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Sample records for beta cyclodextrin inclusion

  1. Study on inclusion interaction of piroxicam with beta-cyclodextrin derivatives.

    PubMed

    Xiliang, Guo; Yu, Yang; Guoyan, Zhao; Guomei, Zhang; Jianbin, Chao; Shaomin, Shuang

    2003-12-01

    The inclusion behavior of piroxicam (PX) with beta-cyclodextrin (beta-CD), hydroxypropyl-beta-cyclodextrin (HP-beta-CD), and carboxymethyl-beta-cyclodextrin (CM-beta-CD) was investigated by using steady-state fluorescence and nuclear magnetic resonance (NMR) technique. The various factors affecting the inclusion process were examined in detail. The remarkable fluorescence emission enhancement upon addition of CDs suggested that cyclodextrins (CDs) were most suitable for inclusion of the uncharged species of PX. The stoichiometry of the PX-CDs inclusion complexes was 1:1, except for beta-CD where a 1:2 inclusion complex was formed. The formation constants showed the strongest inclusion capacity of beta-CD. NMR showed the inclusion mode of PX with CDs.

  2. [UV-vis spectroscopic characterization of inclusion compounds of beta-cyclodextrin with lycopene].

    PubMed

    Wang, Luo-xin; Lü, Jun; Du, Zong-liang; Li, Rui-xia; Wu, Da-cheng

    2004-02-01

    Water-soluble inclusion compounds of beta-cyclodextrin with lycopene were prepared by two methods: (1) complexation in solution and (2) complexation by kneading. It was found that UV-Vis spectra of the inclusion complexes in water are different from those of lycopene in water-miscible organic solvents (tetrahydrofuran) and beta-cyclodextrin in water, which confirms the formation of the inclusion complexes. Specific interactions of lycopene and beta-cyclodextrin cause great changes in absorbance maximum (lambdamax) of lycopene. It is considered that the inclusion complexes in water are formed as supermolecular aggregates with nanometer size, after card-pack type lycopene is included by beta-cyclodextrin in molecular level. PMID:15769012

  3. Biodegradable star polymers functionalized with beta-cyclodextrin inclusion complexes.

    PubMed

    Setijadi, Eki; Tao, Lei; Liu, Jingquan; Jia, Zhongfan; Boyer, Cyrille; Davis, Thomas P

    2009-09-14

    Three-armed biodegradable star polymers made from polystyrene (polySt) and poly (polyethylene glycol) acrylate (polyPEG-A) were synthesized via a "core first" methodology using a trifunctional RAFT agent, created by attaching RAFT agents to a core via their R-groups. The resultant three-armed polymeric structures were well-defined, with polydispersity indices less than 1.2. Upon aminolysis and further reaction with dithiodipyridine (DTDP), these three-armed polymers could be tailored with sulfhydryl and pyridyldisulfide (PDS) end functionalities, available for further reaction with any free-sulfhydryl group containing precursors to form disulfide linkages. Nuclear magnetic resonance (NMR) confirmed that more than 98% of the polymer arms retained integral trithiocarbonate active sites after polymerization. Intradisulfide linkages between the core and the arms conferred biodegradability on the star architectures. Subsequently, the arm-termini were attached to cholesterol also via disulfide linkages. The cholesterol terminated arms were then used to form supramolecular structures via inclusion complex formation with beta-cyclodextrin (beta-CD). The star architectures were found to degrade rapidly on treatment with DL-dithiothereitol (DTT). The star polymers and supramolecular structures were characterized using gel permation chromatography (GPC), static light scattering (SLS), 2D NMR, and fluorescence spectroscopy.

  4. Analytical applications of retinoid-cyclodextrin inclusion complexes. 1. Characterization of a retinal-beta-cyclodextrin complex.

    PubMed

    Muñoz Botella, S; Martìn, M A; del Castillo, B; Menéndez, J C; Vázquez, L; Lerner, D A

    1996-06-01

    In studies in these laboratories on the supramolecular chemistry of the retinoids, it has been recently confirmed that inclusion of these substances within the cavity of cyclodextrins protects their excited states, thus improving their photochemical stability. In the present paper, the isolation is described of a crystalline stable complex between retinal and beta-cyclodextrin, which has been characterized by means of several techniques including atomic force microscopy (AFM). The complex shows distinct spectroscopic differences from both retinal and beta-cyclodextrin. Thus, it absorbs at lambda(max) = 380 nm in water whereas retinal is insoluble; it shows room-temperature luminescence, which retinal does not; finally, it give 1H-NMR and 13C-NMR spectra in d6-DMSO with clear differences in chemical shifts with respect to those of beta-cyclodextrin. Besides these studies in solution, the behaviour of the complex in the solid state has been compared with that of physical mixtures of retinal and beta-cyclodextrin. IR spectroscopy shows clear differences, particularly a shift in the retinal carbonyl absorption (1644-1672 cm-1). AFM studies reveal the existence of aggregates; X-ray diffractometry also supports the formation of a cyclodextrin-retinal complex.

  5. Spectroscopic studies of inclusion complexes of 1-naphthol-4-sulfonate with beta-cyclodextrin in aqueous solution.

    PubMed

    Al-Shihry, Shar S

    2005-09-01

    The photophysical properties of 1-naphthol-4-sulfonate (1N4S) in some solvents and in aqueous beta-cyclodextrin solution have been investigated. The effect of beta-cyclodextrin on the fluorescence quantum yield and on the proton transfer is examined. Fluorescence measurements show 1:1 inclusion of 1N4S in the beta-cyclodextrin cavity with an association constant of 108M(-1). NMR studies are used to study the inclusion phenomena and to provide information on the geometry of 1N4S inside the cavity of beta-cyclodextrin.

  6. Spectroscopic characterization of the inclusion complexes of luteolin with native and derivatized beta-cyclodextrin.

    PubMed

    Jullian, Carolina; Cifuentes, Constanza; Alfaro, Muriel; Miranda, Sebastián; Barriga, Germán; Olea-Azar, Claudio

    2010-07-15

    The inclusion complexes of Luteolin (LU) with cyclodextrins (CDs) including beta-cyclodextrin (betaCD), hydroxypropyl-beta-cyclodextrin (HPbetaCD) and dimethyl-beta-cyclodextrin (DMbetaCD), Scheme 1, have been investigated using the method of steady-state fluorescence. The stoichiometric ratio of the three complexes was found to be 1:1 and the stability constants (K) were estimated from spectrofluorometric titrations, as well as the thermodynamic parameters. Maximum inclusion ability was obtained in the case of HPbetaCD followed by DMbetaCD and betaCD. Moreover, 1H NMR and 2D NMR were carried out, revealing that LU has different form of inclusion which is in agreement with molecular modeling studies. These models confirm that when LU-betaCD and LU-DMbetaCD complexes are formed, the B-ring is oriented toward the primary rim; however, for LU-HPbetaCD complex this ring is oriented toward the secondary rim. The ESR results showed that the antioxidant activity of luteolin was the order LU-HPbetaCD>LU-DMbetaCD>LU-betaCD>LU, hence the LU-complexes behave are better antioxidants than luteolin free.

  7. Inclusion complexes of pyrimethamine in 2-hydroxypropyl-beta-cyclodextrin: characterization, phase solubility and molecular modelling.

    PubMed

    de Araújo, Márcia Valéria Gaspar; Vieira, Elze Kelly Barbosa; Lázaro, Gilderman Silva; de Souza Conegero, Leila; Ferreira, Odair Pastor; Almeida, Lui S Eduardo; Barreto, Ledjane Silva; da Costa, Nivan Bezerra; Gimenez, Iara F

    2007-09-01

    The inclusion complexation of pyrimethamine in 2-hydroxypropyl-beta-cyclodextrin has been investigated by 2D (1)H NMR, FTIR and UV/visible spectroscopy and also by molecular modelling methods (AM1, PM3, MM3). From the phase-solubility diagram a linear increase was observed in pyrimethamine aqueous solubility in the presence of 2-hydroxypropyl-beta-cyclodextrin, evidencing the formation of a soluble inclusion complex. According to the continuous variation method (Job's plot) applied to fluorescence measurements, a 1:1 stoichiometry has been proposed for the complex. Concerning the structure of the complex, a Cl-in orientation of pyrimethamine in the 2-hydroxypropyl-beta-cyclodextrin cavity has been proposed from the theoretical calculations, being confirmed by two-dimensional (1)H NMR spectroscopy (ROESY). The thermal behaviour has also been studied, providing complementary evidences of complex formation.

  8. [Preparation and evaluation of valerian oil-beta-cyclodextrin inclusion complex].

    PubMed

    Si, Qi; Wu, Dan; Cao, Qing-Ri; Cui, Jing-Hao

    2013-07-01

    The aim of this study was to improve the stability and cover the unpleasant odor of valerian oil by preparation of beta-cyclodextrin inclusion complex. The preparation method was established based on the yield of inclusion complex and entrapment efficiency of valerian volatile oil. After that, the formulation and processing parameters were optimized by uniform design table. The formations of inclusion complex were validated by DSC and X-RD method. The stability of valerian oil beta-cyclodextrin inclusion was studied under stressed conditions. In conclusion, relatively high yield of inclusion complex and entrapment efficiency were obtained by saturated solution-ultrasonication method. Inclusion complex yield and entrapment efficiency of the valerian oil were (84.78 +/- 3.23)% and (86.23 +/- 2.48)%, which were prepared under the optimized conditions, respectively. The results of DSC and X-RD were indicated the formation of inclusion complex. The stability of test showed that the valerian oil-beta-cyclodextrin inclusion complex was improved significantly. PMID:24199561

  9. Preparation and spectral investigation of inclusion complex of caffeic acid with hydroxypropyl-beta-cyclodextrin.

    PubMed

    Zhang, Min; Li, Jinxia; Zhang, Liwei; Chao, Jianbin

    2009-01-01

    The inclusion complexation behavior of caffeic acid (CA) with hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was studied by UV-vis, fluorescence spectroscopy and nuclear magnetic resonance spectroscopy (NMR). Experimental conditions including the concentration of HP-beta-CD and media acidity were investigated in detail. The result suggested HP-beta-CD was more suitable for including CA in acidity solution. The binding contants (K) of the inclusion complexes were determined by linear regression analysis and the inclusion ratio was found to be 1:1. The water solubility of CA was increased by inclusion with HP-beta-CD according to the phase-solubility diagram. The spatial configuration of complex has been proposed based on (1)H NMR and two-dimensional (2D) NMR, the result suggested that CA was entrapped inside the hydrophobic core of HP-beta-CD with the lipophilic aromatic ring and the portion of ethylene.

  10. Inclusion complex of butachlor with beta-cyclodextrin: characterization, solubility, and speciation-dependent adsorption.

    PubMed

    Bian, Haitao; Chen, Jingwen; Cai, Xiyun; Liu, Ping; Liu, Huihui; Qiao, Xianliang; Huang, Liping

    2009-08-26

    Due to soil adsorption, higher amounts of the herbicide butachlor are necessary to achieve its herbicidal activity, hence increasing its environmental risks. In this study, the effects of beta-cyclodextrin (beta-CD) on solubility and soil adsorption of butachlor were investigated. Formation of a 1:1 stoichiometric inclusion complex between them with an apparent stability constant of 443 L mol(-1) was confirmed in the solution. Fourier transform infrared spectroscopy showed that the (N-CO) amide bond and alkyl ether moiety of butachlor molecule could enter into the cavity of beta-CD, but the double-substituted aromatic ring was excluded because it was larger size than the cavity. Significant enhancing dissolution of butachlor in the inclusion complex occurred in comparison to the free herbicide. The adsorption of butachlor on soil was reduced with an increase of beta-CD concentration because of the formation of the inclusion complex with low adsorption potency. Although the sorption distribution coefficient of complexed butachlor (i.e., butachlor/beta-cyclodextrin inclusion complex) (K(d,c) = 6.14) was about 14% of that of the free herbicide (K(d,f) = 44.54), the proportion of the adsorbed amount of complexed butachlor to the total adsorbed amount rose with the increase of beta-CD concentration. Thus, the adsorption of inclusion complex cannot be neglected in the presence of high concentrations cyclodextrins, although its water solubility was much higher than that of the free herbicide. These results indicate that beta-CD may be used as a formation additive to improve the solubility of butachlor, reduce its adsorption on soil, and increase the availability of butachlor for weeds.

  11. Study on the inclusion interactions of beta-cyclodextrin and its derivative with dyes by spectrofluorimetry and its analytical application.

    PubMed

    Zhu, Xiashi; Sun, Jing; Wu, Jun

    2007-04-15

    The inclusion interactions of beta-cyclodextrin (beta-CD) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) with dyes were developed by spectrofluorimetry, and the inclusion constants of inclusion complexes were determined by direct fluorescence technique. The main factors (the host molecule, the guest molecule, and the pH) for the inclusion interaction were discussed in detail. At the same time, the inclusion interaction of HP-beta-CD and vitamin B(6) (VB(6)) was investigated with the competitive fluorescence inclusion method and the inclusion constant of HP-beta-CD and vitamin B(6) (VB(6)) was obtained by indirect fluorescence technique. On the basis of the linear relationship between the change of fluorescence intensity (DeltaF) and the concentration of VB(6), a competitive fluorescence inclusion method was used to the determination of VB(6). The method has been successfully applied to the analysis of VB(6) in synthetic samples, tablets and injections with satisfactory results.

  12. Preparation, characterization and molecular modeling studies of the inclusion complex of Caffeine with Beta-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Prabu, Samikannu; Swaminathan, Meenakshisundaram; Sivakumar, Krishnamoorthy; Rajamohan, Rajaram

    2015-11-01

    The formation through supramolecular interaction of a host-guest inclusion complex of caffeine (CA) with nano-hydrophobic cavity beta-cyclodextrin (β-CD) is achieved by a physical mixture, a kneading method and a co-precipitation method. The formation of the inclusion complex of CA with β-CD in solution state is confirmed by UV-visible spectrophotometer, fluorescence spectrophotometer and time-resolved fluorescence spectrophotometer. The stoichiometry of the inclusion complex is 1:1; the imidazole ring and pyrimidine ring of caffeine is deeply entrapped in the beta-cyclodextrin as confirmed by spectral shifts. The Benesi-Hildebrand plot is used to calculate the binding constant of the inclusion complex of CA with β-CD at room temperature. The Gibbs free energy change of the inclusion complex process is calculated and the process is found to be spontaneous. The thermal stability of the inclusion complex of CA with β-CD is analyzed using differential scanning calorimetry. The crystal structure modification of a solid inclusion complex is confirmed by scanning electron microscopy image analysis. The formation of the inclusion complex of CA with β-CD in the solid phase is also confirmed by FT-IR and XRD. The formation of the inclusion complex between CA and β-CD, as confirmed by molecular docking studies, is in good relationship with the results obtained through different experimental methods.

  13. Thermodynamic study on the effects of beta-cyclodextrin inclusion with berberine.

    PubMed

    Yu, Jun-Sheng; Wei, Fang-Di; Gao, Wei; Zhao, Chang-Chun

    2002-01-15

    The fluorescence enhancement of berberine (Berb) as a result of complex with beta-cyclodextrin (beta-CD) is investigated. The association constants of alpha-CD and beta-CD with Berb are 60 and 137 M(-1) at 20 degrees C in pH 7.20 aqueous solution. Effects of temperature on the forming inclusion complexes of beta-CD with Berb have been examined through using fluorescence titration. Enthalpy and entropy values calculated from fluorescence data are -33.7 kJ mol(-1) and 74.3 J x mol(-1) K(-1) respectively. It was found that the dielectric constant of beta-CD cavity is about 24 in a rough analogy with absolute alcohol. These results suggest that the extrusion of 'high energy water' molecules from the cavity of beta-CD and hydrophobic interaction upon the inclusion complex formation are the main forces of the inclusion reaction. Effect of pH on the association of beta-CD with Berb was also studied. Mechanism of the inclusion of beta-CD with Berb is further studied by absorption and NMR measurements. Results show that beta-CD forms a 1:1 inclusion complex with Berb.

  14. Liquid chromatographic determination of beta-cyclodextrin derivatives based on fluorescence enhancement after inclusion complexation.

    PubMed

    Reeuwijk, H J; Irth, H; Tjaden, U R; Merkus, F W; van der Greef, J

    1993-04-21

    A liquid chromatographic method using fluorescence detection for the determination of beta-cyclodextrin (beta CD) and its derivatives is presented. The chromatographic system is based on size-exclusion chromatography with the addition of the fluorophoric compound 1-naphthol to the mobile phase. Detection is based on fluorescence enhancement caused by the formation of inclusion complexes. By incorporating 10(-4) M 1-naphthol in the mobile phase, detection limits of 90, 27, 370 and 37 pmol were obtained for beta CD, hydroxypropyl-beta CD, trimethyl-beta CD and dimethyl-beta CD, respectively. The method was applied to the determination of dimethyl-beta CD in urine: the minimum detectable concentration was 0.2 microgram/ml after preconcentration of 10 ml of urine.

  15. Fluorometric study of the inclusion interaction of beta-cyclodextrin derivatives with tetraphenylporphyrin and its analytical application.

    PubMed

    Yang, R; Wang, K; Xiao, D; Yang, X

    2001-07-01

    The effects of native beta-cyclodextrin (beta-CD) and four kinds of alkylated beta-cyclodextrin (beta-CDs), i.e. heptakis (2,6-di-O-isobutyl-beta-cyclodextrin) (I), heptakis (2,6-di-O-octyl-beta-cyclodextrin) (II), heptakis (2,6-di-O-dodecyl-beta-cyclodextrin) (III), and heptakis (2,6-di-O-hexadecyl-beta-cyclodextrin) (IV), on the fluorescence behaviors of tetraphenylporphyrin (TPP) are investigated. An obvious fluorescence enhancement is observed from TPP by using alkylated derivatives compared to that obtained in beta-CD aqueous or in water. A 114-N fluorescence emission intensity enhancement is found for the complex with 2,6-di-O-octyl-beta-cyclodextrin relative to the free analyte. The exact stoichiometric ratios and the formation constants of the inclusion complexes have been examined by application of curve fitting method. The linear calibration plots between fluorescence intensity and TPP concentration are determined in the 1.14 x 10(-8)-5.06 x 10(-6) mol l(-1) range.

  16. Structure of PEO-b-PPO-b-PEO Triblock Copolymer Inclusion Complexes with Beta-Cyclodextrin

    NASA Astrophysics Data System (ADS)

    Tsai, Chi-Chun; Cheng, Stephen Z. D.; Lotz, Bernard; Huang, Jin; Chen, Yongming

    2009-03-01

    Inclusion complexes, formed by non-covalent host-guest interactions, have been extensively investigated because they can be useful as building blocks for constructing supramolecular structures. Cyclodextrins (CDs), due to their good water-solubility and ability to include a wide range of guest molecules, have been the most intensively studied host molecules. CDs are shaped like a shallow truncated cone, with a hydrophilic outer surface as well as primary (narrower end) and secondary (wider end) hydroxyl groups on the rim of the molecule. The cavity, which is constructed with alkyl groups and glycosidic oxygen atoms, is hydrophobic and can act as a host for a great variety of hydrophobic molecular guests. A series of host-guest inclusion complexes were prepared with beta-cyclodextrin (beta-CD) and PEO-PPO-PEO triblock copolymers of varying molecular weights and compositions. The middle PPO block of the copolymers can be selectively included by beta-CD to form an inclusion complex while the PEO blocks cannot. These inclusion complexes can further self-assembled into supramolecular structures in aqueous solution. The inclusion complexes and self-assembled supramolecular structures were characterized by Nuclear Magnetic Resonance, X-ray diffraction, and Differential Scanning Calorimetry experimental methods.

  17. Inclusion complexation of novocaine by beta-cyclodextrin in aqueous solutions.

    PubMed

    Iglesias, Emilia

    2006-06-01

    The formation of inclusion complexes between beta-cyclodextrin (beta-CD) and the local anesthetic 2-(diethylamino)ethyl-p-amino-benzoate (novocaine) in aqueous solutions under different acidity conditions, using steady-state fluorescence or UV-vis spectroscopies, electrical conductivity, or the kinetic study of both the nitrosation reaction of the primary amine group in a mild acid medium and the hydrolysis of the ester function under an alkaline medium, has been studied. The inclusion complex formation between neutral or protonated novocaine and beta-CD of 1:1 stoichiometry was observed; however, the magnitude of the binding constants depends on the nature of both the guest and the host, and the higher-affinity guest-host was found under conditions when both the novocaine and the beta-CD were neutral molecules.

  18. Comparative study on the inclusion behavior between meso-tetrakis(4-N-ethylpyridiniurmyl)porphyrin and beta-cyclodextrin derivatives.

    PubMed

    Xiliang, Guo; Shaomin, Shuang; Chuan, Dong; Feng, Feng; Wong, M S

    2005-01-14

    5,10,15,20-Tetrakis(4-N-ethylpyridiniurmyl)porphyrin (TEPyP) formed 1:1 stoichiometry inclusion complexes with beta-cyclodextrin (beta-CD) and its derivatives including hydroxypropyl-beta-cyclodextrin (HP-beta-CD), sulfobutylether-beta-cyclodextrin (SBE-beta-CD) in basic aqueous solution. The supramolecular system was investigated by the methods of fluorescence, UV-vis absorption spectroscopy, nuclear magnetic resonance (NMR) technique. The inclusion ability of cyclodextrins exhibited remarkable difference for beta-CD, HP-beta-CD and SBE-beta-CD. Association constants as high as K=1.1 x 10(4) M(-1) in the case of HP-beta-CD/TEPyP and 2.0 x 10(5) M(-1) in the case of SBE-beta-CD/TEPyP complexes were determined, whereas a lower value (K=550 M(-1)) was given in the case of beta-CD/TEPyP. The results showed that hydrogen bonding and charge attraction play important roles in the processes of host-guest interaction. The interaction mechanism of inclusion processes could be explained by the analysis of NMR spectroscopy. The supramolecular assembly was formed. beta-CD and HP-beta-CD approached from the primary face of cavities of CDs.

  19. Structure, dynamics, and stability of beta-cyclodextrin inclusion complexes of aspartame and neotame.

    PubMed

    Garbow, J R; Likos, J J; Schroeder, S A

    2001-04-01

    Studies of the high-intensity sweetener aspartame show that its stability is significantly enhanced in the presence of beta-cyclodextrin (beta-CyD). At a 5:1 beta-CyD/aspartame molar ratio, the stability of aspartame is 42% greater in 4 mM phosphate buffer (pH 3.1) compared to solutions prepared without beta-CyD. Solution-state (1)H NMR experiments demonstrate the formation of 1:1 beta-CyD/aspartame complexes, stabilized by the interaction of the phenyl-ring protons of aspartame with the H3 and H5 protons of beta-CyD. Inclusion complex formation clearly accounts for the observed stability enhancement of aspartame in solution. The formation of inclusion complexes in solution is also demonstrated for beta-CyD and neotame, a structural derivative of aspartame containing an N-substituted 3,3-dimethylbutyl group. These complexes are stabilized by the interaction of beta-CyD with both phenyl-ring and dimethylbutyl protons. Solid-state NMR experiments provide additional characterization, clearly demonstrating the formation of inclusion complexes in lyophilized solids prepared from solutions of beta-CyD and either aspartame or neotame.

  20. Physico-chemical characterization of benzocaine-beta-cyclodextrin inclusion complexes.

    PubMed

    Pinto, Luciana M A; Fraceto, Leonardo Fernandes; Santana, Maria Helena A; Pertinhez, Thelma A; Junior, Sérgio Oyama; de Paula, Eneida

    2005-10-01

    Local anesthetics are able to induce pain relief by binding to the sodium channel of excitable membranes, blocking the influx of sodium ions and the propagation of the nervous impulse. Benzocaine (BZC) is a local anesthetic whose low water-solubility limits its application to topical formulations. The present work focuses on the characterization of inclusion complexes of BZC in beta-cyclodextrin (beta-CD). Differential scanning calorimetry and electron microscopy gave evidences of the formation and the morphology of the complex. Fluorescence spectroscopy showed a BZC/beta-CD 1:1 stoichiometry. Phase-solubility diagrams allowed the determination of the association constants between BZC and beta-CD (549 M(-1)) and revealed that a three-fold increase in BZC solubility can be reached upon complexation with beta-CD. The details of BZC/beta-CD molecular interaction were analyzed by 1H 2D NMR allowing the proposition of an inclusion model for BZC into beta-CD where the aromatic ring of the anesthetic is located near the head of the beta-CD cavity. Moreover, in preliminary toxicity studies, the complex seems to be less toxic than BZC alone, since it induced a decrease in the in vitro oxidation of human hemoglobin. These results suggest that the BZC/beta-CD complex represents an effective novel formulation to enhance BZC solubility in water, turning it promising for use outside its traditional application, i.e., in infiltrative anesthesia.

  1. Spectral and photophysical studies of inclusion complexes of 2-amino-4,6-dimethyl pyrimidine with beta-cyclodextrin.

    PubMed

    El-Kemary, M A; El-Gezawy, H S; El-Baradie, H Y; Issa, R M

    2002-02-01

    The interaction of 2-amino-4,6-dimethyl pyrimidine (ADMP) with beta-cyclodextrin (beta-CD) has been studied by means of UV absorption, steady state and time resolved fluorescence techniques. Spectral characteristics, bandwidths and photophysical parameters indicating that ADMP experience two different environments in aqueous solutions: bulk water and 1:1 (ADMP:beta-CD) inclusion complexation. The size restriction of the upper rim of beta-CD partially include ADMP and prevent the possibility of formation of 1:2 complex. The effective polarity of the cyclodextrin cavity experienced by the induced ADMP is equivalent with the polarity of an 80:20 methanol-water mixture.

  2. Specific interactions in the inclusion complexes of pyronines Y and B with beta-cyclodextrin.

    PubMed

    Reija, Belén; Al-Soufi, Wajih; Novo, Mercedes; Vazquez Tato, José

    2005-02-01

    The aim of this work is to analyze the role of specific interactions in host-guest association processes. The formation of inclusion complexes between pyronines Y and B and beta-cyclodextrin and the nature of the interactions involved have been studied using absorption, steady-state fluorescence, and time-resolved fluorescence spectroscopies. The two pyronines form 1:1 complexes with beta-cyclodextrin, with the association equilibrium constant being much higher in the case of pyronine B. Complexation causes a slight red shift of the emission spectra of the pyronines but decreases significantly their fluorescence quantum yields and lifetimes. To explain this atypical behavior, the photophysical properties of the pyronines in different solvents were determined and compared with those of the complexes. The similarities observed between the pyronines in dioxane and in the interior of the cyclodextrin cavity suggest that there are important specific interactions of the pyronines with the electron-rich oxygens present in these media. A possible explanation for the increase in the nonradiative rate constants in these media involves the existence of a charge-transfer excited state with the location of the positive charge at the xanthene moiety, which would be stabilized by the mentioned interactions. The observed differences between pyronine Y and B can be understood on the basis of these specific interactions.

