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1
Labes, Antje, and Peter Schönheit. "Unusual Starch Degradation Pathway via Cyclodextrins in the Hyperthermophilic Sulfate-Reducing Archaeon Archaeoglobus fulgidus Strain 7324." Journal of Bacteriology 189, no. 24 (October 5, 2007): 8901–13. http://dx.doi.org/10.1128/jb.01136-07.
Анотація:
ABSTRACT The hyperthermophilic archaeon Archaeoglobus fulgidus strain 7324 has been shown to grow on starch and sulfate and thus represents the first sulfate reducer able to degrade polymeric sugars. The enzymes involved in starch degradation to glucose 6-phosphate were studied. In extracts of starch-grown cells the activities of the classical starch degradation enzymes, α-amylase and amylopullulanase, could not be detected. Instead, evidence is presented here that A. fulgidus utilizes an unusual pathway of starch degradation involving cyclodextrins as intermediates. The pathway comprises the combined action of an extracellular cyclodextrin glucanotransferase (CGTase) converting starch to cyclodextrins and the intracellular conversion of cyclodextrins to glucose 6-phosphate via cyclodextrinase (CDase), maltodextrin phosphorylase (Mal-P), and phosphoglucomutase (PGM). These enzymes, which are all induced after growth on starch, were characterized. CGTase catalyzed the conversion of starch to mainly β-cyclodextrin. The gene encoding CGTase was cloned and sequenced and showed highest similarity to a glucanotransferase from Thermococcus litoralis. After transport of the cyclodextrins into the cell by a transport system to be defined, these molecules are linearized via a CDase, catalyzing exclusively the ring opening of the cyclodextrins to the respective maltooligodextrins. These are degraded by a Mal-P to glucose 1-phosphate. Finally, PGM catalyzes the conversion of glucose 1-phosphate to glucose 6-phosphate, which is further degraded to pyruvate via the modified Embden-Meyerhof pathway.
2
Bansal, Paramjit S., Craig L. Francis, Noel K. Hart, Scott A. Henderson, David Oakenfull, Alan D. Robertson та Gregory W. Simpson. "Regioselective Alkylation of β-Cyclodextrin". Australian Journal of Chemistry 51, № 10 (1998): 915. http://dx.doi.org/10.1071/c98064.
Анотація:
Methodology for preparation of heptakis(2,6-di-O-alkyl)-β-cyclodextrins, heptakis(2-O-alkyl)-β- cyclodextrins, and heptakis(6-O-alkyl)-β-cyclodextrins in substantially purified form has been developed. Treatment of β-cyclodextrin (1) with sodium or barium hydroxide and various alkyl halides in dimethyl sulfoxide or a mixture of dimethyl sulfoxide and N,N-dimethylformamide provided the corresponding heptakis(2,6-di-O-alkyl)-β-cyclodextrins. Treatment of heptakis(6-O-t-butyldimethylsilyl)-β-cyclodextrin (5) with sodium hydroxide and several haloalkanes in dimethyl sulfoxide followed by desilylation provided heptakis(2-O-alkyl)-β-cyclodextrins. Protection of the secondary hydroxy groups of the t-butyldimethylsilyl-β-cyclodextrin (5) as benzyl ethers, followed by desilylation, alkylation, and debenzylation afforded several heptakis(6-O-alkyl)-β-cyclodextrins. Analytical methodology has been developed to characterize all of these compounds, with the homogeneity of the pattern of substitution verified by h.p.l.c. analysis, f.a.b.–mass spectrometry and n.m.r. spectroscopy.
3
Wang, Runmiao, Hui Zhou, Shirley W. I. Siu, Yong Gan, Yitao Wang, and Defang Ouyang. "Comparison of Three Molecular Simulation Approaches for Cyclodextrin-Ibuprofen Complexation." Journal of Nanomaterials 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/193049.
Анотація:
Cyclodextrins are widely used for the solubilisation of poorly soluble drugs in the formulations. However, current cyclodextrin formulation development strongly depends on trial-and-error in the laboratory, which is time-consuming and high cost. The aim of this research was to compare three modeling approaches (Docking, molecular dynamics (MD), and quantum mechanics (QM)) for cyclodextrin/drug complexation. Ibuprofen was used as a model drug. Binding free energy from three simulation methods was calculated as an important parameter to compare with the experimental results. Docking results from AutoDock Vina program showed that the scoring of complexation capability between ibuprofen and cyclodextrins is alpha (α), gamma (γ), beta (β), and HP-beta-cyclodextrins, which indicated similar ranking with the results from phase, solubility diagram experiments. MD simulation indicated that ibuprofen could form the stable complexes withβ-,γ-, and HP-β-cyclodextrins, but not for alpha cyclodextrin. Binding free energies from the MD simulation forβ-,γ-, and HP-β-cyclodextrins were −3.67, −0.67, and −3.87 kcal/mol, individually. The enthalpies of QM simulation forβ-,γ-, and HP-β-cyclodextrins were −17.22, −14.75, and −20.28 kcal/mol, respectively. Results from all three modeling approaches showed similar ranking between ibuprofen and four cyclodextrin molecules as the experimental data. However, MD simulation with entropy calculation had the closest value to experimental data forβand HP-beta-cyclodextrins. Thus, MD simulation with MM-PBSA method may be fit toin silicoscreen for cyclodextrin formulations.
4
Lavandier, CD, MP Pelletier та VC Reinsborough. "Surfactant Inclusions by Modified β-Cyclodextrins". Australian Journal of Chemistry 44, № 3 (1991): 457. http://dx.doi.org/10.1071/ch9910457.
Анотація:
Binding constants for the inclusion of sodium alkane-1-sulfonates (C5-C10, C12) by four modified β- cyclodextrins (2,6-O-dimethyl-β-cyclodextrin, 2,3,6-O-trimethyl-β-cyclodextrin, hydroxypropyl-β-cyclodextrin and maltosyl-β-cyclodextrin ) were determined conductimetrically at 25°C. Binding increased with increasing length of the alkyl chain. Generally, the substituted β- cyclodextrins were no more effective as encapsulating agents than ordinary β- cyclodextrin with the persubstituted 2,3,6-O-trimethyl-β-cyclodextrin being the weakest.
5
Easton, Christopher J., Steven J. van Eyk, Stephen F. Lincoln, Bruce L. May, John Papageorgiou, and Michael L. Williams. "A Versatile Synthesis of Linked Cyclodextrins." Australian Journal of Chemistry 50, no. 1 (1997): 9. http://dx.doi.org/10.1071/c96168.
Анотація:
Reactions of amino-substituted cyclodextrins with bis(3-nitrophenyl) oxalate, malonate, succinate and glutarate, and with diphenyl carbonate, afford a range of linked cyclodextrins. These include α- and β-cyclodextrin dimers, joined by substitution at either C6 or C3, and asymmetric species with a β-cyclodextrin bonded to an a-cyclodextrin and a C3-substituted cyclodextrin attached to a C6-substituted moiety.
6
Fenyvesi, Ferenc. "Biological Studies on Cyclodextrins." Proceedings 78, no. 1 (December 1, 2020): 60. http://dx.doi.org/10.3390/iecp2020-08692.
Анотація:
In recent years, our knowledge of the biological effects of cyclodextrins has grown significantly. Cellular actions of cyclodextrins originate in their ability to form complexes with lipophilic biomolecules. Cyclodextrins can target different types of molecules according to their size, for instance, alpha-cyclodextrins form complexes with phospholipids, while beta-cyclodextrins can bind cholesterol or prostaglandin E2. Due to their interactions with the main membrane constituents, cyclodextrins can affect the barrier function of biological barriers or influence the function of membrane proteins. Nevertheless, cyclodextrins can enter the cells by endocytosis and affect the intracellular cholesterol storage. Based on these findings, 2-hydroxypropyl-beta cyclodextrin (HPBCD) received the orphan designation for the treatment of Niemann–Pick disease type C. The endocytosis of cyclodextrins works in different cell types and can be applied in the delivery of drugs into the cells. The tissue distribution and pharmacokinetics of cyclodextrins could be further characterized by imaging techniques. Radiolabeled HPBCD and randomly methylated beta-cyclodextrin (RAMEB) were recently used to study their in vivo behavior by positron emission tomography. Interestingly, RAMEB accumulation was detected in prostaglandin E2 (PGE2)-positive tumors. These findings can promote further research and the application of cyclodextrins in inflammation and tumor diagnosis or targeting. The presentation aims to give an overview of the main biological effects of cyclodextrins and the recent results of this research field.
7
Yhaya, Firdaus, Andrew M. Gregory, and Martina H. Stenzel. "Polymers with Sugar Buckets - The Attachment of Cyclodextrins onto Polymer Chains." Australian Journal of Chemistry 63, no. 2 (2010): 195. http://dx.doi.org/10.1071/ch09516.
