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Drug repositioning is a high-priority and feasible strategy in the field of oncology research, where the unmet medical needs are continuously unbalanced. Disulfiram is a potential non-chemotherapeutic, adjuvant anticancer agent. However, the clinical translation is limited by the drug's poor bioavailability. Therefore, the molecular encapsulation of disulfiram with cyclodextrins is evaluated to enhance the solubility and stability of the drug. The present work describes for the first time the complexation of disulfiram with randomly methylated-β-cyclodextrin. A parallel analytical andin vitrobiological comparison of disulfiram inclusion complexes with hydroxypropyl-β-cyclodextrin, randomly methylated-β-cyclodextrin and sulfobutylether-β-cyclodextrin is conducted. A significant drug solubility enhancement by about 1000-folds and fast dissolution in 1 min is demonstrated. Thein vitrodissolution-permeation studies and proliferation assays demonstrate the solubility-dependent efficacy of the drug. Throughout the different cancer cell lines' characteristics and disulfiram unspecific antitumoral activity, the inhibitory efficacy of the cyclodextrin encapsulated drug on melanoma (IC 50 about 100 nM) and on glioblastoma (IC 50 about 7000 nM) cell lines differ by a magnitude. This pre-formulation screening experiment serves as a proof of concept of using cyclodextrin encapsulation as a platform tool for further drug delivery development in repositioning areas., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Mycotoxins are toxic metabolites of filamentous fungi; they are common contaminants in numerous foods and beverages. Cyclodextrins are ring-shaped oligosaccharides, which can form host-guest type complexes with certain mycotoxins. Insoluble beta-cyclodextrin bead polymer (BBP) extracted successfully some mycotoxins (e.g., alternariol and zearalenone) from aqueous solutions, including beverages. Therefore, in this study, we aimed to examine the ability of BBP to remove other 12 mycotoxins (including aflatoxin B1, aflatoxin M1, citrinin, dihydrocitrinone, cyclopiazonic acid, deoxynivalenol, ochratoxin A, patulin, sterigmatocystin, zearalanone, α-zearalanol, and β-zearalanol) from different buffers (pH 3.0, 5.0, and 7.0). Our results showed that BBP can effectively extract citrinin, dihydrocitrinone, sterigmatocystin, zearalanone, α-zearalanol, and β-zearalanol at each pH tested. However, for the removal of ochratoxin A, BBP was far the most effective at pH 3.0. Based on these observations, BBP may be a suitable mycotoxin binder to extract certain mycotoxins from aqueous solutions for decontamination and/or for analytical purposes., (© 2021. The Author(s).)

