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

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.     

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

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.     

Enantiomer separation on monolithic silica HPLC columns using chemically bonded methylated and methylated/acetylated 6-O-tert-butyldimethylsilylated beta-cyclodextrin

A new 2,3-methylated 3*-monoacetylated 6-O-tert-butyldimethylsilylated beta-CD derivative was synthesized and chemically bonded onto aminopropyl derivatized monolithic silica HPLC columns. In this CD derivative, only one of seven methyl groups in 3-position was substituted by an acetyl group. Its applicability as a chiral stationary phase for HPLC was tested and compared with exclusively 2,3-methylated 6-O-tert-butyldimethylsilylated beta-CD immobilized onto aminopropyl-modified monoliths. Thirty-two chiral compounds from different chemical classes and different functionalities were tested under RP conditions. Fourteen compounds were resolved into their enantiomers by methylated 6-O-tert-butyldimethylsilylated beta-CD. By use of methylated/acetylated 6-O-tert-butyldimethylsilylated beta-CD as the chiral stationary phase 7 analytes were successfully stereodifferentiated.     

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

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.     

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

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.     

Effect of temperature on enantiomer separation of oxzepam and lorazepam by high-performance liquid chromatography on a beta-cyclodextrin derivatized bonded chiral stationary phase

A reversed-phase high-performance liquid chromatography (HPLC) method with beta-cyclodextrin (beta-CD) derivatized as chiral stationary phase is used to directly separate oxazepam (Oxa) and lorazepam (Lor) enantiomers. The effect of temperature on the direct HPLC separation of Oxa and Lor enantiomers is studied for the commercially available beta-CD derivatized bonded chiral stationary phase. Chromatographic peak coalescence, appearing as a plateau between the resolved peaks, is observed at column temperatures of above 13 degrees C. Peak coalescence on the beta-CD derivatized bonded column is attributable to racemization of the Oxa enantiomer. By reducing the column temperature to 13 degrees C, the enantiomeric composition of Oxa and Lor could be determined on the chiral column. This method is expected to be useful for the resolution of 3-hydroxybenzodiazepines. At the same time, the separation mechanism is studied by calculating the thermodynamic parameters. The results reveal that the separation of Oxa and Lor enantiomer is a case of enthalpy-controlled separation, inclusion mechanism does not control the separation. The interaction between Oxa and beta-CD is an additionally strong pi-pi interaction or hydrogen bonding, but that between Lor or beta-CD derivatized is a weak pi-pi interaction or hydrogen bonding.     

Preparation and enantioseparation characteristics of a novel chiral stationary phase based on mono (6(A)-azido-6(A)-deoxy)-per(p-chlorophenylcarbamoylated) beta-cyclodextrin

A novel cyclodextrin (CD) derivative-mono (6(A)-azido-6(A)-deoxy)-per(p-chlorophenylcarbamoylated) beta-CD was synthesized and chemically immobilized onto the surface of amino-functionalized silica gel to afford a structurally well-defined chiral stationary phase (CSP) for high performance liquid chromatography (HPLC). The p-chlorophenyl groups introduced on the beta-CD are pi-electron deficient (i.e., pi-acidic moieties); therefore the stronger pi-pi interaction which plays an important role in chiral recognition process is expected between aromatic analytes and this type of the CSP. The enantiomeric separations of 11 piperazine derivatives as well as six racemates have been successfully achieved on this CSP in the normal and reversed phase modes.     