Анотація:
This Review summarizes the structures obtained when marrying synthetic polymers of varying architectures with cyclodextrins. Polymers with cyclodextrin pendant groups were obtained by directly polymerizing cyclodextrin-based monomers or by postmodification of reactive polymers with cyclodextrins. Star polymers with cyclodextrin as the core with up to 21 arms were usually obtained by using modified cyclodextrins as initiator or controlling agent. Limited reports are available on the synthesis of star polymers by arm-first techniques, which all employed azide-functionalized cyclodextrin and ‘click’ chemistry to attach seven polymer arms to the cyclodextrin core. Polymer chains with one or two cyclodextrin terminal units were reported as well as star polymers carrying a cyclodextrin molecule at the end of each arm. Cyclodextrin polymers were obtained using different polymerization techniques ranging from atom transfer radical polymerization, reversible addition–fragmentation chain transfer polymerization, nitroxide-mediated polymerization, free radical polymerization to (ionic) ring-opening polymerization, and polycondensation. Cyclodextrin polymers touch all areas of polymer science from gene delivery, self-assembled structures, drug carriers, molecular sensors, hydrogels, and liquid crystalline polymers. This Review attempts to focus on the range of work conducted with polymers and cyclodextrins and highlights some of the key areas where these macromolecules have been applied.
8
Sivakumar, Ponnurengam M., Shohreh Peimanfard, Ali Zarrabi, Arezoo Khosravi, and Matin Islami. "Cyclodextrin-Based Nanosystems as Drug Carriers for Cancer Therapy." Anti-Cancer Agents in Medicinal Chemistry 20, no. 11 (July 8, 2020): 1327–39. http://dx.doi.org/10.2174/1871520619666190906160359.
Анотація:
Background and Objective: Cyclodextrins have been of great interest as excellent candidates for fabricating versatile nano-drug delivery systems due to their commercial availability, easy functionalization, low immunogenicity, biocompatibility and safety. The possibility of reversible inclusion complex formation between cyclodextrins and various guest molecules in association with versatile exclusive properties of cyclodextrins offer a route towards the fabrication of highly sophisticated nanostructures with enormous potential for cancer treatment. Methods and Results: The current review discusses important recent advances in the fabrication and development of cyclodextrin-based nanostructures for cancer therapy. Firstly, the formation of inclusion complexes between cyclodextrin derivatives and anticancer compounds, as well as their application, are summarized. Secondly, the cyclodextrins -based nanosystems including cyclodextrin-containing polymers, cyclodextrin-based supramolecular necklaces, which consist of polyrotaxanes and polypseudorotaxanes and cyclodextrin based hydrogels accompanied by their applications in cancer treatment are highlighted. In the end, the future perspective of this field is discussed. Conclusion: Numerous investigations in this area pave the way for the flourishing of the next generation of nano-therapeutics towards enhanced cancer therapy.
9
Masoumi, Saeideh, Sahar Amiri, and Seyed Hajir Bahrami. "PCL-based nanofibers containing ibuprofen/cyclodextrins nanocontainers: A potential candidate for drug delivery application." Journal of Industrial Textiles 48, no. 9 (March 21, 2018): 1420–38. http://dx.doi.org/10.1177/1528083718764910.
Анотація:
Poor solubility and low dissolution rate of ibuprofen (IBU) in the aqueous gastro-intestinal fluids restrict its application, absorption, distribution, target organ delivery, and bioavailability. For improvement of aqueous solubility of IBU, supramolecular nanocontainers of IBU/cyclodextrin were prepared via formation of inclusion complex between ibuprofen and cyclodextrins (α-cyclodextrin and β-cyclodextrin) at various conditions (at room temperature at 25℃ and under sonic energy). The formation of inclusion complex between IBU and cyclodextrins can be confirmed by hydrogen nuclear magnetic resonance, differential scanning calorimetry, fourier transform Infrared spectroscopy (FTIR), X-ray diffraction, and scanning electron microscopy study. FTIR of pure IBU and cyclodextrins is similar to the obtained complex, which indicated intactness of drug in the complex. The encapsulation of IBU in cyclodextrins cavity improved its solubility, phase solubility, and in vitro dissolution and also controlled its release which ensures the long-term delivery. Electro-spun nanofibers of poly-ɛ-caprolactone containing IBU/cyclodextrins is a promising method for controlled drug delivery electro-spun which is bead-free without any aggregation on the surface.
10
Prior, Marguerite, Sylvain Lehmann, Man-Sun Sy, Brendan Molloy, and Hilary E. M. McMahon. "Cyclodextrins Inhibit Replication of Scrapie Prion Protein in Cell Culture." Journal of Virology 81, no. 20 (August 15, 2007): 11195–207. http://dx.doi.org/10.1128/jvi.02559-06.
Анотація:
ABSTRACT Prion diseases are fatal neurodegenerative disorders that are caused by the conversion of a normal host-encoded protein, PrPC, to an abnormal, disease-causing form, PrPSc. This paper reports that cyclodextrins have the ability to reduce the pathogenic isoform of the prion protein PrPSc to undetectable levels in scrapie-infected neuroblastoma cells. Beta-cyclodextrin removed PrPSc from the cells at a concentration of 500 μM following 2 weeks of treatment. Structure activity studies revealed that antiprion activity was dependent on the size of the cyclodextrin. The half-maximal inhibitory concentration (IC50) for beta-cyclodextrin was 75 μM, whereas α-cyclodextrin, which possessed less antiprion activity, had an IC50 of 750 μM. This report presents cyclodextrins as a new class of antiprion compound. For decades, the pharmaceutical industry has successfully used cyclodextrins for their complex-forming ability; this ability is due to the structural orientation of the glucopyranose units, which generate a hydrophobic cavity that can facilitate the encapsulation of hydrophobic moieties. Consequently, cyclodextrins could be ideal candidates for the treatment of prion diseases.
11
Gatiatulin, Askar K., Ivan A. Grishin, Aleksey V. Buzyurov, Timur A. Mukhametzyanov, Marat A. Ziganshin, and Valery V. Gorbatchuk. "Determination of Melting Parameters of Cyclodextrins Using Fast Scanning Calorimetry." International Journal of Molecular Sciences 23, no. 21 (October 28, 2022): 13120. http://dx.doi.org/10.3390/ijms232113120.
Анотація:
The first evidence of native cyclodextrins fusion was registered using fast scanning calorimetry (FSC) with heating rates up to 40,000 K s−1. The endothermal effects, detected at low heating rates, correspond to the decomposition processes. Upon the increase of the heating rate the onset of these effects shifts to higher temperatures, reaching a limiting value at high heating rates. The limiting temperatures were identified as the melting points of α-, β- and γ-cyclodextrins, as the decomposition processes are suppressed at high heating rates. For γ-cyclodextrin the fusion enthalpy was measured. The activation energies of thermal decomposition of cyclodextrins were determined by dependence of the observed thermal effects on heating rates from 4 K min−1 in conventional differential scanning calorimetry to 40,000 K s−1 in FSC. The lower thermal stability and activation energy of decomposition of β-cyclodextrin than for the other two cyclodextrins were found, which may be explained by preliminary phase transition and chemical reaction without mass loss. The obtained values of fusion parameters of cyclodextrins are needed in theoretical models widely used for prediction of solubility and solution rates and in preparation of cyclodextrin inclusion compounds involving heating.
12
Székely-Szentmiklósi, Blanka, and B. Tőkés. "Study of Cyclodextrin/Fluoroquinolone Inclusion Complexes by Capillary Electrophoresis." Acta Medica Marisiensis 59, no. 2 (April 1, 2013): 107–10. http://dx.doi.org/10.2478/amma-2013-0026.
Анотація:
AbstractIntroduction: In the present work we evaluated the complexation role of cyclodextrins toward fluoroquinolones in an attempt to assess their potential as new formulation additives for more efficient fluoroquinolone delivery and as selectors in capillary electrophoresis.Material and method: Guest-host interactions of two second generation quinolones, ciprofloxacin and norfloxacin with four cyclodextrins, beta-cyclodextrin (β-CD), gamma-cyclodextrin (γ-CD) and two beta-cyclodextrin derivatives, 2-hydroxypropyl beta-cyclodextrin (HP-β-CD) and randomly methylated beta-cyclodextrin (RAMEB), were tested by capillary electrophoresis in borate running buffer. Experimental parameters like buffer concentration, pH, organic modifier, voltage and cyclodextrin concentration have been varied for a better resolution.Results: In capillary zone electrophoresis ciprofloxacin and norfloxacin are migrating together, a difference in their migration times and thus separation occured by the addition of cyclodextrins.Conclusion: Our results suggest formation of inclusion complexes between fluoroquinolones and cyclodextrins. Differences in their affinity to host molecules resulted in separation of the two fluoroquinolones
13
Braga, Susana Santos, Karyna Lysenko, Firas El-Saleh, and Filipe A. Almeida Paz. "Cyclodextrin-Efavirenz Complexes Investigated by Solid State and Solubility Studies." Proceedings 78, no. 1 (December 1, 2020): 15. http://dx.doi.org/10.3390/iecp2020-08690.