Veklury™ by Gilead Sciences, Inc., containing antiviral drug, remdesivir (REM) has received emergency authorization in the USA and in Europe for COVID-19 therapy. Here, for the first time, we describe details of the non-covalent, host-guest type interaction between REM and the solubilizing excipient, sulfobutylether-beta-cyclodextrin (SBECD) that results in significant solubility enhancement. Complete amorphousness of the cyclodextrin-enabled REM formulation was demonstrated by X-ray diffraction, thermal analysis, Raman chemical mapping and electron microscopy/energy dispersive spectroscopy. The use of solubilizing carbohydrate resulted in a 300-fold improvement of the aqueous solubility of REM, and enhanced dissolution rate of the drug enabling the preparation of stable infusion solutions for therapy. 2D ROESY NMR spectroscopy provided information on the nature of REM-excipient interaction and indicated the presence of inclusion phenomenon and the electrostatic attraction between anionic SBECD and nitrogen-containing REM in aqueous solution., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2) pathway plays an important role in tumor development and formation of metastases. It was earlier reported that cyclodextrin derivatives have a high affinity to form complexes with PGE2. Based on these results radiolabeled cyclodextrins - as new radiopharmaceuticals - may open a new pathway in the in vivo imaging and diagnosis of PGE2 positive tumors. The aims of this study were to synthetize the PGE2 specific 68 Ga-labeled NODAGA-randomly methylated beta-cyclodextrin ( 68 Ga-NODAGA-RAMEB) and investigate its tumor-targeting properties. NODAGA-RAMEB was labeled with Gallium-68 ( 68 Ga), and the radiochemical purity (RCP%), partition coefficient (logP values), and in vitro-in vivo stability of 68 Ga-NODAGA-RAMEB were determined. After intravenous injection of 68 Ga-NODAGA-RAMEB the accumulation in organs and tissues was monitored in vivo by positron emission tomography (PET) and ex vivo by gamma counter in BxPC-3 and PancTu-1 tumor-bearing CB17 SCID mice. The RCP% of the newly synthesized 68 Ga-NODAGA-RAMEB was higher than 98%. The molar activity was 15.34 ± 1.93 GBq/μmol. The logP of 68 Ga labeled NODAGA-RAMEB was - 3.63 ± 0.04. Biodistribution studies showed high accumulation of 68 Ga-NODAGA-RAMEB in PGE2 positive BxPC-3 tumors; approximately 15-20-fold higher radiotracer uptake was observed, than that of the background. 68 Ga-labeled RAMEB is a promising radiotracer in PET diagnostics of PGE2 positive tumors., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Zearalenone is a xenoestrogenic mycotoxin produced by Fusarium species. High exposure with zearalenone induces reproductive disorders worldwide. Cyclodextrins are ring-shaped host molecules built up from glucose units. The apolar cavity of cyclodextrins can entrap so-called guest molecules. The formation of highly stable host-guest type complexes with cyclodextrins can decrease the biological effect of the guest molecule. Therefore, cyclodextrins may be suitable to decrease the toxicity of some xenobiotics even after the exposure. In this study, the protective effect of beta-cyclodextrins against zearalenone-induced toxicity was investigated in HeLa cells and zebrafish embryos. Fluorescence spectroscopic studies demonstrated the formation of stable complexes of zearalenone with sulfobutyl-, methyl-, and succinyl-methyl-substituted beta-cyclodextrins at pH 7.4 (K = 1.4-4.7 × 10 4  L/mol). These chemically modified cyclodextrins considerably decreased or even abolished the zearalenone-induced loss of cell viability in HeLa cells and mortality in zebrafish embryos. Furthermore, the sublethal effects of zearalenone were also significantly alleviated by the co-treatment with beta-cyclodextrins. To test the estrogenic effect of the mycotoxin, a transgenic bioindicator zebrafish model (Tg(vtg1:mCherry)) was also applied. Our results suggest that the zearalenone-induced vitellogenin production is partly suppressed by the hepatotoxicity of zearalenone in zebrafish. This study demonstrates that the formation of stable zearalenone-cyclodextrin complexes can strongly decrease or even abolish the zearalenone-induced toxicity, both in vitro and in vivo. Therefore, cyclodextrins appear as promising new mycotoxin binders., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Sulfamethazine is a representative member of the sulfonamide antibiotic drugs; it is still used in human and veterinary therapy. The protonation state of this drug affects its aqueous solubility, which can be controlled by its inclusion complexes with native or chemically-modified cyclodextrins. In this work, the temperature-dependent (298-313 K) interaction of sulfamethazine with native and randomly methylated β-cyclodextrins have been investigated at acidic and neutral pH. Surprisingly, the interaction between the neutral and anionic forms of the guest molecule and cyclodextrins with electron rich cavity are thermodynamically more favorable compared to the cationic guest. This property probably due to the enhanced formation of zwitterionic form of sulfamethazine in the hydrophobic cavities of cyclodextrins. Spectroscopic measurements and molecular modeling studies indicated the possible driving forces (hydrophobic interaction, hydrogen bonding, and electrostatic interaction) of the complex formation, and highlighted the importance of the reorganization of the solvent molecules during the entering of the guest molecule into the host's cavity.

Alternariol is an Alternaria mycotoxin that appears in fruits, tomatoes, oilseeds, and corresponding products. Chronic exposure to it can induce carcinogenic and xenoestrogenic effects. Cyclodextrins (CDs) are ring-shaped molecules built up by glucose units, which form host-guest type complexes with some mycotoxins. Furthermore, insoluble CD polymers seem suitable for the extraction/removal of mycotoxins from aqueous solutions. In this study, the interactions of alternariol with β- and γ-CDs were tested by employing fluorescence spectroscopic and modeling studies. Moreover, the removal of alternariol from aqueous solutions by insoluble β-CD bead polymer (BBP) was examined. Our major observations/conclusions are the following: (1) CDs strongly increased the fluorescence of alternariol, the strongest enhancement was induced by the native γ-CD at pH 7.4. (2) Alternariol formed the most stable complexes with the native γ-CD (log K = 3.2) and the quaternary ammonium derivatives (log K = 3.4-3.6) at acidic/physiological pH and at pH 10.0, respectively. (3) BBP effectively removed alternariol from aqueous solution. (4) The alternariol-binding ability of β-CD polymers was significantly higher than was expected based on their β-CD content. (5) CD technology seems a promising tool to improve the fluorescence detection of alternariol and/or to develop new mycotoxin binders to decrease alternariol exposure., Competing Interests: The authors declare no conflict of interest.

