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Peluso P, Chankvetadze B. Recognition in the Domain of Molecular Chirality: From Noncovalent Interactions to Separation of Enantiomers. Chem Rev 2022; 122:13235-13400. [PMID: 35917234 DOI: 10.1021/acs.chemrev.1c00846] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
It is not a coincidence that both chirality and noncovalent interactions are ubiquitous in nature and synthetic molecular systems. Noncovalent interactivity between chiral molecules underlies enantioselective recognition as a fundamental phenomenon regulating life and human activities. Thus, noncovalent interactions represent the narrative thread of a fascinating story which goes across several disciplines of medical, chemical, physical, biological, and other natural sciences. This review has been conceived with the awareness that a modern attitude toward molecular chirality and its consequences needs to be founded on multidisciplinary approaches to disclose the molecular basis of essential enantioselective phenomena in the domain of chemical, physical, and life sciences. With the primary aim of discussing this topic in an integrated way, a comprehensive pool of rational and systematic multidisciplinary information is provided, which concerns the fundamentals of chirality, a description of noncovalent interactions, and their implications in enantioselective processes occurring in different contexts. A specific focus is devoted to enantioselection in chromatography and electromigration techniques because of their unique feature as "multistep" processes. A second motivation for writing this review is to make a clear statement about the state of the art, the tools we have at our disposal, and what is still missing to fully understand the mechanisms underlying enantioselective recognition.
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Affiliation(s)
- Paola Peluso
- Istituto di Chimica Biomolecolare ICB, CNR, Sede secondaria di Sassari, Traversa La Crucca 3, Regione Baldinca, Li Punti, I-07100 Sassari, Italy
| | - Bezhan Chankvetadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Avenue 3, 0179 Tbilisi, Georgia
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2
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Peluso P, Chankvetadze B. Native and substituted cyclodextrins as chiral selectors for capillary electrophoresis enantioseparations: Structures, features, application, and molecular modeling. Electrophoresis 2021; 42:1676-1708. [PMID: 33956995 DOI: 10.1002/elps.202100053] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 02/06/2023]
Abstract
CDs are cyclic oligosaccharides consisting of α-d-glucopyranosyl units linked through 1,4-linkages, which are obtained from enzymatic degradation of starch. The coexistence of hydrophilic and hydrophobic regions in the same structure makes these macrocycles extremely versatile as complexing host with application in food, cosmetics, environmental, agriculture, textile, pharmaceutical, and chemical industries. Due to their inherent chirality, CDs have been also successfully used as chiral selectors in enantioseparation science, in particular, for CE enantioseparations. In the last decades, multidisciplinary approaches based on CE, NMR spectroscopy, X-ray crystallography, microcalorimetry, and molecular modeling have shed light on some aspects of recognition mechanisms underlying enantiodiscrimination. With the ever growing improvement of computer facilities, hardware and software, computational techniques have become a useful tool to model at molecular level the dynamics of diastereomeric associate formation to sample low-energy conformations, the binding energies between the enantiomer and the CD, and to profile noncovalent interactions contributing to the stability of CD/enantiomer association. On this basis, the aim of this review is to provide the reader with a critical overview on the applications of CDs in CE. In particular, the contemporary theory of the electrophoretic technique and the main structural features of CDs are described, with a specific focus on techniques, methods, and approaches to model CE enantioseparations promoted by native and substituted CDs. A systematic compilation of all published literature has not been attempted.
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Affiliation(s)
- Paola Peluso
- Istituto di Chimica Biomolecolare ICB, CNR, Sede secondaria di Sassari, Traversa La Crucca 3, Li Punti, Sassari, Italy
| | - Bezhan Chankvetadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Tbilisi, Georgia
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3
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Gogolashvili A, Lomsadze K, Chankvetadze L, Takaishvili N, Peluso P, Dallocchio R, Salgado A, Chankvetadze B. Separation of tetrahydrozoline enantiomers in capillary electrophoresis with cyclodextrin-type chiral selectors and investigation of chiral recognition mechanisms. J Chromatogr A 2021; 1643:462084. [PMID: 33789195 DOI: 10.1016/j.chroma.2021.462084] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/16/2021] [Accepted: 03/19/2021] [Indexed: 12/13/2022]
Abstract
The recognition power and affinity pattern of various cyclodextrins (CD) towards the enantiomers of tetrahydrozoline (THZ) were studied using capillary electrophoresis (CE). As expected, affinity of THZ enantiomers and selectivity of recognition towards CD derivatives was strongly dependent on the cavity size and substituent type and pattern on the CD rims. Not only were the affinity strength and selectivity of recognition affected by the size of the cavity and chemistry of the CDs but also the affinity pattern. Another interesting example of opposite affinity pattern of enantiomers towards α- and β-CD was observed here. In addition, opposite affinity pattern of THZ enantiomers was seen towards β-CD and its acetylated derivatives, while methylation of β-CD did not affect the affinity pattern of THZ enantiomers. In order to get more information about structural mechanisms of the multivariate dependences mentioned above, rotating frame Overhauser enhancement spectroscopy (ROESY) and computation techniques were used. Significant differences between the structure of THZ complexes with different CDs with both methods were encountered. Good correlations between experimentally determined and computed structure of complexes, as well as between computed complex stabilities and enantiomer migration order (EMO) in CE were observed.
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Affiliation(s)
- Ann Gogolashvili
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Ave 3, Tbilisi 0179, Georgia
| | - Ketevan Lomsadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Ave 3, Tbilisi 0179, Georgia; School of Science and Technology, The University of Georgia, 77a, M. Kostava Str., Tbilisi 0171, Georgia
| | - Lali Chankvetadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Ave 3, Tbilisi 0179, Georgia
| | - Nino Takaishvili
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Ave 3, Tbilisi 0179, Georgia
| | - Paola Peluso
- Istituto di Chimica Biomolecolare ICB-CNR, Sede secondary a di Sassari, Traversa La Crucca 3, Regione Baldinca, Sassari, Li Punti 07100, Italy
| | - Roberto Dallocchio
- Istituto di Chimica Biomolecolare ICB-CNR, Sede secondary a di Sassari, Traversa La Crucca 3, Regione Baldinca, Sassari, Li Punti 07100, Italy
| | - Antonio Salgado
- NMR Spectroscopy Centre (CERMN), CAI Químicas, Faculty of Pharmacy, University of Alcalá, Alcalá de Henares, Madrid E-28805, Spain
| | - Bezhan Chankvetadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Ave 3, Tbilisi 0179, Georgia.