  3. Study on beta-cyclodextrin inclusion of Zn(II) aromatic complex and its analytical application.

    PubMed

    Ding, Lixiu; He, Jiang; Fu, Junkai; Zhang, Jinlong

    2010-02-01

    A new beta-cyclodextrin (beta-CD) inclusion compound Zn(2H1NA)(2)x 2beta-CD (2H1NA=2-hydroxy-1-naphthoic acid) was prepared. The structure was characterized by (1)H NMR, IR, the fluorescence spectra, thermogravimetric analysis (TG-DTA) and elementary analysis. Meanwhile, the mechanism of the formation of the supramolecular system (2H1NA:Zn(II):beta-CD) was studied and discussed by spectrofluorimetry. The results showed that the naphthalene rings of the Zn(II) aromatic complex Zn(2H1NA)(2) were encapsulated within the beta-CD's cavity to form a 2:1 stoichiometry host-guest compound. The inclusion constant calculated was 1.27 x 10(4)(L/mol)(2). A spectrofluorimetric method for the determination of 2H1NA in bulk aqueous solution in the presence of beta-CD was developed based on the great enhancement of the fluorescence intensity of 2H1NA. The linear relationship was obtained in the range of 9.00 x 10(-7) to 2.50 x 10(-5)mol/L and the detection limit was 8.00 x 10(-7)mol/L. The proposed method was successfully applied to determine 2H1NA in waste water with recoveries of 97-104%.

  4. Inclusion phenomena of clove oil with alpha-, beta-, gamma- and heptakis (2,6-di-O-methyl)-beta-cyclodextrin.

    PubMed

    Song, L X; Xu, P; Wang, H M; Yang, Y

    2009-01-01

    Inclusion interactions of alpha-, beta-, gamma- and heptakis (2,6-di-O-methyl)-beta-cyclodextrin (DMbeta-CD) as hosts with clove oil (an impure eugenol, I-Eug) as guest in aqueous solution were investigated by fluorescence emission spectra. The binding constants of different hosts to I-Eug in aqueous solution decreased in the order: gamma- > beta- > DMbeta- > alpha-CD. Two solid supramolecular inclusion complexes, I-Eug-beta-CD and I-Eug-gamma-CD, were prepared and characterised by nuclear magnetic resonance, powder X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis. All the results proved the formation of I-Eug-CD. The inclusion differences between I-Eug and pure eugenol were discussed. The relative contents of the main component eugenol (Eug), second component (eugenol acetate, Eua) and others in I-Eug were found to be fairly different before and after being included by beta-CD, according to the data obtained from high performance liquid chromatography. This could be a practical method to extract the effective components (Eug and Eua) from I-Eug.

  5. Remarkably stable inclusion complexes with heptakis-[6-deoxy-6-(2-aminoethylsulfanyl)]-beta-cyclodextrin.

    PubMed

    Gómez-Biagi, Rodolfo F; Jagt, Richard B C; Nitz, Mark

    2008-12-21

    Complexes of heptakis-[6-deoxy-6-(2-aminoethylsulfanyl)]-beta-cyclodextrin (1) and a series of common cyclodextrin guests were studied by NMR, fluorescence spectroscopy, and ITC experiments. NMR conformational analysis shows that the thioethers of 1 are positioned over the hydrophobic cavity of the cyclodextrin, increasing potential hydrophobic interactions with guest molecules. The combination of the increased hydrophobic character, the electrostatic complementarity and a hypothesized conformational change in 1 lead to a complex with the dye 2,6-ANS (5) that is over 2000 times more stable than with the native beta-cyclodextrin. One of the most stable host-guest complexes between a cyclodextrin and a small molecule measured to date was revealed between 1 and lithocholic acid (4) with an association constant of 5.5 x 10(7) M(-1).

  6. Thermodynamic study on the effects of beta-cyclodextrin inclusion with anilinonaphthalenesulfonates.

    PubMed

    Catena, G C; Bright, F V

    1989-04-15

    Thermodynamic parameters and stoichiometries for the binding of anilinonaphthalenesulfonates to beta-cyclodextrin are obtained from steady-state fluorescence intensity and anisotropy measurements. Specifically, formation constant, enthalpy, and entropy values are obtained for complexes of beta-cyclodextrin with eight different substrate molecules at five different temperatures and six different pH values, and their associated errors are given. We propose an explanation of the relative magnitudes of the values obtained with regard to the geometry of the substrate and the importance of the various noncovalent interactions responsible for the complexation.

  7. Stoichiometrically different inclusion complexes of 2-aminofluorene and 2-amino-9-hydroxyfluorene in beta-cyclodextrin: a spectrofluorimetric study.

    PubMed

    Enoch, I V Muthu Vijayan; Swaminathan, M

    2006-09-01

    Beta-cyclodextrin (beta-CDx) forms inclusion complexes with 2-aminofluorene (2AF) and 2-amino-9-hydroxyfluorene (2AHF) in different stoichiometries (Guest-host ratio 1:1 and 1:2 respectively) which is discussed on the basis of study by absorption and fluorescence spectroscopy. The ground and the excited state acidity constants for the neutral-monocation equilibrium of the two fluorophores in aqueous beta-CDx medium are determined by spectrophotometric and fluorimetric titration methods respectively. The dual fluorescence observed for 2AHF monocation in aqueous solution is due to the formation of monocation-water exciplex. This monocation-water exciplex formation is hindered in beta-CDx solution by the inclusion complexation. Based on the results obtained, the structures of the inclusion complexes are proposed.

  8. Inclusion complexes of nabumetone with beta-cyclodextrins: thermodynamics and molecular modelling studies. Influence of sodium perchlorate.

    PubMed

    Goyenechea, N; Sánchez, M; Vélaz, I; Martín, C; Martínez-Ohárriz, M C; González-Gaitano, G

    2001-01-01

    Fluorescence, (1)H-NMR and molecular mechanics have been used to study the inclusion complexes of nabumetone (4,6-methoxy-2-naphthyl-butan-2-one; NAB) with beta-cyclodextrin (beta-CD), randomly methylated-beta (M beta-CD) and hydroxypropyl-beta-cyclodextrins (HP beta-CD). The emission spectrum of NAB shows a maximum whose fluorescence intensity increases with the different beta-CDs growing concentrations. This phenomenon allows calculation of the stability constants at 15, 25, 37 and 45 degrees C. The thermodynamic parameters Delta H degrees and Delta S degrees for the inclusion process were obtained from the temperature dependence of the stability constants. Molecular mechanics calculations, together with proton NMR measurements, for the complex with beta-CD prove that the complex can be formed by penetration through any of the rims, with the naphthalene nucleus included and the substituents outside the cavity. The influence of NaClO(4) in the aforementioned complexes has been analysed by spectrofluorimetric measurements. It has been found that the stability constants for the complexes decrease with the salt concentration; the causes are discussed.

  9. Environmental effects of inclusion complexation between methylated beta-cyclodextrin and diclofop-methyl.

    PubMed

    Cai, Xiyun; Liu, Weiping; Chen, Shengwen

    2005-08-24

    Diclofop-methyl (DM) is a broad-spectrum herbicide but often shows a reduced biological activity against the target grasses due to its poor water solubility and slow translocation within plant tissues. Randomly methylated beta-cyclodextrin (MCD) is an effective inclusion complexation agent and, as a potential formulation additive, may thus improve the behavior of DM. We evaluated the complexing role of MCD by measuring the solubility and soil sorption of DM as a function of MCD concentration, as well as the dissolution rates of DM-MCD complexes. The complex was also extensively characterized by UV, fluorescence, Fourier transform infrared, nuclear magnetic resonance, and differential scanning calorimetry techniques. The apparent solubility of DM linearly increased with MCD concentration, indicating the formation of a 1:1 complex. In contrast, diclofop was not complexed by MCD. The DM-MCD complex appeared to have formed within the hydrophobic cavity of MCD. With the measured stability constant of 4740 L mol(-)(1), the complex was apparently stable, which resulted in DM resistant to hydrolysis, and hence the ratio of DM to the sum of DM and diclofop increased toward unity with increasing MCD concentration. The DM-MCD complex also quickly dissolved to a maximum within 5 min, due presumably to the hydrophilicity of MCD. The sorption of DM by soil was significantly reduced in the presence of MCD. All the results suggest that MCD may effectively improve the availability of DM to pests and for bioremediation.

  10. Bridged bis(beta-cyclodextrin)s possessing coordinated metal center(s) and their inclusion complexation behavior with model substrates: enhanced molecular binding ability by multiple recognition.

    PubMed

    Liu, Y; Chen, Y; Li, L; Zhang, H Y; Liu, S X; Guan, X D

    2001-12-14

    To investigate quantitatively the cooperative binding ability of several beta-cyclodextrin oligomers bearing single or multiligated metal center(s), the inclusion complexation behavior of four bis(beta-cyclodextrin)s (2-5) linked by 2,2'-bipyridine-4,4'-dicarboxy tethers and their copper(II) complexes (6-9) with representative dye guests, i.e., methyl orange (MO), acridine red (AR), rhodamine B (RhB), ammonium 8-anilino-1-naphthalenesulfonic acid (ANS), and sodium 6-(p-toludino)-2-naphthalenesulfonate (TNS), have been examined in aqueous solution at 25 degrees C by means of UV-vis, circular dichroism, fluorescence, and 2D NMR spectroscopy. The results obtained indicate that bis(beta-cyclodextrin)s 2-5 can associate with one or three copper(II) ion(s) producing 2:1 or 2:3 bis(beta-cyclodextrin)-copper(II) complexes. These metal-ligated oligo(beta-cyclodextrin)s can bind two model substrates to form intramolecular 2:2 host-guest inclusion complexes and thus significantly enhance the original binding abilities of parent beta-cyclodextrin and bis(beta-cyclodextrin) toward model substrates through the cooperative binding of two guest molecules by four tethered cyclodextrin moieties, as well as the additional binding effect supplied by ligated metal center(s). Host 6 showed the highest enhancement of the stability constant, up to 38.3 times for ANS as compared with parent beta-cyclodextrin. The molecular binding mode and stability constant of substrates by bridged bis- and oligo(beta-cyclodextrin)s 2-9 are discussed from the viewpoint of the size/shape-fit interaction and molecular multiple recognition between host and guest.

  11. Controlled synthesis and inclusion ability of a hyaluronic acid derivative bearing beta-cyclodextrin molecules.

    PubMed

    Charlot, Aurélia; Heyraud, Alain; Guenot, Pierre; Rinaudo, Marguerite; Auzély-Velty, Rachel

    2006-03-01

    A new synthetic route to beta-cyclodextrin-linked hyaluronic acid (HA-CD) was developed. This was based on the preparation of a HA derivative selectively modified with adipic dihydrazide (HA-ADH) and a beta-cyclodextrin derivative possessing an aldehyde function on the primary face, followed by their coupling by a reductive amination-type reaction. The CD-polysaccharide was fully characterized in terms of chemical integrity and purity by high-resolution NMR spectroscopy. The complexation ability of the grafted CD was further demonstrated by isothermal titration calorimetry using sodium adamantane acetate (ADAc) and Ibuprofen as model guest molecules. The thermodynamic parameters for the complexation of these negatively charged guest molecules by the beta-CD grafted on negatively charged HA were shown to be largely influenced by the ionic strength of the aqueous medium. PMID:16529430

  12. Inclusion compounds of plant growth regulators in cyclodextrins. V. 4-Chlorophenoxyacetic acid encapsulated in beta-cyclodextrin and heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin.

    PubMed

    Tsorteki, Frantzeska; Bethanis, Kostas; Pinotsis, Nikos; Giastas, Petros; Mentzafos, Dimitris

    2005-04-01

    The crystal structures of 4-chlorophenoxyacetic acid (4CPA) included in beta-cyclodextrin (beta-CD) and heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin (TMbetaCD) have been studied by X-ray diffraction. The 4CPA/beta-CD complex crystallizes as a head-to-head dimer in the space group C2 in the Tetrad packing mode. The packing modes of some beta-CD dimeric complexes, having unique stackings, are also discussed. The 4CPA/TMbetaCD inclusion complex crystallizes in the space group P2(1) and its asymmetric unit contains two crystallographically independent complexes, complex A and complex B, exhibiting different conformations. The host molecule of complex A is significantly distorted, as a glucosidic residue rotated about the O4'-C1 and C4-O4 bonds forms an aperture where the guest molecule is accommodated. The phenyl moiety of the guest molecule of complex B is nearly perpendicular to the mean plane of the O4n atoms. The conformations of the guest molecules of the two complexes are similar. The crystal packing consists of antiparallel columns as in the majority of the TMbetaCD complexes published so far.

  13. Investigating the inclusion properties of aromatic amino acids complexing beta-cyclodextrins in model peptides.

    PubMed

    Caso, Jolanda Valentina; Russo, Luigi; Palmieri, Maddalena; Malgieri, Gaetano; Galdiero, Stefania; Falanga, Annarita; Isernia, Carla; Iacovino, Rosa

    2015-10-01

    Cyclodextrins are commonly used as complexing agents in biological, pharmaceutical, and industrial applications since they have an effect on protein thermal and proteolytic stability, refolding yields, solubility, and taste masking. β-cyclodextrins (β-CD), because of their cavity size are a perfectly suited complexing agent for many common guest moieties. In the case of peptide-cyclodextrin and protein-cyclodextrin host-guest complexes the aromatic amino acids are reported to be the principal responsible of the interaction. For these reasons, we have investigated the inclusion properties of nine designed tripeptides, obtained permuting the position of two L-alanines (Ala, A) with that of one L-tryptophan (Trp, W), L-phenylalanine (Phe, F), or L-tyrosine (Tyr, Y), respectively. Interestingly, the position of the aromatic side-chain in the sequence appears to modulate the β-CD:peptide binding constants, determined via UV-Vis and NMR spectroscopy, which in turn assumes values higher than those reported for the single amino acid. The tripeptides containing a tyrosine showed the highest binding constants, with the central position in the Ac-AYA-NH2 peptide becoming the most favorite for the interaction. A combined NMR and Molecular Docking approach permitted to build detailed complex models, highlighting the stabilizing interactions of the neighboring amino acids backbone atoms with the upper rim of the β-CD.

  14. [In-vitro evaluation of cinnarizine as a competing agent to beta-cyclodextrin inclusion complexes: effect of cinnarizine on the membrane permeation rate of progesterone from its beta-cyclodextrin inclusion complex].

    PubMed

    Muraoka, Atsushi; Tokumura, Tadakazu; Machida, Yoshiharu

    2008-01-01

    The use of competing agents is considered a powerful tool for the development of a drug-delivery system with drug/cyclodextrin inclusion complexes. However, there are very few studies examining this issue. To explain this phenomenon, it was thought that a competing agent with a sufficiently high stability constant had not yet been reported. In this study, cinnarizine (CN), which has a high stability constant with beta-cyclodextrin (beta-CD) and unique solubility characteristics, was selected, and its ability as a competing agent was examined in a membrane permeability study. The permeability study showed that the permeation rates of the drugs flurbiprofen, progesterone, and spironolactone decreased with their stability constants with the addition of beta-CD. In one of the drugs, progesterone (Pro), the decrease was restored by the addition of CN. The amount of CN added was a 1:1 molar ratio to the amount of Pro. However, no similar action was induced with the addition of DL-phenylalanine (Phe) in the permeation study at the 1:5 (Pro:Phe) molar ratio. These finding indicate that CN acts as a competing agent, and its action is much stronger than that of Phe. PMID:18176059

  15. Characterization of beta-cyclodextrin inclusion complexes containing an essential oil component.

    PubMed

    Abarca, Romina L; Rodríguez, Francisco J; Guarda, Abel; Galotto, María J; Bruna, Julio E

    2016-04-01

    An important issue in food technology is that antimicrobial compounds can be used for various applications, such as the development of antimicrobial active packaging materials. Yet most antimicrobial compounds are volatile and require protection. In the present study, the inclusion complexes of 2-nonanone (2-NN) with β-cyclodextrin (β-CD), were prepared by a co-precipitation method. Entrapment efficiency (EE), thermal analysis (DSC and TGA), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), sorption isotherms and antifungal activity were evaluated for the characterization of the inclusion complex (β-CD:2-NN). A higher EE was obtained (34.8%) for the inclusion complex 1:0.5 than for other molar rates. Both DSC and TGA of the inclusion complexes showed the presence of endothermic peaks between 80 °C and 150 °C, attributed to a complexation phenomenon. Antimicrobial tests for mycelial growth reduction under atmospheric conditions proved the fungistatic behaviour of the inclusion complexes against Botrytis cinerea. PMID:26593579

  16. Improvement of oral bioavailability of flurbiprofen from flurbiprofen/beta-cyclodextrin inclusion complex by action of cinnarizine.

    PubMed

    Tokumura, Tadakazu; Muraoka, Atsushi; Machida, Yoshiharu

    2009-09-01

    Improvement of the oral bioavailability of flurbiprofen (Flu) after oral administration of flurbiprofen/beta-cyclodextrin inclusion complex (Flu/beta-CD) by the action of cinnarizine (CN) was investigated. Flu and Flu/beta-CD were administered orally to fasted rats at a dose of 20mg/kg as Flu. Thirty minutes after drug administration, CN dissolved in pH 4.0 buffer solution or pH 4.0 buffer solution alone was administered to the rats. The dose of CN was 0.17 mg/kg. Blood samples were taken from rats and Flu concentrations in plasma samples were determined by HPLC. It was found from the comparison of Flu and Flu with CN (Flu+CN) that CN had no effect on plasma concentrations of Flu after oral administration of Flu. The mean plasma levels after oral administration of Flu/beta-CD with CN (Flu/beta-CD+CN) were larger not only than those of Flu and Flu+CN but also than those of Flu/beta-CD. The value of C(max) in Flu/beta-CD+CN was significantly larger than that of Flu/beta-CD. This is considered to be caused by the action of CN as a competing agent. This mechanism was supported by the result of solubility study in which Flu solubility in beta-CD solution decreased with the addition of CN. It was found from these results that CN had strong ability as a competing agent in vivo. PMID:19442722

  17. The inclusion complexes of hesperetin and its 7-rhamnoglucoside with (2-hydroxypropyl)-beta-cyclodextrin.

    PubMed

    Tommasini, S; Calabrò, M L; Stancanelli, R; Donato, P; Costa, C; Catania, S; Villari, V; Ficarra, P; Ficarra, R

    2005-09-15

    The effect of (2-hydroxypropyl)-beta-cyclodextrin (HP-beta-CyD) on the solubility properties and spectroscopic features of hesperetin and its 7-rhamnoglucoside, hesperidin, was qualitatively and quantitatively investigated in water, by means of UV-vis absorption and fluorescence spectroscopy. The stoichiometric ratios and stability constants describing the extent of formation of the complexes have been determined by phase-solubility measurements; in both cases type-A(L) diagrams have been obtained (soluble 1:1 complexes). The higher degree of interaction showed by hesperetin may be attributed to the higher hydrophobicity and smaller size of the aglycone molecule, which therefore exhibits a greater affinity for the CyD and fits better into the cavity. The effect of molecular encapsulation on the two flavanones antioxidant activity was afterwards evaluated by means of different biological assays, concerned to the different mechanisms of in vivo action. The protection efficacy was in all cases higher for the complexed drugs, with respect to the free ones; these results are of great interest for their potential usefulness in pharmaceutics.

  18. Improvement of dissolution properties of a new Helicobacter pylori eradicating agent (TG44) by inclusion complexation with beta-cyclodextrin.

    PubMed

    Anzai, Kinsei; Mizoguchi, Jun-ichi; Yanagi, Toshiharu; Hirayama, Fumitoshi; Arima, Hidetoshi; Uekama, Kaneto

    2007-10-01

    The interaction of a newly developed Helicobacter pylori eradicating agent (TG44, 4-methylbenzyl-4'-[trans-4-(guanidinomethyl)cyclohexylcarbonyloxy]biphenyl-4-carboxlylate monohydrochloride) with beta-cyclodextrin (beta-CyD) in aqueous solution and in solid state was studied to gain insight into the high in-vivo H. pylori eradicating activity of TG44/beta-CyD complex. The interaction was studied by the solubility method, spectroscopic methods, powder X-ray diffractometry and differential scanning colorimetry (DSC). TG44 gave A(L)-type phase solubility diagram with beta-CyD in water, showing a linear increase in solubility of the drug up to 8 mM beta-CyD concentration. The solubility of TG44 (0.04 mM in water at 25 degrees C) increased about 70-folds at 8 mM beta-CyD. Ultraviolet, circular dichroism, fluorescence and (1)H-nuclear magnetic resonance spectroscopic studies indicated that TG44 forms the inclusion complex with beta-CyD in a 1:1 stoichiometry and the biphenyl moiety of TG44 is preferably included in the beta-CyD cavity in water. The Giordano plot made by monitoring changes in the fusion enthalpy of TG44 (about 184 degrees C) suggested that TG44 forms the 1:1 complex with beta-CyD in the solid state. The TG44/beta-CyD solid complex in a 1:1 stoichiometry was prepared by the grinding and spray-drying methods and confirmed by powder X-ray diffractometry and DSC that the complex is in an amorphous state. The initial dissolution rate of TG44/beta-CyD complex was significantly faster than those of the drug alone and the physical mixture of both components, maintaining higher supersaturated concentrations of the drug for a long time. The results suggested that the higher eradicating activity of TG44/beta-CyD complex to Helicobacter pylori, compared with that of the drug alone, is attributable at least partly to the faster dissolving property of the complex and its ability to maintain the supersaturated state of the drug in the gastric fluid.

  19. Biosynthesis of ketomycin. (II) biomimetic model for beta-lactamase catalysis: host-guest interactions in cyclodextrin-penicillin inclusion complex

    SciTech Connect

    Mak, H.W.

    1986-01-01

    The antibiotic ketomycin is formed from shikimic acid via chorismic acid and prephenic acid. Phenylalanine and 2',5'-dihydrophenylalanine derived from shikimic acid are not intermediates in the biosynthesis. Degradation of ketomycin derived from (1,6-/sup 14/C)shikimic acid showed that prephenic acid is converted into ketomycin with stereospecific discrimination between the two enantiotopic edges of the ring, the pro-S-R edge giving rise to the C-2', C-3' side of the cyclohexane ring of ketomycin. The resistance of pathogenic bacteria to the action of ..beta..-lactam antibiotics is mainly ascribed to their ability to produce ..beta..-lactamase to cleave the ..beta..-lactam ring. It is essential to understand the molecular nature of ..beta..-lactamase-penicillin recognition for designing and formulating more effective ..beta..-lactam antibiotics. A biomimetic study of ..beta..-lactamase is therefore initiated. To meet the requirements of hydrophobic and serine protease characteristics of ..beta..-lactamase, ..cap alpha..-cyclodextrin is chosen as a biomimetic model for ..beta..-lactamase. The structural specificity and the chemical dynamics of ..cap alpha..-cyclodextrin-phenoxymethyl penicillin inclusion complex in solid state and in solution have been determined by IR and NMR spectroscopy. The spectral results strongly indicate that the phenyl portion of the phenoxymethyl penicillin forms a stable inclusion complex with the hydrophobic cavity of ..cap alpha..-cyclodextrin in solution as well as in the solid state. Kinetic studies followed by /sup 1/HNMR and HPLC analyses under alkaline condition have shown that the ..cap alpha..-cyclodextrin mimics the catalytic function of serine of ..beta..-lactamase in the stereospecific hydrolysis of the ..beta..-lactam ring of phenoxymethyl penicillin.

  20. Inclusion complexation behavior of dyestuff guest molecules by a bridged bis(cyclomaltoheptaose)[bis(beta-cyclodextrin)] with a pyromellitic acid diamide tether.

    PubMed

    Liu, Yu; Li, Li; Zhang, Heng-Yi; Liang, Peng; Wang, Hao

    2003-08-12

    A novel bridged bis(beta-cyclodextrin) with a pyromellitic acid 2,5-diamide tether (2) has been synthesized by reaction of 6(I)-(2-aminoethyleneamino)-6-deoxycyclomaltoheptaose [mono 6-(2-aminoethyleneamino)-6-deoxy-beta-cyclodextrin] with 1,2,4,5-benzenetetracarboxylic dianhydride. Its inclusion complexation behavior with some representative dyestuffs, i.e., Acridine Red (AR), Rhodamine B (RhB), Neutral Red (NR), Brilliant Green (BG), was studied by using UV-absorption, fluorescence, and 2D NMR spectroscopy. Fluorescence titrations have been performed at 25 degrees C in pH 7.2 buffer solution to calculate the binding constants of resulting complexes. These results obtained indicated that bis(beta-cyclodextrin) 2 exhibits the strongly enhanced binding ability with all dye molecules examined compared with natural cyclodextrins. The binding modes of 2 with dye molecules have been deduced by 2D NMR experiments to establish the correlations between molecular conformations and binding constants of inclusion complexation. It is found that the improved binding ability and molecular selectivity of 2 could be attributed to double-cavity cooperative inclusion interaction and the size/shape matching between the host and guest.

  1. In situ intestinal absorption behaviors of tanshinone IIA from its inclusion complex with hydroxypropyl-beta-cyclodextrin.

    PubMed

    Ling, Wang; Rui, Li Chen; Hua, Jiang Xue

    2007-10-01

    In this paper, the intestinal permeability of the inclusion complex of tanshinone IIA (TS IIA) with 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was investigated. The corresponding complexation of TS IIA-HP-beta-CD was obtained by coevaporation and characterized by differential scanning calorimetry and X-ray diffraction. The recirculation intestinal perfusion technique in rats was used to study the absorption behavior of free and complexed TS IIA. The change of concentration of TS IIA was separately calculated according to Michaelis-Menten and the Fick's equation to investigate its absorption rate-limiting step. Using the mathematical models above, it was concluded that the limit step to absorption of TS IIA was the dissolution process. Different concentrations of complexed TS IIA were administrated to three intestinal segments, with the intestinal permeability ranging from 3.16x10(-5) cm.s(-1) in the duodenum (50 microg.ml(-1)) to 4.11x10(-5) cm.s(-1) in the jejunum (100 microg.ml(-1)). With the increase of dosage of complex, TS IIA's absorption did not show saturated phenomenon, suggesting its transport mechanism in vivo might primary be passive transport. Besides, the permeability of TS IIA was not apparently influenced by the perfusion section studied, which indicated that there might not exist specific absorption site for TS IIA.

  2. In situ intestinal absorption behaviors of tanshinone IIA from its inclusion complex with hydroxypropyl-beta-cyclodextrin.