Free essential oils and their active components have a low physiochemical stability and low aqueous solubility which limit their applications as food preservatives and in packaging industry. The aim of this study was to characterize the physicochemical properties, antioxidant activities and antimicrobial activity of randomly methylated β cyclodextrin (RAMEB) encapsulated thyme oil, lemon balm oil, lavender oil, peppermint oil and their active components that include thymol, citral, linalool, menthol and borneol. Inclusion complex formation of essential oils (EOs) and RAMEB were evaluated by several methods. Antioxidant capacities of RAMEB-EOs/components were reported to be more stable than free EOs/components (P < 0.05). Rapid SYBR green I/propidium iodide live/dead microbial cellular discrimination assay for Schizosaccharomyces pombe, Escherichia coli and Staphylococcus aureus showed similar results when compared with flow cytometry analysis (P < 0.01) suggesting that our novel microplate fluorescence method could be applied for the fast live/dead microbial discrimination in antimicrobial assays., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Zearalenone (ZEN) is a Fusarium -derived mycotoxin, exerting xenoestrogenic effects in animals and humans. ZEN and its derivatives commonly occur in cereals and cereal-based products. During the biotransformation of ZEN, its reduced metabolites, α-zearalenol (α-ZEL) and β-zearalenol (β-ZEL), are formed; α-ZEL is even more toxic than the parent compound ZEN. Since previous studies demonstrated that ZEN and ZELs form stable complexes with β-cyclodextrins, it is reasonable to hypothesize that cyclodextrin polymers may be suitable for mycotoxin removal from aqueous solutions. In this study, the extraction of ZEN and ZELs from water, buffers, and corn beer was investigated, employing insoluble β-cyclodextrin bead polymer (BBP) as a mycotoxin-binder. Our results demonstrate that even relatively small amounts of BBP can strongly decrease the mycotoxin content of aqueous solutions (including beer). After the first application of BBP for mycotoxin binding, BBP could be completely reactivated through the elimination of ZEN from the cyclodextrin cavities by washing with a 50 v / v% ethanol-water mixture. Therefore, our study suggests that insoluble cyclodextrin polymers may be suitable tools in the future to deplete mycotoxins from contaminated drinks.

Resazurin (or Alamar Blue) is a poorly fluorescent dye. During the cellular reduction of resazurin, its highly fluorescent product resorufin is formed. Resazurin assay is a commonly applied method to investigate viability of bacterial and mammalian cells. In this study, the interaction of resazurin and resorufin with β-cyclodextrins was investigated employing spectroscopic and molecular modeling studies. Furthermore, the influence of β-cyclodextrins on resazurin-based cell viability assay was also tested. Both resazurin and resorufin form stable complexes with the examined β-cyclodextrins (2.0-3.1 × 10³ and 1.3-1.8 × 10³ L/mol were determined as binding constants, respectively). Cells were incubated for 30 and 120 min and treated with resazurin and/or β-cyclodextrins. Our results suggest that cyclodextrins are able to interfere with the resazurin-based cell viability assay that presumably results from the following mechanisms: (1) inhibition of the cellular uptake of resazurin and (2) enhancement of the fluorescence signal of the formed resorufin., Competing Interests: The authors declare no conflict of interest.

Zearalenone (ZEN) is a mycotoxin produced by Fusarium fungi. ZEN primarily contaminates different cereals, and exerts a strong xenoestrogenic effect in animals and humans. ZEN is a fluorescent mycotoxin, although molecular interactions and microenvironmental changes significantly modify its spectral properties. During biotransformation, ZEN is converted into α-zearalenol (α-ZOL) and β-zearalenol (β-ZOL), the toxic metabolites of ZEN, which mimick the effect of estrogen. Cyclodextrins (CDs) are host molecules, and have been studied extensively; they can form stable complexes with several mycotoxins, including ZEN. However, information is limited regarding the interactions of CDs with ZOLs. Therefore, we studied the interactions of α- and β-ZOLs with native and six chemically modified β-CDs by fluorescence spectroscopy. Fluorescence enhancement during complex formation, as well as binding constants, were determined. To understand ZOL-CD interactions better, molecular modeling studies were also carried out. Both mycotoxin derivatives formed the most stable complexes with methylated and sulfobutylated CD-derivatives; however, the CD complexes of α-ZOL were significantly stronger than those of β-ZOL. The data presented here indicate which of the chemically modified β-CDs appear more suitable as fluorescence enhancers or as potential mycotoxin binders., Competing Interests: The authors declare no conflict of interest.