Cyclodextrin‐mediated capillary electrophoresis enantioseparation of dansylated β‐amino acids with bicyclo[2.2.2]octane,bicyclo[3.1.1]heptane and cyclopenta[d][1,2]oxazole core structures

The present study investigated the separation of bicyclic β‐amino acids with bicyclo[2.2.2]octane, bicyclo[3.1.1]heptane and cyclopenta[d][1,2]oxazole core structures by capillary electrophoresis using native cyclodextrins as well as neutral and charged derivatives as chiral selectors. The amino acids were derivatized with dansyl chloride to provide a UV chromophore. Separations were carried out at 20°C in a 48.5/40 cm, 50 µm fused‐silica capillary at an applied voltage of 20 kV. Fifty millimolar sodium phosphate background electrolytes pH 2.5 and 7.2 containing either 5 or 30 mg/mL of the CDs were used. For the majority of the investigated CDs, enantioseparations could only be achieved at pH 2.5 when the analytes are positively charged. Successful enantioseparations as negatively charged analytes at pH 7.2 were only observed for few compounds. In the case of methyl‐γ‐cyclodextrin, opposite enantiomer migration order was observed in pH 2.5 or 7.2 background electrolytes. Dependence of the enantiomer migration order on the size of the cavity of the cyclodextrins was also found. Furthermore, the degree of methylation of β‐cyclodextrin derivatives affected the migration order of several analyte enantiomers.     

Separation of enantiomers of ephedrine by capillary electrophoresis using cyclodextrins as chiral selectors: comparative CE, NMR and high resolution MS studies

The enantiomer migration order (EMO) of ephedrine was investigated in the presence of various CDs in CE. The molecular mechanisms of chiral recognition were followed for the ephedrine complexes with native α- and β-CD and heptakis(2,3-di-O-acetyl-6-O-sulfo)-β-CD (HDAS-β-CD) by CE, NMR spectroscopy and high-resolution MS. Minor structural differences were observed between the complexes of ephedrine with α- and β-CD although the migration order of enantiomers was opposite when these two CDs were applied as chiral selectors in CE. The EMO was also opposite between β-CD and HDAS-β-CD. Significant structural differences were observed between ephedrine complexes with the native CDs and HDAS-β-CD. The latter CD was advantageous as chiral CE selector not only due to its opposite electrophoretic mobility compared with that of the cationic chiral analyte, but also primarily due to its enhanced chiral recognition ability towards the enantiomers of ephedrine.     

Enantioseparation of Chiral Antimycotic Drugs by HPLC with Polysaccharide-Based Chiral Columns and Polar Organic Mobile Phases with Emphasis on Enantiomer Elution Order

The separation of enantiomers of 10 chiral antimycotic drugs was studied on polysaccharide-based chiral columns with polar organic mobile phases. The emphasis was placed on some interesting examples of enantiomer elution order reversal observed depending on the chemistry of the chiral selector, separation temperature, major component, as well as the minor additive in the mobile phase. In particular, it was found that the elution order of enantiomers of chiral drug terconazole was opposite on cellulose- and amylose-based columns with the same pendant group. The affinity pattern of enantiomers of another chiral drug bifonazole was opposite towards to two amylose-based chiral selectors with different pendant groups. The affinity pattern of terconazole enantiomers also changed on some columns when the alcohol-based mobile phase was replaced with acetonitrile. An interesting effect of the minor acidic (formic acid) additives to the mobile phase on the affinity pattern of terconazole enantiomers was observed on Cellulose-2 and Cellulose-4 columns. In addition, a reversal of elution order of bifonazole enantiomers was observed on Amylose-2 column by variation of a separation temperature.     

Preparation of novel beta-cyclodextrin chiral stationary phase based on click chemistry

A facile strategy based on click chemistry for preparation of the structurally well-defined native beta-cyclodextrin (beta-CD) based chiral stationary phase (CSP) was proposed. The beta-CD CSP was evaluated by enatioseparation of benzoin, trans-stilbene oxide, Troger's base, bendroflumethiazide, ketoprofen, chlorthalidone, three flavanone compounds and two beta-adrenergic blocking agents under reversed phase high performance liquid chromatography. The chromatographic results demonstrate the chiral separation ability of click beta-CD CSP and illustrate the usefulness of click chemistry in the preparation of beta-CD based CSP.     

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

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.     