    PubMed

    Ling, Wang; Rui, Li Chen; Hua, Jiang Xue

    2007-10-01

    In this paper, the intestinal permeability of the inclusion complex of tanshinone IIA (TS IIA) with 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was investigated. The corresponding complexation of TS IIA-HP-beta-CD was obtained by coevaporation and characterized by differential scanning calorimetry and X-ray diffraction. The recirculation intestinal perfusion technique in rats was used to study the absorption behavior of free and complexed TS IIA. The change of concentration of TS IIA was separately calculated according to Michaelis-Menten and the Fick's equation to investigate its absorption rate-limiting step. Using the mathematical models above, it was concluded that the limit step to absorption of TS IIA was the dissolution process. Different concentrations of complexed TS IIA were administrated to three intestinal segments, with the intestinal permeability ranging from 3.16x10(-5) cm.s(-1) in the duodenum (50 microg.ml(-1)) to 4.11x10(-5) cm.s(-1) in the jejunum (100 microg.ml(-1)). With the increase of dosage of complex, TS IIA's absorption did not show saturated phenomenon, suggesting its transport mechanism in vivo might primary be passive transport. Besides, the permeability of TS IIA was not apparently influenced by the perfusion section studied, which indicated that there might not exist specific absorption site for TS IIA. PMID:17917262

  3. Inclusion complexes of cypermethrin and permethrin with monochlorotriazinyl-beta-cyclodextrin: A combined spectroscopy, TG/DSC and DFT study

    NASA Astrophysics Data System (ADS)

    Yao, Qi; You, Bin; Zhou, Shuli; Chen, Meng; Wang, Yujiao; Li, Wei

    2014-01-01

    The suitable size hydrophobic cavity and monochlorotriazinyl group as a reactive anchor make MCT-β-CD to be widely used in fabric finishing. In this paper, the inclusion complexes of monochlorotriazinyl-beta-cyclodextrin (MCT-β-CD) with cypermethrin (CYPERM) and permethrin (PERM) are synthesized and analyzed by TG/DSC, FT-IR and Raman spectroscopy. TG/DSC reveals that the decomposed temperatures of inclusion complexes are lower by 25-30 °C than that of physical mixtures. DFT calculations in conjunction with FT-IR and Raman spectral analyses are used to study the structures of MCT-β-CD and their inclusion complexes. Four isomers of trisubstituted MCT-β-CD are designed and DFT calculations reveal that 1,3,5-trisubstituted MCT-β-CD has the lowest energy and can be considered as main component of MCT-β-CD. The ground-state geometries, vibrational wavenumbers, IR and Raman intensities of MCT-β-CD and their inclusion complexes were calculated at B3LYP/6-31G (d) level of theory. Upon examining the optimized geometry of inclusion complex, we find that the CYPERM and PERM are inserted into the toroid of MCT-β-CD from the larger opening. The band at 1646 cm-1 in IR and at 1668 cm-1 in Raman spectrum reveals that monochloroazinyl group of MCT-β-CD exists in ketone form but not in anion form. The noticeable IR and Raman shift of phenyl reveals that these two benzene rings of CYPERM and PERM stays inside the cavity of MCT-β-CD and has weak interaction with MCT-β-CD. This spectroscopy conclusion is consistent with theoretical predicted structure.

  4. Inclusion complexes of cypermethrin and permethrin with monochlorotriazinyl-beta-cyclodextrin: a combined spectroscopy, TG/DSC and DFT study.

    PubMed

    Yao, Qi; You, Bin; Zhou, Shuli; Chen, Meng; Wang, Yujiao; Li, Wei

    2014-01-01

    The suitable size hydrophobic cavity and monochlorotriazinyl group as a reactive anchor make MCT-β-CD to be widely used in fabric finishing. In this paper, the inclusion complexes of monochlorotriazinyl-beta-cyclodextrin (MCT-β-CD) with cypermethrin (CYPERM) and permethrin (PERM) are synthesized and analyzed by TG/DSC, FT-IR and Raman spectroscopy. TG/DSC reveals that the decomposed temperatures of inclusion complexes are lower by 25-30 °C than that of physical mixtures. DFT calculations in conjunction with FT-IR and Raman spectral analyses are used to study the structures of MCT-β-CD and their inclusion complexes. Four isomers of trisubstituted MCT-β-CD are designed and DFT calculations reveal that 1,3,5-trisubstituted MCT-β-CD has the lowest energy and can be considered as main component of MCT-β-CD. The ground-state geometries, vibrational wavenumbers, IR and Raman intensities of MCT-β-CD and their inclusion complexes were calculated at B3LYP/6-31G (d) level of theory. Upon examining the optimized geometry of inclusion complex, we find that the CYPERM and PERM are inserted into the toroid of MCT-β-CD from the larger opening. The band at 1646 cm(-1) in IR and at 1668 cm(-1) in Raman spectrum reveals that monochloroazinyl group of MCT-β-CD exists in ketone form but not in anion form. The noticeable IR and Raman shift of phenyl reveals that these two benzene rings of CYPERM and PERM stays inside the cavity of MCT-β-CD and has weak interaction with MCT-β-CD. This spectroscopy conclusion is consistent with theoretical predicted structure.

  5. Experimental and theoretical studies on the inclusion complexation of syringic acid with alpha-, beta-, gamma- and heptakis(2,6-di-O-methyl)-beta-cyclodextrin.

    PubMed

    Song, Le Xin; Wang, Hai Ming; Xu, Peng; Yang, Yan; Zhang, Zi Qiang

    2008-04-01

    Intermolecular interactions of alpha-, beta-, gamma- and heptakis(2,6-di-O-methyl)-beta-cyclodextrin (CD) with syringic acid (Syr) in aqueous solution are investigated by fluorescence spectroscopy. The fluorescence intensity of Syr gradually increases with the addition of the CDs. The formation constants (K) of the host-guest inclusion complexes are determined using a nonlinear analysis. The association abilities of Syr with the CDs decrease in the order gamma->beta->alpha- approximately DMbeta-CD. Both the intrinsic binding abilities of the CDs and the structural effect of Syr are taken into consideration when comparing the K values. Based on the results of NMR experimental and theoretical PM3 calculations both in vacuo and in water, it is found that Syr stays near the wider rim of alpha-CD cavity. Both the number of substituted groups (NSG) in a guest and the molar volume ratio of the guest to host cavity (MVR) play an important role in forming the CD supramolecular complexes of a homologous series of phenol derivatives, such as 2-methoxylphenol (2-Mop), eugenol (Eug) and Syr, i.e., an appropriate NSG or MVR in an inclusion system, such as in 2-Mop-alpha-CD, Eug-beta-CD and Syr-gamma-CD systems, can maximize the intermolecular interaction between host and guest.

  6. Synthesis and spectroscopy studies of the inclusion complex of 3-amino-5-methyl pyrazole with beta-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Louiz, S.; Labiadh, H.; Abderrahim, R.

    2015-01-01

    Amino pyrazole belongs to anti-inflammatory class, and is characterized by a low solubility in water. (In order to increase its solubility in water, inclusion complex of amino pyrazole with β-CD was obtained.) The inclusion complex obtained between AMP and β-cyclodextrin, was characterized by FT-IR, 1H NMR, 1H-1H NOESY, 13C NMR, DEPT, XHCOR, spectra, through TG analysis, DTA, DSC and Scanning Electron Microscopy (SEM). The stoichiometry of inclusion complex is 1:1 (guest-host) and K stability is 1.1 × 104 M-1.

  7. Spectroscopic and theoretical study on inclusion complexation of beta-cyclodextrin with permethrin

    NASA Astrophysics Data System (ADS)

    Li, Wei; Lu, Bitai; Sheng, Aiguo; Yang, Feng; Wang, Zhendong

    2010-09-01

    Due to the poor water solubility of permethrin (PERM), an inclusion technique has been developed to modify its physical and chemical properties so as to improve its function finishing properties. In this paper, the inclusion complex of permethrin (PERM) and β-CD was synthesized and characterized. To reveal the inclusion mechanism, FT-IR and Raman spectrum analyses in conjugation with DFT calculations were performed on PERM, β-CD and β-CD·PERM inclusion complex. The ground-state geometries, vibrational wavenumbers, IR and Raman intensities were calculated by DFT at B3LYP/6-31G (d) level. The calculated mean bond lengths of glucose units for β-CD and β-CD·PERM inclusion complex are longer by 0.005-0.029 Å and 0.002-0.025 Å than those of the XRD structure of β-CD·11H 2O inclusion complex, respectively. Upon examining the optimized geometry of inclusion complex, we notice that a PERM molecule is inserted into the toroid of β-CD from the larger opening. Calculated vibrational wavenumbers are calibrated and compared with experimental fundamentals and the errors are within 20 cm -1. The significant changes on Raman spectrum of PERM, when it is encapsulated by β-CD, in combination with normal mode analysis reveal that the ring A of PERM penetrates through the toriod of β-CD and is exposed to the outside of the cavity, but the ring B is inside the cavity. The good agreements between predicted spectra and experimental ones prove that the theoretical predicted geometries are correct and accord with the real structures.

  8. Cyclodextrin Inclusion Polymers Forming Hydrogels

    NASA Astrophysics Data System (ADS)

    Li, Jun

    This chapter reviews the advances in the developments of supramolecular hydrogels based on the polypseudorotaxanes and polyrotaxanes formed by inclusion complexes of cyclodextrins threading onto polymer chains. Both physical and chemical supramolecular hydrogels of many different types are discussed with respect to their preparation, structure, property, and gelation mechanism. A large number of physical supramolecular hydrogels were formed induced by self-assembly of densely packed cyclodextrin rings threaded on polymer or copolymer chains acting as physical crosslinking points. The thermo-reversible and thixotropic properties of these physical supramolecular hydrogels have inspired their applications as injectable drug delivery systems. Chemical supramolecular hydrogels synthesized from polypseudorotaxanes and polyrotaxanes were based on the chemical crosslinking of either the cyclodextrin molecules or the included polymer chains. The chemical supramolecular hydrogels were often made biodegradable through incorporation of hydrolyzable threading polymers, end caps, or crosslinkers, for their potential applications as biomaterials.

  9. Effect of peracylation of beta-cyclodextrin on the molecular structure and on the formation of inclusion complexes: an X-ray study.

    PubMed

    Añibarro, M; Gessler, K; Usón, I; Sheldrick, G M; Harata, K; Uekama, K; Hirayama, F; Abe, Y; Saenger, W

    2001-12-01

    The molecular structures of peracylated beta-cyclodextrins (CDs)--heptakis(2,3,6-tri-O-acetyl)-beta-CD (TA), heptakis(2,3,6-tri-O-propanoyl)-beta-CD (TP), and heptakis(2,3,6-tri-O-butanoyl)-beta-CD (TB)--have been determined by single crystal X-ray structure analysis. Due to the lack of O2...O3' hydrogen bonds between adjacent glucose units of the peracylated CDs, the macrocycles are elliptically distorted into nonplanar boat-shaped structures. The glucose units are tilted with respect to the O4 plane to relieve steric hindrance between adjacent acyl chains. In TB, all glucose units adopt the common (4)C(1)-chair conformation and one butanoyl chain intramolecularly penetrates the cavity, whereas, in TA and TP, one glucose unit each occurs in (O)S(2)-skew-boat conformation and one acyl chain closes the O6 side like a lid. In each of the three homologous molecules the intramolecular self-inclusion and lidlike orientation of acyl chains forces the associated O5-C5-C6-O6 torsion angle into a trans-conformation never observed before for unsubstituted CD; the inclusion behavior of TA, TP, and TB in solution has been studied by circular dichroism spectroscopy with the drug molsidomine and several organic compounds. No inclusion complexes are formed, which is attributed to the intramolecular closure of the molecular cavity by one of the acyl chains.

  10. Mass spectrometry and molecular modeling studies on the inclusion complexes between [alpha], [beta]-cyclodextrins and simvastatin

    NASA Astrophysics Data System (ADS)

    Wen, Xianhong; Liu, Ziyang; Zhu, Tianqiang

    2005-03-01

    Complexation of simvastatin (SV) with α, β-cyclodextrins (CDs) was studied by means of UV spectrometry and ESI-mass spectrometry. The experimental results showed that stable 1:1 inclusion complexes between two CDs and SV were formed. In addition, the 1:2 complex between β-CD and SV was observed. Semi-empirical PM3 calculations were performed to elucidate the different inclusion behaviors between SV and CDs. The calculation results indicated that the formations of some conventional hydrogen bonds and C-H⋯O interactions (weak H bond) were the main factors for the non-covalent CD:SV complex formation and stabilization in gas phase.

  11. Insulin complexation with hydroxypropyl-beta-cyclodextrin: Spectroscopic evaluation of molecular inclusion and use of the complex in gel for healing of pressure ulcers.

    PubMed

    Valentini, Sóstenes Rosa; Nogueira, Ana Cláudia; Fenelon, Vanderson Carvalho; Sato, Francielle; Medina, Antonio N; Santana, Rosângela Getirana; Baesso, Mauro Luciano; Matioli, Graciette

    2015-07-25

    The pressure ulcer healing is a complex process and difficult to be achieved. Insulin is known to promote wound healing, and when complexed with cyclodextrin presents improved solubility, stability and biological activity. Complexation of insulin with hydroxypropyl-beta-cyclodextrin (HPβCD) was performed in this work through the coprecipitation method, providing the inclusion complex (HPβCD-I). The spectroscopic techniques used to analyze the complex were H(1) NMR, FT-Raman and FT-IR/ATR. A gel containing the HPβCD-I complex was prepared and a clinical study was conducted in patients with pressure ulcers. The spectroscopic techniques allowed to confirm the complex formation through the inclusion of aromatic amino acids, such as phenylalanine present in the HPβCD cavity. Data obtained from the FT-Raman and FT-IR/ATR techniques, combined with the H(1) NMR results, showed the effectiveness of these techniques in evaluating the inclusion complex of HPβCD with insulin. Clinical studies demonstrated tissue revitalization and a trend (p=0.06) for a significant difference between the healing effect of the control gel and that with HPβCD-I complex. The creation of the gel prepared with insulin and HPβCD-I complex and its use in patients with pressure ulcers appears to be promising in wound healing and its possible use in hospital care.

  12. Evaluation of the bioavailability of flurbiprofen and its beta-cyclodextrin inclusion complex in four different doses upon oral administration to rats.

    PubMed

    Muraoka, Atsushi; Tokumura, Tadakazu; Machida, Yoshiharu

    2004-11-01

    The dissolution profiles of flurbiprofen (Flu) and its beta-cyclodextrin inclusion complex (Flu/beta-CD) in buffer solutions at various pH values were examined. The percent dissolved at 15 min for Flu and Flu/beta-CD was almost 100% at pH 6.8 and 8.0 but the dissolution rate of Flu was extremely reduced at pH 1.2 and 4.0. In these lower pH conditions, Flu/beta-CD improved the dissolution rate of Flu. The percent dissolved at 1 h for Flu/beta-CD at pH 1.2 and 4.0 were 33.4 and 41.3%, respectively, and about 10 times larger than those for Flu. The oral bioavailability of Flu from Flu or Flu/beta-CD at doses of 1, 3, 10, and 30 mg/kg (as Flu) was examined in rats. An apparent linear relationship between doses and C(max) and AUC was observed after administration of Flu and Flu/beta-CD. The Flu C(max) and AUC values at 30 mg/kg, however, were much lower than would have been predicted from doses of 1-10 mg/kg. Those of Flu/beta-CD were also lower than the predicted values, but the gap was quite small. The results suggest that the absorption of Flu in rats was saturated at 10 mg/kg, and that the enhanced dissolution rate of Flu/beta-CD increased the saturation dose to 30 mg/kg.

  13. Supramolecular Inclusion in Cyclodextrins: A Pictorial Spectroscopic Demonstration

    ERIC Educational Resources Information Center

    Haldar, Basudeb; Mallick, Arabinda; Chattopadhyay, Nitin

    2008-01-01

    A spectroscopic experiment is presented that reveals that the hydrophobically end-modified water-soluble polymeric fluorophore, pyrene end-capped poly(ethylene oxide) (PYPY), interacts differently with [alpha], [beta], and [gamma]-cyclodextrins (CD) to form supramolecular inclusion complexes. The emission spectrum of PYPY in aqueous solution shows…

  14. The inclusion complex of rosmarinic acid into beta-cyclodextrin: A thermodynamic and structural analysis by NMR and capillary electrophoresis.

    PubMed

    Aksamija, Amra; Polidori, Ange; Plasson, Raphaël; Dangles, Olivier; Tomao, Valérie

    2016-10-01

    This work focuses on the characterization of the rosmarinic acid (RA)-β-cyclodextrin (CD) complex in aqueous solution by (1)H NMR (1D- and 2D-ROESY), completed with studies by capillary electrophoresis (CE). From the (1)H NMR data, the stoichiometry of the complex was determined by a Job's plot and the binding constant was estimated from a linear regression (Scott's method). At pH 2.9, the results showed that RA binds CD with a 1:1 stoichiometry and a binding constant Kb of 445 (±53) M(-1) or 465 (±81) M(-1) depending on the CD protons (H-5 or H-3) selected for the evaluation. The Kb value was also calculated from the CD-induced chemical shifts of each RA proton in order to collect information on the structure of the complex. The pH dependence of Kb revealed that the RA carboxylic form displays the highest affinity for CD. An investigation by capillary electrophoresis fully confirmed these results. 2D ROESY analysis provided detailed structural information on the complex and showed a strong correlation between H-3 and H-5 of CD and most RA protons. In conclusion, RA, an efficient phenolic antioxidant from rosemary with a marketing authorization, spontaneously forms a relatively stable inclusion complex with CD in water. PMID:27132848

  15. 1H NMR titration and quantum calculation for the inclusion complexes of cis-cyclooctene, cis, cis-1, 3-cyclooctadiene and cis, cis-1, 5-cyclooctadiene with beta-cyclodextrin.

    PubMed

    Yujuan, Cao; Runhua, Lu

    2009-08-15

    The inclusion behavior of cis-cyclooctene, cis, cis-1, 3-cyclooctadiene and cis, cis-1, 5-cyclooctadiene with beta-cyclodextrin (beta-CD) was studied by using (1)H NMR method in D(2)O/CD(3)OD solution and PM3 quantum-chemical simulation in vacuum. The experimental results indicate that each guest molecule penetrates deeply into beta-CD cavity and forms equimolecular inclusion complex with the host. The association constants of the complexes were determined by non-linear least-square method on the bases of the conversion-dependent chemical shift of two protons of the host molecule. The inclusion process and the most probable structure of the inclusion complexes were simulated using PM3 energy scanning and optimization. The trend of stability of the three inclusion complexes deduced from their calculated stabilization energies agrees well with the order of their association constants obtained from NMR experiments.

  16. Optical properties and inclusion of an organic fluorophore in organized media of micellar solutions and beta-cyclodextrin

    NASA Astrophysics Data System (ADS)

    El-Sayed, Yusif S.

    2013-02-01

    In this study, we prepared a new chalcone compound (3-(4'-diethylaminophenyl)-1-(2-pyridinyl) prop-2-en-1-one abbreviated as DEAPPP) and examined its characterization and photophysical properties such as singlet absorption, molar absorptivity, fluorescence spectra, and fluorescence quantum yield (ϕf). DEAPPP dye exhibited a large red shift in both absorption and emission spectra as solvent polarity increases, indicating a large change in dipole moment of molecule upon excitation. Also, the fluorescence quantum yield was solvent dependent. The absorption and fluorescence emission spectral properties of DEAPPP have been investigated in organized media of aqueous micellar and β-cyclodextrin (CD) solutions. While the absorption spectra were less sensitive to the nature of the added surfactant or CD, the characteristics of the intramolecular charge transfer (ICT) fluorescence were highly sensitive to the properties of the medium. The ICT maximum was strongly blue-shifted with a great enhancement in the fluorescence quantum yield on adding micellar or CD. This indicated that the solubilization of DEAPPP increased in the micellar core and an inclusion complex with β-CD was formed. The critical micelle concentration (CMC) as well as the polarity of the micellar core of sodium dodecyl sulfate (SDS), Cetyltrimethylammonium bromide (CTAB) and Triton X-100 (TX-100) have been determined. The CMC values were in good agreement with the reported values while the polarity was lower indicating that DEAPPP molecules were incorporated in the micellar core not at the micellar interface. The binding constants of DEAPPP: micelles or DEAPPP: CD complexes have been also determined.

  17. Bupivacaine hydrochloride complexation with some alpha- and beta-cyclodextrins studied by potentiometry with membrane electrodes.

    PubMed

    Kopecký, Frantisek; Vojteková, Mária; Kaclík, Pavol; Demko, Marek; Bieliková, Zuzana

    2004-05-01

    Membrane electrodes selective to bupivacaine cations were developed and those with PVC-dibutylphthalate membrane containing sparingly soluble bupivacaine phosphotungstate appeared to be the most suitable. Inclusion complexation of bupivacaine cations with cyclodextrins was studied by potentiometric measurements of the free bupivacaine cation concentration in aqueous solutions of bupivacaine hydrochloride with cyclodextrin using the prepared electrodes. Native alpha-cyclodextrin (alpha-CD) and beta-cyclodextrin (beta-CD), as well as their random-substituted derivatives hydroxypropyl-alpha-cyclodextrin (HP-alpha-CD), hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and methyl-beta-cyclodextrin (M-beta-CD), were chosen for the study. The measured potentiometric data processed both by a linear and nonlinear regression corroborated the formation of weak 1:1 bupivacaine cation-cyclodextrin complexes and the corresponding complexation constants K(11) approximately 50-155 M(-1) were evaluated by the non-linear least-squares method. The mutual order of K(11) values, especially alpha-CD > beta-CD, suggested that the bupivacaine butyl group was mainly responsible for the inclusion complexation; the highest K(11) was exhibited by M-beta-CD followed by alpha-CD. The observed complexation may substantially modify properties of bupivacaine hydrochloride dosage forms with sufficient concentration of cyclodextrin but bupivacaine cations are readily released from the weak cyclodextrin complexes by dilution.

  18. Protonation effects on the inclusion complexation of 6-deoxy-6-diethylamino-beta-cyclodextrin with 2-anthracenesulfonate, 2-naphthalenesulfonate, 2,6-naphthalenedisulfonate, and 2,7-naphthalenedisulfonate in aqueous solutions.

    PubMed

    Hamai, S; Ishikawa, S

    2001-01-01

    At pH values 5.5 and 10.3, 6-deoxy-6-diethylamino-beta-cyclodextrin (DD-beta-CD) as well as beta-CD forms 1:1 inclusion complexes with 2-anthracenesulfonate (2AS), 2-naphthalenesulfonate (2NS), 2,6-naphthalenedisulfonate (2,6NDS), and 2,7-naphthalenedisulfonate (2,7NDS). The equilibrium constants (K) for the formation of the 1:1 inclusion complexes have been evaluated from the absorbance and/or fluorescence intensity changes. With respect to the beta-CD inclusion complexes of 2AS, 2NS, 2,6NDS, and 2,7NDS, the K values at pH 5.5 are nearly the same as the corresponding ones at pH 10.3. In the case of the DD-beta-CD inclusion complexes, the K values of 2AS and 2NS similarly do not depend on the pH value. However, the K values of 2,6NDS and 2,7NDS for DD-beta-CD at pH 5.5 have been found to be more than two times greater than the corresponding ones at pH 10.3, suggesting the electrostatic attraction between the protonated diethylamino group of DD-beta-CD and the sulfonato group of the NDSs.

  19. Preparation and characterization of inclusion complexes of pefloxacin mesylate with three kinds of cyclodextrins.

    PubMed

    Chao, Jian-Bin; Tong, Hong-Bo; Liu, Dian-Sheng; Huang, Shu-Ping

    2006-05-01

    The ability of alpha-cyclodextrin, beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin (alpha-CD, beta-CD and HP-beta-CD) to break pefloxacin mesylate (PM) aggregates by forming inclusion complexes has been studied using 1H NMR (nuclear magnetic resonance spectroscopy), 13C NMR and fluorescence spectra. The inclusion constants are determined to compare the corresponding inclusion capacity. Solid-inclusion complexes of PM with CDs are synthesized by coprecipitation method, and all the inclusion ratios are found to be 1:1. Additionally, spatial characterization of complexes has been proposed based on two-dimensional nuclear magnetic resonance technique (2D NMR) and spatial conformation is also investigated to propose two possible models between PM and CDs.

  20. Rayleigh light scattering study on the supramolecular interactions of beta-cyclodextrin derivatives with tetrakis(4-methoxylphenyl)porphyrin.

    PubMed

    Yang, Ronghua; Li, Ke'an; Wang, Kemin; Liu, Feng; Li, Na; Zhao, Fenglin

    2003-01-01

    The supramolecular interactions of beta-cyclodextrin(beta-CD) and four kinds of alkylated beta-cyclodextrin (beta-CDs), i.e. heptakis (2,6-di-O-isobutyl)-beta-cyclodextrin (Ob-beta-CD), heptakis (2,6-di-O-n-octyl)-beta-cyclodextrin (Oc-beta-CD), heptakis (2,6-di-O-n-dodecyl)-beta-cyclodextrin (Od-beta-CD) and heptakis (2,6-di-O-n-hexadecyl)-beta-cyclodextrin (Oh-beta-CD) with tetrakis(4-methoxylphenyl)porphyrin (TMOPP) have been investigated by Rayleigh light scattering (RLS) technique. Beta-CDs form 2:1 inclusion complex with TMOPP following an obvious RLS enhancement of TMOPP. The inclusion abilities of different beta-CDs were compared. The results show that the inclusion ability of beta-CDs is related to the size of the alkylated substituent. Thus, a new mechanism of inclusion interaction has been proposed. The exact stoichiometric ratios and the association constants of the inclusion complexes have been examined by application of curve fitting method.

  1. Fosinopril-cyclodextrin inclusion complexes: phase solubility and physicochemical analysis.

    PubMed

    Sbârcea, L; Udrescu, L; Drăgan, L; Trandafirescu, C; Szabadai, Z; Bojiţă, M

    2011-08-01

    Fosinopril is one of the most hydrophobic substances among the angiotensin-converting enzyme inhibitors, exhibiting low water solubility and poor bioavailability following oral administration. Inclusion complexes between the drug substance and cyclodextrins (CDs) were obtained in order to improve its solubility. The purpose of this study was to investigate the guest-host interaction of fosinopril sodium (FOS) with beta-cyclodextrin (beta-CD) and its derivative, randomly methylated beta-cyclodextrin (RAMEB) in solution by phase solubility diagrams (PSD) and in solid state by using thermal analysis, powder X-ray diffractometry (PXRD) and Fourier transform infrared spectroscopy (FTIR). The phase solubility analysis indicated that the solubility of FOS in simulated gastric fluid was increased in the presence of CDs and revealed for RAMEB an A(L)-type diagram, suggesting the formation of a 1:1 inclusion complex, and for beta-CD a B(s)-type phase diagram. The estimated apparent stability constant (K1:1), according to the Higuchi and Connors method, is 3209.99 M(-1) and 1770.34 M(-1) for RAMEB and beta-CD complexes respectively. The binary systems FOS/CDs were prepared using the kneading method in the molar ratio 1:1. The PXRD patterns and the thermograms indicated a drug amorphization process, higher for FOS/RAMEB binary system and the FTIR analysis suggested that the ester group of FOS is probably enclosed in the CD's cavity. The results of this study confirm the formation of inclusion complexes both in solution and in solid state and suggest that the complexes formation between FOS and CDs could improve the bioavailability of the drug due to the enhancing absorption expected from increased drug solubility.