Анотація:
This short paper investigates the solubilizing ability of various cyclodextrins with efavirenz as well as the formation of solid inclusion complexes of efavirenz with β-CD and γ-CD. (1) Background: Efavirenz is a non-nucleoside reverse transcriptase inhibitor used as first-line treatment for adult and pediatric human immunodeficiency virus type 1 infection (HIV-1). Belonging to class II of Biopharmaceutical Classification System (BCS), efavirenz is poorly water-soluble. Inclusion into cyclodextrins is a possible strategy for increasing its solubility. (2) Methods: Solubility modulation was investigated by the phase solubility method; inclusion of efavirenz with β- and γ-cyclodextrins was attempted by co-dissolution with co-precipitation; the precipitates were studied by DSC, FT-IR, powder X-ray diffraction and optical microscopy. (3) Results: Solid state analysis of the precipitates shows evidence of separate recrystallization of β-cyclodextrin and efavirenz, whereas in the case of γ-cyclodextrin, a single new phase was observed. (4) Conclusion: Results show that the cavity of β-cyclodextrin is too narrow to accommodate efavirenz and only γ-cyclodextrin, the largest of native cyclodextrins, is able to form a true inclusion complex with this bulky guest.
14
Wang, Lei, Xuguo Duan та Jing Wu. "Enhancing the α-Cyclodextrin Specificity of Cyclodextrin Glycosyltransferase from Paenibacillus macerans by Mutagenesis Masking Subsite −7". Applied and Environmental Microbiology 82, № 8 (5 лютого 2016): 2247–55. http://dx.doi.org/10.1128/aem.03535-15.
Анотація:
ABSTRACTCyclodextrin glycosyltransferases (CGTases) (EC 2.4.1.19) catalyze the conversion of starch or starch derivates into mixtures of α-, β-, and γ-cyclodextrins. Because time-consuming and expensive purification procedures hinder the widespread application of single-ingredient cyclodextrins, enzymes with enhanced specificity are needed. In this study, we tested the hypothesis that the α-cyclodextrin selectivity ofPaenibacillus maceransα-CGTase could be augmented by masking subsite −7 of the active site, blocking the formation of larger cyclodextrins, particularly β-cyclodextrin. Five single mutants and three double mutants designed to remove hydrogen-bonding interactions between the enzyme and substrate at subsite −7 were constructed and characterized in detail. Although the rates of α-cyclodextrin formation varied only modestly, the rate of β-cyclodextrin formation decreased dramatically in these mutants. The increase in α-cyclodextrin selectivity was directly proportional to the increase in the ratio of theirkcatvalues for α- and β-cyclodextrin formation. The R146A/D147P and R146P/D147A double mutants exhibited ratios of α-cyclodextrin to total cyclodextrin production of 75.1% and 76.1%, approximately one-fifth greater than that of the wild-type enzyme (63.2%), without loss of thermostability. Thus, these double mutants may be more suitable for the industrial production of α-cyclodextrin than the wild-type enzyme. The production of β-cyclodextrin by these mutants was almost identical to their production of γ-cyclodextrin, which was unaffected by the mutations in subsite −7, suggesting that subsite −7 was effectively blocked by these mutations. Further increases in α-cyclodextrin selectivity will require identification of the mechanism or mechanisms by which these small quantities of larger cyclodextrins are formed.
15
Healy, Bronach, Tian Yu, Daniele C. da Silva Alves, Cynthia Okeke, and Carmel B. Breslin. "Cyclodextrins as Supramolecular Recognition Systems: Applications in the Fabrication of Electrochemical Sensors." Materials 14, no. 7 (March 28, 2021): 1668. http://dx.doi.org/10.3390/ma14071668.
Анотація:
Supramolecular chemistry, although focused mainly on noncovalent intermolecular and intramolecular interactions, which are considerably weaker than covalent interactions, can be employed to fabricate sensors with a remarkable affinity for a target analyte. In this review the development of cyclodextrin-based electrochemical sensors is described and discussed. Following a short introduction to the general properties of cyclodextrins and their ability to form inclusion complexes, the cyclodextrin-based sensors are introduced. This includes the combination of cyclodextrins with reduced graphene oxide, carbon nanotubes, conducting polymers, enzymes and aptamers, and electropolymerized cyclodextrin films. The applications of these materials as chiral recognition agents and biosensors and in the electrochemical detection of environmental contaminants, biomolecules and amino acids, drugs and flavonoids are reviewed and compared. Based on the papers reviewed, it is clear that cyclodextrins are promising molecular recognition agents in the creation of electrochemical sensors, chiral sensors, and biosensors. Moreover, they have been combined with a host of materials to enhance the detection of the target analytes. Nevertheless, challenges remain, including the development of more robust methods for the integration of cyclodextrins into the sensing unit.
16
Murai, Hisao, Yoshinori Yamamoto, and Yasumasa J. I'Haya. "Time-resolved ESR study on photochemical formation of radical pair in cyclodextrin cavities." Canadian Journal of Chemistry 69, no. 11 (November 1, 1991): 1643–48. http://dx.doi.org/10.1139/v91-241.
Анотація:
The photoreduction of xanthone with diethylaniline in cyclodextrin cavities was studied at 77 K and room temperature by a time-resolved ESR technique. The radical pair observed in β- and γ-cyclodextrins showed inverted spin polarization compared to that of precursor excited triplet xanthone. This result is rationalized by taking account of the fixed orientation of the radical ion pair in the cyclodextrins. Frozen aqueous solutions and dried powder-like samples provided similar results. The spectrum of the radical pair was also detected in an aqueous solution of β-cyclodextrin at room temperature. Key words: cyclodextrins, xanthone, spin polarization, radical ion-pair, time-resolved ESR.
17
Raut, Sushil Y., Alekhya S. N. Manne, Guruprasad Kalthur, Sanyog Jain, and Srinivas Mutalik. "Cyclodextrins as Carriers in Targeted Delivery of Therapeutic Agents: Focused Review on Traditional and Inimitable Applications." Current Pharmaceutical Design 25, no. 4 (June 3, 2019): 444–54. http://dx.doi.org/10.2174/1381612825666190306163602.
Анотація:
The objective of the article is to provide a comprehensive review on the application of cyclodextrin complexation in the delivery of drugs, bioactive molecules or macromolecules, with more emphasis on targeted drug delivery. Classically the cyclodextrins have been considered only as a means of improving the solubility of drugs; however, many attempts have been made to use cyclodextrins as drug delivery carriers. The cyclodextrin surface can be modified with various ligands for active targeting of drugs. It can also be passively targeted through various triggering mechanisms like thermal, magnetic, pH dependent, light dependent, ultrasound, etc. A comprehensive literature review has been done in the area of drug delivery using cyclodextrins. Applications of inclusion complexes in the drug delivery through various routes with examples are discussed. This review focuses on receptor mediated active targeting as well as stimuli responsive passive targeting of drugs/genes by using cyclodextrins. The article provides a detailed insight of the use of cyclodextrins and their derivatives on the targeted delivery of the drugs/genes.
18
Belyakova, L. A. "Encapsulation of benzene carboxylic acids using cyclodextrins." Himia, Fizika ta Tehnologia Poverhni 12, no. 1 (March 30, 2021): 40–51. http://dx.doi.org/10.15407/hftp12.01.040.