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Kundu M, Rahaman H, Roy MN. Physicochemical investigations on non-covalent interactions between Padimate O and cyclodextrin receptors in both solution and solid states. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 218:9-14. [PMID: 30954802 DOI: 10.1016/j.saa.2019.03.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 02/23/2019] [Accepted: 03/18/2019] [Indexed: 06/09/2023]
Abstract
Ultraviolet B (UV-B) radiation is very harmful to human body. It can cause serious health problem mainly skin cancer, sunburn and photo-aging. Padimate O (PMO) is a sunscreen agent. The aim of this work is to form inclusion complexes with α-cyd and β-cyd in both aqueous environment and solid state that established by UV-Vis, FTIR spectroscopy, mass spectra, powder X-ray diffraction pattern and as α-cyd and β-cyd are known to us as good drug vehicles, hence, the experimental results suggest that they can be used as good sunscreen agent carrier and photostabilizer additive for increasing the photostability and other properties of PMO. In solution phase, UV-Vis spectroscopy demonstrated that the entire process of formation of complexes is observed with 1:1 stoichiometry which is further justified by mass spectra. Thermodynamic parameters support the whole process in both cases and it is revealed that β-cyd forms more firmly inclusion complex than α-cyd with PMO. Successful formation of solid inclusion complexes is supported by FTIR spectroscopy and powder-XRD. The enhancement of the thermal stability of the α-cyd/PMO and β-cyd/PMO complexes is demonstrated by TGA study.
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Affiliation(s)
- Mitali Kundu
- Department of Chemistry, University of North Bengal, Darjeeling 734013, India
| | - Habibur Rahaman
- Department of Chemistry, University of North Bengal, Darjeeling 734013, India
| | - Mahendra Nath Roy
- Department of Chemistry, University of North Bengal, Darjeeling 734013, India.
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Chankvetadze B. Contemporary theory of enantioseparations in capillary electrophoresis. J Chromatogr A 2018; 1567:2-25. [PMID: 30025609 DOI: 10.1016/j.chroma.2018.07.041] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 07/05/2018] [Accepted: 07/12/2018] [Indexed: 11/17/2022]
Abstract
The first separation of enantiomers in capillary electrophoresis (CE) counts slightly longer than three decades. Fast development of the practice and theory of chiral CE occurred in the past 30 years and today one can consider this technology to have a solid and mature theoretical background. The goal of the present review is not only to summarize the history and contemporary theory of enantioseparations by using CE but also to present the authors personal view where shall we head to with this attractive technology not only from the viewpoint of separation of enantiomers but also for better understanding the mechanisms of non-covalent (enantioselective) interactions in chemistry, biology, medicine and related disciplines.
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Affiliation(s)
- Bezhan Chankvetadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Ave 1, 0179 Tbilisi, Georgia.
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Yao Y, Zhou L, Li M, Guo X. The cation-selective exhaustive injection and sweeping capillary electrophoresis method for the analysis of chlorpheniramine enantiomers in rat plasma. J Pharm Biomed Anal 2018; 148:142-148. [DOI: 10.1016/j.jpba.2017.09.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 09/11/2017] [Accepted: 09/15/2017] [Indexed: 02/07/2023]
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7
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Puentes CM, Wenzel TJ. Phosphated cyclodextrins as water-soluble chiral NMR solvating agents for cationic compounds. Beilstein J Org Chem 2017; 13:43-53. [PMID: 28179947 PMCID: PMC5238554 DOI: 10.3762/bjoc.13.6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 12/22/2016] [Indexed: 11/27/2022] Open
Abstract
The utility of phosphated α-, β- and γ-cyclodextrins as water-soluble chiral NMR solvating agents for cationic substrates is described. Two sets of phosphated cyclodextrins, one with degrees of substitution in the 2–6 range, the other with degrees of substitution in the 6–10 range, are examined. Results with 33 water-soluble cationic substrates are reported. We also explored the possibility that the addition of paramagnetic lanthanide ions such as praseodymium(III) and ytterbium(III) further enhances the enantiomeric differentiation in the NMR spectra. The chiral differentiation with the phosphated cyclodextrins is compared to prior results obtained with anionic carboxymethylated cyclodextrins. There are a number of examples where a larger differentiation is observed with the phosphated cyclodextrins.
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Affiliation(s)
| | - Thomas J Wenzel
- Department of Chemistry, Bates College, Lewiston, Maine 04240 USA
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Salgado A, Chankvetadze B. Applications of nuclear magnetic resonance spectroscopy for the understanding of enantiomer separation mechanisms in capillary electrophoresis. J Chromatogr A 2016; 1467:95-144. [PMID: 27604161 DOI: 10.1016/j.chroma.2016.08.060] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 08/23/2016] [Accepted: 08/25/2016] [Indexed: 10/21/2022]
Abstract
This review deals with the applications of nuclear magnetic resonance (NMR) spectroscopy to understand the mechanisms of chiral separation in capillary electrophoresis (CE). It is accepted that changes observed in the separation process, including the reversal of enantiomer migration order (EMO), can be caused by subtle modifications in the molecular recognition mechanisms between enantiomer and chiral selector. These modifications may imply minor structural differences in those selector-selectand complexes that arise from the above mentioned interactions. Therefore, it is mandatory to understand the fine intermolecular interactions between analytes and chiral selectors. In other words, it is necessary to know in detail the structures of the complexes formed by the enantiomer (selectand) and the selector. Any differences in the structures of these complexes arising from either enantiomer should be detected, so that enantiomeric bias in the separation process could be explained. As to the nature of these interactions, those have been extensively reviewed, and it is not intended to be discussed here. These interactions contemplate ionic, ion-dipole and dipole-dipole interactions, hydrogen bonding, van der Waals forces, π-π stacking, steric and hydrophobic interactions. The main subject of this review is to describe how NMR spectroscopy helps to gain insight into the non-covalent intermolecular interactions between selector and selectand that lead to enantiomer separation by CE. Examples in which diastereomeric species are created by covalent (irreversible) derivatization will not be considered here. This review is structured upon the different structural classes of chiral selectors employed in CE, in which NMR spectroscopy has made substantial contributions to rationalize the observed enantioseparations. Cases in which other techniques complement NMR spectroscopic data are also mentioned.