  2. Temperature Dependence of Positron Annihilation in beta-Cyclodextrin and beta-Cyclodextrin Complexes

    NASA Astrophysics Data System (ADS)

    Hu, Y.; Hsu Hadley, F. H., Jr.; Trinh, T.

    1996-11-01

    The effects of temperature on positron annihilation in beta-cyclodextrin and beta-cyclodextrin complexed with benzyl salicylate, benzyl acetate, ethyl salicylate, geraniol, linalool and nerol were studied. Samples were prepared by slurry, air-dried and freeze-dried methods. Lifetime spectra were measured as a function of temperature for each sample. Comparison of the annihilation rate and intensity of the longer-lived component showed that positronium formation was affected by guest molecules, preparation methods and temperature variations. Results can be used to explain beta-cyclodextrin complex formation with different guest molecules.

  3. Determination of individual proton affinities of ofloxacin from its UV-Vis absorption, fluorescence and charge-transfer spectra: effect of inclusion in beta-cyclodextrin on the proton affinities.

    PubMed

    Ghosh, Bankim Chandra; Deb, Nipamanjari; Mukherjee, Asok K

    2010-08-01

    Individual proton affinities of the four dissociable functional groups of (+/-)-9-fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid (commonly called "ofloxacin" and to be denoted henceforth as OflH), have been determined from the pH-dependent variation of the UV-vis absorption and fluorescence spectra of the compound itself and of its charge transfer complexes (CT) with p-bromanil and p-chloranil (in aqueous medium containing 0.1% ethanol, v/v). To utilize the CT spectra for determination of the proton affinity of the anilinic N, the CT absorption band of the ofloxacin-p-bromanil complex has been studied by changing the pH of the medium. Further, the effect of inclusion on the proton affinities of the four dissociable groups of OflH has been studied in presence of beta-cyclodextrin (beta-CD). Two pK(a) values corresponding to anilinic and tertiary N atoms change, whereas those corresponding to phenolic -OH and aromatic -COOH groups remain unchanged by the addition of beta-CD, a fact that indicates partial inclusion of the ofloxacin molecule in beta-CD. Formation constant and related thermodynamic parameters for the OflH(2)(+).beta-CD inclusion complex in aqueous solution have been determined from absorption intensities. A general relation between pK(a) values of guests having proton-releasing functional groups and formation constants of the inclusion complexes of the protonated and deprotonated forms with a host molecule has been utilized for determination of the formation constant of the OflH(3)(+2).beta-CD complex from the pK(a) values of OflH(3)(+2) in the presence and absence of beta-CD, along with the formation constant of the OflH(2)(+).beta-CD complex. Results of the present study reveal that the N-methylpiperazinyl moiety of ofloxacin is included in beta-CD, and the remaining part of the guest molecule remains outside. Also, in molecular interaction with quinone-type electron acceptors

  4. Effect of inclusion complexation with cyclodextrins on photostability of nifedipine in solid state.

    PubMed

    Bayomi, Mohsen A; Abanumay, Khalid A; Al-Angary, Abdulaziz A

    2002-08-28

    Nifedipine is a highly photosensitive drug that requires restricted protection from light during manufacturing, storage and handling of its dosage forms. Inclusion complexation of nifedipine with cyclodextrins (CDs) could be advantageous in protecting the drug against the effect of light. In this study, solid inclusion complexes of nifedipine with beta-cyclodextrin (beta-CD), hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and dimethyl-beta-cyclodextrin (DM-beta-CD) were prepared using the coprecipitation method. The obtained solid inclusion complexes have been confirmed by differential scanning calorimetry (DSC), X-ray diffraction and infrared spectroscopy (IR). The IR spectra indicated partial inclusion of nifedipine molecules into CD cavities through the dihydropyridine ring. Inclusion complexation was also associated with a dramatic enhancement of drug dissolution with magnitudes depended on the type of CD. The effect of exposure to fluorescent lamp and sunlight on the photodegradation of uncomplexed and complexed nifedipine was tested. Photodegradation of nifedipine was monitored using a high performance liquid chromatographic (HPLC) assay method. Inclusion complexation of nifedipine showed to retard drug photodegradation as indicated by degradation rate constant lowering with values depended on light source and type of complexing agent. This effect was the least with beta-CD compared with that of modified beta-CD. It was also interesting to notice that inclusion complexation of nifedipine offered much higher protection against the effect of fluorescent lamp than that of sunlight. The obtained results suggests that the design of solid dosage forms of nifedipine such as a fast dissolving nifedipine tablets is possible with the advantages of low required light protection.

  5. Host-guest interaction of L-tyrosine with beta-cyclodextrin.

    PubMed

    Shanmugam, M; Ramesh, D; Nagalakshmi, V; Kavitha, R; Rajamohan, R; Stalin, T

    2008-11-01

    The inclusion complexes of beta-cyclodextrin (beta-CD) with L-tyrosine (L-TYN) were investigated by using spectrophotometers. The absorption and fluorescence enhancement occurs with beta-CD and L-TYN forms 1:1 inclusion complex. The unusual blue shift of hydroxyl ion in the beta-CD medium confirms OH groups present in the interior part of the beta-CD cavity and -COOH group present in the upper part of the beta-CD cavity. A mechanism is proposed to explain inclusion process. The inclusion interaction was examined and the thermodynamic parameters of inclusion process DeltaG, DeltaH and DeltaS were determined. The results indicated that the inclusion process was an exergonic and spontaneous process. Stable solid inclusion complexes were established and characterized by FT-IR, scanning electron microscope (SEM) methods.

  6. Inclusion Behavior of 4-Nonylphenol into Cyclodextrin Derivatives.

    PubMed

    Kawasaki, Naohito; Araki, Mamiko; Nakamura, Takeo; Tanada, Seiki

    2001-06-01

    The solubilities of 4-nonylphenol in five kinds of hydroxypropyl-cyclodextrin (HP-CDs) solutions were investigated in order to evaluate them for soil remediation. The relative aqueous-phase concentration of 4-nonylphenol linearly increased with the increasing HP-CD concentration. The addition of HP-beta-CD (degree of substitution, D.S.=0.6) produced the largest change because the inner core of HP-beta-CD is the most hydrophobic. The solubility of 4-nonylphenol in the HP-CD solutions depended upon the cavity diameter and the degree of HP-CD substitution. Both ozone and activated carbon treatments have been using for removing organic compounds and foul odor compounds from tap water. As the inclusion complexes moved into the groundwater, the ozone degradation of the inclusion complexes was estimated. The 4-nonylphenol-HP-CD inclusion complexes were easily degraded by ozone. The degree of degradation increased with the increasing ozonization time. Weakly acidic compounds were produced from the 4-nonylphenol-HP-CD inclusion complexes by ozonization. HP-CDs could be used for the removal of 4-nonylphenol from soil. Copyright 2001 Academic Press.

  7. pH dependent in-out isomerism of an amino-beta-cyclodextrin derivative.

    PubMed

    Alcalde, Mercedes Alvarez; Gancedo, Cristina; Jover, Aida; Carrazana, Jorge; Soto, Victor H; Meijide, Francisco; Tato, José Vazquez

    2006-07-13

    An amino derivative of beta-cyclodextrin [6-(6-aminehexanamide)-6-deoxy)-beta-cyclodextrin (6-betaCD)] was synthesized, and the formation of an intramolecular inclusion complex was studied by NMR techniques. The deprotonation/protonation of the amino group stimulates an in/out movement of the pendant group toward/from the cyclodextrin cavity, the protonated species lying outside the hydrophobic cyclodextrin cavity but the unprotonated one residing inside and outside the cavity. The protonation of the amino group is a fast exchange rate NMR time-scale process, but the chain movement is a slow one. The equilibrium constants of both processes were determined from 1H NMR experiments and the kinetic constants for the slow process were determined from exchange spectroscopy (EXSY) experiments. PMID:16821861

  8. Spectrofluorimetric determination of stoichiometry and association constants of the complexes of harmane and harmine with beta-cyclodextrin and chemically modified beta-cyclodextrins.

    PubMed

    Martín, L; León, A; Olives, A I; Del Castillo, B; Martín, M A

    2003-06-13

    The association characteristics of the inclusion complexes of the beta-carboline alkaloids harmane and harmine with beta-cyclodextrin (beta-CD) and chemically modified beta-cyclodextrins such as hydroxypropyl-beta-cyclodextrin (HPbeta-CD), 2,3-di-O-methyl-beta-cyclodextrin (DMbeta-CD) and 2,3,6-tri-O-methyl-beta-cyclodextrin (TMbeta-CD) are described. The association constants vary from 112 for harmine/DMbeta-CD to 418 for harmane/HPbeta-CD. The magnitude of the interactions between the host and the guest molecules depends on the chemical and geometrical characteristics of the guest molecules and therefore the association constants vary for the different cyclodextrin complexes. The steric hindrance is higher in the case of harmine due to the presence of methoxy group on the beta-carboline ring. The association obtained for the harmane complexes is stronger than the one observed for harmine complexes except in the case of harmine/TMbeta-CD. Important differences in the association constants were observed depending on the experimental variable used in the calculations (absolute value of fluorescence intensity or the ratio between the fluorescence intensities corresponding to the neutral and cationic forms). When fluorescence intensity values were considered, the association constants were higher than when the ratio of the emission intensity for the cationic and neutral species was used. These differences are a consequence of the co-existence of acid-base equilibria in the ground and in excited states together with the complexation equilibria. The existence of a proton transfer reaction in the excited states of harmane or harmine implies the need for the experimental dialysis procedure for separation of the complexes from free harmane or harmine. Such methodology allows quantitative results for stoichiometry determinations to be obtained, which show the existence of both 1:1 and 1:2 beta-carboline alkaloid:CD complexes with different solubility properties.

  9. Improvement of tetracaine antinociceptive effect by inclusion in cyclodextrins.

    PubMed

    Franco de Lima, Roberta Aline; de Jesus, Marcelo Bispo; Saia Cereda, Cíntia Maria; Tofoli, Giovana Radomille; Cabeça, Luis Fernando; Mazzaro, Irineu; Fraceto, Leonardo Fernandes; de Paula, Eneida

    2012-01-01

    Local anesthetics (LA) are among the most important pharmacological compounds used to attenuate or eliminate pain. However, systemic toxicity is still a limitation for LA application, especially for ester-type drugs, such as tetracaine (TTC) that presents poor chemical stability (due to hydrolysis by plasma esterases). Several approaches have been used to improve LA pharmaceutical properties, including the employment of drug-delivery systems. Here we used beta-cyclodextrin (β-CD) or hydroxypropyl-beta-cyclodextrin (HP-β-CD) to develop two new TTC formulations (TTC:β-CD and TTC:HP-β-CD). The inclusion complexes formation, in a 1:1 stoichiometry, was confirmed by differential scanning calorimetry, X-ray diffraction, UV-VIS absorption and fluorescence. Nuclear magnetic resonance (DOSY experiments) revealed that TTC association with HP-β-CD is stronger (Ka=1200 mol/L(-1)) than with β-CD (Ka=845 mol/L(-1)). Moreover, nuclear Overhauser effect (NOE) experiments provided information on the topology of the complexes, where TTC aromatic ring is buried inside the CD hydrophobic cavity. In vitro tests with 3T3 fibroblast cells culture revealed that complexation decreased TTC cytotoxicity. In addition, the total analgesic effect of TTC, tested in rats through the infraorbital nerve test, was improved in 36% with TTC:β-CD and TTC:HP-β-CD. In conclusion, these formulations presented potential for future clinical use, by reducing the toxicity and increasing the antinociceptive effect of tetracaine.

  10. [A study on inclusion complexes of cyclodextrin with three anticancer xanthines by fluorescence].

    PubMed

    Wei, Yan-li; Dong, Chuan

    2004-07-01

    The inclusion complexes of beta-Cyclodextrin (beta-CD) and HP-beta-Cyclodextrin (HP-beta-CD) with 6-Mercaptopurine (6-MP), Azathioprine (BAN) and 8-Azaguanine (Azan) were investigated by fluorescence. Various factors affecting the formation of inclusion complexes were discussed in detail including formation time and pH effect. The formation constants of their inclusion complexes were determined. The results indicated that their inclusion was affected significantly by laying time and pH. The formation time of beta-CD inclusion complexes is much longer than that of HP-beta-CD. The optimum pH is about pH = 7.7-12. Their maximum excitation wavelengths are all in the range of 276-285 nm and the maximum emission wavelengths are all in the range of 328-353 nm. The fluorescence signals are intensified with increasing concentration of CD. The stoichiometries of the inclusion complexes of CD with these three anticancer xanthines are all 1:1 and the formation constants are calculated.

  11. Interaction of ochratoxin A with quaternary ammonium beta-cyclodextrin.

    PubMed

    Poór, Miklós; Kunsági-Máté, Sándor; Szente, Lajos; Matisz, Gergely; Secenji, Györgyi; Czibulya, Zsuzsanna; Kőszegi, Tamás

    2015-04-01

    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. PMID:25442535

  12. Interaction of ochratoxin A with quaternary ammonium beta-cyclodextrin.

    PubMed

    Poór, Miklós; Kunsági-Máté, Sándor; Szente, Lajos; Matisz, Gergely; Secenji, Györgyi; Czibulya, Zsuzsanna; Kőszegi, Tamás

    2015-04-01

    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.

  13. Antibacterial electrospun nanofibers from triclosan/cyclodextrin inclusion complexes.

    PubMed

    Celebioglu, Asli; Umu, Ozgun C O; Tekinay, Turgay; Uyar, Tamer

    2014-04-01

    The electrospinning of nanofibers (NF) from cyclodextrin inclusion complexes (CD-IC) with an antibacterial agent (triclosan) was achieved without using any carrier polymeric matrix. Polymer-free triclosan/CD-IC NF were electrospun from highly concentrated (160% CD, w/w) aqueous triclosan/CD-IC suspension by using two types of chemically modified CD; hydroxypropyl-beta-cyclodextrin (HPβCD) and hydroxypropyl-gamma-cyclodextrin (HPγCD). The morphological characterization of the electrospun triclosan/CD-IC NF by SEM elucidated that the triclosan/HPβCD-IC NF and triclosan/HPγCD-IC NF were bead-free having average fiber diameter of 520 ± 250 nm and 1,100 ± 660 nm, respectively. The presence of triclosan and the formation of triclosan/CD-IC within the fiber structure were confirmed by (1)H-NMR, FTIR, XRD, DSC, and TGA studies. The initial 1:1 molar ratio of the triclosan:CD was kept for triclosan/HPβCD-IC NF after the electrospinning and whereas 0.7:1 molar ratio was observed for triclosan/HPγCD-IC NF and some uncomplexed triclosan was detected suggesting that the complexation efficiency of triclosan with HPγCD was lower than that of HPβCD. The antibacterial properties of triclosan/CD-IC NF were tested against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. It was observed that triclosan/HPβCD-IC NF and triclosan/HPγCD-IC NF showed better antibacterial activity against both bacteria compared to uncomplexed pure triclosan.

  14. Comparative study on the inclusion behaviour of cyclodextrin derivatives with venoruton and rutin by thin layer chromatography.

    PubMed

    Guo, Xiliang; Shuang, Shaomin; Wang, Xiaoping; Dong, Chuan; Pan, Jinghao; Aboul-Enein, Hassan Y

    2004-10-01

    The interaction of rutin and venoruton (troxerutin), with alpha-, beta- and gamma-cyclodextrin (CD), hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and methyl-beta-cyclodextrin (M-beta-CD) was investigated by reversed-phase thin layer chromatography on polyamide plates. A mobile phase consisted of NH(4)OH; NH(4)Cl buffer solution containing various CD concentrations (pH = 9.7, 20 degrees C) was used as mobile phase. The equilibrium constants (K(f)) and the retention factor (R(f)) were determined and used to study the inclusion process. The in fluence of CDs on the solubility of rutin and venoruton was characterized by R(M) values and the increasing hydrophilicity of drugs. The results show that the inclusion capacity of cyclodextrins follows the order HP-beta-CD > M-beta-CD > beta-CD > gamma-CD, and rutin is more easily included by the studied cyclodextrins than venoruton. In addition, the thermodynamic parameters (Delta H, Delta S) for the formation of complexes were obtained from the van't Hoff equation, displaying the enthalpy-entropy compensation effect.

  15. Ferrocene-beta-cyclodextrin conjugates: synthesis, supramolecular behavior, and use as electrochemical sensors.

    PubMed

    Casas-Solvas, Juan M; Ortiz-Salmerón, Emilia; Fernández, Ignacio; García-Fuentes, Luís; Santoyo-González, Francisco; Vargas-Berenguel, Antonio

    2009-08-17

    Ferrocene with a beta-cyclodextrin unit bound to one or both cyclopentadienyl rings through the secondary face were conveniently synthesized by regiospecific copper(I)-catalyzed cycloaddition of 2-O-propargyl-beta-cyclodextrin to azidomethyl or bis(azidomethyl)ferrocene. The supramolecular behavior of the synthesized conjugates in both the absence and presence of bile salts (sodium cholate, deoxycholate, and chenodeoxycholate) was studied by using electrochemical methods (cyclic and differential pulse voltammetry), isothermal titration calorimetry, and NMR spectroscopy (PGSE, CPMG, and 2D-ROESY). These techniques allowed the determination of stability constants, mode of inclusion, and diffusion coefficients for complexes formed with the neutral and, in some cases, the oxidized states of the ferrocenyl conjugates. It was found that the ferrocenyl conjugate with one beta-cyclodextrin unit forms a redox-controllable head-to-head homodimer in aqueous solution. The ferrocene-bis(beta-cyclodextrin) conjugate is present in two distinguishable forms in aqueous solution, each one having a different half-wave oxidation potential for the oxidation of the ferrocene. By contrast, only one distinguishable form for the oxidized state of the ferrocene-beta-cyclodextrin conjugate is detectable. The redox-sensing abilities of the synthesized conjugates towards the bile salts were evaluated based on the observed guest-induced changes in both the half-wave potential and the current peak intensity of the electroactive moiety.

  16. Investigation of inclusion complex of epothilone A with cyclodextrins.

    PubMed

    Xiao, Chuan-Fan; Li, Ke; Huang, Rong; He, Guo-Jin; Zhang, Jian-Qiang; Zhu, Li; Yang, Qing-Yi; Jiang, Kun-Ming; Jin, Yi; Lin, Jun

    2014-02-15

    The inclusion complexation of Epothilone A with native cyclodextrin (β- or γ-CD) and its derivative hydroxypropyl-β-cyclodextrin (HPβCD) were prepared. Their behavior, characterization, and binding ability were investigated in both solution and the solid state by means of UV-vis, NMR, XRD, DSC and SEM. The results show that the water solubility and solution stability obviously increased in the inclusion complex with cyclodextrins. Meanwhile, the inclusion complexes still retained anticancer activity against A549 and MCF-7 cells, similar to free Epothilone A. This satisfactory water solubility, high solution stability, and high anticancer activity of the Epothilone A/CD complexes will be potentially useful as an anticancer therapy.

  17. β-Cyclodextrin- para-aminosalicylic acid inclusion complexes

    NASA Astrophysics Data System (ADS)

    Roik, N. V.; Belyakova, L. A.; Oranskaya, E. I.

    2010-11-01

    Complex formation of β-cyclodextrin with para-aminosalicylic acid in buffer solutions is studied by UV spectroscopy. It is found that the stoichiometric proportion of the components in the β-cyclodextrin-para-aminosalicylic acid inclusion complex is 1:1. The Ketelar equation is used to calculate the stability constants of the inclusion complexes at different temperatures. The thermodynamic parameters of the complex formation process (ΔG, ΔH, ΔS) are calculated using the van't Hoff equation. The 1:1 β-cyclodextrin-para-aminosalicylic acid inclusion complex is prepared in solid form and its characteristics are determined by IR spectroscopic and x-ray diffraction techniques.

  18. Selective binding of chiral molecules of cinchona alkaloid by beta- and gamma-cyclodextrins and organoselenium-bridged bis(beta-cyclodextrin)s.

    PubMed

    Liu, Yu; Li, Li; Zhang, Heng-Yi; Fan, Zhi; Guan, Xu-Dong

    2003-02-01

    The inclusion complexation behavior of chiral members of cinchona alkaloid with beta- and gamma-cyclodextrins (1 and 2) and 6,6(')-trimethylenediseleno-bridged bis(beta-cyclodextrin) (3) was assessed by means of fluorescence and 2D-NMR spectroscopy. The spectrofluorometric titrations have been performed in aqueous buffer solution (pH 7.20) at 25.0 degrees C to determine the stability constants of the inclusion complexation of 1-3 with guest molecules (i.e., cinchonine, cinchonidine, quinine, and quinidine) in order to quantitatively investigate the molecular selective binding ability. The stability constants of the resulting complexes of 2 with guest molecules are larger than that of 1. As a result of cooperative binding, the stability constants of inclusion complexation of dimeric beta-cyclodextrin 3 with cinchonidine and cinchonine are higher than that of parent 1 by factor of 4.5 and 2.4, respectively. These results are discussed from the viewpoint of the size-fit and geometric complementary relationship between the host and guest.

  19. [Study on the molecular recognization of fungicide of kresoxim-methyl with beta-cyclodextrin and its derivatives].

    PubMed

    Xiao, Yu-mei; Wu, Yan-hua; Liu, Ji-ping; Li, Yan-fang; Li, Nan; Qin, Zhao-hai

    2008-10-01

    The molecular recognition of fungicide of kresoxim-methyl with beta-cyclodextrin (beta-CD), methyl-beta-cyclodextrin (RAMEB)and hydroxypropyl-beta-cyclodextrin (RAMEB) was investigated by using UV-Vis spectroscopy analysis. The effect of temperature and polarity of solvent on the recognition interaction was studied. The driving force and the possible structure of the inclusion complexes were also discussed. The results presented that they formed inclusion complexes with a stoichiometry of 1:1, and the formation constant of inclusion complexes was in the order of Ku(HP-beta-CD)>(beta-CD)Kp(RAMEB) at 298.15 K. Elevation of the temperature triggered a decrease in stability of the inclusion complexes and the value of K(beta-D) was the biggest at > or =303.15 K. The formation constant reduced sharply with the decreasing polarity of the solvent. The standard molar Gibbs energies, enthalpies and entropies were all negative. All the results indicated that the association of the guest molecule with beta-CD was favored by enthalpy changes, and hydrophobicity and hydrogen bond interaction were main driving forces for the inclusion reaction. Our findings provided an important proof for the use of inclusion complexes of kresoxim-methyl with CDs.

  20. Studying on inclusion complexes of Wogonin with β-cyclodextrin and hydroxypropyl-cyclodextrin.

    PubMed

    Li, Jinxia; Chao, Jianbin; Zhang, Min

    2012-02-15

    The formation of the complexes of Wogonin with β-cyclodextrin (β-CD) and hydroxypropyl-cyclodextrin (HP-β-CD) was studied by fluorescence spectra and nuclear magnetic resonance spectroscopy (NMR). The formation constants (Ks) of complexes were determined by fluorescence method. The results suggested that HP-β-CD was easier to form inclusion with Wogonin than β-CD in solution. In different pH solutions, CDs have different inclusive capacity to Wo. β-CD was most suitable for inclusion of neutral form and HP-β-CD was suitable for acidic form. In addition, the experimental resulted confirmed the existence of 1:1 inclusion complex of Wogonin with CDs. Besides, kinetic studies of DPPH with Wogonin and CDs complexes were done. The results obtained indicated that the complex was the most reactive form. Special configuration of complex has been proposed on NMR technique.

  1. Studying on inclusion complexes of Wogonin with β-cyclodextrin and hydroxypropyl-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Li, Jinxia; Chao, Jianbin; Zhang, Min

    2012-02-01

    The formation of the complexes of Wogonin with β-cyclodextrin (β-CD) and hydroxypropyl-cyclodextrin (HP-β-CD) was studied by fluorescence spectra and nuclear magnetic resonance spectroscopy (NMR). The formation constants (Ks) of complexes were determined by fluorescence method. The results suggested that HP-β-CD was easier to form inclusion with Wogonin than β-CD in solution. In different pH solutions, CDs have different inclusive capacity to Wo. β-CD was most suitable for inclusion of neutral form and HP-β-CD was suitable for acidic form. In addition, the experimental resulted confirmed the existence of 1:1 inclusion complex of Wogonin with CDs. Besides, kinetic studies of DPPH rad with Wogonin and CDs complexes were done. The results obtained indicated that the complex was the most reactive form. Special configuration of complex has been proposed on NMR technique.

  2. Poly(l-Lactic Acid)/Gelatin Fibrous Scaffold Loaded with Simvastatin/Beta-Cyclodextrin-Modified Hydroxyapatite Inclusion Complex for Bone Tissue Regeneration.

    PubMed

    Lee, Jung Bok; Kim, Ji Eun; Balikov, Daniel A; Bae, Min Soo; Heo, Dong Nyoung; Lee, Donghyun; Rim, Hyun Joon; Lee, Deok-Won; Sung, Hak-Joon; Kwon, Il Keun

    2016-07-01

    Recently, the application of nanostructured materials in the field of tissue engineering has garnered attention to mediate treatment and regeneration of bone defects. In this study, poly(l-lactic acid) (PLLA)/gelatin (PG) fibrous scaffolds are fabricated and β-cyclodextrin (βCD) grafted nano-hydroxyapatite (HAp) is coated onto the fibrous scaffold surface via an interaction between βCD and adamantane. Simvastatin (SIM), which is known to promote osteoblast viability and differentiation, is loaded into the remaining βCD. The specimen morphologies are characterized by scanning electron microscopy. The release profile of SIM from the drug loaded scaffold is also evaluated. In vitro proliferation and osteogenic differentiation of human adipose derived stem cells on SIM/HAp coated PG composite scaffolds is characterized by alkaline phosphatase (ALP) activity, mineralization (Alizarin Red S staining), and real time Polymerase chain reaction (PCR). The scaffolds are then implanted into rabbit calvarial defects and analyzed by microcomputed tomography for bone formation after four and eight weeks. These results demonstrate that SIM loaded PLLA/gelatin/HAp-(βCD) scaffolds promote significantly higher ALP activity, mineralization, osteogenic gene expression, and bone regeneration than control scaffolds. This suggests the potential application of this material toward bone tissue engineering. PMID:26996294

  3. Poly(l-Lactic Acid)/Gelatin Fibrous Scaffold Loaded with Simvastatin/Beta-Cyclodextrin-Modified Hydroxyapatite Inclusion Complex for Bone Tissue Regeneration.