Анотація:
The encapsulation of medicinal substances in various polymers is a common way to increase their thermal, hydrolytic, and chemical stability. However, the bioavailability of the encapsulated drugs decreases. The solution to this important problem can be the preparation of nanocapsules of medicinal substances using complexing agents, for example, cyclodextrins. The purpose of this work is to study the possibility of encapsulation of benzoic, salicylic, and β-resorcylic acids using α- and β-cyclodextrins. The interaction of benzene carboxylic acids with cyclodextrins in aqueous solutions at 20–30 оС has been studied by spectrophotometry. The formation of complexes with a composition of 1:1 in the cyclodextrin – benzene carboxylic acid systems has been proven. The stability constants of the complexes and the main thermodynamic parameters of complex formation have been calculated. It has been shown that the nature of changes in the spectral characteristics of benzene carboxylic acids in the presence of cyclodextrins can be used to predict the possibility of aromatic organic compounds encapsulation. The determining role of the complementarity of geometric parameters of cyclodextrins and benzene carboxylic acids in the preparation of inclusion complexes with features of nanocapsules has been found. The prospects of using β-cyclodextrin for encapsulation of benzene carboxylic acids have been demonstrated. The complexes of β-cyclodextrin with benzene carboxylic acids were synthesized and studied by IR spectroscopy, X-ray analysis and derivatography. The formation of two types of complexes in the β-cyclodextrin – benzene carboxylic acid system was established. The first type of complexes is formed due to nonspecific interactions between the hydrophobic cavity of β-cyclodextrin and the benzene carboxylic acid molecule, the second type is due to specific interactions between the functional groups of molecules. Benzoic and salicylic acids form nanocapsules with β-cyclodextrin, and their hydrolytic and thermal stability increases. Complexes of the second type acquire the properties of a new compound: β-resorcylic acid loses its individuality, forming strong supramolecular structures with β-cyclodextrin.
19
Easton, CJ, S. Kassara, SF Lincoln, and BL May. "Amino Substituents as a Probe of Reactions of Phenyl Acetates With Cyclodextrins." Australian Journal of Chemistry 48, no. 2 (1995): 269. http://dx.doi.org/10.1071/ch9950269.
Анотація:
The effects of α- and β- cyclodextrin and 6A-amino-6A-deoxy-α- and -β- cyclodextrin on the rates of reactions of m- and p-nitrophenyl acetate, in borate buffer at pH 10.0 and 298.2 K, show that the amino substituents of the modified cyclodextrins have only a modest influence on the dissociation constants of the complexes formed with each ester and the first-order rate constants for the reactions of complexed m-nitrophenyl acetate. By contrast, the amino substituents significantly increase the rate constants for the reactions of complexes of p- nitrophenyl acetate. These results indicate that one mode of inclusion of p-nitrophenyl acetate in α- and β- cyclodextrin has the ester oxycarbonyl group in the vicinity of the cyclodextrin primary hydroxy groups. While this mode of inclusion in the unmodified cyclodextrins does not lead to reaction and has not been detected previously for that reason, in analogous complexes of the amino-substituted cyclodextrins, the nucleophilic amino group is proximate to the carboxy group of the ester and reaction proceeds. There is no kinetic evidence for this mode of inclusion of m-nitrophenyl acetate. This interpretation of the kinetic effects is consistent with the extent of acetamide formation in reactions of the esters with the amino-substituted cyclodextrins.
20
Vranić, Edina, and Alija Uzunović. "Dissolution Studies of Physical Mixtures of Indomethacin with Alpha- and Gamma-Cyclodextrins." Bosnian Journal of Basic Medical Sciences 10, no. 3 (August 20, 2010): 197–203. http://dx.doi.org/10.17305/bjbms.2010.2685.
Анотація:
Oral administration of indomethacin has been limited by its poor water solubility. Cyclodextrins have been recognized as potential candidates to overcome the poor solubility of indomethacin through the formation of inclusion complexes.The aim of our study was to compare the dissolution profiles of pure indomethacin and its mixtures with α- and γ-cyclodextrins The inclusion complexes of indomethacin with α- and γ-cyclodextrins were prepared by direct mixing in dissolution vessel. Fixed volumes of the dissolution medium were withdrawn at 0,5; 1 and 4 hours. Dissolution tests were performed on the USP Apparatus 2, rotating speed 100 rpm at 37±0,5°C, 500 ml, distilled water and 0,1 M HCl solution). Quantification of dissolved indomethacin was performed by UV/VIS spectrophotometric method at the absorption maximum around 320 nm.The results were expressed as relative dissolution rate (ratio between indomethacin dissolved from its physical mixtures with α- and γ-cyclodextrins and that dissolved the pure drug).Relative dissolution rates of indomethacin in combination with α- and γ-cyclodextrins at the end of testing were in the range of 91,66 to 337,14 % (for α- cyclodextrin) and in the range of 128,57 to 301,92 % (for γ-cyclodextrin).The complexation of indomethacin with α- and γ-cyclodextrins resulted in the enhancement of dissolution rate.
21
Easton, Christopher J., Stephen F. Lincoln, Bruce L. May, and John Papageorgiou. "Reactions of Amino-Substituted Cyclodextrins with 2-Arylpropanoic Acid Derivatives." Australian Journal of Chemistry 50, no. 5 (1997): 451. http://dx.doi.org/10.1071/c97034.
Анотація:
Reactions of 6A-amino-6A-deoxy-β-cyclodextrin and 3A-amino-3A-deoxy-(2AS,3AS)-β-cyclodextrin with the 3-nitrophenyl esters of 2-phenylpropanoic acid and Ibuprofen occur with only low diastereoselectivity, to afford the corresponding arylpropanamido-substituted cyclodextrins. These amides are also formed by decarboxylation of corresponding malonates, again with only low diastereoselectivity. The n.m.r. spectra of the amido-substituted cyclodextrins indicate that the aryl substituent is included within the cyclodextrin annulus at low temperature, but becomes dissociated from the cavity as the temperature is increased.
22
Cabal, Jiří. "Hydrolytic Reactions of Methylfluorophosphonates with Cyclodextrins." Collection of Czechoslovak Chemical Communications 60, no. 7 (1995): 1162–69. http://dx.doi.org/10.1135/cccc19951162.
Анотація:
Reactions of three methylfluorophosphonates (isopropyl, 1,2,2-trimethylpropyl, and cyclohexyl) with α-, β- and γ-cyclodextrins were investigated. The cyclodextrins were found to react with stereoisomers of the methylfluorophosphonates at different rates depending on the location of the substituents at the phosphorus atom. The dependence of the rate increase on cyclodextrin concentration showed a saturation effect. The reactivity of the inclusion complexes of the cyclodextrins with the methylfluorophosphonates depended on the size of the alkyl part of the phosphonate molecule as well as on the size of the cavity of the cyclodextrins. Dependences of the reaction rates on temperature and pH of the reaction medium were recorded. Kinetic data have been used to evaluate the cyclodextrins as the catalysts.
23
Kazlauskaite, Jurga Andreja, Liudas Ivanauskas, and Jurga Bernatoniene. "Cyclodextrin-Assisted Extraction Method as a Green Alternative to Increase the Isoflavone Yield from Trifolium pratensis L. Extract." Pharmaceutics 13, no. 5 (April 26, 2021): 620. http://dx.doi.org/10.3390/pharmaceutics13050620.
Анотація:
Trifolium pratense L. is receiving increasing attention due to the isoflavones it contains, which have been studied for their benefits to human health. A common problem with isoflavone aglycones is a rather low water solubility and limited pharmaceutical applications. The use of excipients, such as cyclodextrins in the production of isoflavone rich extracts, could become one of the new strategies for the extraction of target compounds. The aim of this study was to evaluate an eco-friendly method using the effects of α-, β- and γ-cyclodextrins for isoflavone solubilization in plant extracts in comparison to a standard extract without excipients. Extractions of red clover were prepared using ultrasound-assisted combined with thermal hydrolysis and heat reflux. It was determined that cyclodextrins significantly increased the isoflavones aglycone yields. By increasing cyclodextrins in the extraction media from 1 to 5%, the daidzin concentration increased on average by 1.06 (α-cyclodextrins), 1.4 (β-cyclodextrins) and 1.25 (γ-cyclodextrins) times. Genistein concentration increased using α- and γ-cyclodextrins (1.28 and 1.12 times, α- and γ-cyclodextrins, respectively), but decreased using β-cyclodextrins. The results showed that the cyclodextrin-assisted extraction enhanced the yields of isoflavones from red clover, which suggests using cyclodextrins as a green alternative and a cost-effective method to increase its pharmaceutical application.
24
Yannakopoulou, Konstantina, Laszlo Jicsinszky, Crysie Aggelidou, Nikolaos Mourtzis, Tanisha M. Robinson, Adiamseged Yohannes, Ekaterina M. Nestorovich, Sergey M. Bezrukov та Vladimir A. Karginov. "Symmetry Requirements for Effective Blocking of Pore-Forming Toxins: Comparative Study with α-, β-, and γ-Cyclodextrin Derivatives". Antimicrobial Agents and Chemotherapy 55, № 7 (9 травня 2011): 3594–97. http://dx.doi.org/10.1128/aac.01764-10.
Анотація:
ABSTRACTWe compared the abilities of structurally related cationic cyclodextrins to inhibitBacillus anthracislethal toxin andStaphylococcus aureusα-hemolysin. We found that both β- and γ-cyclodextrin derivatives effectively inhibited anthrax toxin action by blocking the transmembrane oligomeric pores formed by the protective antigen (PA) subunit of the toxin, whereas α-cyclodextrins were ineffective. In contrast, α-hemolysin was selectively blocked only by β-cyclodextrin derivatives, demonstrating that both symmetry and size of the inhibitor and the pore are important.