The enantioselectivity of neutral single-isomer synthetic precursors of sulfated-β-cyclodextrins was studied. Four neutral single-isomer cyclodextrins substituted on the secondary side with acetyl and/or methyl functional groups, heptakis(2-O-methyl-3,6-dihydroxy)-β-cyclodextrin (HM-β-CD), heptakis(2,3-di-O-acetyl-6-hydroxy)-β-cyclodextrin (HDA-β-CD), heptakis(2,3-di-O-methyl-6-hydroxy)-β-cyclodextrin (HDM-β-CD), heptakis(2-O-methyl-3-O-acetyl-6-hydroxy)-β-cyclodextrin (HMA-β-CD), and their sulfated analogs the negatively charged heptakis(2,3-di-O-methyl-6-sulfato)-β-cyclodextrin (HDMS-β-CD) and heptakis(2,3-di-O-acetyl-6-sulfato)-β-cyclodextrin (HDAS-β-CD) were investigated by non-aqueous capillary electrophoresis in the view of enantiodiscrimination for various drugs and related pharmaceutical compounds. The focus of the present work was on the chiral selectivity studies of the neutral derivatives, which are the synthesis intermediates of the sulfated products. The chiral recognition experiments proved that among the neutral compounds the HMA-β-CD shows remarkable enantioselectivity towards chiral guests in non-aqueous capillary electrophoresis, while HM-β-CD, HDA-β-CD and HDM-β-CD failed to resolve any of the 25 studied racemates under the applied experimental conditions. In order to get deeper insight into the molecular interactions between the studied single-isomer cyclodextrin and chiral fluoroquinolones (ofloxacin, gatifloxacin and lomefloxacin) and β-blockers (propranolol), 1 H and ROESY NMR experiments were performed. The 2-O-methylation in combination with the 3-O-acetylation of the host was evidenced to exclusively carry the essential spatial arrangement for chiral recognition., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The enantiomers of asenapine maleate (ASN), a novel antipsychotic against schizophrenia and mania with bipolar I disorder have been separated by cyclodextrin (CD) modified capillary zone electrophoresis for the first time. 15 different CDs were screened as complexing agents and chiral selectors, investigating the stability of the inclusion complexes and their enantiodiscriminating capacities. Although initially, none of the applied chiral selectors gave baseline separation, β-CD proved to be the most effective chiral selector. In order to improve resolution, an orthogonal experimental design was employed, altering the concentration of background electrolyte, organic modifier, pH, capillary temperature and applied voltage in a multivariate manner. The developed method (160 mM TRIS-acetate buffer pH 3.5, 7 mM β-CD, at 20 °C, applying 15 kV) was successful for baseline separation of ASN enantiomers (R(s)=2.40±0.04). Our method was validated according to ICH guidelines and proved to be sensitive, linear, accurate and precise for the chiral separation of ASN. Properties of the inclusion complexes, such as stoichiometry, atomic level intermolecular host-guest connections are proposed on the basis of ROESY NMR measurement, ESI-MS spectrometry and molecular modeling studies. It was found that the ASN-β-CD complex is of 1:1 composition, and either of the aromatic rings can be accommodated in the β-CD cavity., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Ochratoxin A (OTA) is a widely spread nephrotoxic food contaminant mycotoxin. Unfortunately, attenuation or prevention of the toxic effects of OTA is still an unresolved problem. Molecular inclusion of OTA by cyclodextrins (CDs) results in complexes with low stability. In the human organism, OTA exists mostly in the dianionic state (OTA(2-)). Therefore, our major goal was to develop a chemically modified cyclodextrin which gives a more stable complex with OTA than the previously published derivatives and which shows stronger preference towards OTA(2-). In our fluorescence spectroscopic study we demonstrate that quaternary ammonium beta-cyclodextrin (QABCD) fulfils both of these requirements. The calculated stability constant of the QABCD-OTA(2-) complex was 28,840 M(-1) (about 200-fold higher than that of the β-CD-OTA(2-) complex). We hypothesize, that QABCD may be a suitable tool for the decontamination of different OTA-contaminated drinks; furthermore, for alleviation of the toxic effects of OTA, such complex formation may reduce its absorption from the intestine., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Biological barriers are the main defense systems of the homeostasis of the organism and protected organs. The blood-brain barrier (BBB), formed by the endothelial cells of brain capillaries, not only provides nutrients and protection to the central nervous system but also restricts the entry of drugs, emphasizing its importance in the treatment of neurological diseases. Cyclodextrins are increasingly used in human pharmacotherapy. Due to their favorable profile to form hydrophilic inclusion complexes with poorly soluble active pharmaceutical ingredients, they are present as excipients in many marketed drugs. Application of cyclodextrins is widespread in formulations for oral, parenteral, nasal, pulmonary, and skin delivery of drugs. Experimental and clinical data suggest that cyclodextrins can be used not only as excipients for centrally acting marketed drugs like antiepileptics, but also as active pharmaceutical ingredients to treat neurological diseases. Hydroxypropyl-β-cyclodextrin received orphan drug designation for the treatment of Niemann-Pick type C disease. In addition to this rare lysosomal storage disease with neurological symptoms, experimental research revealed the potential therapeutic use of cyclodextrins and cyclodextrin nanoparticles in neurodegenerative diseases, stroke, neuroinfections and brain tumors. In this context, the biological effects of cyclodextrins, their interaction with plasma membranes and extraction of different lipids are highly relevant at the level of the BBB., (Copyright © 2015 IMSS. Published by Elsevier Inc. All rights reserved.)