    PubMed

    Lee, Jung Bok; Kim, Ji Eun; Balikov, Daniel A; Bae, Min Soo; Heo, Dong Nyoung; Lee, Donghyun; Rim, Hyun Joon; Lee, Deok-Won; Sung, Hak-Joon; Kwon, Il Keun

    2016-07-01

    Recently, the application of nanostructured materials in the field of tissue engineering has garnered attention to mediate treatment and regeneration of bone defects. In this study, poly(l-lactic acid) (PLLA)/gelatin (PG) fibrous scaffolds are fabricated and β-cyclodextrin (βCD) grafted nano-hydroxyapatite (HAp) is coated onto the fibrous scaffold surface via an interaction between βCD and adamantane. Simvastatin (SIM), which is known to promote osteoblast viability and differentiation, is loaded into the remaining βCD. The specimen morphologies are characterized by scanning electron microscopy. The release profile of SIM from the drug loaded scaffold is also evaluated. In vitro proliferation and osteogenic differentiation of human adipose derived stem cells on SIM/HAp coated PG composite scaffolds is characterized by alkaline phosphatase (ALP) activity, mineralization (Alizarin Red S staining), and real time Polymerase chain reaction (PCR). The scaffolds are then implanted into rabbit calvarial defects and analyzed by microcomputed tomography for bone formation after four and eight weeks. These results demonstrate that SIM loaded PLLA/gelatin/HAp-(βCD) scaffolds promote significantly higher ALP activity, mineralization, osteogenic gene expression, and bone regeneration than control scaffolds. This suggests the potential application of this material toward bone tissue engineering.

  4. Polymer bilayer formation due to specific interactions between beta-cyclodextrin and adamantane: a surface force study.

    PubMed

    Blomberg, Eva; Kumpulainen, Atte; David, Christelle; Amiel, Catherine

    2004-11-23

    The purposes of this study are to utilize the interactions between an adamantane end-capped poly(ethylene oxide) (PEO) and a cationic polymer of beta-cyclodextrin to build polymer bilayers on negatively charged surfaces, and to investigate the interactions between such layers. The association of this system in solution has been studied by rheology, light scattering, and fluorescence measurements. It was found that the adamantane-terminated PEO (PEO-Ad) mixed with the beta-cyclodextrin polymer gives complexes where the interpolymer links are formed by specific inclusion of the adamantane groups in the beta-cyclodextrin cavities. This results in a higher viscosity of the solution and growth of intermolecular clusters. The interactions between surfaces coated with a cationized beta-cyclodextrin polymer across a water solution containing PEO-Ad polymers were studied by employing the interferometric surface force apparatus (SFA). In the first step, the interaction between mica surfaces coated with the cationized beta-cyclodextrin polymer in pure water was investigated. It was found that the beta-cyclodextrin polymer adsorbs onto mica and almost neutralizes the surface charge. The adsorbed layers of the beta-cyclodextrin polymer are rather compact, with a layer thickness of about 60 A (30 A per surface). Upon separation, a very weak attractive force is observed. The beta-cyclodextrin solution was then diluted by pure water by a factor of 3000 and a PEO-Ad polymer was introduced into the solution. Two different architectures of the PEO-Ad polymer were investigated: a four-arm structure and a linear structure. After the adsorption of the PEO polymer onto the beta-cyclodextrin layer reached equilibrium, the forces were measured again. It was found that the weak repulsive long-range force had disappeared and an attractive force caused the surfaces to jump into contact, and that the compressed layer thickness had increased. The attractive force is interpreted as being due to

  5. Removal of polychlorinated biphenyls from aqueous solutions using beta-cyclodextrin grafted multiwalled carbon nanotubes.

    PubMed

    Shao, Dadong; Sheng, Guodong; Chen, Changlun; Wang, Xiangke; Nagatsu, Masaaki

    2010-04-01

    Cyclodextrins have excellent ability in the preconcentration of organic pollutants from aqueous solutions by forming inclusion complexes. Multiwalled carbon nanotubes (MWCNTs) possess high adsorption capacity in the removal of organic pollutants through the formation of conjugated complexes. In this paper, beta-cyclodextrin (beta-CD) was grafted on the surfaces of MWCNTs by using plasma technique. The beta-CD grafted MWCNTs (MWCNT-g-CD) were characterized by using Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, thermo gravimetric analysis-differential thermal analysis, and scanning electron microscopy in detail. The prepared MWCNT-g-CD were used to remove polychlorinated biphenyls (PCBs) from aqueous solutions under ambient conditions. The results suggest that MWCNT-g-CD have much higher adsorption capacity than MWCNTs in the removal of PCBs from aqueous solutions. MWCNT-g-CD are suitable materials in the preconcentration and immobilization of PCBs from large volumes of aqueous solutions in environmental pollution cleanup.

  6. Effect of beta-cyclodextrin nanocavity confinement on the photophysics of robinetin.

    PubMed

    Banerjee, Anwesha; Basu, Kaushik; Sengupta, Pradeep K

    2007-12-14

    We have studied the confinement of robinetin, a therapeutically active plant flavonol, in cyclodextrin (CDx) nanocavities, using steady state and time resolved fluorescence spectroscopy. Enhanced tautomer emission (arising from excited state intramolecular proton transfer (ESIPT)) as well as dramatically blue shifted (approximately 10 nm in beta-CDx and approximately 33 nm in SHP beta-CDx) normal fluorescence observed upon addition of the beta-CDxs indicate that robinetin readily enters the doughnut-shaped hydrophobic cavity of beta-CDx where the chromone moiety is well shielded from external hydrogen bonding perturbations. Detailed analyses of the fluorescence data (emission profile, anisotropy, decay times) indicate that robinetin forms 1:1 inclusion complexes with both natural and chemically modified beta-cyclodextrins (beta-CDx and SHP beta-CDx) with affinity constant values K=195+/-17 M(-1) and 1055+/-48 M(-1) respectively, indicating the prospective utility of SHP beta-CDx in particular as an effective drug carrier. Unlike beta-CDxs, alpha-CDxs do not form inclusion complexes with robinetin. To further characterize the robinetin/beta-CDxs complexes, circular dichroism (CD) spectroscopic studies have been performed, which reveal that incorporation of robinetin molecules in the chiral environment of the beta-CDxs strongly affects the electronic transitions of robinetin leading to the occurrence of positive induced circular dichroism (ICD) bands in the near ultra-violet (UV) region. Molecular mechanics calculations show that the inclusion complex with the chromone ring inserted into the beta-CDx cavity is most favorable, in agreement with our spectroscopic data.

  7. How does beta-cyclodextrin affect oxygen solubility in aqueous solutions of sodium perfluoroheptanoate?

    PubMed

    Dias, A M A; Andrade-Dias, C; Lima, S; Coutinho, J A P; Teixeira-Dias, J J C; Marrucho, I M

    2006-11-15

    The solubility of oxygen in aqueous solutions of sodium perfluoroheptanoate (NaPFHept) at different concentrations was measured at 310.15 K with an apparatus based on the saturation method. The effect of adding beta-cyclodextrin (betaCD) on the solubility of oxygen was also studied. Conductimetry measurements showed that the presence of betaCD in aqueous solutions of NaPFHept increases its critical micellar concentration (CMC). In the presence of betaCD (15 mM), the characteristic minimum of oxygen solubility observed at the CMC is shifted from 83 to 114 mM, and the curvature at the minimum is reduced to 64% of the value in the absence of betaCD. Chemical shift changes for the H5 protons of betaCD, recorded as functions of the initial concentration of NaPFHept, point to the formation of a relatively strong 1:1 inclusion in betaCD of the perfluoroheptanoate anion. Hence, it is suggest that the effect of adding betaCD on the solubility of oxygen cannot be accounted for only by the perfluoroheptanoate anion inclusion in betaCD, but has to be ascribed to the direct influence of this inclusion complex on disrupting the aggregation process reducing the increase of oxygen solubility after the CMC value.

  8. Spectrofluorometric study of complexation of some amino derivatives of 9,10-anthraquinone with beta-cyclodextrin.

    PubMed

    Shamsipur, Mojtaba; Yari, Abdullah; Sharghi, Hashem

    2005-11-01

    Complexation reactions between 1-amino-9,10-anthraquinone (AA1), 1-amino-2-methyl-9,10-anthraquinone (AA2), 1-amino-2,4-dimethyl-9,10-anthraquinone (AA3) and 1-amino-2-ethyl-9,10-anthraquinone (AA4) and beta-cyclodextrin were studied spectrofluorometrically, under optimized experimental conditions. The formation constants of the resulting 1:1 beta-cyclodextrin complexes were evaluated and found to decrease in the order AA4>AA1>AA3>AA2. Possible reasons for the observed stability sequence are discussed based on the structures proposed for the resulting inclusion complexes.

  9. Evaluation of the cytotoxicity of beta-cyclodextrin derivatives: evidence for the role of cholesterol extraction.

    PubMed

    Kiss, T; Fenyvesi, F; Bácskay, I; Váradi, J; Fenyvesi, E; Iványi, R; Szente, L; Tósaki, A; Vecsernyés, M

    2010-07-11

    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.

  10. Inclusion of terpenes in cyclodextrins: Preparation, characterization and pharmacological approaches.

    PubMed

    Lima, Pollyana S S; Lucchese, Angélica M; Araújo-Filho, Heitor G; Menezes, Paula P; Araújo, Adriano A S; Quintans-Júnior, Lucindo J; Quintans, Jullyana S S

    2016-10-20

    Terpenes constitute the largest class of natural products and are important resources for the pharmaceutical, food and cosmetics industries. However, due to their low water solubility and poor bioavailability there has been a search for compounds that could improve their physicochemical properties. Cyclodextrins (natural and derived) have been proposed for this role and have been complexed with different types of terpenes. This complexation has been demonstrated by using analytical techniques for characterizing complexes such as DSC, NMR, XRD, FTIR, and TGA. The formation of inclusion complexes has been able to improve drug characteristics such as bioavailability, solubility and stability; and to enhance biological activity and efficacy. This review shows strong experimental evidence that cyclodextrins improve the pharmacological properties of terpenes, and therefore need to be recognized as being possible targets for clinical use. PMID:27474645

  11. Inclusion complex of sulfadimethoxine with cyclodextrins: preparation and characterization.

    PubMed

    Rajendiran, N; Siva, S

    2014-01-30

    The inclusion complexation behavior, characterization and binding ability of sulfadimethoxine (SDMO) with α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD) have been investigated both in solution and solid state by means of absorption, fluorescence, time-resolved fluorescence, (1)H NMR, FT-IR, DSC, SEM, TEM, XRD and molecular modeling methods. The spectral shifts revealed that the part of pyrimidine and aniline rings of SDMO are entrapped in the CD cavity. The stoichiometric ratio and association constant were determined by Benesi-Hildebrand plots and spectroscopic studies respectively. FT-IR spectroscopy was used to compare inclusion systems with physical mixtures, and demonstrated the complex formation in the solid state. The morphology and size of the nanoparticles of SDMO/CD complexes in aqueous solution were observed by TEM. The DSC analysis showed that the thermal stability of SDMO was enhanced in the presence of CD. Investigations of energetic and thermodynamic properties by PM3 method confirmed the stability of the inclusion complexes.

  12. Modified β-Cyclodextrin Inclusion Complex to Improve the Physicochemical Properties of Albendazole. Complete In Vitro Evaluation and Characterization

    PubMed Central

    García, Agustina; Leonardi, Darío; Salazar, Mario Oscar; Lamas, María Celina

    2014-01-01

    The potential use of natural cyclodextrins and their synthetic derivatives have been studied extensively in pharmaceutical research and development to modify certain properties of hydrophobic drugs. The ability of these host molecules of including guest molecules within their cavities improves notably the physicochemical properties of poorly soluble drugs, such as albendazole, the first chosen drug to treat gastrointestinal helminthic infections. Thus, the aim of this work was to synthesize a beta cyclodextrin citrate derivative, to analyze its ability to form complexes with albendazole and to evaluate its solubility and dissolution rate. The synthesis progress of the cyclodextrin derivative was followed by electrospray mass spectrometry and the acid-base titration of the product. The derivative exhibited an important drug affinity. Nuclear magnetic resonance experiments demonstrated that the tail and the aromatic ring of the drug were inside the cavity of the cyclodextrin derivative. The inclusion complex was prepared by spray drying and full characterized. The drug dissolution rate displayed exceptional results, achieving 100% drug release after 20 minutes. The studies indicated that the inclusion complex with the cyclodextrin derivative improved remarkably the physicochemical properties of albendazole, being a suitable excipient to design oral dosage forms. PMID:24551084

  13. Inclusion complexes of PBN-type nitrone spin traps and their superoxide spin adducts with cyclodextrin derivatives: parallel determination of the association constants by NMR titrations and 2D-EPR simulations.

    PubMed

    Bardelang, David; Rockenbauer, Antal; Karoui, Hakim; Finet, Jean-Pierre; Tordo, Paul

    2005-05-26

    (1)H NMR and electron paramagnetic resonance (EPR) titrations were used to determine the association constants of the complexes of alpha-phenyl-N-tert-butylnitrone (PBN) analogues and their superoxide spin adducts, respectively, with methylated beta-cyclodextrins. A 1:1 stoichiometry for the nitrones with randomly methylated beta-cyclodextrin and 2,6-di-O-methyl-beta-cyclodextrin and 1:1 and 1:2 stoichiometries for the corresponding cyclodextrin-nitroxide complexes were observed. After the superoxide radical spin trapping reaction, EPR titrations afforded the association constants of the corresponding cyclodextrin-nitroxide complexes. Two-dimensional EPR simulations indicated a bimodal inclusion of the nitroxide free radical spin adducts into the cyclodextrins. For all the nitrone-cyclodextrin and nitroxide-cyclodextrin complexes, the association constants were always higher for the nitroxide complexes than for the nitrone complexes. A cooperative system concerning the complexation of the nitroxide spin adduct with a cyclodextrin was evidenced by EPR titrations. The efficiency of the cyclodextrin inclusion technique to trap superoxide and to resist bioreduction by sodium l-ascorbate was also investigated.

  14. Study on inclusion interaction of piroxicam with β-cyclodextrin derivatives

    NASA Astrophysics Data System (ADS)

    Xiliang, Guo; Yu, Yang; Guoyan, Zhao; Guomei, Zhang; Jianbin, Chao; Shaomin, Shuang

    2003-12-01

    The inclusion behavior of piroxicam (PX) with β-cyclodextrin (β-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD), and carboxymethyl-β-cyclodextrin (CM-β-CD) was investigated by using steady-state fluorescence and nuclear magnetic resonance (NMR) technique. The various factors affecting the inclusion process were examined in detail. The remarkable fluorescence emission enhancement upon addition of CDs suggested that cyclodextrins (CDs) were most suitable for inclusion of the uncharged species of PX. The stoichiometry of the PX-CDs inclusion complexes was 1:1, except for β-CD where a 1:2 inclusion complex was formed. The formation constants showed the strongest inclusion capacity of β-CD. NMR showed the inclusion mode of PX with CDs.

  15. Study on the interaction between the inclusion complex of hematoxylin with β-cyclodextrin and DNA.

    PubMed

    Xu, Dongling; Wang, Xingming; Fei, Dan; Ding, Lisheng

    2010-11-01

    Ultraviolet-visible (UV-vis) spectra, fluorescence spectra, electrochemistry, and the thermodynamic method were used to discuss the interaction mode between the inclusion complex of hematoxylin with β-cyclodextrin and herring sperm DNA. On the condition of physiological pH, the result showed that hematoxylin and β-cyclodextrin formed an inclusion complex with binding ratio n(hematoxylin):n(β-cyclodextrin) = 1:1. The interaction mode between β-cyclodextrin-hematoxylin and DNA was a mixed binding, which contained intercalation and electrostatic mode. The binding ratio between β-cyclodextrin-hematoxylin and DNA was n(β-cyclodextrin -hematoxylin):n(DNA) = 2:1, binding constant was K(⊖)(298.15K) = 5.29 × 10⁴ L·mol⁻¹, and entropy worked as driven force in this action.

  16. Inclusion and functionalization of polymers with cyclodextrins: current applications and future prospects.

    PubMed

    Folch-Cano, Christian; Yazdani-Pedram, Mehrdad; Olea-Azar, Claudio

    2014-01-01

    The numerous hydroxyl groups available in cyclodextrins are active sites that can form different types of linkages. They can be crosslinked with one another, or they can be derivatized to produce monomers that can form linear or branched networks. Moreover, they can form inclusion complexes with polymers and different substrates, modifying their physicochemical properties. This review shows the different applications using polymers with cyclodextrins, either by forming inclusion complexes, ternary complexes, networks, or molecularly imprinted polymers (MIPs). On one hand, the use of cyclodextrins enhances the properties of each polymer, and on the other the use of polymers decreases the amount of cyclodextrins required in different formulations. Both cyclodextrins and polymers contribute synergistically in several applications such as pharmacological, nutritional, environmental, and other industrial fields. The use of polymers based on cyclodextrins is a low cost easy to use potential tool with great future prospects.

  17. Host-guest inclusion system of mangiferin with β-cyclodextrin and its derivatives.

    PubMed

    Yang, Xuemin; Zhao, Yulin; Chen, Yunjian; Liao, Xiali; Gao, Chuanzhu; Xiao, Dan; Qin, Qixue; Yi, Dong; Yang, Bo

    2013-05-01

    The characterization, inclusion complexation behavior and binding ability of the inclusion complexes of mangiferin (MGF) with β-cyclodextrin and its derivatives (hydroxypropyl-β-cyclodextrin (HPβCD), sulfobutyl ether β-cyclodextrin (SBEβCD) and mono (6-ethylene-diamino-6-deoxy)-β-cyclodextrin (ENβCD)) were investigated in both solution and solid state by means of PL spectroscopy, (1)H and 2D NMR, XRD, TG and DSC. The results showed that the water solubility and thermal stability of MGF were significantly increased in the inclusion complex with cyclodextrins. The MGF/CDs complexes will be potentially useful for the design of a novel formulation of mangiferin for herbal medicine.

  18. Antipyrine-gamma cyclodextrin inclusion complex: Molecular modeling, preparation, characterization and cytotoxicity studies

    NASA Astrophysics Data System (ADS)

    Gannimani, Ramesh; Perumal, Amanda; Ramesh, Muthusamy; Pillay, Karen; Soliman, Mahmoud E.; Govender, Patrick

    2015-06-01

    Molecular docking, semi-empirical and molecular dynamics studies were conducted for α, β and γ-cyclodextrin-associated inclusion complexes of antipyrine. The results of molecular modeling were systematically analyzed to determine the stability of inclusion complexes. In preliminary computational screening, β and γ-cyclodextrin inclusion complexes of antipyrine were found to be more stable as compared to α-cyclodextrin based on docking score and binding free energies. Further, inclusion complex of antipyrine with γ-cyclodextrin was prepared by freeze drying method. Formation of the inclusion complex was investigated by solid state characterization techniques such as thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. The changes observed in decomposition temperature, diffractogram, vibrational frequencies and morphological appearance confirmed the formation of inclusion complex. In addition, results from 1H NMR and 2D NOESY studies supported the inclusion phenomenon. The results obtained from computational studies were found to be in consistent with experimental data to ascertain the encapsulation of antipyrine into γ-cyclodextrin. The inclusion complex was found to be non-toxic toward MDCK-1 cell lines. Thus, this approach may be helpful in the formulation of drug molecules using cyclodextrins.

  19. Preparation and physicochemical characterization of amoxicillin beta-cyclodextrin complexes.

    PubMed

    Bisson-Boutelliez, Catherine; Fontanay, Stephane; Finance, Chantal; Kedzierewicz, Francine

    2010-06-01

    Amoxicillin (AMOX), a penicillin A, belongs to the beta-lactam family It is usually the drug of choice within the class because it is better absorbed, following oral administration, than other beta-lactam antibiotics. Its beta-lactamase degradation might be prevented by using a molecular [AMOX:beta-CD] complex. The aim of this work was to prepare complexes using two methods and then characterize interactions between AMOX and the native beta-CD. The extent of complexation in solution has been evaluated by high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), and 2D rotating-frame Overhauser enhancement spectroscopy (2D ROESY). Mass changes (TG), calorimetric effects (DSC), and mass spectrometry (MS) were determined on the same sample under identical conditions using the Skimmer coupling system. Skimmer and infrared spectroscopy (FT-IR) were used to characterize the solid state of the binary system. Complexation of AMOX with beta-CD was proven by FT-IR, NMR, DSC, and HPLC. The 2D ROESY spectra did not show any dipolar proton interaction of the AMOX with cyclodextrin. The 1:1 stoichiometry of the complex was obtained by HPLC. The stability constant for AMOX with beta-CD was determined to be 1,878 M(-1). In the [AMOX:beta-CD] complex, the phenyl group is included inside the beta-CD, and the ionized carboxyl group on the penam ring forms hydrogen bonds with the secondary hydroxyl groups of another beta-CD to keep the complex stable. Preparation methods allowed exactly the same complex. PMID:20352533

  20. Probing inclusion complexes of cyclodextrins with amino acids by physicochemical approach.

    PubMed

    Roy, Mahendra Nath; Roy, Aditi; Saha, Subhadeep

    2016-10-20

    Formations of host-guest inclusion complexes of two natural amino acids, viz., l-Leucine and l-Isoleucine as guests with α and β-cyclodextrins have been investigated which include diverse applications in modern science such as controlled delivery in the field of pharmaceuticals, food processing etc. Surface tension and conductivity studies establish the formation of inclusion complexes with 1:1 stoichiometry. The interactions of cyclodextrins with amino acids have been supported by density, viscosity, refractive index, hydration and solvation number measurements indicating higher degree of inclusion in case of α-cyclodextrin. l-Leucine interacts more with the hydrophobic cavity of cyclodextrin than its isomer. With the help of stability constant by NMR titration, hydrophobic effect, H-bonds and structural effects the formations of inclusion complexes have been explained. PMID:27474589

  1. Inclusion complexes of phosphorylated daidzein derivatives with β-cyclodextrin: Preparation and inclusion behavior study.

    PubMed

    Xiao, Yongmei; Yang, Liangru; Mao, Pu; Yuan, Jinwei; Deng, Yuxia; Qu, Lingbo

    2012-01-01

    In the present work the feasibility of β-cyclodextrin in complexation was explored, as a tool for improving the solubility and biological ability of daidzein derivatives. A series of phosphorylated daidzein derivatives featuring different chain lengths were synthesized through a modified Atherton-Todd reaction and their inclusion complexes with βCD were prepared by coprecipitation method. The inclusion complexation behavior was studied by fluorescence, UV, FT-IR, MS and (1)H NMR. The results showed that only phosphorylated daidzein derivative carrying small substituent group ((C(2)H(5)O)(2)PO) entered the cavity of βCD and formed 1:1 inclusion complex. The formation constant was 175(mol/L)(-1).

  2. Inclusion complexes of phosphorylated daidzein derivatives with β-cyclodextrin: Preparation and inclusion behavior study

    NASA Astrophysics Data System (ADS)

    Xiao, Yongmei; Yang, Liangru; Mao, Pu; Yuan, Jinwei; Deng, Yuxia; Qu, Lingbo

    2012-01-01

    In the present work the feasibility of β-cyclodextrin in complexation was explored, as a tool for improving the solubility and biological ability of daidzein derivatives. A series of phosphorylated daidzein derivatives featuring different chain lengths were synthesized through a modified Atherton-Todd reaction and their inclusion complexes with βCD were prepared by coprecipitation method. The inclusion complexation behavior was studied by fluorescence, UV, FT-IR, MS and 1H NMR. The results showed that only phosphorylated daidzein derivative carrying small substituent group ((C 2H 5O) 2P dbnd O) entered the cavity of βCD and formed 1:1 inclusion complex. The formation constant was 175 (mol/L) -1.

  3. Study on vitamin K 3-cyclodextrin inclusion complex and analytical application

    NASA Astrophysics Data System (ADS)

    Zhenming, Dong; Xiuping, Liu; Guomei, Zhang; Shaomin, Shuang; Jinghao, Pan

    2003-07-01

    The inclusion interaction of the complexes between Vitamin K 3 (VK 3) and β-cyclodextrin (β-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD) and sulfobutylether-β-cyclodextrin (SBE-β-CD) were studied by using steady-state fluorescence measurements. The various factors affecting the inclusion process were examined in detail. The formation constants and inclusion stoichiometry for VK 3-CDs were determined. The results showed that the inclusion ability of β-CD and its derivatives was the order: SBE-β-CD>HP-β-CD>β-CD. The related inclusion mechanism is proposed to explain the inclusion process. A method of determining VK 3 was established with the linear range was 2.5×10 -6-5.0×10 -4 M, and was used to determine the VK 3 tablets. The recoveries were in the range of 97.52-103.5%. The results were satisfactory.

  4. Solubility Enhancement of Steviol Glycosides and Characterization of Their Inclusion Complexes with Gamma-Cyclodextrin

    PubMed Central

    Upreti, Mani; Strassburger, Ken; Chen, You L.; Wu, Shaoxiong; Prakash, Indra

    2011-01-01

    Steviol glycosidesrebaudioside (reb) A, C and D have low aqueous solubilities. To improve their aqueous solubilities, inclusion complex of steviol glycosides, reb A, C and D and gamma cyclodextrin were prepared by freeze drying method and further characterized by means of differential scanning calorimetry, Fourier transform infrared spectroscopy and Raman spectroscopy. The effect of gamma cyclodextrin on chemical shifts of the steviol glycosides was also studied in proton NMR experiments as well as in solid state 13C CP/MAS NMR experiments. These results indicated that the steviol glycosides were clearly in inclusion complex formation with the gamma cyclodextrin which also results in solubility enhancement of these steviol glycosides. Phase solubility studies showed that amounts of soluble reb A, C and D increased with increasing amounts of gamma cyclodextrin indicating formation of 1:1 stoichiometric and higher order inclusion complexes. PMID:22174615

  5. Preparation and characterization of inclusion complexes of pefloxacin mesylate with three kinds of cyclodextrins

    NASA Astrophysics Data System (ADS)

    Chao, Jian-Bin; Tong, Hong-Bo; Liu, Dian-Sheng; Huang, Shu-Ping

    2006-05-01

    The ability of α-cyclodextrin, β-cyclodextrin and hydroxypropyl-β-cyclodextrin (α-CD, β-CD and HP-β-CD) to break pefloxacin mesylate (PM) aggregates by forming inclusion complexes has been studied using 1H NMR (nuclear magnetic resonance spectroscopy), 13C NMR and fluorescence spectra. The inclusion constants are determined to compare the corresponding inclusion capacity. Solid-inclusion complexes of PM with CDs are synthesized by coprecipitation method, and all the inclusion ratios are found to be 1:1. Additionally, spatial characterization of complexes has been proposed based on two-dimensional nuclear magnetic resonance technique (2D NMR) and spatial conformation is also investigated to propose two possible models between PM and CDs.