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Affiliation(s)
- Antonio Salgado
- Centro de Espectroscopía de RMN (CERMN), Faculty of Pharmacy, University of Alcalá, University Campus, 28805 Alcalá de Henares, Madrid, Spain.
| | - Bezhan Chankvetadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Ave 3, 0179 Tbilisi, Georgia
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Li X, Li Y, Zhao L, Shen J, Zhang Y, Bao JJ. Velocity gap mode of capillary electrophoresis developed for high-resolution chiral separations. Electrophoresis 2014; 35:2778-84. [DOI: 10.1002/elps.201400081] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 05/19/2014] [Accepted: 05/19/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Xue Li
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency; School of Pharmaceutical Science and Technology, Tianjin University; Tianjin P. R. China
| | - Youxin Li
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency; School of Pharmaceutical Science and Technology, Tianjin University; Tianjin P. R. China
| | - Lumeng Zhao
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency; School of Pharmaceutical Science and Technology, Tianjin University; Tianjin P. R. China
| | - Jianguo Shen
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency; School of Pharmaceutical Science and Technology, Tianjin University; Tianjin P. R. China
| | - Yong Zhang
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency; School of Pharmaceutical Science and Technology, Tianjin University; Tianjin P. R. China
| | - James J. Bao
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency; School of Pharmaceutical Science and Technology, Tianjin University; Tianjin P. R. China
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Sánchez-López E, Salgado A, Crego AL, Marina ML. Investigation on the enantioseparation of duloxetine by capillary electrophoresis, NMR, and mass spectrometry. Electrophoresis 2014; 35:2842-7. [DOI: 10.1002/elps.201300656] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 03/12/2014] [Accepted: 03/18/2014] [Indexed: 11/07/2022]
Affiliation(s)
- Elena Sánchez-López
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Faculty of Biology; Environmental Sciences and Chemistry, University of Alcalá; Madrid Spain
| | - Antonio Salgado
- Center of Applied Chemistry and Biotechnology (CQAB); University of Alcalá; Madrid Spain
| | - Antonio L. Crego
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Faculty of Biology; Environmental Sciences and Chemistry, University of Alcalá; Madrid Spain
| | - María Luisa Marina
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Faculty of Biology; Environmental Sciences and Chemistry, University of Alcalá; Madrid Spain
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11
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Lomsadze K, Vega ED, Salgado A, Crego AL, Scriba GK, Marina ML, Chankvetadze B. Separation of enantiomers of norephedrine by capillary electrophoresis using cyclodextrins as chiral selectors: Comparative CE and NMR studies. Electrophoresis 2012; 33:1637-47. [DOI: 10.1002/elps.201200062] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ketevan Lomsadze
- Institute of Physical and Analytical Chemistry; School of Exact and Natural Sciences; Tbilisi State University; Tbilisi; Georgia
| | - Elena Domínguez Vega
- Department of Analytical Chemistry; Faculty of Chemistry; University of Alcalá; Madrid; Spain
| | - Antonio Salgado
- Department of Medicinal Chemistry; Centro Nacional de Investigaciones Oncológicas (CNIO); Madrid; Spain
| | - Antonio L. Crego
- Department of Analytical Chemistry; Faculty of Chemistry; University of Alcalá; Madrid; Spain
| | - Gerhard K.E. Scriba
- Department of Pharmaceutical Chemistry; Friedrich-Schiller-University Jena; Jena; Germany
| | - Maria Luisa Marina
- Department of Analytical Chemistry; Faculty of Chemistry; University of Alcalá; Madrid; Spain
| | - Bezhan Chankvetadze
- Institute of Physical and Analytical Chemistry; School of Exact and Natural Sciences; Tbilisi State University; Tbilisi; Georgia
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12
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Vega ED, Lomsadze K, Chankvetadze L, Salgado A, Scriba GKE, Calvo E, López JA, Crego AL, Marina ML, Chankvetadze B. Separation of enantiomers of ephedrine by capillary electrophoresis using cyclodextrins as chiral selectors: Comparative CE, NMR and high resolution MS studies. Electrophoresis 2011; 32:2640-7. [DOI: 10.1002/elps.201100015] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 03/04/2011] [Accepted: 03/05/2011] [Indexed: 11/11/2022]
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13
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Sohajda T, Varga E, Iványi R, Fejős I, Szente L, Noszál B, Béni S. Separation of vinca alkaloid enantiomers by capillary electrophoresis applying cyclodextrin derivatives and characterization of cyclodextrin complexes by nuclear magnetic resonance spectroscopy. J Pharm Biomed Anal 2010; 53:1258-66. [DOI: 10.1016/j.jpba.2010.07.032] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 07/19/2010] [Accepted: 07/21/2010] [Indexed: 10/19/2022]
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Phatthiyaphaibun K, Som-Aum W, Srisa-ard M, Threeprom J. Chiral separation of pheniramine by capillary electrophoresis partial-filling technique using hydroxypropyl-β-cyclodextrin as chiral selector. JOURNAL OF ANALYTICAL CHEMISTRY 2010. [DOI: 10.1134/s106193481008006x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Servais AC, Rousseau A, Fillet M, Lomsadze K, Salgado A, Crommen J, Chankvetadze B. Capillary electrophoretic and nuclear magnetic resonance studies on the opposite affinity pattern of propranolol enantiomers towards various cyclodextrins. J Sep Sci 2010; 33:1617-24. [DOI: 10.1002/jssc.201000040] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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16