25
Kazlauskaite, Jurga Andreja, Liudas Ivanauskas, Mindaugas Marksa, and Jurga Bernatoniene. "The Effect of Traditional and Cyclodextrin-Assisted Extraction Methods on Trifolium pratense L. (Red Clover) Extracts Antioxidant Potential." Antioxidants 11, no. 2 (February 21, 2022): 435. http://dx.doi.org/10.3390/antiox11020435.
Анотація:
Red clover is the subject of numerous studies because of its antioxidant properties, the positive influence of isoflavones on the health, and its potential use in the prevention and treatment of chronic diseases. The right excipients, such as cyclodextrins, can increase the profile of valuable phenolic compounds in extraction media to obtain rich in antioxidants, extracts that can be used in nutraceuticals production. The aim of this study was to investigate and compare the total phenolic content, flavonoid content, and antioxidant activity of red clover aerial parts, aqueous and ethanolic extracts prepared using traditional and cyclodextrins-assisted methods. The antioxidant activity of the extracts was established using ABTS, DPPH, FRAP, and ABTS-post column methods. It was determined that cyclodextrins significantly increased total phenolic content (compared with control)—using β-cyclodextrin 20.29% (in aqueous samples); γ-cyclodextrin 22.26% (in ethanolic samples). All the samples prepared with excipients demonstrated a strong relationship between total phenolic content and DPPH assay. Study showed that for extraction with water, the highest amounts of phenolic compounds, flavonoids and antioxidant activity will be achieved with β-cyclodextrin, but extractions with ethanol will give the best results with γ-cyclodextrin. Therefore, cyclodextrins are a great and safe tool for obtaining rich, red clover flower extracts that are high in antioxidant activity, which can be used in the pharmaceutical industry for nutraceuticals production.
26
Li, Shujing, Li Yuan, Bing Zhang, Wei Zhou, Xinrui Wang та Dongsheng Bai. "Photostability and antioxidant activity studies on the inclusion complexes of trans-polydatin with β-cyclodextrin and derivatives". RSC Advances 8, № 46 (2018): 25941–48. http://dx.doi.org/10.1039/c8ra04778b.
27
Rusznyák, Ágnes, Mercédesz Palicskó, Milo Malanga, Éva Fenyvesi, Lajos Szente, Judit Váradi, Ildikó Bácskay, et al. "Cellular Effects of Cyclodextrins: Studies on HeLa Cells." Molecules 27, no. 5 (February 28, 2022): 1589. http://dx.doi.org/10.3390/molecules27051589.
Анотація:
Cyclodextrins are high molecular weight, hydrophilic, cyclic, non-reducing oligosaccharides, applied as excipients for the improvement of the solubility and permeability of insoluble active pharmaceutical ingredients. On the other hand, beta-cyclodextrins are used as cholesterol sequestering agents in life sciences. Recently, we demonstrated the cellular internalization and intracellular effects of cyclodextrins on Caco-2 cells. In this study, we aimed to further investigate the endocytosis of (2-hydroxylpropyl)-beta-(HPBCD) and random methylated-beta-cyclodextrin (RAMEB) to test their cytotoxicity, NF-kappa B pathway induction, autophagy, and lysosome formation on HeLa cells. These derivatives were able to enter the cells; however, major differences were revealed in the inhibition of their endocytosis compared to Caco-2 cells. NF-kappa B p65 translocation was not detected in the cell nuclei after HPBCD or RAMEB pre-treatment and cyclodextrin treatment did not enhance the formation of autophagosomes. These cyclodextrin derivates were partially localized in lysosomes after internalization.
28
Musilová, Lenka, Aleš Mráček, Eduarda F. G. Azevedo, Artur J. M. Valente, Ana M. T. D. P. V. Cabral, Ana C. F. Ribeiro та Miguel A. Esteso. "Interactions between Sodium Hyaluronate and β-Cyclodextrin as Seen by Transport Properties". International Journal of Molecular Sciences 24, № 3 (2 лютого 2023): 2889. http://dx.doi.org/10.3390/ijms24032889.
Анотація:
Knowledge of mass transport parameters, diffusion, and viscosity of hyaluronic acid (HA) in the presence of cyclodextrins is of considerable importance for areas such as food packaging and drug delivery, among others. Despite a number of studies investigating the functionalization of HA or the corresponding sodium salt by cyclodextrins, only a few studies have reported the effect of cyclodextrins on the mass transport of HA in the presence of these oligosaccharides. Here, we report the tracer binary and ternary interdiffusion coefficients of sodium hyaluronate (NaHy) in water and aqueous β-cyclodextrin solutions. The diffusion behavior of sodium hyaluronate was dependent on the reduced viscosity of NaHy, which, in turn, presented a concave dependence on concentration, with a minimum at approximately 2.5 g dm−3. The significant decrease in the limiting diffusion coefficient of NaHy (at most 45%) at NaHy concentrations below 1 g dm−3 in the presence of β-cyclodextrin, taking water as the reference, allowed us to conclude that NaHy strongly interacted with the cyclodextrin.
29
Rassu, Giovanna, Silvia Fancello, Marta Roldo, Milo Malanga, Lajos Szente, Rossana Migheli, Elisabetta Gavini, and Paolo Giunchedi. "Investigation of Cytotoxicity and Cell Uptake of Cationic Beta-Cyclodextrins as Valid Tools in Nasal Delivery." Pharmaceutics 12, no. 7 (July 12, 2020): 658. http://dx.doi.org/10.3390/pharmaceutics12070658.
Анотація:
Cyclodextrin polymers have high applicability in pharmaceutical formulations due to better biocompatibility, solubility enhancement, loading capacity and controlled drug release than their parent, cyclodextrins. The cytotoxicity and cell uptake of new cationic beta-cyclodextrin monomers and polymers were evaluated as suitable materials for nasal formulations and their protective effects on cells exposed to hydrogen peroxide were studied. PC12 and CACO-2 cells were selected as the neuronal- and epithelial-type cells, respectively, to mimic the structure of respiratory and olfactory epithelia of the nasal cavity. All cationic beta-cyclodextrin polymers tested showed dose- and time-dependent toxicity; nevertheless, at 5 µM concentration and 60 min of exposure, the quaternary-ammonium-beta-cyclodextrin soluble polymer could be recognized as nontoxic. Based on these results, a fluorescently labelled quaternary-ammonium-beta-cyclodextrin monomer and polymer were selected for uptake studies in CACO-2 cells. The monomeric and polymeric beta-cyclodextrins were internalized in the cytoplasm of CACO-2 cells; the cationic monomer showed higher permeability than the hydroxypropyl-beta-cyclodextrin, employed as comparison. Therefore, these cationic beta-cyclodextrins showed potential as excipients able to improve the nasal absorption of drugs. Furthermore, amino-beta-cyclodextrin and beta-cyclodextrin soluble polymers were able to reduce oxidative damage in PC12 and CACO-2 cells and thus could be studied as bioactive carriers or potential drugs for cell protection against oxidative stress.
30
Rusznyák, Ágnes, Milo Malanga, Éva Fenyvesi, Lajos Szente, Judit Váradi, Ildikó Bácskay, Miklós Vecsernyés, et al. "Investigation of the Cellular Effects of Beta- Cyclodextrin Derivatives on Caco-2 Intestinal Epithelial Cells." Pharmaceutics 13, no. 2 (January 25, 2021): 157. http://dx.doi.org/10.3390/pharmaceutics13020157.
Анотація:
Cyclodextrins are widely used excipients for increasing water-solubility, delivery and bioavailability of lipophilic drugs. By using fluorescent cyclodextrin derivatives, we showed previously that cyclodextrins are able to enter Caco-2 intestinal cells by endocytosis, but the influence of different fluorescent labeling on the same cyclodextrin derivative has not been studied. The consequences of the cellular internalization of cyclodextrins have not been revealed yet either. The aims of this study were to compare the cellular internalization of fluorescein- and rhodamine-labeled (2-hydroxypropyl)-, (HPBCD) and randommethyl-β-cyclodextrins (RAMEB) and to investigate the intracellular effects of these derivatives on Caco-2 cells. Stimulation of the NF-kappa B pathway and autophagy and localization of these derivatives in lysosomes were tested. The endocytosis of these derivatives was examined by fluorescence microscopy and flow cytometry. Both fluorescein- and rhodamine-labeled derivatives entered the cells, therefore the type of the fluorescent labeling did not influence their internalization. Cyclodextrin pretreatment did not activate the translocation of the p65 subunit of the NF-kappa B heterodimer into the cell nuclei from the cytoplasm. After HPBCD or RAMEB treatment, formation of the autophagosomes did not increase compared to the control sample and at the same time these derivatives could be detected in lysosomes after internalization.