  6. Complexation study of brilliant cresyl blue with beta-cyclodextrin and its derivatives by UV-vis and fluorospectrometry.

    PubMed

    Zhang, Qing-Feng; Jiang, Zi-Tao; Guo, Yu-Xian; Li, Rong

    2008-01-01

    The complexation reactions of brilliant cresyl blue (BCB) with beta-cyclodextrin (beta-CD), mono[2-O-(2-hydroxypropyl)]-beta-CD (2-HP-beta-CD), mono[2-O-(2-hydroxyethyl)]-beta-CD (2-HE-beta-CD), and heptakis(2,6-di-methyl) -beta-CD (DM-beta-CD) were investigated using UV-vis and fluorospectrometry. The complexation between BCB and CDs could inhibit the aggregation of BCB molecules and could cause its absorbance at 634nm gradually increasing. The fluorescence of BCB was also enhanced with the addition of CDs. The fluorescence enhancement was more notable in neutral and acidic media than in basic media. Hildebrand-Benesi equation was used to calculate the formation constants of beta-CDs with BCB based on the fluorescence differences in the CDs solution. The stoichiometry ratio was found to be 1:1. The complexing capacities of beta-CD and its three derivatives were compared and the results followed the order: 2-HP-beta-CD>2-HE-beta-CD>DM-beta-CD>beta-CD. The effect of temperature on the formation of BCB-beta-CD inclusion complexes has also been examined. The results revealed that the formation constants decreased with the increase of temperature from 1038.9 to 491.6l/mol. Enthalpy and entropy values were calculated and the values were -25.77kJ/mol and 35.04J/kmol, respectively. The thermodynamic measurements suggest that the inclusive process was enthalpic favor. The release of high-energy water molecules and Van der Waals force played an important role in the inclusive process.

  7. Complexation study of brilliant cresyl blue with beta-cyclodextrin and its derivatives by UV-vis and fluorospectrometry.

    PubMed

    Zhang, Qing-Feng; Jiang, Zi-Tao; Guo, Yu-Xian; Li, Rong

    2008-01-01

    The complexation reactions of brilliant cresyl blue (BCB) with beta-cyclodextrin (beta-CD), mono[2-O-(2-hydroxypropyl)]-beta-CD (2-HP-beta-CD), mono[2-O-(2-hydroxyethyl)]-beta-CD (2-HE-beta-CD), and heptakis(2,6-di-methyl) -beta-CD (DM-beta-CD) were investigated using UV-vis and fluorospectrometry. The complexation between BCB and CDs could inhibit the aggregation of BCB molecules and could cause its absorbance at 634nm gradually increasing. The fluorescence of BCB was also enhanced with the addition of CDs. The fluorescence enhancement was more notable in neutral and acidic media than in basic media. Hildebrand-Benesi equation was used to calculate the formation constants of beta-CDs with BCB based on the fluorescence differences in the CDs solution. The stoichiometry ratio was found to be 1:1. The complexing capacities of beta-CD and its three derivatives were compared and the results followed the order: 2-HP-beta-CD>2-HE-beta-CD>DM-beta-CD>beta-CD. The effect of temperature on the formation of BCB-beta-CD inclusion complexes has also been examined. The results revealed that the formation constants decreased with the increase of temperature from 1038.9 to 491.6l/mol. Enthalpy and entropy values were calculated and the values were -25.77kJ/mol and 35.04J/kmol, respectively. The thermodynamic measurements suggest that the inclusive process was enthalpic favor. The release of high-energy water molecules and Van der Waals force played an important role in the inclusive process. PMID:17433764

  8. Sulfisoxazole/cyclodextrin inclusion complex incorporated in electrospun hydroxypropyl cellulose nanofibers as drug delivery system.

    PubMed

    Aytac, Zeynep; Sen, Huseyin Sener; Durgun, Engin; Uyar, Tamer

    2015-04-01

    Herein, hydroxypropyl-beta-cyclodextrin (HPβCD) inclusion complex (IC) of a hydrophobic drug, sulfisoxazole (SFS) was incorporated in hydroxypropyl cellulose (HPC) nanofibers (HPC/SFS/HPβCD-IC-NF) via electrospinning. SFS/HPβCD-IC was characterized by DSC to investigate the formation of inclusion complex and the stoichiometry of the complex was determined by Job's plot. Modeling studies were also performed on SFS/HPβCD-IC using ab initio technique. SEM images depicted the defect free uniform fibers and confirmed the incorporation of SFS/HPβCD-IC in nanofibers did not alter the fiber morphology. XRD analyses showed amorphous distribution of SFS/HPβCD-IC in the fiber mat. Release studies were performed in phosphate buffered saline (PBS). The results suggest higher amount of SFS released from HPC/SFS/HPβCD-IC-NF when compared to free SFS containing HPC nanofibers (HPC/SFS-NF). This was attributed to the increased solubility of SFS by inclusion complexation. Sandwich configurations were prepared by placing HPC/SFS/HPβCD-IC-NF between electrospun PCL nanofibrous mat (PCL-HPC/SFS/HPβCD-IC-NF). Consequently, PCL-HPC/SFS/HPβCD-IC-NF exhibited slower release of SFS as compared with HPC/SFS/HPβCD-IC-NF. This study may provide more efficient future strategies for developing delivery systems of hydrophobic drugs. PMID:25769282

  9. Theoretical study on β-cyclodextrin inclusion complexes with propiconazole and protonated propiconazole.

    PubMed

    Fifere, Adrian; Marangoci, Narcisa; Maier, Stelian; Coroaba, Adina; Maftei, Dan; Pinteala, Mariana

    2012-01-01

    The synthesis of the β-cyclodextrin/propiconazole nitrate inclusion complex and the advantages of the encapsulation of this drug were recently reported, but the experimental data only partially revealed the structure of the supramolecular complex due to the limitations in understanding the intermolecular association mechanism. The present work describes the equilibrium molecular geometries of β-cyclodextrin/propiconazole and β-cyclodextrin/protonated propiconazole, established by the AM1 and PM3 semi-empirical methods. The affinity between different parts of the guest molecule and the cyclodextrin cavity was studied considering that propiconazole possesses three residues able to be included into the host cavity through primary or secondary hydroxyl rims. The results have revealed that the most stable complex is formed when the azole residue of the propiconazole enters the cavity of the cyclodextrin through the narrow hydroxyl's rim.

  10. Vibrational properties of inclusion complexes: The case of indomethacin-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Rossi, Barbara; Verrocchio, Paolo; Viliani, Gabriele; Scarduelli, Giorgina; Guella, Graziano; Mancini, Ines

    2006-07-01

    Vibrational properties of inclusion complexes with cyclodextrins are studied by means of Raman spectroscopy and numerical simulation. In particular, Raman spectra of the nonsteroidal, anti-inflammatory drug indomethacin undergo notable changes in the energy range between 1600 and 1700cm-1 when inclusion complexes with cyclodextrins are formed. By using both ab initio quantum chemical calculations and molecular dynamics, we studied how to relate such changes to the geometry of the inclusion process, disentangling single-molecule effects, from changes in the solid state structure or dimerization processes.

  11. Vibrational properties of inclusion complexes: the case of indomethacin-cyclodextrin.

    PubMed

    Rossi, Barbara; Verrocchio, Paolo; Viliani, Gabriele; Scarduelli, Giorgina; Guella, Graziano; Mancini, Ines

    2006-07-28

    Vibrational properties of inclusion complexes with cyclodextrins are studied by means of Raman spectroscopy and numerical simulation. In particular, Raman spectra of the nonsteroidal, anti-inflammatory drug indomethacin undergo notable changes in the energy range between 1600 and 1700 cm(-1) when inclusion complexes with cyclodextrins are formed. By using both ab initio quantum chemical calculations and molecular dynamics, we studied how to relate such changes to the geometry of the inclusion process, disentangling single-molecule effects, from changes in the solid state structure or dimerization processes.

  12. Controlled fragrant molecule release from surface-tethered cyclodextrin host-guest inclusion complexes.

    PubMed

    Schofield, W C E; Badyal, J P S

    2011-06-01

    β-cyclodextrin barrels can be tethered to solid surfaces using the Williamson ether synthesis reaction via an intermediate pulsed plasma deposited poly(4-vinylbenzyl chloride) linker layer. The loading and release of perfume molecules through host-guest inclusion complex formation with surface tethered β-cyclodextrin has been followed by infrared spectroscopy and quartz crystal microbalance measurements. Fragrance release lasts for several months and can be easily recharged.

  13. Solubility, spectroscopic properties and photostability of Rhein/cyclodextrin inclusion complex

    NASA Astrophysics Data System (ADS)

    Petralito, Stefania; Zanardi, Iacopo; Memoli, Adriana; Annesini, Maria Cristina; Travagli, Valter

    2009-12-01

    The host-guest interaction between Rhein (Rh) - an anthraquinonic drug characterized by low water solubility and recently considered for its potential antidiabetic and antitumoral activities other than for the well-established anti-inflammatory properties - with cyclodextrins (CDs) was investigated using phase-solubility diagrams. The typical A L phase-solubility profiles suggest the formation of the 1:1 inclusion complexes between Rh and the two CDs investigated, namely β-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin and the resulting constant values of complex formation, Kc, were estimated. Due to the higher Kc value, complex of Rhein with 2-hydroxypropyl-β-cyclodextrin was chosen for further investigation. Characterization in solution of 2-hydroxypropyl-β-cyclodextrin/Rhein complex was achieved both by fluorescence and visible spectroscopic techniques. These results confirm the formation of inclusion complexes in solution and the 1:1 stoichiometry of the binary system. With respect to Rhein aqueous solution behavior, the inclusion complex appears to be able: (i) to enhance Rhein solubility; (ii) to control its neutral/anionic equilibrium; (iii) to affect both its electronic absorption and fluorescence spectra. Finally, the photostability of Rhein in the presence of cyclodextrins was evaluated.

  14. Redox-controlled interaction of biferrocenyl-terminated dendrimers with beta-cyclodextrin molecular printboards.

    PubMed

    Nijhuis, Christian A; Dolatowska, Karolina A; Ravoo, Bart Jan; Huskens, Jurriaan; Reinhoudt, David N

    2007-01-01

    This paper describes the synthesis and electrochemistry of biferrocenyl-terminated dendrimers and their beta-cyclodextrin (beta-CD) inclusion complexes in aqueous solution and at surfaces. Three generations of poly(propylene imine) (PPI) dendrimers, decorated with 4, 8, and 16 biferrocenyl (BFc) units, respectively, were synthesized. A water-soluble BFc derivative forms stable inclusion complexes with beta-CD. The intrinsic binding constant is K(i)=2.5 x 10(4) M(-1). The BFc dendrimers were solubilized in water by complexation of the end groups with beta-CD, resulting in large water-soluble supramolecular assemblies. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) showed that all the end groups are complexed to beta-CD. Adsorption of the dendrimers at self-assembled monolayers (SAMs) of heptathioether-functionalized beta-CD on gold ("molecular printboards") resulted in stable monolayers of the dendrimers due to the formation of multivalent host-guest interactions between the BFc end groups of the dendrimers and the immobilized beta-CD molecules. The number of interacting end groups is 3, 4, and 4 for dendrimer generations 1, 2, and 3, respectively. The complexation of BFc to beta-CD is sensitive to the oxidation state of the BFc unit. Oxidation of neutral BFc-Fe(2) ((II,II)) to the cationic, mixed-valence biferrocenium BFc-Fe(2) ((II,III)+) resulted in dissociation of the host-guest complexes. Scan-rate-dependent CV and DPV analyses of the dendrimer-beta-CD assemblies immobilized at the beta-CD host surface and in solution revealed that the dendrimers are oxidized in three steps. First, the surface-beta-CD-bound BFc moieties are oxidized to the mixed-valence state, Fe(2) ((II,III)+), followed by the oxidation of the non-surface-interacting BFc groups to the Fe(2) ((II,III)+) state. The third step involves the oxidation of all the BFc moieties to the Fe(2) ((III,III)2+) state.

  15. Fluorescence enhancement of warfarin induced by interaction with beta-cyclodextrin.

    PubMed

    Vasquez, Jacob M; Vu, Andrew; Schultz, Jerome S; Vullev, Valentine I

    2009-01-01

    Warfarin is the most common agent used for control and prevention of venous as well as arterial thromboembolism (blood clots). In aqueous media, warfarin forms inclusion complexes with a family of cyclic oligosaccharides, alpha, beta, gamma-cyclodextrins (CD). The formation of these complexes results in enhancement of the fluorescence of warfarin. Such spectroscopic changes offer a venue for the development of bioanalytical methodologies for warfarin quantification in biological liquids. We characterized the photophysical properties of warfarin in solvents with varying polarity and viscosity. The fluorescence quantum yield of warfarin correlated: (1) strongly with the solvent viscosity (R = 0.979) and (2) weakly with the solvent polarity (R = 0.118). These findings indicate that it is the change of the viscosity, rather than polarity, of the microenvironment that causes the fluorescence enhancement of warfarin upon binding to beta-CD. Utilizing the observed fluorescence enhancement in fluorescence titration measurements, the binding constants of warfarin to beta-CD were obtained (2.6 x 10(2) M(-1)-3.7 x 10(2) M(-1)). Using multivariable linear analysis, we extracted the stoichiometry of warfarin-beta-CD interaction (1:1).

  16. Use of Carboxymethyl-beta-cyclodextrin (CMCD) as Flushing Agent for Remediation of Metal Contaminated Soil

    NASA Astrophysics Data System (ADS)

    Skold, M. E.; Thyne, G. D.; McCray, J. E.; Drexler, J. W.

    2005-12-01

    One of the major challenges in remediating soil and ground water is the presence of mixed organic and inorganic contaminants. Due to their very different behavior, research has to a large extent focused on remediation of either organic or inorganic contaminants rather than mixed waste. Cyclodextrins (CDs) are a group of non-toxic sugar based molecules that do not sorb to soil particles and do not experience pore size exclusion. Thus, they have good hydraulic properties. CDs enhance the solubility of organic compounds by forming inclusion complexes between organic contaminants and the non-polar cavity at the center of the CD. By substituting functional groups to the cyclodextrin molecule it can form complexes with heavy metals. Previous studies have shown that carboxymethyl-beta-cyclodextrin (CMCD) can simultaneously complex organic and inorganic contaminants. The aim of this study is to compare how strongly CMCD complexes several common heavy metals, radioactive elements and a common divalent cation. Results from batch experiments show that CMCD has the ability to complex a wide array of heavy metals and radioactive elements. The solubility of metal oxalates and metal oxides clearly increased in the presence of CMCD. Logarithmic conditional formation constants ranged from 3.5 to 6 for heavy metals and from 3 to 6 for radioactive elements. Calcium, which may compete for binding sites, has a logarithmic conditional formation constant of 3.1. Batch experiments performed at 10 and 25 degrees C showed little temperature effect on conditional formation constants. Results from batch experiments were compared to results from column experiments where Pb was sorbed onto hydrous ferric oxide coated sand and subsequently removed by a CMCD solution. The results indicate that CMCD is a potential flushing agent for remediation of mixed waste sites.

  17. In vitro antiviral efficacy of the ganciclovir complexed with beta-cyclodextrin on human cytomegalovirus clinical strains.

    PubMed

    Nicolazzi, Céline; Venard, Véronique; Le Faou, Alain; Finance, Chantal

    2002-05-01

    The toxicity of the compounds currently used in the treatment of human cytomegalovirus (HCMV) infections in immunocompromised hosts may force the treatment to be discontinued. The aim of this study was to improve the antiviral activity of ganciclovir (GCV), one the most widely used drug, by complexing it with beta-cyclodextrin. Cyclodextrins (cds) have the property to form inclusion complexes with a great number of molecules and to enhance bioavailability and biological properties of these molecules. In this study, we investigated the in vitro antiviral activity of complexed GCV against several strains of HCMV: AD169, a reference strain, RCL-1, a laboratory mutant resistant to GCV, and four clinical isolates. The complexed GCV was more effective than free GCV against all HCMV strains tested. Cds as carriers for antiviral drugs would represent a useful adjunct to classical treatment procedures. They may make it possible to administer lower doses, thus reducing the toxic side effects of the drugs. PMID:12062397

  18. Exploration of inclusion complexes of neurotransmitters with β-cyclodextrin by physicochemical techniques

    NASA Astrophysics Data System (ADS)

    Roy, Mahendra Nath; Saha, Subhadeep; Kundu, Mitali; Saha, Binoy Chandra; Barman, Siti

    2016-07-01

    Molecular assemblies of β-cyclodextrin with few of the most important neurotransmitters, viz., dopamine hydrochloride, tyramine hydrochloride and (±)-epinephrine hydrochloride in aqueous medium have been explored by reliable spectroscopic and physicochemical techniques as potential drug delivery systems. Job plots confirm the 1:1 host-guest inclusion complexes, while surface tension and conductivity studies illustrate the inclusion process. The inclusion complexes were characterized by 1H NMR spectroscopy and association constants have been calculated by using Benesi-Hildebrand method. Thermodynamic parameters for the formation of inclusion complexes have been derived by van't Hoff equation, which demonstrate that the overall inclusion processes are thermodynamically favorable.

  19. Spectroscopic studies of inclusion complexes of 1-naphthol-4-sulfonate with β-cyclodextrin in aqueous solution

    NASA Astrophysics Data System (ADS)

    Al-Shihry, Shar S.

    2005-09-01

    The photophysical properties of 1-naphthol-4-sulfonate (1N4S) in some solvents and in aqueous β-cyclodextrin solution have been investigated. The effect of β-cyclodextrin on the fluorescence quantum yield and on the proton transfer is examined. Fluorescence measurements show 1:1 inclusion of 1N4S in the β-cyclodextrin cavity with an association constant of 108 M -1. NMR studies are used to study the inclusion phenomena and to provide information on the geometry of 1N4S inside the cavity of β-cyclodextrin.

  20. Encapsulation of Prodan in beta-cyclodextrin environments: A critical study via electronic spectroscopy and molecular mechanics

    NASA Astrophysics Data System (ADS)

    Banerjee, Anwesha; Sengupta, Bidisa; Chaudhuri, Sudip; Basu, Kaushik; Sengupta, Pradeep K.

    2006-08-01

    We present a detailed study on the binding of the naphthalene based fluorescence probe Prodan with two cyclic oligosachharides namely, natural beta-cyclodextrin (β-CD) and its synthetic derivative, succinyl-2-hydroxypropyl beta-cyclodextrin (SHPβ-CD) using electronic absorption and fluorescence spectroscopy along with theoretical techniques. The encapsulation of Prodan inside the β-CD cavities leads to pronounced changes in its emission characteristics, including dramatic blue shifts (27 nm in 10 mM SHPβ-CD and 19 nm in 10 mM β-CD) in the emission maximum accompanied by increase in the emission yield, fluorescence anisotropy and lifetime values. Detailed analyses of the fluorescence along with relevant absorption spectroscopic data indicate that Prodan readily enters the doughnut-shaped hydrophobic cavities of the β-CDs and forms 1:1 inclusion complexes, the binding affinity being significantly higher in case of SHPβ-CD. Furthermore, docking studies performed via molecular mechanics methods (MM+) indicate that the dimethylamino group of Prodan is most likely to be oriented towards the wider rim of the cyclodextrin cavity. Quantum mechanical calculations reveal that incorporation of Prodan into the β-CD cavities, results in the formation of a N-TICT (dimethylamino twisted intramolecular charge transfer) state.

  1. Supramolecular interactions between beta-cyclodextrin and hydrophobically end-capped poly(ethylene glycol)s: a quartz crystal microbalance study.

    PubMed

    Kham, Khémara; Guerrouache, Mohamed; Carbonnier, Benjamin; Lazerges, Mathieu; Perrot, Hubert; Millot, Marie-Claude

    2007-11-15

    In this study, the supramolecular interactions occurring between beta-cyclodextrin-based surfaces and macromolecular chains modified at one end with naphthyl, adamantyl, or phenyladamantyl hydrophobic groups were investigated by means of a quartz crystal microbalance. beta-Cyclodextrin-functionalized gold electrodes were obtained through the amide-coupling reaction between mono-6-deoxy-6-amino-beta-cyclodextrin and 11-mercaptoundecanoic acid self-assembled monolayer allowing the reproducible preparation of densely grafted surfaces with host properties. The interaction data obtained for the three different modified poly(ethylene glycol)s are in good agreement with our previous studies performed by high performance liquid chromatography and surface plasmon resonance. This evidences that the driving force for the supramolecular interaction is based on the inclusion of the hydrophobic terminal group of the chains within the cyclodextrin cavities. The reversibility of the inclusion process was proven through the regeneration of the original host properties of the sensing surfaces using sodium dodecylsulfate as a competitor for the desorption of the poly(ethylene glycol) chains.

  2. Fluorescence correlation spectroscopy, a tool to investigate supramolecular dynamics: inclusion complexes of pyronines with cyclodextrin.

    PubMed

    Al-Soufi, Wajih; Reija, Belén; Novo, Mercedes; Felekyan, Suren; Kühnemuth, Ralf; Seidel, Claus A M

    2005-06-22

    The control of supramolecular systems requires a thorough understanding of their dynamics on a molecular level. We present fluorescence correlation spectroscopy (FCS) as a powerful spectroscopic tool to study supramolecular dynamics with single molecule sensitivity. The formation of a supramolecular complex between beta-cyclodextrin (beta-CD) as host and pyronines Y (PY) and B (PB) as guests is studied by FCS. Global target analysis of full correlation curves with a newly derived theoretical model yields in a single experiment the fluorescence lifetimes and the diffusion coefficients of free and complexed guests and the rate constants describing the complexation dynamics. These data give insight into the recently published surprising fact that the association equilibrium constant of beta-CD with PY is much lower than that with the much bulkier guest PB. FCS shows that the stability of the complexes is dictated by the dissociation and not by the association process. The association rate constants are very similar for both guests and among the highest reported for this type of systems, although much lower than the diffusion-controlled collision rate constant. A two-step model including the formation of an encounter complex allows one to identify the unimolecular inclusion reaction as the rate-limiting step. Simulations indicate that this step may be controlled by geometrical and orientational requirements. These depend on critical molecular dimensions which are only weakly affected by the different alkyl substituents of PY and PB. Diffusion coefficients of PY and PB, of their complexes, and of rhodamine 110 are given and compared to those of similar molecules.

  3. Solid state characterization of α-tocopherol in inclusion complexes with cyclodextrins.

    PubMed

    Lange, Kinga; Gierlach-Hładon, Teresa

    2015-01-01

    The alternative for a pure soluble, sensible for physical and chemical conditions oil form of α-tocopherol (α-T) is its complexation with cyclodextrins. A different influence of cyclodextrins on the included substance demands a stability investigation of the substance enclosed in a host-guest complex. Hence, the thermal stability of α-T in inclusion complexes (InCs) with cyclodextrins (CDs) was studied. The inclusion complexes were obtained by two different methods: a lyophilization and a kneading method, and their formation was examined by IR spectroscopy, differential scanning calorimetry and 1H-NMR spectroscopy. The inclusion complexes were subjected to the test of accelerated aging at 323 K, 333 K, 338 and 343 K, for comparison α-T as a substance and physical mixtures (PhM) of α-T with CDs were used. Changes in α-T concentration during the experiment were followed by HPLC method and next, the products of thermal decomposition were studied by LC-ESI-MS/MS method. The reaction of α-T decomposition in inclusion complexes with CDs was found to be of the first order. The same order of a decomposition reaction was observed in a sample of α-T as a substance. It seems that cyclodextrins protect α-T against thermal decomposition, moreover, the protective effect of natural β-cyclodextrin (β-CD) appears to be greater than that of 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD). However, the CDs do not influence the type of a formed product of decomposition. This product, i.e., the dimer of α-T (m/z 859 Da), was found in all tested samples. The protective effect of CDs and transformation from the liquid state to the solid state of α-T can be used to create a new pharmaceutical form--tablets with α-T.

  4. Inclusion Complexes of Ionic Liquids and Cyclodextrins: Are They Formed in the Gas Phase?

    NASA Astrophysics Data System (ADS)

    Fernandes, Ana M.; Schröder, Bernd; Barata, Tânia; Freire, Mara G.; Coutinho, João A. P.

    2014-05-01

    The interaction of imidazolium-based ionic liquids with α- and β-cyclodextrins was investigated by electrospray ionization mass spectrometry with variable collision induced dissociation energy and quantum chemical gas-phase calculations. The center-of-mass energy at which 50 % of a precursor ion decomposes (Ecm,1/2) was determined for the isolated [cyclodextrin + cation]+ or [cyclodextrin + anion]- adduct ions of imidazolium-based ionic liquids with different alkyl chain lengths combined with a large set of anions, such as chloride, bromide, bis(trifluoromethylsulfonyl)imide, tetrafluoroborate, hexafluorophosphate, trifluoromethanesulfonate, methanesulfonate, dicyanamide, and hydrogensulfate. Moreover, both symmetric and asymmetric imidazolium cationic cores were evaluated. The relative interaction energies in the adduct ions were interpreted in terms of the influence of cation/anion structures and their inherent properties, such as hydrophobicity and hydrogen bond accepting ability, in the complexation process with the cyclodextrins. The trends observed in the mass spectral data together with quantum-chemical calculations suggest that in the gas phase, cations and anions will preferentially interact with the lower or upper rim of the cyclodextrin, respectively, as opposed to what has been reported in condensed phase where the formation of an inclusion complex between ionic liquid and cyclodextrin is assumed.

  5. Inclusion complexation between baicalein and β-cyclodextrin and the influence of β-cyclodextrin on the binding of baicalein with DNA: a spectroscopic approach.

