last phenomenon has scarcely been observed.…”

Section: Introductionmentioning

confidence: 77%

Enantioselective separation of azole compounds by EKC. Reversal of migration order of enantiomers with CD concentration

Castro‐Puyana¹,

Crego²,

Marina³

et al. 2007

Electrophoresis

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The enantioselective separation of a group of six weak base azole compounds was achieved in this work using EKC with three neutral b-CDs as chiral selectors. The native b-CD and two other b-CD derivatives with different types and positions of the substituents on the CD rim ((2-hydroxy)propyl-b-CD (HP-b-CD) and heptakis-2,3,6-tri-O-methyl-b-CD (TM-b-CD)) were employed. Apparent binding constants for each pair compound-CD were determined in order to study analyte-CD interactions. The best enantiomeric resolutions for miconazole, econazole, and sulconazole were observed with HP-b-CD whereas for the separation of the enantiomers of ketoconazole, terconazole, and bifonazole, TM-b-CD was the best chiral selector. The enantioseparations obtained were discussed on the basis of the structure of the compounds taking into account that inclusion into the hydrophobic CD cavity occurred through the phenyl ring closer to the azole group. In addition, a change in the migration order for the enantiomers of two of the compounds studied (ketoconazole and terconazole) with the concentration of HP-b-CD was observed for the first time.

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Section: Introductionmentioning

confidence: 77%

Enantioselective separation of azole compounds by EKC. Reversal of migration order of enantiomers with CD concentration

Castro‐Puyana¹,

Crego²,

Marina³

et al. 2007

Electrophoresis

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“…A method development and validation with a well-characterized, singlecomponent chiral selector is much easier and reliable. Recent studies with single-isomer sulfates of b-CD revealed that they may offer alternative chiral recognition mechanisms compared to native b-CD [16][17][18]. Thus, the enantiomer affinity pattern of chiral drugs clenbuterol (CL) [16], warfarin [17] and promethazine (PMZ) [18] was opposite to native b-CD and heptakis-(2,3-diacetyl-6-sulfo)-b-CD (HDAS-b-CD).…”

Section: Introductionmentioning

confidence: 99%

Comparative enantioseparations with native β-cyclodextrin and heptakis-(2-O-methyl- 3,6-di-O-sulfo)-β-cyclodextrin in capillary electrophoresis

et al. 2002

Self Cite

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Twenty-three cationic chiral analytes were resolved in capillary electrophoresis using native beta-cyclodextrin and single isomer heptakis-(2-O-methyl-3,6-di-O-sulfo)-beta-cyclodextrin as chiral selectors. For 12 of 16 chiral analytes resolved with both chiral selectors the enantiomer migration order was opposite. In selected cases the structure of cyclodextrin-analyte complexes in aqueous solution was investigated using one-dimensional transverse rotating frame nuclear Overhauser and exchange spectroscopy. It was found that in contrast to mainly inclusion-type complexes between chiral analytes and beta-cyclodextrin, external complexes are formed between the chiral analytes and structurally crowded, highly charged heptakis-(2-O-methyl-3,6-di-O-sulfo)-beta-cyclodextrin.

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“…Opposite migration order between b-CD and HS-b-CD on one hand and HDAS-b-CD on the other hand has also been observed for alanine b-naphthylamide [9] and a number on nonpeptide analytes [22][23][24].…”

Section: Ce Enantioseparationsmentioning

confidence: 75%

Studies on the chiral recognition of peptide enantiomers by neutral and sulfated β-cyclodextrin and heptakis-(2,3-di-O-acetyl)-β-cyclodextrin using capillary electrophoresis and nuclear magnetic resonance

Süß¹,

Kahle

Holzgrabe

et al. 2002

Electrophoresis

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The separation of dipeptide and tripeptide enantiomers using a neutral single isomer cyclodextrin (CD) derivative, heptakis-(2,3-di-O-acetyl)-beta-CD (DIAC-beta-CD), was investigated with respect to the amino acid sequence applying standard separation conditions. With only one exception the DD-enantiomers migrated faster than the LL-stereoisomers. Separations obtained for the same set of peptides using beta-CD and the sulfated single isomer derivatives heptakis-(2,3-di-O-acetyl-6-sulfo)-beta-CD (HDAS-beta-CD) and heptakis-6-sulfo-beta-CD (HS-beta-CD) revealed identical enantiomer migration order in the presence of the 2,3-disubstituted derivatives DIAC-beta-CD and HDAS-beta-CD. In contrast, reversed migration sequence was found for beta-CD and HS-beta-CD compared to DIAC-beta CD and HDAS-beta-CD indicating the importance of the substitution pattern on the wider rim of the CD cavity on the chiral recognition of the peptide enantiomers by the CDs. Nuclear magnetic resonance (NMR) experiments indicated different complexation modes between the enantiomers and the CDs depending on the presence of acetyl substituents on the wider rim of the CD torus. Thus, the CD-induced chemical shifts observed in samples containing Ala-Phe or Ala-Tyr and beta-CD or HS-beta-CD were consistent with an inclusion of the aromatic moiety into the CD cavity. Although the CD-induced chemical shifts in the presence of DIAC-beta-CD and HDAS-beta-CD did not allow direct conclusions on the complexation mode they substantially differed from those observed in the presence of 2,3-unsubstituted CDs indicating different structures of the peptide-CD complexes.

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Mechanistic study on the opposite migration order of clenbuterol enantiomers in capillary electrophoresis with β-cyclodextrin and single-isomer heptakis(2,3-diacetyl-6-sulfo)-β-cyclodextrin

Cited by 42 publications

References 47 publications

Enantioselective separation of azole compounds by EKC. Reversal of migration order of enantiomers with CD concentration

Enantioselective separation of azole compounds by EKC. Reversal of migration order of enantiomers with CD concentration

Comparative enantioseparations with native β-cyclodextrin and heptakis-(2-O-methyl- 3,6-di-O-sulfo)-β-cyclodextrin in capillary electrophoresis

Studies on the chiral recognition of peptide enantiomers by neutral and sulfated β-cyclodextrin and heptakis-(2,3-di-O-acetyl)-β-cyclodextrin using capillary electrophoresis and nuclear magnetic resonance

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