31
Lemli, Beáta, Péter Vilmányi, Eszter Fliszár-Nyúl, Balázs Zoltán Zsidó, Csaba Hetényi, Lajos Szente, and Miklós Poór. "Testing Serum Albumins and Cyclodextrins as Potential Binders of the Mycotoxin Metabolites Alternariol-3-Sulfate, Alternariol-9-Monomethylether and Alternariol-9-Monomethylether-3-Sulfate." International Journal of Molecular Sciences 23, no. 22 (November 18, 2022): 14353. http://dx.doi.org/10.3390/ijms232214353.
Анотація:
Alternaria mycotoxins, including alternariol (AOH), alternariol-9-monomethylether (AME), and their masked/modified derivatives (e.g., sulfates or glycosides), are common food contaminants. Their acute toxicity is relatively low, while chronic exposure can lead to the development of adverse health effects. Masked/modified metabolites can probably release the more toxic parent mycotoxin due to their enzymatic hydrolysis in the intestines. Previously, we demonstrated the complex formation of AOH with serum albumins and cyclodextrins; these interactions were successfully applied for the extraction of AOH from aqueous matrices (including beverages). Therefore, in this study, the interactions of AME, alternariol-3-sulfate (AS), and alternariol-9-monomethylether-3-sulfate (AMS) were investigated with albumins (human, bovine, porcine, and rat) and with cyclodextrins (sulfobutylether-β-cyclodextrin, sugammadex, and cyclodextrin bead polymers). Our major results/conclusions are the following: (1) The stability of mycotoxin–albumin complexes showed only minor species dependent variations. (2) AS and AMS formed highly stable complexes with albumins in a wide pH range, while AME–albumin interactions preferred alkaline conditions. (3) AME formed more stable complexes with the cyclodextrins examined than AS and AMS. (4) Beta-cyclodextrin bead polymer proved to be highly suitable for the extraction of AME, AS, and AMS from aqueous solution. (5) Albumins and cyclodextrins are promising binders of the mycotoxins tested.
32
ZHEKOVA, BORIANA Y., and VESELIN S. STANCHEV. "Reaction Conditions for Maximal Cyclodextrin Production by Cyclodextrin Glucanotransferase from Bacillus megaterium." Polish Journal of Microbiology 60, no. 2 (2011): 113–18. http://dx.doi.org/10.33073/pjm-2011-015.
Анотація:
The effect of the reaction conditions (substrate concentration, enzyme dosage, and pH) on cyclodextrin production by cyclodextrin glucanotransferase from Bacillus megaterium was investigated by applying mathematical modeling methods. Adequate models were developed and they were used for determination of the optimal conditions for maximal formation of beta-cyclodextrins at minimal concentrations of a- and gamma-cydclodextrins. The main factor affecting the ratio of the products was pH of the reaction mixture. At pH 9 the enzyme formed mainly beta- and y-cyclodextrins and the ratio a:beta:gamma was 2.6:83.5:13.9; at pH 5 the ratio changed to 8.6:84.6:6.8. Mathematical models were used for determination of the conditions for maximal conversion of the substrate into cyclodextrins. 45.88% conversion of starch was achieved at 5% substrate concentration, 3.5 U/g enzyme dosage, and pH 7.4.
33
Kean, Suzanna D., Christopher J. Easton та Stephen F. Lincoln. "Metallo-β-cyclodextrins of 6A-(2-(2-(2-Aminoethylamino)-ethylamino)ethylamino)-6A-deoxy-β-cyclodextrin and 6A-Deoxy-6A-(1,4,7,10-tetraazacyclododecan-1-yl)-β-cyclodextrin: Their Formation and Complexation of (R)- and (S)-Tryptophan and Tryptophanate in Aqueous Solution". Australian Journal of Chemistry 53, № 5 (2000): 375. http://dx.doi.org/10.1071/ch00052.
Анотація:
The binary metallo-β-cyclodextrins formed by 6A-(2-(2-(2-aminoethylamino)ethylamino)ethylamino)-6A-deoxy-β-cyclodextrin, [M(βCDtrien)]2+, where M2+ = Ni2+, Cu2+ and Zn2+, are characterized by log(K/dm3 mol-1) = 11.500.02, 10.700.07 and 9.400.01, respectively, in aqueous solution at 298.2 K and I = 0.1 mol dm-3 (NaClO4), where K is the stability constant. For those formed by 6A-deoxy-6A-(1,4,7,10-tetraazacyclododecan-1-yl)-β-cyclodextrin, [M(βCDcyclen)]2+, where M2+ = Cu2+ and Zn2+, log(K/dm3 mol-1) = 13.610.02 and 11.620.04, respectively. The ternary metallo-β-cyclodextrins formed by [M(βCDtrien)]2+ and (R)- and (S)-tryptophanate, [M(βCDtrien)((R)-Trp)]+ and [M(βCDtrien)((S)-Trp)]+ are characterized by log(K/dm3 mol-1) = 6.900.04 and 6.790.04, 8.20.3 and 7.90.2, and 6.640.08 and 7.010.07, respectively, where M2+ = Ni2+, Cu2+ and Zn2+. For the ternary metallo-β-cyclodextrins formed by [M(βCDcyclen)]2+ and (R)- and (S)-tryptophanate, [M(βCDcyclen)((R)-Trp)]+ and [M(βCDcyclen)((S)-Trp)]+, log(K/dm3 mol-1) = 6.840.06 and 6.850.06, and 4.950.05 and 4.940.04, respectively, where M2+ = Cu2+ and Zn2+. Other binary and ternary metallo-β-cyclo-dextrins are also formed. Binary complexes formed by the substituted β-cyclodextrins are exemplified by βCDcyclen.(R)-Trp- and βCDcyclen.(S)-Trp- for which log(Kd/m3 mol-1) = 3.690.04 and 3.950.03, respectively. These data are discussed together with those from the literature characterizing other metallo-β-cyclodextrin and substituted β-cyclodextrin systems.
34
Dumanski, Paul G., Christopher J. Easton, Stephen F. Lincoln, and Jamie S. Simpson. "Effect of Cyclodextrins on Electrophilic Aromatic Bromination in Aqueous Solution." Australian Journal of Chemistry 56, no. 11 (2003): 1107. http://dx.doi.org/10.1071/ch03102.
Анотація:
Cyclodextrins act as molecular reactors to change the ratios of the products of reactions of anisole, acetanilide, 3-methylanisole, and 3-methylacetanilide with pyridinium dichlorobromate. With anisole and acetanilide, bromination at the para position is favoured over ortho substitution, and the effect is greatest with α-cyclodextrin. In the reactions of the methylanisole and methylacetanilide, the cyclodextrins afford higher yields of monobrominated products and less of the di- and tribromides, and β-cyclodextrin has the greatest effect. These outcomes can be attributed to inclusion of the substrates within the cyclodextrins restricting access of the reagent adjacent to the methoxy and acetamido groups. The yields of 4-bromoanisole, 4-bromoacetanilide, 4-bromo-3-methylanisole, and 4-bromo-3-methylacetanilide are thus increased from 73 to 94, 55 to 98, 37 to 86, and 39 to 72%, respectively. Perhaps more significantly, the quantities of the corresponding by-products are substantially reduced, from 27 to 6, 45 to 2, 63 to 14, and 61 to 28%. Since the reactions occur readily in water at ambient temperature, the cyclodextrins make them very efficient.
35
Meier-Augenstein, Wolfram, Barend V. Burger, Hendrik S. C. Spies та Wina J. G. Burger. "Conformational Analyses of Alkylated β-Cyclodextrins by NMR Spectroscopy". Zeitschrift für Naturforschung B 47, № 6 (1 червня 1992): 877–86. http://dx.doi.org/10.1515/znb-1992-0618.
Анотація:
β-Cyclodextrin was derivatized with 1-bromoalkanes of different chain lengths. The yield as well as the purity of the resulting cyclodextrin derivatives were improved by using solvent mixtures instead of pure solvents. The heptakis(2,6-di-O-alkyl)- and heptakis(2,3,6-tri-O-alkyl)-β-cyclodextrins were studied by means of NMR spectroscopy employing one-dimensional as well as two-dimensional NMR techniques. Analysis of the NMR data showed that only in completely derivatized β-cyclodextrins the cyclodextrin torus undergoes a conformational change. Best separation factors were found for the cyclodextrin derivative with the highest internal mobility as determined from the corresponding NT1-values, the validity of which was confirmed by NOE determinations. Therefore, 13C relaxation times could be used as a measure of the efficiency and usefulness of a given cyclodextrin derivative as an enantioselective stationary phase.