Methylated cyclodextrins (CDs) are effective solubilizers of poorly soluble organic compounds. In this work, we compared various methylated β-CDs concerning their structure characterized by nuclear magnetic resonance spectroscopy, composition analyzed by HPLC and solubilizing capability by using model compounds such as cholesterol, fatty acids, furosemide, tamoxifen, and amiodarone. All the commercially available methylated β-CDs are mixtures of various isomers and homologues except trimethyl β-CD. The effects of the degree of methylation, the composition, as well as the influence of further derivatization with ionic groups were studied. The number of methyl groups in a CD ring should be around 14 to get the highest solubility for the included guest molecules. Although the distribution of isomers and related compounds has hardly any effect at constant degree of substitution, the introduction of amino and succinyl moieties on the CD ring adds ionic interactions to the hydrophobic interactions of the inclusion complex formation, which might result in synergic effect in solubilization., (© 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.)

Cyclodextrins are widely used excipients for increasing the bioavailability of poorly water-soluble drugs. Their effect on drug absorption in the gastrointestinal tract is explained by their solubility- and permeability-enhancement. The aims of this study were to investigate penetration properties of fluorescently labeled randomly methylated-beta-cyclodextrin (FITC-RAMEB) on Caco-2 cell layer and examine the cellular entry of cyclodextrins on intestinal cells. The permeability of FITC-RAMEB through Caco-2 monolayers was very limited. Using this compound in 0.05 mM concentration the permeability coefficient was 3.35±1.29×10(-8) cm/s and its permeability did not change in the presence of 5 mM randomly methylated-beta-cyclodextrin. Despite of the low permeability, cellular accumulation of FITC-RAMEB in cytoplasmic vesicles was significant and showed strong time and concentration dependence, similar to the characteristics of the macropinocytosis marker Lucifer Yellow. The internalization process was fully inhibited at 0°C and it was drastically reduced at 37°C applying rottlerin, an inhibitor of macropinocytosis. Notably, FITC-RAMEB colocalized with the early endosome organizer Rab5a. These results have revealed that FITC-RAMEB is able to enter intestinal epithelial cells by fluid-phase endocytosis from the apical side. This mechanism can be an additional process which helps to overcome the intestinal barrier and contributes to the bioavailability enhancement of cyclodextrins.