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Wang LF. Halogenation effects of pheniramines on the complexation with β-cyclodextrin. J Pharm Biomed Anal 2009; 50:392-6. [DOI: 10.1016/j.jpba.2009.05.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Revised: 05/13/2009] [Accepted: 05/22/2009] [Indexed: 11/26/2022]
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17
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Krajian H, Mofaddel N, Villemin D, Desbène PL. A new example of reversal of the order of migration of enantiomers, as a function of cyclodextrin concentration and pH, by cyclodextrin-modified capillary zone electrophoresis: enantioseparation of 6,6′-dibromo-1,1′-binaphthyl-2,2′-diol. Anal Bioanal Chem 2009; 394:2193-201. [DOI: 10.1007/s00216-009-2925-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Revised: 06/16/2009] [Accepted: 06/18/2009] [Indexed: 11/24/2022]
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Hazekamp A, Verpoorte R. Structure elucidation of the tetrahydrocannabinol complex with randomly methylated beta-cyclodextrin. Eur J Pharm Sci 2006; 29:340-7. [PMID: 16934442 DOI: 10.1016/j.ejps.2006.07.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Revised: 06/28/2006] [Accepted: 07/02/2006] [Indexed: 11/19/2022]
Abstract
The low aqueous solubility of the bioactive cannabinoid tetrahydrocannabinol (THC) is a serious obstacle for the development of more efficient administration forms. In this study the aqueous solubility of THC was tested in the presence of alpha-, beta- and gamma-CD, and randomly methylated beta-CD (RAMEB). It was found that only RAMEB was able to increase the aqueous solubility of THC to a significant level. A THC concentration of about 14 mg/ml was reached by using a 24% (187 mM) RAMEB solution, which means an increase in solubility of four orders of magnitude. The resulting THC/RAMEB complex was investigated through phase-solubility analysis, complemented by (1)H NMR, NOESY- and UV-studies in order to obtain details on the stoichiometry, geometry and thermodynamics of the complexation. The binding ratio of THC to CD was found to be 2:1, with the second THC molecule bound by non-inclusion interactions. Based on the obtained results a model for the complex structure is presented. Stability of the complex under laboratory room conditions was tested up to 8 weeks. Results show that complexation with RAMEB seems to be promising for the development of water-based THC formulations.
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Affiliation(s)
- Arno Hazekamp
- Department of Pharmacognosy, Leiden University, Institute of Biology, Leiden, The Netherlands.
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19
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Danel C, Azaroual N, Foulon C, Goossens JF, Vermeersch G, Bonte JP, Vaccher C. NMR studies of chiral recognition mechanisms: interaction of enantiomers of N-imidazole derivatives with cyclodextrin hosts. Correlation with the CD-EKC studies. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.tetasy.2006.03.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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20
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Lin CE, Lin SL, Liao WS, Liu YC. Enantioseparation of benzoins and enantiomer migration reversal of hydrobenzoin in capillary zone electrophoresis with dual cyclodextrin systems and borate complexation. J Chromatogr A 2004; 1032:227-35. [PMID: 15065800 DOI: 10.1016/j.chroma.2004.01.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Enantioseparations of racemic hydrobenzoin and structurally related compounds, including benzoin and benzoin methyl ether, in capillary zone electrophoresis (CZE) with dual cyclodextrin (CD) systems consisting of S-beta-CD (mixed isomers) and a neutral CD, including beta-CD and hydroxypropyl-beta-CD (HP-beta-CD), as chiral selectors in the presence of borate complexation at pH 9.0 were investigated. Effective enantioseparations of hydrobenzoin were achieved with addition of dual CD systems and also with neutral CDs in a borate buffer. The enantioseparation and migration behavior of hydrobenzoin in such an electrophoretic system are primarily governed by the interaction of the borate complex of hydrobenzoin with beta-CDs. The CD complexations of both hydrobenzoin and the borate complexes of hydrobenzoin with beta-CDs increase in the order S-beta-CD < HP-beta-CD < beta-CD. As a result, enantioseparations of hydrobenzoin with the use of dual CD systems consisting of S-beta-CD/beta-CD and S-beta-CD/HP-beta-CD as chiral selectors are more advantageous than that with the use of S-beta-CD alone. With these dual CD systems in the presence of borate complexation, the enantiomer migration reversal was observed for hydrobenzoin. The interactions of hydrobenzoin with neutral CDs and with S-beta-CD exhibit the same chiral recognition pattern, but opposite effect on the mobility of the enantiomers. The (S,S)-enantiomer of hydrobenzoin was found to interact more strongly than the (R,R)-enantiomer with neutral CDs. For comparison, enantioseparation of hydrobenzoin, together with benzoin and benzoin methyl ether, with dual CD systems in a phosphate background electrolyte at pH 9.0 was also examined. The migration order and enantioselectivity of these three benzoins depend on the degree of CD complexations between benzoins and both S-beta-CD and neutral CD in a phosphate background electrolyte. In addition, effective enantioseparations of hydrobenzoin were also achievable with addition of either beta-CD at concentrations greater than 1.0 mM or HP-beta-CD at concentrations exceeding 2.0 mM in a borate buffer at pH 9.0.
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Affiliation(s)
- Ching-Erh Lin
- Department of Chemistry, National Taiwan University, 1 Roosevelt Road Section 4, Taipei 10674, Taiwan.