36
Welliver, Mark, and John P. McDonough. "Anesthetic Related Advances with Cyclodextrins." Scientific World JOURNAL 7 (2007): 364–71. http://dx.doi.org/10.1100/tsw.2007.83.
Анотація:
Cyclodextrins encapsulate and electrostatically bind to lipophilic molecules. The exterior of cyclodextrins are water-soluble and maintain aqueous solubility despite encapsulation of non-aqueous soluble molecules. This unique ability to encapsulate lipophilic molecules and maintain water solubility confers numerous pharmacologic advantages for both drug delivery and removal. Cyclodextrins, a component part of supramolecular chemistry, may be in its infancy of anesthetic application but recent advances have been described as novel and revolutionary. A review of current research coupled with an understanding of cyclodextrin properties is necessary to fully appreciate the current uses and future potentials of these unique molecules.
37
Rajput, Kiransinh N., Kamlesh C. Patel та Ujjval B. Trivedi. "β-Cyclodextrin Production by Cyclodextrin Glucanotransferase from an Alkaliphile Microbacterium terrae KNR 9 Using Different Starch Substrates". Biotechnology Research International 2016 (25 серпня 2016): 1–7. http://dx.doi.org/10.1155/2016/2034359.
Анотація:
Cyclodextrin glucanotransferase (CGTase, EC 2.4.1.19) is an important member of α-amylase family which can degrade the starch and produce cyclodextrins (CDs) as a result of intramolecular transglycosylation (cyclization). β-Cyclodextrin production was carried out using the purified CGTase enzyme from an alkaliphile Microbacterium terrae KNR 9 with different starches in raw as well as gelatinized form. Cyclodextrin production was confirmed using thin layer chromatography. Six different starch substrates, namely, soluble starch, potato starch, sago starch, corn starch, corn flour, and rice flour, were tested for CD production. Raw potato starch granules were found to be the best substrate giving 13.46 gm/L of cyclodextrins after 1 h of incubation at 60°C. Raw sago starch gave 12.96 gm/L of cyclodextrins as the second best substrate. To achieve the maximum cyclodextrin production, statistical optimization using Central Composite Design (CCD) was carried out with three parameters, namely, potato starch concentration, CGTase enzyme concentration, and incubation temperature. Cyclodextrin production of 28.22 (gm/L) was achieved with the optimized parameters suggested by the model which are CGTase 4.8 U/L, starch 150 gm/L, and temperature 55.6°C. The suggested optimized conditions showed about 15% increase in β-cyclodextrin production (28.22 gm/L) at 55.6°C as compared to 24.48 gm/L at 60°C. The degradation of raw potato starch granules by purified CGTase was also confirmed by microscopic observations.
38
Kontogiannidou, Eleni, Martina Ferrari, Asteria-Danai Deligianni, Nikolaos Bouropoulos, Dimitrios A. Andreadis, Milena Sorrenti, Laura Catenacci, et al. "In Vitro and Ex Vivo Evaluation of Tablets Containing Piroxicam-Cyclodextrin Complexes for Buccal Delivery." Pharmaceutics 11, no. 8 (August 8, 2019): 398. http://dx.doi.org/10.3390/pharmaceutics11080398.
Анотація:
In the current study, the development of mucoadhesive tablets for buccal delivery of a non-steroidal anti-inflammatory drug was investigated. Binary complexes with piroxicam and cyclodextrins (β-cyclodextrin (β-CD), methylated-β-cyclodextrin (Me-β-CD), and hydroxypropyl-β-cyclodextrin (HP-β-CD)) were prepared by the co-evaporation method. All formulations were characterized by means of differential scanning calorimetry, infrared spectroscopy and powder X-ray diffractometry. Mucoadhesive tablets of binary systems were formulated by direct compression using chitosan as mucoadhesive polymer. The in vitro release profiles of tablets were conducted in simulated saliva and, the drug permeation studies, across porcine buccal mucosa. The results suggest that the rank order effect of cyclodextrins for the drug release was Me-β-CD > HP-β-CD > β-CD, whereas the ex vivo studies showed that the tablets containing chitosan significantly increased the transport of the drug compared to their free complexes. Finally, histological assessment revealed loss of the superficial cell layers, which might be attributed to the presence of cyclodextrins.
39
Poulson, Benjamin Gabriel, Qana A. Alsulami, Abeer Sharfalddin, Emam F. El Agammy, Fouzi Mouffouk, Abdul-Hamid Emwas, Lukasz Jaremko, and Mariusz Jaremko. "Cyclodextrins: Structural, Chemical, and Physical Properties, and Applications." Polysaccharides 3, no. 1 (December 28, 2021): 1–31. http://dx.doi.org/10.3390/polysaccharides3010001.
Анотація:
Due to their unique structural, physical and chemical properties, cyclodextrins and their derivatives have been of great interest to scientists and researchers in both academia and industry for over a century. Many of the industrial applications of cyclodextrins have arisen from their ability to encapsulate, either partially or fully, other molecules, especially organic compounds. Cyclodextrins are non-toxic oligopolymers of glucose that help to increase the solubility of organic compounds with poor aqueous solubility, can mask odors from foul-smelling compounds, and have been widely studied in the area of drug delivery. In this review, we explore the structural and chemical properties of cyclodextrins that give rise to this encapsulation (i.e., the formation of inclusion complexes) ability. This review is unique from others written on this subject because it provides powerful insights into factors that affect cyclodextrin encapsulation. It also examines these insights in great detail. Later, we provide an overview of some industrial applications of cyclodextrins, while emphasizing the role of encapsulation in these applications. We strongly believe that cyclodextrins will continue to garner interest from scientists for many years to come, and that novel applications of cyclodextrins have yet to be discovered.
40
Braga, Susana Santos, Jéssica S. Barbosa, Nádia E. Santos, Firas El-Saleh, and Filipe A. Almeida Paz. "Cyclodextrins in Antiviral Therapeutics and Vaccines." Pharmaceutics 13, no. 3 (March 19, 2021): 409. http://dx.doi.org/10.3390/pharmaceutics13030409.
Анотація:
The present review describes the various roles of cyclodextrins (CDs) in vaccines against viruses and in antiviral therapeutics. The first section describes the most commonly studied application of cyclodextrins—solubilisation and stabilisation of antiviral drugs; some examples also refer to their beneficial taste-masking activity. The second part of the review describes the role of cyclodextrins in antiviral vaccine development and stabilisation, where they are employed as adjuvants and cryopreserving agents. In addition, cyclodextrin-based polymers as delivery systems for mRNA are currently under development. Lastly, the use of cyclodextrins as pharmaceutical active ingredients for the treatment of viral infections is explored. This new field of application is still taking its first steps. Nevertheless, promising results from the use of cyclodextrins as agents to treat other pathologies are encouraging. We present potential applications of the results reported in the literature and highlight the products that are already available on the market.
41
Djordjevic, Dragan, Mile Novakovic, and Sandra Konstantinovic. "The application of cyclodextrins in textile area." Chemical Industry 60, no. 9-10 (2006): 259–68. http://dx.doi.org/10.2298/hemind0610259d.
Анотація:
The application of Cyclodextrins for textiles was reviewed in this paper. Cyclodextrins are crystalline, water soluble, cyclic, non-reducing oligosaccharides consisting of six, seven, or eight glucopyranose units. Cyclodextrins are known as products which are able to form inclusion complexes. The ability of Cyclodextrins to form inclusion complexes can be used, e.g., to remove malodor from textile materials, etc. Furthermore, some modifications of the parent Cyclodextrins are possible. The derivatives can be reactive (e.g. cyclodextrin with a monochlorotriazinyl group), more hydrophilic (by means of hydrophilic side groups, such as hydroxypropyl and hydroxyethyl), less hydrophilic (by means of lipophilic side groups, such as ethylhexyl glycidyl) or ionic (by means of ionic side groups, such as hydroxypropyl trimethyl ammonium chloride).The methods for treating textiles are thus quite simple. The method using anchor-bearing Cyclodextrins is especially useful, since no fixation agent is needed, enabling they use of conventional textile treatment techniques and equipment. Furthermore, this method has virtually no limitations with respect to the textile materials that can be used.
42
Dehabadi, Vahid Ameri, Hans-Jürgen Buschmann та Jochen Stefan Gutmann. "Spectrophotometric estimation of the accessible inclusion sites of β-cyclodextrin fixed on cotton fabrics using phenolic dyestuffs". Anal. Methods 6, № 10 (2014): 3382–87. http://dx.doi.org/10.1039/c4ay00293h.