The complete physico-chemical characterization of the single enantiomer analgesic drug R,R-tapentadol was quantitated in terms of protonation macro- and microconstants and octanol-water partition coefficient using pH-potentiometry, UV-pH and (1)H NMR-pH titrations. The protonation macroconstants were found to be logK1=10.59±0.01 and logK2=9.44±0.01, while the individual basicity of each protonation site was found to be logk(O)=9.94 and logk(N)=10.48 for the phenolate and tertiary amine functions, respectively. As a consequence, the zwitterionic form of tapentadol predominates in aqueous solutions. The potential optical impurity (S,S-tapentadol) was synthesized for the first time in a seven-step chiral synthetic procedure. The enantiomers of tapentadol were separated by cyclodextrin modified capillary zone electrophoresis. Over 15 cyclodextrins were investigated in terms of apparent complex stability and screened as chiral selectors, and the sulfated alpha-cyclodextrin was found to resolve the enantiomers with excellent resolution (Rs=16.2 and 9.1) at pH 4.75 and pH 9.0, respectively. The system containing 12mM selector in a 50mM TRIS-acetate buffer was amenable to detect S,S-tapentadol potential optical impurity at 0.1% concentration level., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Inclusion complexes of warfarin enantiomers with permethylated monoamino-β-cyclodextrin (PMMABCD) were characterized using CE and (1)H NMR spectroscopy in aqueous solution. These techniques gave complementary information on the stability and the structure of the diastereomeric host-guest inclusion complexes. The stability constants were determined from CE experiments in a wide pH range. Change in the migration order on the variation of the pH was observed. (1)H NMR assignments have been established for the seven non-equivalent carbohydrate units of the host in the complex at pH 7-9. Specific H-H distance restraints were obtained from NOESY experiments and were introduced into molecular modeling to establish the geometry of the inclusion complexes. It was found that the open side chain warfarin enters the cavity from the primary side of the CD. The orientation of the coumarin ring within the cavity has the same preference for the two warfarin enantiomers owing to an ionic interaction with the amino group of the CD. Accordingly, enantioselectivity at pH 8.5 arises from the difference in the CH/π interactions between warfarin aromatics and the manifold of CH groups of the CD., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Three β-cyclodextrin-based chiral stationary phases were developed applying novel bonding chemistry. The separation performances of β-cyclodextrin, (R,S)-2-hydroxypropyl-β-cyclodextrin, and permethyl-β-cyclodextrin-based CSPs were compared in the resolution of structurally divergent analytes, such as coumarins, dansyl amino acids, and propionic acid derivatives. Separations were carried out in reversed phase mode applying 0.1% triethylammonium phosphate (pH 3.5)/MeOH mobile phase systems in different compositions. Of the three novel CSPs the permethyl-β-cyclodextrin bonded phase proved to be the most effective one for the enantioseparation of investigated analytes., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Cyclodextrins (CDs) are widely used both in pharmaceutical applications to improve drug bioavailability and in cell biology as cholesterol-depleting and -delivering agents. Recently, it was shown that β-CD covalently coupled to fluorescent dextran polymers accumulates in cholesterol-enriched lysosomal storage organelles of human fibroblasts (Rosenbaum et al., 2010). By employing a methyl-βCD tagged with fluorescein (FMβCD), we have characterized the cellular trafficking of the CD in mammalian cell lines and its distribution into the endocytic compartments within the first minutes following addition to cells. FMβCD enters mammalian cells via endocytosis. The colocalization of FMβCD with transferrin-containing endosomes and the inhibition of FMβCD internalization by chlorpromazine or by an antisense RNA against clathrin heavy chain indicate that FMβCD is taken up via receptor-mediated, clathrin-dependent endocytosis. These results not only highlight the possibility of using CDs to target drugs intracellularly, but also warn about potential unwanted effects on cell physiology other than cholesterol extraction/loading at high concentrations, high temperatures and prolonged incubation times., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Intestinal absorption and bioavailability of taxol are limited by its low solubility and P-glycoprotein (Pgp) activity. Methylated β-cyclodextrins (CDs) effectively form complexes with paclitaxel but randomly methylated β-cyclodextrin (RAMEB) is cytotoxic in high concentrations. Second-generation derivatives containing monoamino (MaRAMEB) and succinylated (SuRAMEB) ionic substituents with similar inclusion capacity but less toxicity could be promising alternatives of RAMEB. Our aim was to examine and compare the efficacy of MaRAMEB and SuRAMEB with the parental RAMEB on taxol bidirectional permeability using the Caco-2 model. Taxol permeability was not changed by 30-min pretreatment with CDs. In co-treatment with β-cyclodextrins, the apical to basolateral taxol flux was 4 to 6 times greater than in untreated monolayers and it was also higher than in cells treated with Pgp inhibitor cyclosporin A. No decrease in basolateral to apical taxol flux was observed in pretreatment or co-treatment with CDs, suggesting no Pgp inhibition. All three CDs showed similar effects on taxol permeability but RAMEB altered tight junction protein distribution and significantly decreased transepithelial electrical resistance. None of the CDs modified paracellular permeability to mannitol and polyethylene glycol 4000. In conclusion, second-generation derivatives of methyl-β-cyclodextrin, especially MaRAMEB, enhanced taxol permeability across Caco-2 cells with less toxicity and similar effectiveness as RAMEB., (Copyright © 2011 Wiley-Liss, Inc.)