    PubMed

    Sameena, Yousuf; Chandrasekaran, Sowrirajan; Israel V M V, Enoch

    2016-07-01

    This work deals with the commonly studied cyclic oligosaccharide and gains importance as it is entered on a drug delivering carbohydrate and provides insight into the oligosaccharide complex-biomolecular interaction. The binding of a flavone, baicalein, to β-cyclodextrin and calf thymus DNA is studied. The binding of baicalein to calf thymus DNA in the presence of β-cyclodextrin is analysed using the UV-vis absorption and fluorescence spectroscopy. The mode of binding and structure of the baicalein-β-cyclodextrin complex are reported. The role of the structure and the stoichiometry of the inclusion complex of baicalein-β-cyclodextrin in its influence on DNA binding are analysed. Highlights • This paper deals with the binding of a flavone, baicalein to β-cyclodextrin and/or DNA. • The inclusion complexation between baicalein and β-cyclodextrin is analysed. • The stoichiometry and the binding strength of the inclusion complex is reported. • The role of β-cyclodextrin in tuning the binding of baicalein to DNA is emphasized. • Spectroscopic and docking analysis are used to articulate the results.

  6. Preparation and spectral investigation on inclusion complex of β-cyclodextrin with rutin

    NASA Astrophysics Data System (ADS)

    Haiyun, Ding; Jianbin, Chao; Guomei, Zhang; Shaomin, Shuang; Jinhao, Pan

    2003-12-01

    Solid inclusion complex of rutin with β-cyclodextrin (β-CD) was prepared by coprecipitate method. The formation of inclusion complex was confirmed by differential scanning calorimetry (DSC) and X-ray diffraction. The formation constant was obtained by steady-state fluorescence measurements and the result suggested the complex preferred 1:1 (rutin:CD) stoichiometry. Furthermore, the spatial configuration of the complex has been proposed based on NMR and molecular modeling.

  7. Host-guest inclusion system of artesunate with β-cyclodextrin and its derivatives: Characterization and antitumor activity

    NASA Astrophysics Data System (ADS)

    Xie, Hudie; Yang, Bo; Wang, Fen; Zhao, Yulin

    2015-04-01

    Inclusion complexes between artesunate (ATS) and three cyclodextrins, namely β-cyclodextrin (β-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD), were prepared by a suspension method. The complexes in both liquid and solid were characterized by phase-solubility diagram, nuclear magnetic resonance (NMR), powder X-ray diffraction (XRD) and thermoanalysis. The results suggested that artesunate was partly encapsulated within the cyclodextrin cavity to form a 1:1 stoichiometry host-guest compound. Especially in the SBE-β-CD complex, displayed the greatest stability constant. Significant enhancement of water solubility and thermal stability of ATS in present of β-CDs was shown. The calculated IC50 values indicated that the antitumor activities of inclusion complexes were better than that of ATS. Satisfactory aqueous solubility, along with high thermal stability of inclusion complexes will be potentially useful for their application on the formulation design of natural medicine.

  8. Investigation of the β-cyclodextrin-quinine inclusion complex in aqueous solution by spectroscopic study

    NASA Astrophysics Data System (ADS)

    Wang, Xue-Mei; Chen, Hong-Yuan

    1995-03-01

    The effect of β-cyclodextrin (β-CD) on the spectral properties of quinine molecules has been specifically studied by absorption/fluorescence and Fourier transform infrared (FTIR) spectroscopy. In particular, FTIR studies of the complexation of aqueous quinine hydrochloride with β-CD provide fresh insight into the molecular structure of the complex and reveal some important information in relation to the molecular interactions of the cyclodextrin complex system. Nuclear magnetic resonance data support the inclusion conformation of the interaction sites and the presence of hydrogen bonds which stabilize the complexes.

  9. Determination of the binding constant of indomethacin-beta-cyclodextrin complex by capillary electrophoresis: experimental optimization and temperature study.

    PubMed

    Acosta, G; Linares, D; Olsina, R; Martínez, L D; Gomez, M R

    2007-11-01

    The apparent electrophoretic mobilities of indomethacin in beta-cyclodextrin at a range of concentrations were measured directly by capillary electrophoresis. Three different linear plots and a non linear plot are proposed for the apparent binding constant calculations, based on the fact that the molar ratio of the inclusion complex was 1:1. K values obtained at 298 K were 421 M(-1) (double reciprocal fit), 488 M(-1) (x-reciprocal fit), 428 M(-1) (y-reciprocal fit) and 490 M(-1) (non linear fit). The corresponding K values at 313 K were 380 M(-1) (double reciprocal fit), 355 M(-1) (x-reciprocal fit), 366 M(-1) (y-reciprocal fit) and 339 M(-1) (non linear fit). Using the proposed methods, the binding constant of the indomethacin-beta-cyclodextrin inclusion complex can be obtained easily. The methods have been applied to obtain the values of the constant K under different experimental conditions. Under optimized conditions the K constant is temperature dependent and non-arrhenian behaviour was observed.

  10. Cyclodextrin Inclusion Complex to Improve Physicochemical Properties of Herbicide Bentazon: Exploring Better Formulations

    PubMed Central

    Yáñez, Claudia; Cañete-Rosales, Paulina; Castillo, Juan Pablo; Catalán, Nicole; Undabeytia, Tomás; Morillo, Esmeralda

    2012-01-01

    The knowledge of the host-guest complexes using cyclodextrins (CDs) has prompted an increase in the development of new formulations. The capacity of these organic host structures of including guest within their hydrophobic cavities, improves physicochemical properties of the guest. In the case of pesticides, several inclusion complexes with cyclodextrins have been reported. However, in order to explore rationally new pesticide formulations, it is essential to know the effect of cyclodextrins on the properties of guest molecules. In this study, the inclusion complexes of bentazon (Btz) with native βCD and two derivatives, 2-hydroxypropyl-β-cyclodextrin (HPCD) and sulfobutylether-β-cyclodextrin (SBECD), were prepared by two methods: kneading and freeze-drying, and their characterization was investigated with different analytical techniques including Fourier transform infrared spectroscopy (FT-IR), differential thermal analysis (DTA), X-ray diffractometry (XRD) and differential pulse voltammetry (DPV). All these approaches indicate that Btz forms inclusion complexes with CDs in solution and in solid state, with a stoichiometry of 1∶1, although some of them are obtained in mixtures with free Btz. The calculated association constant of the Btz/HPCD complex by DPV was 244±19 M−1 being an intermediate value compared with those obtained with βCD and SBECD. The use of CDs significantly increases Btz photostability, and depending on the CDs, decreases the surface tension. The results indicated that bentazon forms inclusion complexes with CDs showing improved physicochemical properties compared to free bentazon indicating that CDs may serve as excipient in herbicide formulations. PMID:22952577

  11. Pickering emulsions with α-cyclodextrin inclusions: Structure and thermal stability.

    PubMed

    Diaz-Salmeron, Raul; Chaab, Ismail; Carn, Florent; Djabourov, Madeleine; Bouchemal, Kawthar

    2016-11-15

    This paper explores structural, interfacial and thermal properties of two types of Pickering emulsions containing α-cyclodextrin inclusion complexes: on one hand, emulsions were obtained between aqueous solutions of α-cyclodextrin and different oils (fatty acids, olive oil, silicone oil) and on the other hand, emulsions were obtained between these oils, water and micro or nano-platelet suspensions with inclusion complexes of hydrophobically-modified polysaccharides. The emulsions exhibit versatile properties according to the molecular architecture of the oils. Experiments were performed by microcalorimetry, X-ray diffraction and confocal microscopy. The aptitude of oil molecules to be threaded in α-cyclodextrin cavity is a determining parameter in emulsification and thermal stability. The heat flow traces and images showed dissolution, cooperative melting and de-threading of inclusion complexes which take place progressively, ending at high temperatures, close or above 100°C. Another important feature observed in the emulsions with micro-platelets is the partial substitution of the guest molecules occurring at room temperature at the oil/water interfaces without dissolution, possibly by a diffusion mechanism of the oil. Accordingly, the dissolution and the cooperative melting temperatures of the inclusion crystals changed, showing marked differences upon the type of guest molecules. The enthalpies of dissolution of crystals were measured and compared with soluble inclusions. PMID:27491001

  12. Pickering emulsions with α-cyclodextrin inclusions: Structure and thermal stability.

    PubMed

    Diaz-Salmeron, Raul; Chaab, Ismail; Carn, Florent; Djabourov, Madeleine; Bouchemal, Kawthar

    2016-11-15

    This paper explores structural, interfacial and thermal properties of two types of Pickering emulsions containing α-cyclodextrin inclusion complexes: on one hand, emulsions were obtained between aqueous solutions of α-cyclodextrin and different oils (fatty acids, olive oil, silicone oil) and on the other hand, emulsions were obtained between these oils, water and micro or nano-platelet suspensions with inclusion complexes of hydrophobically-modified polysaccharides. The emulsions exhibit versatile properties according to the molecular architecture of the oils. Experiments were performed by microcalorimetry, X-ray diffraction and confocal microscopy. The aptitude of oil molecules to be threaded in α-cyclodextrin cavity is a determining parameter in emulsification and thermal stability. The heat flow traces and images showed dissolution, cooperative melting and de-threading of inclusion complexes which take place progressively, ending at high temperatures, close or above 100°C. Another important feature observed in the emulsions with micro-platelets is the partial substitution of the guest molecules occurring at room temperature at the oil/water interfaces without dissolution, possibly by a diffusion mechanism of the oil. Accordingly, the dissolution and the cooperative melting temperatures of the inclusion crystals changed, showing marked differences upon the type of guest molecules. The enthalpies of dissolution of crystals were measured and compared with soluble inclusions.

  13. Rare 'head-to-tail' arrangement of guest molecules in the inclusion complexes of (+)- and (-)-menthol with β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Ceborska, Magdalena; Asztemborska, Monika; Lipkowski, Janusz

    2012-11-01

    The inclusion of (+)- and (-)-menthols in β-cyclodextrin has been studied by X-ray crystallography. The obtained [2:2] complexes show typical for β-cyclodextrin form of head-to-head dimer. In both (+)- and (-)-cases, the menthol molecule in one of cyclodextrins forming dimer exhibits disorder and occupies two major sites. Also both of the diastereoisomeric complexes show unusual 'head to tail' arrangement of guest molecules - two guest molecules are differently oriented inside β-cyclodextrin cavity. Stability constants for both complexes in solution were measured.

  14. Cyclodextrins.

    PubMed

    Kurkov, Sergey V; Loftsson, Thorsteinn

    2013-08-30

    Although cyclodextrins (CDs) have been studied for over 100 years and can be found in at least 35 pharmaceutical products, they are still regarded as novel pharmaceutical excipients. CDs are oligosaccharides that possess biological properties that are similar to their linear counterparts, but some of their physicochemical properties differ. CDs are able to form water-soluble inclusion complexes with many poorly soluble lipophilic drugs. Thus, CDs are used to enhance the aqueous solubility of drugs and to improve drug bioavailability after, for example, oral administration. Through CD complexation, poorly soluble drugs can be formulated as aqueous parenteral solutions, nasal sprays and eye drop solutions. These oligosaccharides are being recognized as non-toxic and pharmacologically inactive excipients for both drug and food products. Recently, it has been observed that CDs and CD complexes in particular self-assemble to form nanoparticles and that, under certain conditions, these nanoparticles can self-assemble to form microparticles. These properties have changed the way we perform CD research and have given rise to new CD formulation opportunities. Here, the pharmaceutical applications of CDs are reviewed with an emphasis on their solubilizing properties, their tendency to self-assemble to form aggregates, CD ternary complexes, and their metabolism and pharmacokinetics.

  15. Preparation and study on the solid inclusion complex of cloxacillin sodium with β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Chao, Jian-Bin; Zhang, Bing-Tai

    2007-09-01

    The interaction of cloxacillin sodium with β-cyclodextrin (β-CD) has been studied by several analytical techniques, including 1H NMR, fluorescence spectroscopy, infrared spectroscopy. In this paper, solid inclusion complex of cloxacillin sodium with β-CD was synthesized by the coprecipitation method. In addition, the characterization of the inclusion complex has been proved by fluorimetry, infrared spectroscopy and 1D, 2D NMR. The experimental results confirmed the existence of 1:1 inclusion complex of cloxacillin sodium with β-CD. The formation constant of complex was determined by fluorescence method and 1H NMR. Spacial configuration of complex has been proposed on 2D NMR technique.

  16. Inclusion process of tetracycline in β and γ-cyclodextrins: A theoretical investigation

    NASA Astrophysics Data System (ADS)

    Costa, Mércia A. S.; Anconi, Cleber P. A.; Dos Santos, Hélio F.; De Almeida, Wagner B.; Nascimento, Clebio S.

    2015-04-01

    The present Letter reports results from a comprehensive theoretical analysis of the inclusion process involving the tetracycline (TC) by β and γ-cyclodextrin (CD). Structure and stabilization energies were calculated, both in gas phase and aqueous solution, using a sequential methodology based on semiempirical and density functional theory (DFT) calculations. By the results, a qualitative structure-property relationship could be established with two main structural features being relevant for inclusion complex stabilization: (i) the depth of inclusion, which favors the hydrophobic contact inside the cavity of CDs and (ii) the hydrogen bonds established between guest and host molecules.

  17. A DFT investigation on the host/guest inclusion process of prilocaine into β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    de Sousa, Sara Maria R.; Guimarães, Luciana; Ferrari, Jefferson L.; De Almeida, Wagner B.; Nascimento, Clebio S.

    2016-05-01

    A theoretical analysis of the host/guest inclusion process involving the prilocaine into the β-cyclodextrin was performed. Structure and stabilization energies were calculated, in both gas and aqueous phases, using Density Functional Theory level of theory. As results, a qualitative structure property relationship could be established with structural features being relevant for inclusion complex stabilization: (i) the hydrogen bonds established between guest and host molecules and (ii) the dispersion effect in the formation of the complexes. Besides, a theoretical 1H NMR analysis has shown to be an adequate procedure to predict correctly the inclusion mode of guest molecule into the host.

  18. X-ray structure of beta-cyclodextrin-2,7-dihydroxy-naphthalene.4.6 H(2)O: an unusually distorted macrocycle.

    PubMed

    Añibarro, M; Gessler, K; Usón, I; Sheldrick, G M; Saenger, W

    2001-07-12

    The inclusion complex beta-cyclodextrin.2,7-dihydroxynaphthalene.4.6 H(2)O crystallized in the monoclinic space group P2(1), with a=14.082(3), b=19.079(4), c=12.417(3) A, beta=109.28(3) degrees, V=3149.0(11) A(3), and Z=2. An X-ray study performed at room temperature shows that the crystal packing is of the herringbone type with one 2,7-dihydroxynaphthalene included completely in the beta-CD cavity, its long axis being oriented along the beta-CD molecular axis, and 4.6 water molecules are placed in the interstitial space. The beta-CD macrocycle is elliptically distorted, and the guest molecule is held in the hydrophobic beta-CD cavity by C-H...O and C-H...pi interactions.

  19. Spectroscopic studies on the inclusion complex of 2-naphthol-6-sulfonate with β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Abdel-Shafi, Ayman Ayoub

    2007-03-01

    The photophysical properties of 2-naphthol-6-sulfonate (2-NOH-6-S) in various solvents and in aqueous β-cyclodextrin solution have been investigated. The fluorescence quantum yields in non-aqueous solvents are approximately 0.20 ± 0.02, while in water the yield is higher. The fluorescence quantum yield in water was found to depend on the pH value of the medium and increases as the pH increase up to a pH value of 4.0 where it comes to be constant. Absorption and fluorescence measurements show 1:1 inclusion of 2-NOH-6-S in the β-cyclodextrin cavity. The association constant of 2-NOH-6-S-β-cyclodextrin complex based on fluorescence measurements was calculated using Benesi-Hildbrand relationship and found to be 330 ± 30 M -1. 1H NMR studies are used to confirm the inclusion and to provide information on the geometry of 2-NOH-6-S inside the cavity of β-cyclodextrin.

  20. Improved drug delivery properties of PVDF membranes functionalized with beta-cyclodextrin--application to guided tissue regeneration in periodontology.

    PubMed

    Boschin, F; Blanchemain, N; Bria, M; Delcourt-Debruyne, E; Morcellet, M; Hildebrand, H F; Martel, B

    2006-10-01

    The purpose of this study was to develop a membrane for guided tissue regeneration applicable in periodontology that could release antimicrobial agent during the healing period. Our strategy consisted to graft beta-cyclodextrin (beta-CD), a molecule that is known to form inclusion complexes with a large variety of drugs, onto PVDF membranes. Grafting occurred by using citric acid that provoked a crosslinking reaction of beta-CD, and the resulting polymer was imprisoned into the porous structure of the PVDF membrane. The reaction produced a weight increase of the membrane, the range of which depended on the temperature and on the time of curing applied in the process. The biological behavior of the membranes evaluated by proliferation and vitality tests showed good proliferation and improved activity of L132 epithelial cells on the raw and on the grafted membranes. Doxycyclin (DOX) and chlorhexidine (CHX) were used as antimicrobial agents. Their inclusion into the beta-CD cavity in aqueous solutions was confirmed by NMR spectroscopy. After the impregnation of the membranes with DOX and CHX, their release was studied in vitro in batch type experiments and measured by UV spectrophotometry. Low amounts of DOX and CHX were delivered from the raw membranes within the first few hours of tests. Grafted membranes, however, delivered DOX and CHX in larger quantities within 24 h and 10 days respectively. PMID:16758457

  1. Highly selective oxidative cleavage of beta-cyclodextrin-epoxide/aziridine complexes with IBX in water.

    PubMed

    Surendra, K; Krishnaveni, N Srilakshmi; Reddy, M Arjun; Nageswar, Y V D; Rao, K Rama

    2003-11-14

    Water, an environmentally friendly reaction medium, has been utilized for the reaction of IBX with various epoxides 1 and aziridines 2 as their beta-cyclodextrin complexes to afford for the first time alpha-hydroxyketones 3 and alpha-aminoketones 4, respectively.

  2. Supramolecular enantiodifferentiating photoisomerization of cyclooctene with modified beta-cyclodextrins: critical control by a host structure.

    PubMed

    Lu, Runhua; Yang, Cheng; Cao, Yujuan; Wang, Zhizhong; Wada, Takehiko; Jiao, Wei; Mori, Tadashi; Inoue, Yoshihisa

    2008-01-21

    Enantiodifferentiating photoisomerization of (Z)-cyclooctene included and sensitized by m-methoxybenzoyl-beta-cyclodextrin gave chiral (E)-isomers in up to 46% enantiomeric excess, which is the highest value ever reported for supramolecular photochirogenesis with analogous hosts, thus demonstrating the crucial role of the sensitizer-spacer moiety in supramolecular photochirogenic systems.

  3. Thymus catharinae Camarda essential oil: β-cyclodextrin inclusion complexes, evaluation of antimicrobial activity.

    PubMed

    Delogu, Giovanna; Juliano, Claudia Clelia Assunta; Usai, Marianna

    2016-09-01

    An efficient antimicrobial activity was evidenced in a complex β-cyclodextrin-essential oil of Thymus catharinae Camarda (carvacrol chemotype). The release of carvacrol with respect to the antimicrobial activity was calculated as function of time. The βCD-complex of the bioactive agent was obtained by a simple, efficient and non-expensive method without purification of the carvacrol chemotype essential oil. According to the starting stoichiometry of β-cyclodextrin with respect to carvacrol, two inclusion complexes were produced, 1:1 and 2:1, respectively. The results demonstrate that, although the antimicrobial activity of the essential oil of T. catharinae Camarda is remarkable but acts too quickly in some types of application, its inclusion in a bio-matrix allows a slower release and improves its effectiveness.

  4. Studies on aqueous solubility of 3,3‧-diindolylmethane derivatives using cyclodextrin inclusion complexes

    NASA Astrophysics Data System (ADS)

    Roy, Sutapa; Mandal, Madhumita; Pal, Churala; Giri, Prabal; Kumar, Gopinatha Suresh; Mukherjee, Joydeep; Jaisankar, Parasuraman

    2013-03-01

    The supramolecular interaction of 3,3'-diindolylmethane (DIM) and its derivatives with α-, β-, and γ-cyclodextrins (CDs) has been investigated to improve their aqueous solubility. A series of complexes of α-, β-, and γ-CDs with DIMs were prepared and their inclusion complexation behavior in solution phase assessed by fluorescence, UV-visible spectroscopy and circular dichroism. Circular dichroism spectra revealed that incorporation of DIMs in the chiral environment of the CDs affecting their electric transitions leading to the development of induced circular dichroism bands in the near UV region. A linear increase of aqueous solubility of DIMs in presence of CDs was observed from their phase-solubility diagrams indicating the formation of soluble inclusion complexes. According to the continuous variation method a 1:1 stoichiometry has been proposed for DIM cyclodextrins complexes.

  5. Synthesis and characterization of nano-encapsulated black pepper oleoresin using hydroxypropyl beta-cyclodextrin for antioxidant and antimicrobial applications.

    PubMed

    Teixeira, Bruna N; Ozdemir, Necla; Hill, Laura E; Gomes, Carmen L

    2013-12-01

    Previous studies have reported antimicrobial and antioxidant activity of black pepper oleoresin which is associated to its phenolic compounds and piperine. The ability of cyclodextrins to form an inclusion complex with a guest molecule could improve black pepper oleoresin application, bioavailability, and stability in foods. Hydroxypropyl beta-cyclodextrin (HPBCD) inclusion complex with black pepper olereosin were synthesized using the kneading method and characterized for its physico-chemical properties and its antioxidant and antimicrobial activities. Inclusion complex size was 103.9 ± 7.6 nm and indicated to be a polydisperse system. The entrapment efficiency was 78.3 ± 3.6%, which suggests that other constituents in black pepper oleoresin have higher affinities for HPBCD than piperine (major compound in black pepper oleoresin). Thermograms showed the disappearance of oxidation peaks of black pepper oleoresin, proving complex formation with HPBCD. Phase solubility results indicated 1:1 stoichiometric inclusion complex formation and an increase of black pepper oleoresin aqueous solubility with HPBCD concentration. Nano-encapsulation with HPBCD did not affect (P > 0.05) total phenolic content; however, it enhanced (P < 0.05) black pepper oleoresin antioxidant activity. Black pepper oleoresin and its inclusion complex were analyzed for their antimicrobial activity against Escherichia coli K12 and Salmonella enterica serovar Typhimurium LT2. Both free and encapsulated black pepper oleoresin effectively inhibited bacterial growth within the concentration range tested. Black pepper oleoresin encapsulated in HPBCD was able to inhibit Salmonella at lower (P < 0.05) concentrations than its corresponding free extract. Therefore, black pepper oleoresin-HPBCD nanocapsules could have important applications in the food industry as antimicrobial and antioxidant system. PMID:24329956

  6. Synthesis and characterization of nano-encapsulated black pepper oleoresin using hydroxypropyl beta-cyclodextrin for antioxidant and antimicrobial applications.

    PubMed

    Teixeira, Bruna N; Ozdemir, Necla; Hill, Laura E; Gomes, Carmen L

    2013-12-01

    Previous studies have reported antimicrobial and antioxidant activity of black pepper oleoresin which is associated to its phenolic compounds and piperine. The ability of cyclodextrins to form an inclusion complex with a guest molecule could improve black pepper oleoresin application, bioavailability, and stability in foods. Hydroxypropyl beta-cyclodextrin (HPBCD) inclusion complex with black pepper olereosin were synthesized using the kneading method and characterized for its physico-chemical properties and its antioxidant and antimicrobial activities. Inclusion complex size was 103.9 ± 7.6 nm and indicated to be a polydisperse system. The entrapment efficiency was 78.3 ± 3.6%, which suggests that other constituents in black pepper oleoresin have higher affinities for HPBCD than piperine (major compound in black pepper oleoresin). Thermograms showed the disappearance of oxidation peaks of black pepper oleoresin, proving complex formation with HPBCD. Phase solubility results indicated 1:1 stoichiometric inclusion complex formation and an increase of black pepper oleoresin aqueous solubility with HPBCD concentration. Nano-encapsulation with HPBCD did not affect (P > 0.05) total phenolic content; however, it enhanced (P < 0.05) black pepper oleoresin antioxidant activity. Black pepper oleoresin and its inclusion complex were analyzed for their antimicrobial activity against Escherichia coli K12 and Salmonella enterica serovar Typhimurium LT2. Both free and encapsulated black pepper oleoresin effectively inhibited bacterial growth within the concentration range tested. Black pepper oleoresin encapsulated in HPBCD was able to inhibit Salmonella at lower (P < 0.05) concentrations than its corresponding free extract. Therefore, black pepper oleoresin-HPBCD nanocapsules could have important applications in the food industry as antimicrobial and antioxidant system.

  7. Characterization of mitotane (o,p'-DDD)--cyclodextrin inclusion complexes: phase-solubility method and NMR.

    PubMed

    Alfonsi, R; Attivi, D; Astier, A; Socha, M; Morice, S; Gibaud, S

    2013-05-01

    Mitotane (o,p'-dichlorodimethyl dichloroethane [o,p'-DDD]) is used for the treatment of adrenocortical cancer and occasionally Cushing's syndrome. This drug is very poorly soluble in water, and following oral administration, approximately 60% of the dose is recovered in the feces unaltered. The preparation of a soluble formulation (i.e. by complexation with cyclodextrins) with improved bioavailability is the aim of this work. The inclusion of mitotane in methyl-ß-cyclodextrins was studied using both phase-solubility methods and NMR experiments. To elucidate the inclusion mechanism, o,p'-DDD was compared to its regioisomer (i.e. p,p'-DDD). It was demonstrated that two dimethyl-ß-cyclodextrins (DMßCD) can complex with the aromatic rings. From the phase-solubility diagrams, we observe that both cases are very different: K(1:1) is between 37 000 and 85 000 mol.l(-1), whereas K(1:2) is between 5.3 and 32 mol.l(-1). The NMR experiments confirmed the inclusion but it also gave an insight into the kinetics of the dissociation: the ortho-chloro moiety is in slow exchange on the NMR time scale, whereas the para-chloro moiety is in fast exchange rate.

  8. Spectroscopic investigation on the inclusion complex formation between amisulpride and γ-cyclodextrin.

    PubMed

    Negi, Jeetendra Singh; Singh, Shivpal

    2013-02-15

    The purpose of this research was to investigate inclusion complex formation between poorly soluble drug amisulpride (AMI) and γ-cyclodextrin (γ-CD). The solubility of AMI was enhanced by formation of inclusion complex of AMI with nano-hydrophobic cavity of γ-CD. The stoichiometry of inclusion complex was studied by continuous variation Job's plot method and found 1:1. The binding constant was found 1166.65 M(-1) by Benesi-Hildebrand plot. The molecular docking of AMI and γ-CD was done to investigate complexation. The inclusion complex formation was further confirmed by (1)H NMR and FT-IR, DSC and XRD analysis. The solubility of AMI was increased 3.74 times after inclusion complex formation with γ-CD.