Анотація:
With the known stoichiometry of the complex formation of phenolic dyes with β-cyclodextrin, spectrophotometric study of complexation and decomplexation of these dyestuffs in cavities of cyclodextrins enables us to determine the accessible cyclodextrin sites quantitatively.
43
Lachowicz, Malwina, Andrzej Stańczak, and Michał Kołodziejczyk. "Characteristic of Cyclodextrins: Their Role and Use in the Pharmaceutical Technology." Current Drug Targets 21, no. 14 (October 21, 2020): 1495–510. http://dx.doi.org/10.2174/1389450121666200615150039.
Анотація:
About 40% of newly-discovered entities are poorly soluble in water, and this may be an obstacle in the creation of new drugs. To address this problem, the present review article examines the structure and properties of cyclodextrins and the formation and potential uses of drug – cyclodextrin inclusion complexes. Cyclodextrins are cyclic oligosaccharides containing six or more D-(+)- glucopyranose units linked by α-1,4-glycosidic bonds, which are characterized by a favourable toxicological profile, low local toxicity and low mucous and eye irritability; they are virtually non-toxic when administered orally. They can be incorporated in the formulation of new drugs in their natural form (α-, β-, γ-cyclodextrin) or as chemically-modified derivatives. They may also be used as an excipient in drugs delivered by oral, ocular, dermal, nasal and rectal routes, as described in the present paper. Cyclodextrins are promising compounds with many beneficial properties, and their use may be increasingly profitable for pharmaceutical scientists.
44
Liu, Jinshu, Xiaoyan Ma, Wenzhao Shi, Jianwei Xing, and Chaoqun Ma. "Grafting Modification of Natural Fibres with Cyclodextrin." Fibres and Textiles in Eastern Europe 28, no. 6(144) (December 31, 2020): 15–23. http://dx.doi.org/10.5604/01.3001.0014.3793.
Анотація:
Over the years, a multiplicity of grafting modification techniques have been studied to combine the adsorption and wettability of natural fibres with the capacity of cyclodextrins (CDs) to form inclusion complexes. The fixation of CDs on fibres is possible using crosslinking agents or reactive derivatives of cyclodextrins. Various crosslinking chemicals are suitable to bind the hydroxyl groups of non-reactive cyclodextrins with those of natural fibres by way of spraying, padding, surface coating, and impregnation. Nano-composite dense polymer film could also be formed to anchor the cyclodextrin on the natural fibre surface by the methods of hydrogen binding or covalent binding in sol-gel. A vinyl monomer such as glycidyl methacrylate was used to form polymer coatings due to the pendant epoxy group coupled with the –OH of cyclodextrin and natural fibres. This review also focused on the derivatives of CDs with the reactive group reacting with the hydroxyl groups of natural fibres.
45
Duca, Gh, A. Ivancic, and V. Boldescu. "Cyclodextrins - Fields of Application. Part II." Chemistry Journal of Moldova 7, no. 2 (December 2012): 39–45. http://dx.doi.org/10.19261/cjm.2012.07(2).15.
Анотація:
This paper represents an analysis of potential and current applications of cyclodextrins as biologically active substances in medicine. The main applications described here include use of cyclodextrins as agents that form inclusion complexes with endogenous substances (membrane lipids, cellular cholesterol), agents that form inclusion complexes with exogenous substances with their man role as guest molecules (sugammadex, FBCx), agents that block endogenous and exogenous macromolecules (ion channels, anthrax toxin, α-hemolysin), and agents which activity is based on the chemical nature of them and of their derivatives (cyclodextrin polysulphate derivatives). The fi rst classifi cation for medically important biological activity of cyclodextrins has been proposed.
46
Terekhova, Irina, Iliya Kritskiy, Mikhail Agafonov, Roman Kumeev, Carlos Martínez-Cortés, and Horacio Pérez-Sánchez. "Selective Binding of Cyclodextrins with Leflunomide and Its Pharmacologically Active Metabolite Teriflunomide." International Journal of Molecular Sciences 21, no. 23 (November 30, 2020): 9102. http://dx.doi.org/10.3390/ijms21239102.
Анотація:
The selectivity of encapsulation of leflunomide and teriflunomide by native α-, β- and γ-cyclodextrins was investigated through 1H NMR and molecular modeling. Thermodynamic analysis revealed the main driving forces involved in the binding. For α-cyclodextrin, the partial encapsulation was obtained while deep penetration was characterized for the other two cyclodextrins, where the remaining polar fragment of the molecule is located outside the macrocyclic cavity. The interactions via hydrogen bonding are responsible for high negative enthalpy and entropy changes accompanying the complexation of cyclodextrins with teriflunomide. These results were in agreement with the molecular modeling calculations, which provide a clearer picture of the involved interactions at the atomic level.
47
Kritskiy, Iliya, Roman Kumeev, Tatyana Volkova, Dmitry Shipilov, Natalya Kutyasheva, Mikhail Grachev, and Irina Terekhova. "Selective binding of methotrexate to monomeric, dimeric and polymeric cyclodextrins." New Journal of Chemistry 42, no. 17 (2018): 14559–67. http://dx.doi.org/10.1039/c8nj02632g.
48
Braga, Susana Santos. "Cyclodextrins: Emerging Medicines of the New Millennium." Biomolecules 9, no. 12 (November 28, 2019): 801. http://dx.doi.org/10.3390/biom9120801.
Анотація:
Cyclodextrins, since their discovery in the late 19th century, were mainly regarded as excipients. Nevertheless, developments in cyclodextrin research have shown that some of these hosts can capture and include biomolecules, highlighting fatty acids and cholesterol, which implies that they are not inert and that their action may be used in specific medicinal purposes. The present review, centered on literature reports from the year 2000 until the present day, presents a comprehensive description of the known biological activities of cyclodextrins and their implications for medicinal applications. The paper is divided into two main sections, one devoted to the properties and applications of cyclodextrins as active pharmaceutical ingredients in a variety of pathologies, from infectious ailments to cardiovascular dysfunctions and metabolic diseases. The second section is dedicated to the use of cyclodextrins in a range of biomedical technologies.
49
Cardoso, T., C. I. C. Galhano, M. F. Ferreira Marques та A. Moreira da Silva. "Thymoquinoneβ-Cyclodextrin Nanoparticles System: A Preliminary Study". Spectroscopy: An International Journal 27 (2012): 329–36. http://dx.doi.org/10.1155/2012/902486.
Анотація:
Thymoquinone is a natural product, the main constituent ofNigella sativaseeds, which exhibits anti-inflammatory and anticancer activities. Among several existing molecules capable of forming an inclusion compound structure, cyclodextrins are applied in the pharmaceutical industry either to increase solubility of hydrophobic molecules or to protect molecules from inactivation or degradation.β-Cyclodextrin is currently the most common cyclodextrin in pharmaceutical formulations and probably the best studied in humans. In order to study the properties of inclusion compounds based on cyclodextrins and thymoquinone Fourier Transform Infrared (FTIR), Ultraviolet-Visible, Positron Annihilation Lifetime (PAL) Spectroscopies and calorimetric studies by Differential Scanning Calorimetry (DSC) were used. The obtained results indicate the formation of a 1 : 1 inclusion compound between cyclodextrin and thymoquinone. PALS and DSC measurements also provided evidence of the inclusion compound's activity.
50
Wang, Zhankun, Qingsheng Qi, and Peng George Wang. "Engineering of Cyclodextrin Glucanotransferase on the Cell Surface of Saccharomyces cerevisiae for Improved Cyclodextrin Production." Applied and Environmental Microbiology 72, no. 3 (March 2006): 1873–77. http://dx.doi.org/10.1128/aem.72.3.1873-1877.2006.
Анотація:
ABSTRACT The cyclodextrin glucanotransferase (CGTase) gene (cgt) from Bacillus circulans 251 was cloned into plasmid pYD1, which allowed regulated expression, secretion, and detection. The expression of CGTase with a-agglutinin at the N-terminal end on the extracellular surface of Saccharomyces cerevisiae was confirmed by immunofluorescence microscopy. This surface-anchored CGTase gave the yeast the ability to directly utilize starch as a sole carbon source and the ability to produce the anticipated products, cyclodextrins, as well as glucose and maltose. The resulting glucose and maltose, which are efficient acceptors in the CGTase coupling reaction, could be consumed by yeast fermentation and thus facilitated cyclodextrin production. On the other hand, ethanol produced by the yeast may form a complex with cyclodextrin and shift the equilibrium in favor of cyclodextrin production. The yeast with immobilized CGTase produced 24.07 mg/ml cyclodextrins when it was incubated in yeast medium supplemented with 4% starch.