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. Application of carboxyalkyl- and sulfobutyl-CD derivatives provided improved resolution for primaquine. The impurity in primaquine sample detected by CE was identified as quinocide by MS and NMR. CMBCD provided not only the best separation of primaquine from quinocide but also the simultaneous complete resolution of both compounds., (Copyright © 2010 Elsevier B.V. All rights reserved.)

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. Both the composition and concentration of applied selectors and the pH of background electrolyte were selected. In single systems the structural characteristics of BLs and the complex forming affinity were correlated. Most BLs provided optimal complexation with beta-CD derivatives. In conclusion, the efficiency of combining sulfobutyl-beta-CD and permethylated beta-CD was superior to other single and dual CD systems applied. This method successfully separated each pair of stereoisomers investigated., (Copyright (c) 2010 Elsevier B.V. All rights reserved.)

Several beta-cyclodextrin (beta-CD) derivatives have been synthesized recently to improve the physicochemical properties and inclusion capacities of the parent molecule, however, there is limited information available about their cytotoxic effects. In this study we investigated the cytotoxic and hemolytic properties of various beta-CDs in correlation with their cholesterol-solubilizing capacities to expose the mechanism of toxicity. MTT cell viability test, performed on Caco-2 cells showed significant differences between the cytotoxicity of beta-CD derivatives. Cell toxicity of methylated-beta-CDs was the highest, while ionic derivatives proved to be less toxic than methylated ones. Most of the second generation beta-CD derivatives, having both ionic and methyl substituents showed less cytotoxicity than the parent compounds both on Caco-2 cells and human erythrocytes. Inclusion of cholesterol into the ring of randomly methylated-beta-CD and heptakis(2,6-di-O-methyl)-beta-CD abolished the cell toxicity indicating the role of cholesterol extraction in cytotoxicity. These data demonstrate the correlation between the cytotoxic effect, hemolytic activity and the cholesterol complexation attributes of beta-CD derivatives and we propose that cholesterol-solubilizing properties can be a predictive factor for beta-CD cell toxicity., (2010 Elsevier B.V. All rights reserved.)

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. The development process was supported by CE experiments where the complex formation between cyclodextrins and warfarin was investigated. The results demonstrate good enantio-discrimination for coumarin derivatives.

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=2.96. Based on these values the stability of the complexes formed by aspartame and 21 different cyclodextrins (CDs) were studied at pH 2.5, pH 5.2 and pH 9.0 values where aspartame exists predominantly in monocationic, zwitterionic and monoanionic form, respectively. The host cyclodextrin derivatives differed in various sidechains, degree of substitution, charge and purity so that the effect of these properties could be examined systematically. Concerning size, the seven-membered beta-cyclodextrin and its derivatives have been found to be the most suitable host molecules for complexation. Highest stability was observed for the acetylated derivative with a degree of substitution of 7. The purity of the CD enhanced the complexation while the degree of substitution did not provide obvious consequences. Finally, geometric aspects of the inclusion complex were assessed by 2D ROESY NMR and molecular modelling which proved that the guest's aromatic ring enters the wider end of the host cavity.

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.). 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 2moles/mole cyclodextrin, and sulfopropylated-beta-CD (SP4-beta-CD) with a degree of substitution of 4moles/mole beta-cyclodextrin. With this technique all compounds investigated are baseline resolved using different background electrolytes and chiral additives. The elution sequence was determined in all cases.

