Long-Chain Alkylthio Cyclodextrin Derivatives for Modulation of Quorum-Sensing-Based Bioluminescence in Model System.

Quorum sensing (QS) allows bacteria to coordinate their activities by producing and detecting low-molecular-weight signal molecules based on population density, thereby controlling the infectivity of bacteria through various virulence factors. Quorum-sensing inhibition is a promising approach to tackle bacterial communication. Cyclodextrins (CDs) are a class of cyclic oligosaccharides that reversibly encapsulate the acyl chain of the signal molecules, thereby preventing their binding to receptors and interrupting bacterial communication.

Chiral Separation of Apremilast by Capillary Electrophoresis Using Succinyl-β-Cyclodextrin-Reversal of Enantiomer Elution Order by Cationic Capillary Coating.

A stereospecific capillary electrophoresis method was developed for the separation of the novel, antipsoriatic agent, apremilast (APR). Six anionic cyclodextrin (CD) derivatives were screened for their ability to discriminate between the uncharged enantiomers. Only succinyl-β-CD (Succ-β-CD) presented chiral interactions; however, the enantiomer migration order (EMO) was unfavorable, and the eutomer, -APR, migrated faster.

Chiral Separations of Pyrethroic Acids Using Cyclodextrin Selectors.

Pyrethroid insecticides are broadly used. They have low toxicity for warm-blooded living creatures, but high toxicity for both insects and fish. Therefore, it is important to reduce the environmental impact of pyrethroids.

Enantiomeric separation of antimalarial drugs by capillary electrophoresis using neutral and negatively charged cyclodextrins.

Capillary electrophoresis (CE) methods for chiral resolution of five antimalarial drugs (primaquine, tafenoquine, mefloquine, chloroquine and quinacrine) were developed by using a wide selection of neutral and anionic cyclodextrin (CD) derivatives. The use of sulfobutyl-β-CD and carboxymethyl-β-CD (CMBCD) resulted in good resolution of quinacrine and tafenoquine, respectively. New results are presented for resolutions of chloroquine and mefloquine.

Separation of vinca alkaloid enantiomers by capillary electrophoresis applying cyclodextrin derivatives and characterization of cyclodextrin complexes by nuclear magnetic resonance spectroscopy.

In this work, the enantiomeric separation of three vinca alkaloid enantiomers (vincamine, vinpocetine and vincadifformine) has been investigated in an aqueous capillary electrophoresis (CE) system using cyclodextrins (CDs). The investigated CDs were the native alpha-, beta-, and gamma-CDs and their hydroxypropylated, randomly methylated, carboxymethylated and sulfobutylated derivatives. The first part of this study consisted of the determination of the apparent averaged complex stability constants with the selected CDs.

Separation of cis-beta-lactam enantiomers by capillary electrophoresis using cyclodextrin derivatives.

Chiral separation of 19 pairs of cis-beta-lactam (BL) stereoisomers of pharmacological importance was examined by capillary electrophoresis using cyclodextrin (CD) derivatives. In order to select the most effective conditions separating the highest number of stereoisomers of BLs, single carboxymethyl alpha-, beta- and gamma-, as well as sulfobutyl beta-CD derivatives were applied. Additionally, carboxymethyl and sulfobutyl beta-CD derivatives complemented with neutral beta-CD derivatives as dual CD systems were tested.

CE-MS characterization of negatively charged alpha-, beta- and gamma-CD derivatives and their application to the separation of dipeptide and tripeptide enantiomers by CE.

Sulfated, sulfopropyl and carboxymethyl alpha-, beta- and gamma-CDs were characterized by CE-ESI-MS using an acidic BGE with anodic MS detection and a basic BGE with cathodic MS detection. Isomers of the sulfated CDs comigrated in both systems. The acidic BGE with anodic MS detection resulted in slightly better separation of the isomers of the sulfopropyl CDs, which were separated according to the number of substituents.

Separation and characterization of modified pregabalins in terms of cyclodextrin complexation, using capillary electrophoresis and nuclear magnetic resonance.

The (S)-(+)-isomer of 3-isobutyl-GABA (pregabalin), the blockbuster drug in the treatment of neuropathic pain has been separated from its R isomer by cyclodextrin modified capillary zone electrophoresis (CZE) using uncoated fused-silica capillary. Derivatization of the single isomer and the racemate with tosyl- and dansyl-chloride was carried out to introduce strong UV chromophores of different size. CE-pH titrations were performed to determine the dissociation constants for both derivatives.

Chiral separation by a monofunctionalized cyclodextrin derivative: from selector to permethyl-beta-cyclodextrin bonded stationary phase.

Preparation of (6-monoureido-6-monodeoxy) permethylated beta-cyclodextrin bonded chiral stationary phase from permethylated 6-monoamino-6-monodeoxy-beta-cyclodextrin is described. The optimized chiral stationary phase was evaluated by using HPLC separation of racemates of coumarin derivatives. Column characterization was performed by solid-state (13)C, (15)N, (29)Si NMR using cross-polarization at the magic angle spinning.

Characterization of aspartame-cyclodextrin complexation.