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21
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Mikus P, Valásková I, Havránek E. Chiral separation of dioxopromethazine in eye drops by CZE with charged cyclodextrin. J Pharm Biomed Anal 2003; 33:157-64. [PMID: 12972080 DOI: 10.1016/s0731-7085(03)00254-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Capillary zone electrophoresis (CZE) with carboxyethyl-beta-cyclodextrin (CE-beta-CD) dissolved in the operating buffer was used for the separation and determination of enantiomers of phenothiazine antihistaminic, dioxopromethazine, in commercial pharmaceutical preparation, eye drops. This chiral selector, negatively charged under given separating conditions (20 mmol/l epsilon -aminocaproic acid, acetic acid, pH 4.5), was effective in enantioresolution of the antihistamine even at its low concentrations (3-6 mg/ml) in the buffer solution. CZE identification and quantitation of the relevant constituents present in the preparation (dioxopromethazine enantiomers, phenylephrine) were based on the response of photometric absorbency detector, operating at a 275 nm detection wavelength. Changes in pH, type and concentration of chiral selector were studied in relation to chiral resolution. Acceptable validation criteria for sensitivity, precision, linearity and repeatability are included.
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Affiliation(s)
- Peter Mikus
- Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy, Comenius University, Odbojárov 10, SK-832 32 Bratislava, Slovakia.
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22
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Chankvetadze B, Burjanadze N, Breitkreutz J, Bergander K, Bergenthal D, Kataeva O, Fröhlich R, Luftmann H, Blaschke G. Mechanistic study on the opposite migration order of the enantiomers of ketamine with α- and β-cyclodextrin in capillary electrophoresis. J Sep Sci 2002. [DOI: 10.1002/1615-9314(20021101)25:15/17%3c1155::aid-jssc1155%3e3.0.co;2-m] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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23
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Chankvetadze B, Burjanadze N, Breitkreutz J, Bergander K, Bergenthal D, Kataeva O, Fröhlich R, Luftmann H, Blaschke G. Mechanistic study on the opposite migration order of the enantiomers of ketamine with α- and β-cyclodextrin in capillary electrophoresis. J Sep Sci 2002. [DOI: 10.1002/1615-9314(20021101)25:15/17<1155::aid-jssc1155>3.0.co;2-m] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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24
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Chankvetadze B, Burjanadze N, Maynard DM, Bergander K, Bergenthal D, Blaschke G. Comparative enantioseparations with native beta-cyclodextrin and heptakis-(2-O-methyl- 3,6-di-O-sulfo)-beta-cyclodextrin in capillary electrophoresis. Electrophoresis 2002; 23:3027-34. [PMID: 12207312 DOI: 10.1002/1522-2683(200209)23:17<3027::aid-elps3027>3.0.co;2-v] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
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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Affiliation(s)
- Bezhan Chankvetadze
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany.
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25
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Van Eeckhaut A, Detaevernier MR, Michotte Y. Development of a validated capillary electrophoresis method for enantiomeric purity testing of dexchlorpheniramine maleate. J Chromatogr A 2002; 958:291-7. [PMID: 12134827 DOI: 10.1016/s0021-9673(02)00314-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A capillary zone electrophoresis method has been developed for the detection of 0.1% of (R)-levochlorpheniramine maleate in samples of (S)-dexchlorpheniramine maleate. Using 1.5 mM carboxymethyl-beta-cyclodextrin in an acidic background electrolyte, resolution values of more than 10 were obtained. Under these conditions the R-enantiomer is migrating in front of the bulk S-enantiomer. The assay was validated for linearity (2-10 microg/ml; R2 = 0.9992), selectivity [(RS)-pheniramine maleate and (RS)-brompheniramine maleate], limit of detection (0.25 microg/ml), limit of quantification (0.75 microg/ml), analytical precision (intra- and inter-day variability), repeatability of the method (RSD = 5.0%) and accuracy. In samples of dexchlorpheniramine maleate from two different manufacturers, concentrations of, respectively, 0.15% and 1.95% (m/m) of levochlorpheniramine maleate were detected. The method was compared to the HPLC method described in the European Pharmacopoeia III monograph.
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Affiliation(s)
- Ann Van Eeckhaut
- Department of Pharmaceutical Chemistry and Drug Analysis, Pharmaceutical Institute, Vrije Universiteit Brussel, Belgium
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26
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Fried KM, Young AE, Usdin Yasuda S, Wainer IW. The enantioselective determination of chlorpheniramine and its major metabolites in human plasma using chiral chromatography on a beta-cyclodextrin chiral stationary phase and mass spectrometric detection. J Pharm Biomed Anal 2002; 27:479-88. [PMID: 11755749 DOI: 10.1016/s0731-7085(01)00570-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A sensitive enantioselective high-performance liquid chromatographic (HPLC) method has been developed for the simultaneous determination of plasma concentrations of (-)(R)- and (+)(S)-chlorpheniramine (CP) and their metabolites, desmethyl-chlorpheniramine (DCP), didesmethyl-chorpheniramine (DDCP) and chlorpheniramine N-oxide (CPNO). Enantioselective separations were achieved on a beta-cyclodextrin chiral stationary phase (CYCLOBOND I 2000) with a mobile phase consisting of diethylamine acetate (0.25%, pH 4.4):methanol:acetonitrile [85:7.5:7.5, (v/v/v)]and a flow-rate of 0.5 ml/min. For CP, the enantioselectivity (alpha) of the separation was 1.12 with a resolution factor (R(s)) of 1.17. The method was validated for CP by using mass spectroscopy detection (MSD). Concentrations of each enantiomer could be measured down to 125 pg/ml from a 1-ml plasma sample. Extracted calibration curves were linear from 0.13 to 50.00 ng/ml for each enantiomer. The method was applied to samples from two clinical studies.
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Affiliation(s)
- Karen M Fried
- Bioanalytical Center, Georgetown University Clinical Research Center, Washington, DC, USA
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27
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Wedig M, Laug S, Christians T, Thunhorst M, Holzgrabe U. Do we know the mechanism of chiral recognition between cyclodextrins and analytes? J Pharm Biomed Anal 2002; 27:531-40. [PMID: 11755754 DOI: 10.1016/s0731-7085(01)00579-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The resolution of chiral phenethylamine analogue compounds were studied in presence of single-isomer neutral and negatively charged cyclodextrins (CDs) by means of capillary electrophoresis (CE) and NMR spectroscopy. Whereas the native beta-CD and heptakis(2-N,N-dimethylcarbamoyl)beta-cyclodextrin were not able to separate the racemates of four ephedrine derivatives studied, heptakis(2,3-O-diacetyl)beta-cyclodextrin and especially heptakis(2,3-O-diacetyl-6-sulfo)beta-cyclodextrin could resolve all four pairs of enantiomers in one run. UV and NMR spectroscopic measurements revealed various kinds of complexes of phenethylamines with the CDs. Either defined inclusion complexes or manifold complexes which are mostly characterized by an attachment of the analyte to the outside of the CD cavity were found. No correlation between the kind of complexation and the resolution observed by means of CE could be found.