Isoflavones are suitable guest molecules for inclusion complex formation with cyclodextrins (CDs). The molecular encapsulation with CDs results in a solid, molecularly dispersed form and in a significantly improved aqueous solubility of isoflavones. Genistein, a key isoflavone constituent of Ononidis spinosae radix was found to form a supramolecular, non-covalent inclusion complex with both beta-cyclodextrin (beta-CD) and gamma-cyclodextrin (gamma-CD), while it did not form a stable complex with alpha-CD. The guest genistein was found to spatially located in the less polar cavity of cyclodextrin. The isolated binary genistein/CD complexes appeared novel crystalline lattices. The in vitro dissolution of genistein entrapped into both beta- and gamma-CD, significantly surpassed that of the plain isoflavone.

Cyclodextrins (CDs) are widely used materials and still in the focus of drug development. In spite of the extensive studies, there is limited information about the cytotoxic effect of different derivatives. This study compares the cytotoxic effect of methylated beta-CDs and some ionic derivatives. The methylated CDs involved in this study differ in the number and position of the methyl substituents. Heptakis(2,6-di-O-methyl)-beta-CD (DIMEB) with a degree of substitution (DS) of 14 has two methyl groups in all of the seven glucose subunits mostly at O-2 and O-6 position, each OH group is methylated in heptakis(2,3,6-tri-O-methyl)-beta-CD (TRIMEB) (DS = 21), and an unsystematic substitution is realized in randomly methylated beta-CD (RAMEB). DS is defined as the number of substituents per cyclodextrin ring. Using the above definition, the DS for RAMEB is 12.6. To see the effect of the ionic groups an anionic and a cationic CD derivative were also investigated: (2-hydroxy-3-N,N,N-trimethylamino)propyl beta-CD (QABCD) (DS = 2) and carboxymethylated beta-CD (CMBCD) (DS = 3,5). The in vitro cell toxicity decreases in the order of DIMEB > TRIMEB > or = RAMEB > QABCD > CMBCD. Ionic beta-CDs were less toxic than the methylated derivatives.

The release of alpha-tocopherol from two formulations (with and without complexation with beta-cyclodextrin) of low-density polyethylene (LDPE) film was examined. Specific migration studies were performed at 7.0 +/- 0.5 degrees C using plastic bags filled with 95% ethanol as a fatty food simulant. The amount of complexed and free (non-complexed) alpha-tocopherol migrating into the food simulant was followed by high-performance liquid chromatography (HPLC). It was concluded that complexation with beta-cyclodextrin had a significant effect on the release rate of the antioxidant. Using a mathematical model for the description of the migration, a decrease in diffusion coefficient (D) of one order of magnitude was calculated in the case of complexed alpha-tocopherol compared with the free form. Total migration of alpha-tocopherol from both films was observed, meaning that the partition coefficient of tocopherol was not influenced by incorporation with cyclodextrin. Thus, complexation might be the key to a long-lasting antioxidative effect of such kind of active packaging.

The objective of this mini-review is to summarize the findings concerning the physicochemical properties and the pharmaceutical applications of acidic drugs whose performances have been modified by simultaneous complexation with cyclodextrins and salt formation. Particular attention is paid to the approaches undertaken for increasing the solubility of the drugs by proper choice of the type of counterion analogously to what has been reported for complexes of basic drugs in the presence of hydroxy acids., (Copyright 2001 Wiley-Liss, Inc.)

The dissolution and absorption of poorly water-soluble drugs from rectal suppositories can be enhanced by complexing these substances (e.g., essential oils, indomethacin) with beta-cyclodextrin. Preliminary in vivo studies showed, that the application of cyclodextrin complexes to suppositories, the same as to oral applications, resulted in an increased blood level.

CHINOIN-137 consists of indometacin and beta-cyclodextrin in a 1 : 2 molar ratio. solid phase analytical techniques, as thermal analysis, mass spectrometry and X-ray powder diffraction do not support the existence of a well-defined crystalline complex. However this product dissolved in water more readily and results in a higher indometacin concentration than indometacin itself. The formation of an inclusion complex with a reasonable stability in aqueous solution was proved by diffusion tests and chiroptical properties. Following oral administration of CHINOIN-137 to rats, higher blood levels (by about 25%) of indometacin can be achieved than with the uncomplexed drug. A significant difference was observed in the absorption of 14C-labelled indometacin and its cyclodextrin complex by "in loco" techniques in the small intestines of anaesthetized rats: from indometacin 56%, from the complex 68% of the activity was resorbed within 10 min.

Application of beta-cyclodextrin complexes of volatile substances in suppositories improves the mechanical properties and stability of suppositories. The incompatibility between the volatile components and suppository bases can be eliminated.