Enantioseparations of hydrobenzoin and structurally related compounds in capillary zone electrophoresis using heptakis(2,3-dihydroxy-6-O-sulfo)-beta-cyclodextrin as chiral selector and enantiomer migration reversal of hydrobenzoin with a dual cyclodextrin system in the presence of borate complexation

We investigated the enantioseparations of racemic hydrobenzoin, together with benzoin and benzoin methyl ether, in capillary electrophoresis (CE) using the single-isomer heptakis(2,3-dihydroxy-6-O-sulfo)-beta-cyclodextrin (SI-S-beta-CD) as a chiral selector in the presence and absence of borate complexation and enantiomer migration reversal of hydrobenzoin with a dual CD system consisting of SI-S-beta-CD and beta-CD in the presence of borate complexation at pH 9.0 in a borate buffer. The enantioselectivity of hydrobenzoin increased remarkably with increasing SI-S-beta-CD concentration and the enantioseparation depended on CD complexation between hydrobenzoin-borate and SI-S-beta-CD. The (S,S)-enantiomer of hydrobenzoin-borate complexes interacted more strongly than the (R,R)-enantiomer with SI-S-beta-CD. The enantiomers of hydrobenzoin could be baseline-resolved in the presence of SI-S-beta-CD at a concentration as low as 0.1% w/v, whereas the three test analytes were simultaneously enantioseparated with addition of 0.3% w/v SI-S-beta-CD or at concentrations >2.0% w/v in a borate buffer and 0.5% w/v in a phosphate background electrolyte at pH 9.0. Compared with the results obtained previously using randomly sulfated beta-CD (MI-S-beta-CD) in a borate buffer, enantioseparation of these three benzoin compounds is more advantageously aided by SI-S-beta-CD as the chiral selector. The enantioselectivity of hydrobenzoin depended greatly on the degree of substitution of sulfated beta-CD. Moreover, binding constants of the enantiomers of benzoin compounds to SI-S-beta-CD and those of hydrobenzoin-borate complexes to SI-S-beta-CD were evaluated for a better understanding of the role of CD complexation in the enantioseparation and chiral recognition. Enantiomer migration reversal of hydrobenzoin could be observed by varying the concentration of beta-CD, while keeping SI-S-beta-CD at a relatively low concentration. SI-S-beta-CD and beta-CD showed the same chiral recognition pattern but they exhibited opposite effects on the mobility of the enantiomers.     

Infinite enantiomeric resolution of basic compounds using highly sulfated cyclodextrin as chiral selector in capillary electrophoresis

Four chiral basic analytes, namely methadone, fluoxetine, venlafaxine, and tramadol, were selected as model compounds for investigating their stereoselective separation with highly sulfated gamma-cyclodextrin (HS gamma-CD) by capillary electrophoresis (CE)-UV and CE-mass spectrometry (MS). At high concentration of chiral selector, the preferentially bonded enantiomer migrated faster in the anodic mode to the detector and high resolutions were obtained for all analytes. In the cathodic mode, at lower highly sulphated cyclodextrin (HS-CD) concentration, basic compounds could be detected, with the weakly bonded enantiomer migrating first (enantiomeric migration order inversion). It was also then possible, at intermediate HS-CD concentration, that only one enantiomer migrated to the detector as cation while the other enantiomer complexed with the CD was negatively charged and presented an opposite mobility. The latter never reached the detector achieving a perfect enantiomeric selectivity. Infinite chiral resolutions were thus achieved by CE-UV as well as by CE-electrospray ionisation (ESI)-MS where concentrations of HS-CD were adapted according to the negative contribution of the nebulization gas pressure of the interface.     