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Affiliation(s)
- M Wedig
- Institute of Pharmacy and Food Chemistry, University of Würzburg, Am Hubland, D-97074 Wurzburg, Germany
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28
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Chankvetadze B, Lomsadze K, Bergenthal D, Breitkreutz J, Bergander K, Blaschke G. Mechanistic study on the opposite migration order of clenbuterol enantiomers in capillary electrophoresis with beta-cyclodextrin and single-isomer heptakis(2,3-diacetyl-6-sulfo)-beta-cyclodextrin. Electrophoresis 2001; 22:3178-84. [PMID: 11589277 DOI: 10.1002/1522-2683(200109)22:15<3178::aid-elps3178>3.0.co;2-f] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Opposite migration order was observed for the enantiomers of the chiral beta2-adrenergic drug clenbuterol (CL) in capillary electrophoresis (CE) when resolved with native beta-cyclodextrin (beta-CD) and heptakis (2,3-diacetyl-6-sulfo)-beta-CD (HDAS-beta-CD). The possible mechanisms of the affinity reversal of the CL enantiomers depending on the structure of the CD were studied using 1H-nuclear magnetic resonance (1H-NMR) spectrometry and one-dimensional rotating frame nuclear Overhauser and exchange spectrometry (1-D ROESY). Significant differences were observed between the structure of the (+/-)-CL complexes with beta-CD and HDAS-beta-CD.
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Affiliation(s)
- B Chankvetadze
- Institute of Pharmaceutical Chemistry, University of Münster, Germany
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29
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Affiliation(s)
- R K Gilpin
- College of Science and Mathematics, Wright State University, Dayton, Ohio 45435, USA
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30
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Hellriegel C, Händel H, Wedig M, Steinhauer S, Sörgel F, Albert K, Holzgrabe U. Study on the chiral recognition of the enantiomers of ephedrine derivatives with neutral and sulfated heptakis(2,3-O-diacetyl)-β-cyclodextrins using capillary electrophoresis, UV, nuclear magnetic resonance spectroscopy and mass spectrometry. J Chromatogr A 2001; 914:315-24. [PMID: 11358226 DOI: 10.1016/s0021-9673(00)01015-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The enantiomers of methylephedrine, pseudoephedrine and ephedrine showed a different migration behavior in capillary electrophoresis in the presence of beta-cyclodextrin (beta-CD), heptakis(2,3-O-diacetyl)-beta-cyclodextrin and heptakis(2,3-O-diacetyl-6-sulfato)-beta-cyclodextrin (HDAS). Utilizing UV, MS and NMR spectroscopy, in particular rotating frame Overhauser experiments, an attempt was made to elucidate the chiral recognition mechanism. In the case of the neutral CDs 1:1 complexes were formed with ephedrine and methylephedrine characterized by the inclusion of the phenyl ring in the cavity and the side chain pointing out of the wider rim. In contrast, manifold complexes were formed with HDAS, which on average are characterized by an upside down inclusion of the phenyl ring in the cavity and the side chain pointing out of the narrow rim. This complex geometry is likely be stabilized by an ion-ion interaction between the positively charged nitrogens of the ephedrine derivatives and the negative charges of HDAS. In addition, an attachment of the ligand to the outside of HDAS and other complex stoichiometries are also possible.
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Affiliation(s)
- C Hellriegel
- Pharmaceutical Chemistry, Institute of Pharmacy and Food Chemistry, University of Würzburg, Germany
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31
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Abstract
In this review, the progress in hyphenation of capillary electrophoresis (CE) with electrospray ionization-mass spectrometry (ESI-MS) since the article of Banks (Banks, J. F., Electrophoresis 1997, 18, 2255-2266) is reported. In all capillary-based electromigration techniques, such as capillary gel electrophoresis (CGE), capillary isotachophoresis (CITP), capillary isoelectric focussing (CIEF), micellar electrokinetic chromatography (MEKC), affinity capillary electrophoresis (ACE), as well as in the hybrid techniques capillary electrochromatography (CEC), and pressurized capillary electrochromatography (pCEC) progress has been made in experimental setups, and for many groups of analytes, such as peptides, proteins, nucleotides, saccharides, drugs and their metabolites, CE/ESI-MS has been successfully applied. Electromigration is further miniaturized. New preconcentration methods allow the investigation of compounds, which are not sensitively detected with ESI-MS. Coordination ion spray (CIS) MS is another method for sensitivity enhancement by on-line formation of charged coordination compounds.
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Affiliation(s)
- A von Brocke
- University of Tübingen, Institute of Organic Chemistry, Germany
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32
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Chankvetadz B, Blaschke G. Enantioseparations in capillary electromigration techniques: recent developments and future trends. J Chromatogr A 2001; 906:309-63. [PMID: 11215895 DOI: 10.1016/s0021-9673(00)01124-9] [Citation(s) in RCA: 264] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This review summarizes the current status of enantioseparations using capillary electromigration techniques and gives the authors insights on the selected fundamental aspects and future trends in this field. The most recent developments in the field of chiral separations using capillary electrophoresis (CE) and capillary electrochromatography (CEC) are summarized. The status of chiral electromigration techniques is evaluated tacking into account the most recent developments in related techniques such as chiral HPLC, GC and SFC.
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Affiliation(s)
- B Chankvetadz
- University of Münster, Institute of Pharmaceutical Chemistry, Germany.