The inclusion complex formation of aspartame (guest) and various cyclodextrins (host) were examined using 1H NMR titration and capillary electrophoresis. Initially the protonation constants of aspartame were determined by NMR-pH titration with in situ pH measurement to yield log K1=7.83 and log K2=2.

Enantioseparation of beta-substituted tryptophan analogues with modified cyclodextrins by capillary zone electrophoresis.

Direct capillary zone electrophoretic methods were developed for the separation of the enantiomers of unnatural beta-substituted tryptophan analogues such as erythro- and threo-beta-methyl-, beta-2-propyl-, beta-3-pentyl-, beta-phenyl- and beta-2,5-dimethoxyphenyltryptophan. Cyclodextrins (CDs) were chosen as chiral selectors because of their favorable properties (stability, commercial availability, low cost, UV transparency, inertness, etc.).

Determination of flurbiprofen enantiomers in plasma using a single-isomer amino cyclodextrin derivative in nonaqueous capillary electrophoresis.

A nonaqueous capillary electrophoresis (NACE) assay was developed for the separation and determination of flurbiprofen enantiomers in plasma samples using 6-monodeoxy-6-mono(3-hydroxy)propylamino-beta-cyclodextrin as chiral selector. The nonaqueous background electrolyte was made up of 40 mM ammonium acetate in methanol (MeOH), and flufenamic acid was employed as internal standard. Solid-phase extraction was used for sample cleanup prior to the NACE separation.

Enantioseparation of beta-methyl-substituted amino acids with cyclodextrins by capillary zone electrophoresis.

Direct capillary zone electrophoretic methods were developed for the separation of the enantiomers of unnatural beta-methyl-amino acids such as erythro- and threo-beta-methylphenylalanine, beta-methyltyrosine, beta-methyltryptophan and beta-methyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid. Capillary zone electrophoresis was carried out using sulfopropylated-alpha-CD (SP2-alpha-CD), sulfopropylated-beta-CD (SP2-beta-CD) both with a degree of substitution of 2 moles/mole cyclodextrin, and sulfopropylated-beta-CD (SP4-beta-CD) with a degree of substitution of 4moles/mole beta-cyclodextrin. The effects of selector and buffer concentrations, electrolyte pH and applied voltage were studied on the separation efficiency.

The role of cyclodextrins in chiral capillary electrophoresis.

The members of the enantiomeric pairs frequently show rather different biological effects, so their chiral selective synthesis, pharmacological studies and analysis are necessary. CE has unique advantages in chiral analysis. The most frequently used chiral selectors are CDs in this field.

Cyclodextrin complexes: chiral recognition and complexation behaviour.

Cyclodextrins are well known in supramolecular chemistry as host molecules capable of engulfing molecules in their hydrophobic cavity via noncovalent interactions. Although cyclodextrins are frequently used for chiral separation of racemates, the mechanism of chiral recognition has not yet been fully characterised. The current investigation was aimed at examining chiral recognition mechanism in order to construct an in silico method for prediction of chiral recognition.

[Cytotoxic examinations of various cyclodextrin derivatives on Caco-2 cells].

Cyclodextrins (CDs) are widely used compounds in pharmaceutical industry. They enhance solubility, bioavailability and stability of many drugs. Recently, several of CD derivatives have been synthetized in order to improve their physicochemical properties and inclusion capacities.

Enantiomeric separation of acidic compounds using single-isomer amino cyclodextrin derivatives in nonaqueous capillary electrophoresis.

The enantiomeric separation of a series of acidic pharmaceuticals (mostly nonsteroidal anti-inflammatory drugs) has been investigated in NACE systems using single-isomer amino beta-CD derivatives. The first part of this study consisted of the selection of the basic experimental conditions to separate efficiently the enantiomers of acidic drugs. Several parameters, such as the nature of the ionic BGE components, were studied and a methanolic solution of ammonium acetate containing the cationic CD was selected as BGE.

Influence of (hydroxy)alkylamino substituents on enantioseparation ability of single-isomer amino-beta-cyclodextrin derivatives in chiral capillary electrophoresis.

A family of single-isomer amino-beta-cyclodextrin (amino-beta-CD) derivatives containing an amino or (hydroxy)alkylamino group in one of the primary positions has been synthesized. The steric effect and hydrogen bond forming ability of the different substituents on enantioseparation of acidic enantiomers has been studied by capillary electrophoresis (CE). Three enantiomeric model compounds (mandelic acid, cis-permethrinic acid, and cis-deltamethrinic acid) having significantly different apparent complex stability constants with beta-CD were applied in the experiments.

Synthesis and characterization of water-soluble hydroxybutenyl cyclomaltooligosaccharides (cyclodextrins).

We have examined the synthesis of hydroxybutenyl cyclomaltooligosaccharides (cyclodextrins) and the ability of these cyclodextrin ethers to form guest-host complexes with guest molecules. The hydroxybutenyl cyclodextrin ethers were prepared by a base-catalyzed reaction of 3,4-epoxy-1-butene with the parent cyclodextrins in an aqueous medium. Reaction byproducts were removed by nanofiltration before the hydroxybutenyl cyclodextrins were isolated by co-evaporation of water-EtOH.