Enantioseparation of Chiral Antimycotic Drugs by HPLC with Polysaccharide-Based Chiral Columns and Polar Organic Mobile Phases with Emphasis on Enantiomer Elution Order

The separation of enantiomers of 10 chiral antimycotic drugs was studied on polysaccharide-based chiral columns with polar organic mobile phases. The emphasis was placed on some interesting examples of enantiomer elution order reversal observed depending on the chemistry of the chiral selector, separation temperature, major component, as well as the minor additive in the mobile phase. In particular, it was found that the elution order of enantiomers of chiral drug terconazole was opposite on cellulose- and amylose-based columns with the same pendant group. The affinity pattern of enantiomers of another chiral drug bifonazole was opposite towards to two amylose-based chiral selectors with different pendant groups. The affinity pattern of terconazole enantiomers also changed on some columns when the alcohol-based mobile phase was replaced with acetonitrile. An interesting effect of the minor acidic (formic acid) additives to the mobile phase on the affinity pattern of terconazole enantiomers was observed on Cellulose-2 and Cellulose-4 columns. In addition, a reversal of elution order of bifonazole enantiomers was observed on Amylose-2 column by variation of a separation temperature.

     

Migration order of dipeptide and tripeptide enantiomers in the presence of single isomer and randomly sulfated cyclodextrins as a function of pH

The present study was conducted in order to evaluate the cyclodextrin (CD)-mediated chiral separation of peptide enantiomers as uncharged analytes at pH 5.3 using randomly sulfated beta-cyclodextrin, heptakis-6-sulfato-beta-CD and heptakis-(2,3-diacetyl-6-sulfato)-beta-CD as chiral selectors. Although less effective compared to stronger acidic conditions, the CDs proved to be suitable chiral selectors for the present set of peptides at pH 5.3. The carrier ability of the negatively charged CDs upon reversal of the applied voltage may also be exploited leading to a reversal of the migration order. In addition, reversal of the enantiomer migration order upon increasing the buffer pH from 2.5 to 5.3 was also observed for Ala-Tyr in the presence of randomly sulfated beta-CD, for Ala-Phe, Ala-Tyr, Phe-Phe, Asp-PheNH(2) and Gly-Ala-Phe in the presence of heptakis-6-sulfato-beta-CD, and for Phe-Phe and Ala-Leu in the presence of heptakis-(2,3-diacetyl-6-sulfato)-beta-CD. The migration behavior could be explained on the basis of the complexation constants and the mobilities of the peptide-CD complexes. While a change in the affinity pattern of the CDs upon increasing the pH was observed for some peptides, complex mobility was the primary factor for other peptide-CD combinations affecting the enantiomer migration order at the two pH values studied.     

Effect of the eluent on enantiomer separation of controlled drugs by liquid chromatography-ultraviolet absorbance detection-electrospray ionisation tandem mass spectrometry using vancomycin and native beta-cyclodextrin chiral stationary phases

Enantioseparation of nine amphetamine derivatives, methorphan and propoxyphene was studied by comparing two different chiral stationary phases, macrocyclic antibiotic vancomycin and native beta-cyclodextrin (beta-CD). Effects of 46 eluent compositions on enantioseparation in reversed-phase (RP) and polar organic phase modes were investigated. beta-CD was found to be more suitable to phenethylamines in general and vancomycin for methorphan and propoxyphene. An eluent system capable of separating the enantiomers of all phenethylamines in one run was developed. Also, systems providing competitive analysis times for enantioseparation of methorphan and propoxyphene were reported. The suitability of the eluent systems to electrospray ionisation (ESI) was discussed and methods using a tandem mass spectrometric (MS/MS) detection were developed. The suitability of chiral LC-ESI-MS/MS was tested with 14 seized drug samples. The results were in agreement with conventional non-chiral methods. Repeatability of the methods was good and limits of detection were 25-100 ng/ml for most compounds using mass spectrometric detection.     