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33
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Enantioseparation of warfarin by capillary electrophoresis with UV and LIF detection using single and dual cyclodextrin type chiral selectors. Chromatographia 2001. [DOI: 10.1007/bf02490345] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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34
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Enantioseperation of chiral phenothiazine derivatives in capillary electrophoresis using cyclodextrin type chiral selectors. Chromatographia 2001. [DOI: 10.1007/bf02490344] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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35
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Wind M, Hoffmann P, Wagner H, Thormann W. Chiral capillary electrophoresis as predictor for separation of drug enantiomers in continuous flow zone electrophoresis. J Chromatogr A 2000; 895:51-65. [PMID: 11105848 DOI: 10.1016/s0021-9673(00)00410-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Separation of the enantiomers of chlorpheniramine and methadone in acidic buffers containing carboxymethyl-betacyclodextrin (CMCD) as chiral selector was investigated by capillary zone electrophoresis. For a range of pH and CMCD concentrations, the mobility difference and resolution of the enantiomers were determined. Then, conditions known to provide well resolved enantiomers and optimized chiral separation were applied to chiral continuous flow electrophoresis. In that approach, a thin film of fluid flowing between two parallel plates is employed as carrier for electrophoresis. The electrolytes and the sample are continuously admitted at one end of the electrophoresis chamber and are fractionated by an array of outlet tubes at the other. The number of pure enantiomeric fractions obtained by chiral continuous flow electrophoresis was found to be directly dependent on the enantiomeric mobility difference. For racemic chlorpheniramine separated in a betaine-acetic acid buffer at a total throughput of 5 mg/h, complete enantiomeric separation is shown to require a mobility difference of about 3 x 10(-9) m2/V s. Furthermore, compared to the previous investigations with hydroxypropyl-beta-cyclodextrin, CMCD was found to permit improved fractionation of methadone enantiomers. With a total racemic drug throughput of about 15 mg/h, continuous flow zone electrophoresis processing with CMCD as chiral selector is shown to have the potential of providing pure enantiomers on a mg/h scale. The results indicate that chiral capillary zone electrophoresis data can be employed as predictor for preparative scale chiral separations based upon continuous flow zone electrophoresis.
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Affiliation(s)
- M Wind
- lnstitut für Anorganische und Analytische Chemie und Radiochemie, Fachrichtung 11.4 der Universität des Saarlandes, Saarbrücken, Germany
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36
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Koppenhoefer B, Zhu X, Jakob A, Wuerthner S, Lin B. Separation of drug enantiomers by capillary electrophoresis in the presence of neutral cyclodextrins. J Chromatogr A 2000; 875:135-61. [PMID: 10839142 DOI: 10.1016/s0021-9673(99)01210-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
This is a selected review, highlighting our results obtained in an extended screening program ("The German-Chinese Drug Screening Program"), with a focus on a set of original data obtained with heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin (TM-beta-CD) as the chiral solvating agent (CSA). The enantioseparation of 86 drugs by capillary zone electrophoresis in the presence of this CSA was successful for 47 drugs. The migration separation factors (alpham) and the migration retardation factors (Rm) were compared with those found for native beta-cyclodextrin (beta-CD). The patterns thus obtained were also compared with those observed for hexakis(2,3,6-tri-O-methyl)-alpha-CD (TM-alpha-CD) and octakis(2,3,6-tri-O-methyl)-gamma-CD (TM-gamma-CD), respectively. From the statistical data, it can be concluded that there is a remarkable influence of the analyte structure on the electrophoretic data. A substructure 4H was found in the analyte structure that has a significant influence on the analytes' behaviour. Thus, analytes bearing the substructure 4H do not only have a strong affinity to the CDs but also a high rate of success of chiral separation in all systems reviewed. In light of this, the different ring sizes of native cyclodextrins (alpha-, beta- and gamma-CD) readily explain their behaviour towards a limited test set of chiral drugs. Sterical considerations point to the significance of side-on-binding versus inclusion in the cavity of the host. In addition to the findings from the screening program, numerous references to the literature are given.
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Affiliation(s)
- B Koppenhoefer
- Institute of Organic Chemistry, University of Tübingen, Germany.
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37
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Fanali S. Enantioselective determination by capillary electrophoresis with cyclodextrins as chiral selectors. J Chromatogr A 2000; 875:89-122. [PMID: 10839140 DOI: 10.1016/s0021-9673(99)01309-6] [Citation(s) in RCA: 340] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
This review surveys the separation of enantiomers by capillary electrophoresis using cyclodextrins as chiral selector. Cyclodextrins or their derivatives have been widely employed for the direct chiral resolution of a wide number of enantiomers, mainly of pharmaceutical interest, selected examples are reported in the tables. For method optimisation, several parameters influencing the enantioresolution, e.g., cyclodextrin type and concentration, buffer pH and composition, presence of organic solvents or complexing additives in the buffer were considered and discussed. Finally, selected applications to real samples such as pharmaceutical formulations, biological and medical samples are also discussed.
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Affiliation(s)
- S Fanali
- Istituto di Cromatografia del C.N.R., Area della Ricerca di Roma, Monterotondo Scalo (Rome), Italy.
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38
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Abstract
The review summarizes the most recent developments in the field of enantioseparation of chiral drugs using capillary electromigration techniques. The basic principles of enantioseparations in CE are discussed. Recent developments in sample introduction, separation and detection in capillary electrophoresis and capillary electrochromatography are summarized. The applications are arbitrarily divided into the following three groups: (a) racemates and artificial mixtures of enantiomers, (b) drug forms and (c) chiral drugs and their metabolites in biological fluids. Among the various techniques involved the relatively new developments such as CEC in aqueous and nonaqueous buffers, on-line CE-MS coupling, etc. are emphasized.
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Affiliation(s)
- G Blaschke
- Institute of Pharmaceutical Chemistry, University of Münster, Germany.
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39
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Chankvetadze B, Burjanadze N, Pintore G, Bergenthal D, Bergander K, Mühlenbrock C, Breitkreuz J, Blaschke G. Separation of brompheniramine enantiomers by capillary electrophoresis and study of chiral recognition mechanisms of cyclodextrins using NMR-spectroscopy, UV spectrometry, electrospray ionization mass spectrometry and X-ray crystallography. J Chromatogr A 2000; 875:471-84. [PMID: 10839166 DOI: 10.1016/s0021-9673(00)00153-9] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Opposite migration order was observed for the enantiomers of brompheniramine [N-[3-(4-bromphenyl)-3-(2-pyridyl)propyl]-N,N-dimethylamine] (BrPh) in capillary electrophoresis (CE) when native beta-cyclodextrin (beta-CD) and heptakis(2,3,6-tri-O-methyl)-beta-CD (TM-beta-CD) were used as chiral selectors. NMR spectrometry was applied in order to obtain information about the stoichiometry, binding constants and structure of the selector-selectand complexes in solution. The data were further confirmed by UV spectrometry and electrospray ionization mass spectrometry. The structure of the complexes in the solid state was determined using X-ray crystallography performed on the co-crystals precipitated from the 1:1 aqueous solution of selector and selectand. This multiple approach allowed an elucidation of the most likely structural reason for a different affinity (binding strength) of BrPh enantiomers towards beta-CD and TM-beta-CD. However, the question about a force responsible for the opposite affinity pattern of BrPh enantiomers towards these CDs could not be answered definitely.
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Affiliation(s)
- B Chankvetadze
- Institute of Pharmaceutical Chemistry, University of Münster, Germany
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40
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Chankvetadze B, Pintore G, Burjanadze N, Bergenthal D, Bergander K, Breitkreuz J, Mühlenbrock C, Blaschke G. Mechanistic study of opposite migration order of dimethindene enantiomers in capillary electrophoresis in the presence of native beta-cyclodextrin and heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin. J Chromatogr A 2000; 875:455-69. [PMID: 10839165 DOI: 10.1016/s0021-9673(00)00146-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The possible mechanisms of the opposite affinity pattern of the enantiomers of dimethindene [(R,S)-N,N-dimethyl-3[1(2-pyridyl)ethyl]indene-2-ethylamine] (DIM) towards native beta-cyclodextrin (beta-CD) and heptakis(2,3,6-tri-O-methyl-)-beta-CD (TM-beta-CD) were studied using capillary electrophoresis (CE), NMR spectrometry, electrospray ionization mass spectrometry (ESI-MS) and X-ray crystallography. NMR spectrometry allowed to estimate the stoichiometry of the complex and to determine the binding constants. As found using ESI-MS, together with more abundant 1:1 complex, a complex with 1:2 stoichiometry may also be present in a rather small amount in a solution of DIM and beta-CD. One-dimensional ROESY experiments indicated that the geometry of the complexes of DIM with native beta-CD depends on the ratio of the components in the solution. In the 1:1 solution of DIM and beta-CD the complex may be formed by inclusion of the indene moiety of DIM into the cavity of beta-CD on the primary side and into the cavity of TM-beta-CD into the secondary side. The most likely structural reason for lower affinity of the enantiomers of DIM towards the cavity of TM-beta-CD compared to native beta-CD could be elucidated. The indene moiety does not enter the cavity of TM-beta-CD as deeply as the cavity of beta-CD. This may be the most likely explanation of significantly higher affinity constants of DIM enantiomers towards the latter CD compared to the former one. The marked difference between the structure of the complexes may also be responsible for the opposite affinity pattern of the DIM enantiomers towards beta-CD and TM-beta-CD.
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Affiliation(s)
- B Chankvetadze
- Institute of Pharmaceutical Chemistry, University of Münster, Germany
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41
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Chankvetadze B, Burjanadze N, Pintore G, Strickmann D, Bergenthal D, Blaschke G. Chiral recognition of verapamil by cyclodextrins studied with capillary electrophoresis, NMR spectroscopy, and electrospray ionization mass spectrometry. Chirality 1999; 11:635-44. [PMID: 10467315 DOI: 10.1002/(sici)1520-636x(1999)11:8<635::aid-chir5>3.0.co;2-d] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Capillary electrophoresis (CE) allows the observation of the opposite affinities of the enantiomers of (+/-)-verapamil [2-isopropyl-2,8-bis(3,4-dimethoxyphenyl)-6-methyl-6-azaoctannitrile+ ++, VP] toward beta-cyclodextrin (beta-CD) and heptakis(2,3, 6-tri-O-methyl)-beta-CD (TM-beta-CD). In addition, in the presence of beta-CD in the background electrolyte, longer migration times and lower separation factors were observed compared to TM-beta-CD. The binding constants of (+)- and (-)-VP with beta-CD and TM-beta-CD determined using (13)C NMR spectroscopy explain the results observed in CE. Electrospray ionization mass spectrometry (ESI-MS) was used as an alternative technique for the characterization of VP-CD complexes.
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Affiliation(s)
- B Chankvetadze
- Institute of Pharmaceutical Chemistry, University of Münster, Hittorfstrasse 58-62, 48149 Münster, Germany
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42
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Fillet M, Chankvetadze B, Crommen J, Blaschke G. Designed combination of chiral selectors for adjustment of enantioseparation selectivity in capillary electrophoresis. Electrophoresis 1999; 20:2691-7. [PMID: 10532336 DOI: 10.1002/(sici)1522-2683(19990901)20:13<2691::aid-elps2691>3.0.co;2-s] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In this study an attempt has been made to explain the reasons for changing the enantioseparation selectivity in some dual cyclodextrin (CD) systems compared to the use of single chiral selectors in capillary electrophoresis (CE). An explanation for selectivity changes is proposed based on the effect of the chiral selector on the mobility of the analyte. In order to support the proposed mechanism, several dual systems were designed on the basis of the known recognition pattern of enantiomers for individual CDs. In most cases the separation selectivity could be adjusted in a designed way. There was no experimental evidence for simultaneous binding of a given chiral analyte with both chiral selectors or of chiral recognition of an analyte complex with one CD by another CD.
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Affiliation(s)
- M Fillet
- Institute of Pharmaceutical Chemistry, University of Münster, Germany
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