Ultrashort partial-filling technique in capillary electrophoresis for infinite resolution of tramadol enantiomers and its metabolites with highly sulfated cyclodextrins

The possibility to enhance resolution to infinite value in chiral capillary electrophoresis is attained as soon as the apparent mobility of one enantiomer becomes opposite to the other. This could be achieved on the basis of the carrier ability of multiple charged chiral selectors such as highly sulfated cyclodextrin (HS-CD). With tramadol and its phase I metabolites selected as model compounds, the HS-gamma-CD was found to be the most appropriate chiral selector. The CD concentration was determined where one enantiomer still migrated as a cation while the other migrated in the opposite side. Besides the chiral selector concentration, secondary parameters such as buffer concentration appeared to be critical to reach infinite resolution. The latter was achieved with partial filling technique using ultrashort separation zones (a few mm). In order to better understand the interaction mechanism between the selected CD and the analytes, the classical affinity capillary electrophoresis method, although not fully satisfactory because of ionic strength variations within a series of mobility shift measurements, was applied to estimate complexation constants and complex mobilities. The results obtained point to the prevailing role of complex mobility differences in the enantioselectivity mechanism.     

Influence of the amino acid sequence and nature of the cyclodextrin on the separation of small peptide enantiomers by capillary electrophoresis using randomly substituted and single isomer sulfated and sulfonated cyclodextrins

The separation of dipeptide and tripeptide enantiomers using negatively charged single isomers as well as randomly sulfated and sulfonated cyclodextrins (CDs) was investigated with respect to the amino acid sequence of the peptides and the nature of the CDs. Standardized conditions concerning buffer pH and molarity, CD concentration, and separation voltage were applied. Compared to suffobutylether-beta-CD and heptakis-(2,3-dimethyl-6-sulfato)-beta-CD, randomly sulfated beta-CD as well as the single isomer derivatives heptakis-6-sulfato-beta-CD and heptakis-(2,3-diacetyl-6-sulfato)-beta-CD were the more universal CDs for enantioseparations. The enantiomer migration order depended to a greater extent on the CD than on the amino acid sequence of the peptide although small structural differences such as formation of a peptide amide or ester affected the chiral recognition by the randomly substituted CD derivatives. Using sulfobutylether-beta-CD or heptakis-(2,3-diacetyl-6-sulfato)-beta-CD the DD enantiomers migrated before the LL enantiomers for most peptides while the opposite migration order, i.e. LL before DD, was observed when heptakis-6-sulfato-beta-CD was applied as chiral selector.     

Binding affinity properties of dendritic glycosides based on a beta-cyclodextrin core toward guest molecules and concanavalin A.

The inclusion behavior and concanavalin A binding properties of hepta-antennated and newly synthesized tetradeca-antennated C-6-branched mannopyranosyl and glucopyrannosyl cyclomaltoheptaose (beta-cyclodextrin) derivatives have been evaluated by isothermal titration microcalorimetry and enzyme-linked lectin assay (ELLA), respectively. The synthesis of three first-order dendrimers based on a beta-cyclodextrin core containing 14 1-thio-beta-D-glucose, 1-thio-beta-mannose, and 1-thio-beta-rhamnose residues was performed following a convergent approach and involving (1) preparation of a thiolated bis-branched glycoside building block and (2) attachment of the building block onto heptakis(6-deoxy-6-iodo)-beta-cyclodextrin. Calorimetric titrations performed at 25 degrees C in buffered aqueous solution (pH 7.4) gave the affinity constants and the thermodynamic parameters for the inclusion complex formation of these beta-cyclodextrin derivatives with guests sodium 8-anilino-1-naphthalensulfonate (ANS) and 2-naphthalenesulfonate. The host capability of the persubstituted beta-cyclodextrins decreased with respect to the native beta-CD when sodium 2-naphthalenesulfonate was used as a guest and improved when ANS was used as a guest molecule. Heptavalent mannoclusters based on beta-CD cores enhance the lectin binding affinity due to the cluster effect; however, the increase of the valency from 7 to 14 ligands did not contribute to the improvement of the concanavalin A binding affinity. In addition, the synthesized hyperbranched mannoCDs lost completely the capability as a host molecules.