  9. Inclusion complexes of red bell pepper pigments with β-cyclodextrin: preparation, characterisation and application as natural colorant in yogurt.

    PubMed

    Gomes, Lidiane Martins Mendes; Petito, Nicolly; Costa, Valéria Gonçalves; Falcão, Deborah Quintanilha; de Lima Araújo, Kátia G

    2014-04-01

    This work aimed to prepare inclusion complexes between red bell pepper pigments and β-cyclodextrin using two different procedures (i.e., magnetic stirring and ultrasonic homogenisation), to characterise the prepared inclusion complexes and to evaluate the colour stability of a selected complex added to yogurt. The mass ratio of extract to β-cyclodextrin was 1:4. The formed extract: β-cyclodextrin complexes and a physical mixture of extract and β-cyclodextrin were evaluated by differential scanning calorimetry, Fourier transform-infrared spectroscopy, proton nuclear magnetic resonance, particle size distribution and Zeta potential. The obtained data showed that ultrasonic homogenisation resulted in better yield and inclusion efficiency compared to magnetic stirring. The yogurt with the added complex produced by ultrasonic homogenisation showed slower variations for the a(∗) (redness) and b(∗) (yellowness) indices compared to yogurt with added extract, indicating a higher protection of the colour during storage.

  10. Inclusion complexes of red bell pepper pigments with β-cyclodextrin: preparation, characterisation and application as natural colorant in yogurt.

    PubMed

    Gomes, Lidiane Martins Mendes; Petito, Nicolly; Costa, Valéria Gonçalves; Falcão, Deborah Quintanilha; de Lima Araújo, Kátia G

    2014-04-01

    This work aimed to prepare inclusion complexes between red bell pepper pigments and β-cyclodextrin using two different procedures (i.e., magnetic stirring and ultrasonic homogenisation), to characterise the prepared inclusion complexes and to evaluate the colour stability of a selected complex added to yogurt. The mass ratio of extract to β-cyclodextrin was 1:4. The formed extract: β-cyclodextrin complexes and a physical mixture of extract and β-cyclodextrin were evaluated by differential scanning calorimetry, Fourier transform-infrared spectroscopy, proton nuclear magnetic resonance, particle size distribution and Zeta potential. The obtained data showed that ultrasonic homogenisation resulted in better yield and inclusion efficiency compared to magnetic stirring. The yogurt with the added complex produced by ultrasonic homogenisation showed slower variations for the a(∗) (redness) and b(∗) (yellowness) indices compared to yogurt with added extract, indicating a higher protection of the colour during storage. PMID:24262579

  11. Inclusion complexation and photoprototropic behaviour of 3-amino-5-nitrobenzisothiazole with β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Rajamohan, R.; Kothai Nayaki, S.; Swaminathan, M.

    2008-02-01

    The inclusion complexation and photoprototropic behaviour of 3-amino-5-nitrobenzisothiazole (ANBT) in aqueous β-cyclodextrin (β-CDx) solution have been investigated. Absorption and fluorescence intensities of the neutral form of ANBT are enhanced due to the formation of 1:1 complex with β-CDx. The complex formation has been confirmed by IR spectral and SEM studies. In the presence of β-CDx, no change was observed in the ground and excited state acidity constant values when compared with aqueous medium. Based on its inclusion complexation and photoprototropic characteristics of ANBT in β-CDx, the structure of the 1:1 complex is proposed.

  12. Cyclodextrin inclusion complex of racecadotril: effect of drug-β- cyclodextrin ratio and the method of complexation.

    PubMed

    Semalty, Mona; Panchpuri, Mitali; Singh, Devendra; Semalty, Ajay

    2014-06-01

    Racecadotril is an antisecretory and antidiarrheal agent against watery diarrhoea in children. Racecadotril is a class II drug (as per Biopharmaceutical Classification System) with poor aqueous solubility and dissolution rate limited absorption. β-cyclodextrin complexation of solubility or dissolution rate limited drugs provides an amphiphilic complex with improved solubility and dissolution profile. Thus Racecadotril - β-cyclodextrin complex were prepared to improve its solubility and dissolution by imparting an environment of improved hydrophilicity. Racecadotril was complexed with β-cyclodextrin (in 1:1 and 1:2 molar ratios) by two different methods (solvent evaporation and kneading method). These inclusion complexes were evaluated for solubility, drug content, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X ray powder diffraction (XRPD) and in vitro dissolution study. The highest drug content (30.83%) was found in complex made by kneading method (RK1:1) in 1:1 molar ratio. Complex prepared by solvent evaporation method (RSE1:1, RSE1:2) were found to be showing irregular disc shaped non-porous surface, while the complexes prepared by kneading method (RK1:1, RK1:2) showed rough, fluffy, non-porous and irregular surface in SEM. Solubility of the drug improved up to 2 to 3 folds in the complexes. The complex RK1:1 showed the greatest improvement in solubility (from 28.98 to76.56 µg/ml). The dissolution of the complexes was also found to be improved. Complex prepared by solvent evaporation method in 1:1 molar ratio (RSE1:1) showed a marked improvement in percent drug release (100.33%) than that of pure drug (52.58%) at the end of 1 hour in dissolution study. FTIR, DSC and XRPD data confirmed the formation of inclusion complex. It was concluded that water solubility of all the complexes were increased when the drug was complexed with β-CD in 1:1 molar ratio. The complex made in 1:1 molar ratio (irrespective of the method) showed

  13. Study on inclusion complex of cyclodextrin with methyl xanthine derivatives by fluorimetry

    NASA Astrophysics Data System (ADS)

    Wei, Yan-Li; Ding, Li-Hua; Dong, Chuan; Niu, Wei-Ping; Shuang, Shao-Min

    2003-10-01

    The inclusion complexes of β-cyclodextrin (β-CD) and HP-β-cyclodextrin (HP-β-CD) with caffeine, theophylline and theobromine were investigated by fluorimetry. Various factors affecting the formation of inclusion complexes were discussed in detail including forming time, pH effect and temperature. The results indicate that inclusion process was affected seriously by laying time and pH. The forming time of β-CD inclusion complexes is much longer than that of HP-β-CD. The optimum pH range is about 7-12 for caffeine, 8-10 for TP, 10.5-12 for TB. The intensities of their fluorescence increase with the decreasing of temperature. Their maximum excitation wavelengths are all in the range of 280-290 nm. The emission wavelength of caffeine and theophylline are both in the range of 340-360 nm, and that of theobromine is about 325 nm. The fluorescence signals are intensified with the increasing concentration of CD. The stoichiometry of the inclusion complexes of CD with these three methyl xanthine derivatives are all 1:1 and the formation constant are all calculated.

  14. Azo dye/cyclodextrin: new findings of identical nanorods through 2:2 inclusion complexes.

    PubMed

    Rajendiran, N; Sankaranarayanan, R K

    2014-06-15

    Inclusion complexation behavior of 4-aminoazobenzene (AAB) and 4-amino-2,3'-dimethyl azobenzene (GBC, fast grant GBC) with α- and β-cyclodextrins (α-CD, β-CD) is analyzed by scanning electron microscope, transmission electron microscope, Fourier transform infrared spectroscopy, differential scanning calorimetry, powder X-ray diffraction, and proton nuclear magnetic resonance spectroscopy techniques. Transmission electron microscope analysis suggests that identical nanorods formed in AAB/CD inclusion complexes while different dimension nanostructures were observed in GBC/CD inclusion complexes. The nanostructures confirmed that the ratio of 2:2 (guest:host) inclusion complex has been developed to a miniature nanorod. Nanosecond time-resolved fluorescence studies indicated that AAB/GBC have fast life time in water, whereas slow life time in CDs corresponds to a higher-order structure of 2:2 complexes. Thermodynamic parameters and binding affinity of the inclusion complex formation were determined and discussed. van der Waals interactions are mostly responsible for enthalpy-driven complex formation of AAB and GBC with cyclodextrins.

  15. Inclusion of trans-resveratrol in methylated cyclodextrins: synthesis and solid-state structures

    PubMed Central

    Trollope, Lee; Cruickshank, Dyanne L; Noonan, Terence; Bourne, Susan A; Sorrenti, Milena; Catenacci, Laura

    2014-01-01

    Summary The phytoalexin trans-resveratrol, 5-[(1E)-2-(4-hydroxyphenyl)ethenyl]-1,3-benzenediol, is a well-known, potent antioxidant having a variety of possible biomedical applications. However, its adverse physicochemical properties (low stability, poor aqueous solubility) limit such applications and its inclusion in cyclodextrins (CDs) has potential for addressing these shortcomings. Here, various methods of the attempted synthesis of inclusion complexes between trans-resveratrol and three methylated cyclodextrins (permethylated α-CD, permethylated β-CD and 2,6-dimethylated β-CD) are described. Isolation of the corresponding crystalline 1:1 inclusion compounds enabled their full structure determination by X-ray analysis for the first time, revealing a variety of guest inclusion modes and unique supramolecular crystal packing motifs. The three crystalline inclusion complexes were also fully characterized by thermal analysis (hot stage microscopy, thermogravimetric analysis and differential scanning calorimetry). To complement the solid-state data, phase-solubility studies were conducted using a series of CDs (native and variously derivatised) to establish their effect on the aqueous solubility of trans-resveratrol and to estimate association constants for complex formation. PMID:25670983

  16. Synthesis and molecular recognition of novel oligo(ethylenediamino) bridged bis(beta-cyclodextrin)s and their copper(II) complexes: enhanced molecular binding ability and selectivity by multiple recognition.

    PubMed

    Liu, Y; You, C C; Li, B

    2001-03-16

    Four bridged bis(beta-cyclodextrin)s tethered by different lengths of oligo(ethylenediamine)s have been synthesized and their inclusion complexation behavior with selected substrates elucidated by circular dichroism spectroscopy and fluorescence decay. In order to study their binding ability quantitatively, inclusion complexation stability constants with four dye guests, that is, brilliant green (BG), methyl orange (MO), ammonium 8-anilino-1-naphthalenesulfonic acid (ANS), and sodium 6-(p-toluidino)-2-naphthalenesulfonate (TNS), have been determined in aqueous solution at 25 degrees C with spectrophotometric, spectropolarimetric, or spectrofluorometric titrations. The results obtained indicate that the two tethered cyclodextrin units might cooperatively bind to a guest, and the molecular binding ability toward model substrates, especially linear guests such as TNS and MO, could be extended. The tether length plays a crucial role in the molecular recognition, the binding constants for ANS and TNS decrease linearly with an increase in the tether length of dimeric cyclodextrin. The Gibbs free energy changes (-deltaGo) for the unit increment per ethylene are 0.99 kJ mol(-1) for ANS and 0.44 kJmol(-1) for TNS, respectively. On the other hand, the presence of a copper(II) ion in metallobis(beta-cyclodextrin)s oligo(ethylenediamino) tethers enhances not only the original binding ability, but also the molecular selectivity through triple or multiple recognition, as compared with the parent bis(beta-cyclodextrin)s.

  17. Preparation, spectroscopy and molecular modelling studies of the inclusion complex of cordycepin with cyclodextrins.

    PubMed

    Zhang, Jian-Qiang; Wu, Di; Jiang, Kun-Ming; Zhang, Da; Zheng, Xi; Wan, Chun-Ping; Zhu, Hong-You; Xie, Xiao-Guang; Jin, Yi; Lin, Jun

    2015-04-10

    The inclusion complexes of cordycepin with cyclodextrins (CDs) were prepared, the resultant complexes were characterised by UV-vis, FTIR, DSC, SEM, XRD, ESI-MS and proton nuclear magnetic resonance spectroscopy ((1)H NMR). The stoichiometry was established using a Job plot and the inclusion mechanism was clarified using molecular dynamic simulations. Molecular modelling calculations have been carried out to rationalise the experimental findings and predict the stable molecular structure of the inclusion complex. The stability of the inclusion complexes were confirmed by energetic and thermodynamic properties (ΔE, ΔH, ΔG and ΔS) and HOMO, LUMO orbital. The 1:1 binding model of complexes were visually proved by ESI-MS experiment. Our results showed that the purine group of cordycepin molecule was deeply inserted into the cavity of CDs.

  18. Inclusion complexes of β-cyclodextrin-dinitrocompounds as UV absorber for ballpoint pen ink.

    PubMed

    Srinivasan, Krishnan; Radhakrishnan, S; Stalin, Thambusamy

    2014-08-14

    2,4-Dinitrophenol (2,4-DNP), 2,4-dinitroaniline (2,4-DNA), 2,6-dinitroaniline (2,6-DNA) and 2,6-dinitrobenzoic acid (2,6-DNB) has appeared for the UV absorption bands in different wavelength region below 400 nm, a combination of these dinitro aromatic compounds gave the broad absorption spectra within the UV region. The absorption intensities have been increased by preparation of the inclusion complex of dinitro compounds with β-cyclodextrin (β-CD). Prepared inclusion complexes are used to improve the UV protection properties of the ball point pen ink against photo degradation. The formation of solid inclusion complexes was characterized by FT-IR, and (1)H NMR spectroscopy. The UV protecting properties of these inclusion complexes were calculated their sun protection factor (SPF) is also discussed. The stability of the ballpoint pen ink has been confirmed by UV-Visible spectroscopic method. PMID:24813164

  19. Inclusion complexes of β-cyclodextrin-dinitrocompounds as UV absorber for ballpoint pen ink

    NASA Astrophysics Data System (ADS)

    Srinivasan, Krishnan; Radhakrishnan, S.; Stalin, Thambusamy

    2014-08-01

    2,4-Dinitrophenol (2,4-DNP), 2,4-dinitroaniline (2,4-DNA), 2,6-dinitroaniline (2,6-DNA) and 2,6-dinitrobenzoic acid (2,6-DNB) has appeared for the UV absorption bands in different wavelength region below 400 nm, a combination of these dinitro aromatic compounds gave the broad absorption spectra within the UV region. The absorption intensities have been increased by preparation of the inclusion complex of dinitro compounds with β-cyclodextrin (β-CD). Prepared inclusion complexes are used to improve the UV protection properties of the ball point pen ink against photo degradation. The formation of solid inclusion complexes was characterized by FT-IR, and 1H NMR spectroscopy. The UV protecting properties of these inclusion complexes were calculated their sun protection factor (SPF) is also discussed. The stability of the ballpoint pen ink has been confirmed by UV-Visible spectroscopic method.

  20. Electrospinning of Poly (epsilon-caprolactone) Fibers Functionalized with Cyclodextrins and their Inclusion Complexes

    NASA Astrophysics Data System (ADS)

    Narayanan, Ganesh

    Functionalization of polymeric nanofibers by cyclodextrins offers a novel way to enhance properties such as, small molecule encapsulation, efficient drug delivery, tissue engineering, improved mechanical and thermal behavior, in the resultant nanofibers. The advantage of using CDs, apart from their abundant availability from natural resources, biodegradability and biocompatibility, include their easy manipulation to obtain desired features in the nanofibers. In the first study, a unique way to electrospin PCL nanofibers with alpha- and gamma-CDs, without forming ICs was described. This was achieved by using a binary solvent mixture of chloroform/DMF, which is expected to hinder the formation of ICs. The resultant nanofibers were characterized by FTIR, DSC, TGA, SEM, water contact angle, and for the efficiency of PhP absorption. Based on the results, a simple model was proposed for both alpha- and gamma-CD filled PCL nanowebs. In the second study, electrospinning of PCL with beta-CD was performed from mixture of chloroform/DMF, and the nanofibers were characterized using FTIR, WAXD, TGA, and SEM. An interesting application of this material, i.e., as an absorbant for wound odors, was proposed, and subsequently the potential was studied by GC & XPS analysis. XPS indicated higher absorption of volatile fatty acids with higher CD loadings, whereas the absorption by the neat PCL nanofibers was little. The results found led to the suggestion that stabilizing CD over PCL by cross-linking will enhance the wound odor absorption potential, and this idea should be explored by further experimentation. In the third study, mechanically strong nanofibers were obtained from electrospinning PCL along with non-stochiometric inclusion complexes formed with PCL and alpha-CD, as a solution/suspension, from chloroform/DMF mixture. Non-stochiometric inclusion complexes were prepared from PCL and alpha-CD at various ratios, and were characterized by FTIR, DSC, and 1H-NMR. The electrospun

  1. Inclusion behaviour of Indole-7-Carboxaldehyde inside β-cyclodextrin: A nano cage

    NASA Astrophysics Data System (ADS)

    Singla, Nidhi; Chowdhury, Papia

    2014-09-01

    Encapsulation of Indole-7-Carboxaldehyde (I7C) inside nano sized cyclodextrin (α-, β-, γ-) cavities have been investigated by theoretical (PM3, HF, DFT, ONIOM methods) and experimental (UV-VIS, IR spectroscopy) results. β- cyclodextrin (CD) provides best trapping ability as its cavity size matches perfectly with the dimension of I7C. It is shown that in two specific orientations (P, Q), I7C can be encapsulated inside hydrophobic β-CD cavity by forming 1:1 inclusion complex. Intermolecular hydrogen bonding is observed to play a vital role in this encapsulation process. Present study on complexation mechanism is expected to provide a better knowledge on the reactivity of β-CD as drug carrier.

  2. NMR spectroscopic characterization of β-cyclodextrin inclusion complex with vanillin

    NASA Astrophysics Data System (ADS)

    Pîrnau, Adrian; Bogdan, Mircea; Floare, Calin G.

    2009-08-01

    The inclusion of vanillin by β-cyclodextrin was investigated by 1H NMR. The continuous variation technique was used to evidence the formation of soluble 1:1 complex in aqueous solution. The association constant of vanillin with β-cyclodextrin has been obtained at 298 K by fitting the experimental chemical shifts differences, Δδobs = δfree - δobs of the observed guest and host protons, with a non-linear regression method. Besides the effective association constant, the fitting procedure allows a precise determination of all chemical shift parameters characterizing the pure complex. They can by used for an analysis of the geometry of the molecular complex in solution.

  3. Resonance Rayleigh scattering technology as a new method for the determination of the inclusion constant of β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Li, Nianbing; Luo, Hongqun; Liu, Shaopu; Chen, Guonan

    2002-02-01

    The interaction of procaine hydrochloride and β-cyclodextrin in aqueous solution was studied using resonance Rayleigh scattering technology. The molar ratio of the inclusion complex was 1:1 established by spectrophotometry. The resonance Rayleigh scattering technology was first applied in the determination of the β-cyclodextrin inclusion constant. The inclusion constant of procaine hydrochloride-β-cyclodextrin complex Kf is 1.23×10 2 and 1.27×10 2 l mol -1 for method I and 1.15×10 2 and 1.21×10 2 l mol -1 for method II. These determination results were in correspondence with the results of the spectrophotometric and fluorescence methods. Therefore, the resonance Rayleigh scattering method can be used as a new technology for the determination of the inclusion constant.

  4. Influence of Ethanol as a Co-Solvent in Cyclodextrin Inclusion Complexation: A Molecular Dynamics Study

    PubMed Central

    Boonyarattanakalin, Kanokthip; Viernstein, Helmut; Wolschann, Peter; Lawtrakul, Luckhana

    2015-01-01

    Molecular dynamics (MD) simulations were used to investigate the dynamics and host-guest interactions of the inclusion complexes between a potent anti-HIV agent, UC781, and three different types of cyclodextrins (CDs) including βCD, 2,6-dimethyl-βCD (MβCD), and 2-hydroxypropyl-βCD (HPβCD) in aqueous solution with ethanol (EtOH) as a co-solvent. The MD simulation results revealed that EtOH as the co-solvent and the type of cyclodextrin affected the inclusion complex formation. From this study, UC781/MβCD provided the most stable inclusion complex. The competition for the cavity of βCD between UC781 and EtOH and the ensuing occupation of βCD cavities by EtOH resulted in a weaker interaction between βCD and UC781. In HPβCD, a supramolecular complex of UC781−HPβCD−EtOH was formed. The EtOH could easily fill the residual void space of the interior of unoccupied HPβCD due to the movement of UC781. In MβCD, the strong hydrogen bond interactions between the UC781 amide group and the secondary hydroxyl groups of MβCD significantly stabilized the inclusion complex in the presence of EtOH. PMID:26839825

  5. Study of the inclusion interaction of HP-γ-cyclodextrin with bupropion and its analytical application

    NASA Astrophysics Data System (ADS)

    Misiuk, Wieslawa; Jasiuk, Emilia

    2014-02-01

    Inclusion complex formation between bupropion (BUP) and hydroxypropyl-γ-cyclodextrin (HP-γ-CD) was studied by Fourier transformation infrared (FT-IR), nuclear magnetic resonance (NMR) and UV spectroscopy. The main factors affecting inclusion interaction were discussed in detail. The inclusion complex of bupropion and hydroxypropyl-γ-cyclodextrin was studied at pH 5 in aqueous phase. Stoichiometry of the complex was found to be 1:1 and apparent formation constant (log K) was determined as 3.54 ± 0.01, suggesting a tendency of the drug to enter HP-γ-CD cavity. All obtained information proved the formation of BUP/HP-γ-CD inclusion complex. A significant enhancement of absorption intensity of bupropion in presence of HP-γ-CD was shown. Due to the property a sensitive spectrophotometric method was elaborated for determination of active substance in bulk solution. At optimum experimental conditions, a linear relationship between absorbance and concentration of bupropion is observed in range of 4-60 μg mL-1 with limit detection of 0.32 μg mL-1 and correlation coefficient of 0.9991. The proposed method was applied successfully to the determination of BUP in pharmaceutical preparations and the results were satisfactory in comparison to official method.

  6. Estimation of the pH-independent binding constants of alanylphenylalanine and leucylphenylalanine stereoisomers with beta-cyclodextrin in the presence of urea.

    PubMed

    Li, J; Waldron, K C

    1999-01-01

    The separation of stereoisomers, particularly enantiomers, is important when their physiological activity differs. We have resolved the four stereoisomers each of alanylphenylalanine (Ala-Phe) and of leucylphenylalanine (Leu-Phe) by capillary electrophoresis using beta-cyclodextrin as a buffer additive and urea to enhance its solubility. A study of the influence of pH and beta-cyclodextrin concentration on the separations showed that weak inclusion complexes were formed between the dipeptides and chiral selector. It was found that pH could alter the migration order of enantiomers L-Ala-L-Phe and D-Ala-D-Phe, as well as L-Leu-L-Phe and D-Leu-D-Phe; however, there was no change in order for the other pairs of optical isomers. Electrophoretic mobility data were used to estimate the acid dissociation constants of the dipeptide isomers at pH < 7 with no chiral selector present. By varying the concentration of beta-cyclodextrin, the chiral selector, the binding constants of Ala-Phe and Leu-Phe optical isomers in their fully protonated and zwitterionic forms were estimated. For the four Ala-Phe stereoisomers, K = 42-66 M(-1) and 4-41 M(-1) for the cationic and zwitterionic forms, respectively. For the four Leu-Phe stereoisomers, K = 43-94 M(-1) and 1-28 M(-1) for the cationic and zwitterionic forms, respectively.

  7. Preparation and study on the solid inclusion complex of sparfloxacin with β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Chao, Jian-Bin; Tong, Hong-Bo; Huang, Shu-Ping; Liu, Dian-Sheng

    2004-01-01

    The interaction of sparfloxacin with β-cyclodextrin (β-CD) has been studied by several analytical techniques, including 1H-NMR, 13C-NMR, fluorescence spectroscopy, infrared spectroscopy, thermal analysis, and scanning electron microscope. In this paper, solid inclusion complex of sparfloxacin with β-CD was synthesized by the coprecipitation method. In addition, the characterization of the inclusion complex has been proved by fluorimetry, Infrared, differential scanning calorimetry and 1D, 2D NMR. The experimental results confirmed the existence of 1:1 inclusion complex of sparfloxacin with β-CD. The formation constant of complex was determined by fluorescence method and 1H-NMR. Spacial configuration of complex has been proposed on 2D NMR techniques.

  8. Preparation and study on the solid inclusion complex of ciprofloxacin with β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Jianbin, Chao; Liang, Chen; Hao, Xu; Dongpin, Meng

    2002-11-01

    The interaction of ciprofloxacin with β-cyclodextrin (β-CD) has been studied by several analytical techniques, including 1H-NMR (nuclear magnetic resonance), 13C-NMR, fluorescence spectroscopy, infrared (IR) spectroscopy, thermal analysis, and scanning electron microscope. In this paper, solid inclusion complex of ciprofloxacin with β-CD was synthesized by the coprecipitation method. In addition, the characterization of the inclusion complex has been proved by fluorimetry, IR, differential scanning calorimetry and 1D, 2D NMR. The experimental results confirmed the existence of 1:1 inclusion complex of ciprofloxacin with β-CD. The formation constant of complex was determined by fluorescence method and 1H-NMR. Spatial configuration of complex has been proposed on two dimensional NMR technique.

  9. Computational investigation on the host-guest inclusion process of norfloxacin into β-cyclodextrin.

    PubMed

    Maia, Pollyanna P; de Sousa, Sara Maria R; De Almeida, Wagner B; Guimarães, Luciana; Nascimento, Clebio S

    2016-09-01

    A theoretical (1)H NMR spectroscopy and thermodynamic analysis of the host-guest inclusion process involving the norfloxacin (NFX) into β-cyclodextrin (β-CD) was carried out. DFT structure and stabilization energies were obtained in both gas and aqueous phases. We could establish that the complex formation is enthalpy driven, and the hydrogen bonds established between NFX and β-CD play a major role in the complex stabilization. Besides, a theoretical (1)H NMR analysis has shown to be a supplementary proceeding to predict appropriately the inclusion mode of norfloxacin molecule into the β-CD. In this work, a theoretical study of the NFX@β-CD complex is reported for the first time, seeking a deep understanding of topology and thermodynamics of the inclusion complex formation. Graphical Abstract Topology, thermodynamic and (1)H NMR analysis of NFX@β-CD host-guest complexes. PMID:27558797

  10. Computational investigation on the host-guest inclusion process of norfloxacin into β-cyclodextrin.

    PubMed

    Maia, Pollyanna P; de Sousa, Sara Maria R; De Almeida, Wagner B; Guimarães, Luciana; Nascimento, Clebio S

    2016-09-01

    A theoretical (1)H NMR spectroscopy and thermodynamic analysis of the host-guest inclusion process involving the norfloxacin (NFX) into β-cyclodextrin (β-CD) was carried out. DFT structure and stabilization energies were obtained in both gas and aqueous phases. We could establish that the complex formation is enthalpy driven, and the hydrogen bonds established between NFX and β-CD play a major role in the complex stabilization. Besides, a theoretical (1)H NMR analysis has shown to be a supplementary proceeding to predict appropriately the inclusion mode of norfloxacin molecule into the β-CD. In this work, a theoretical study of the NFX@β-CD complex is reported for the first time, seeking a deep understanding of topology and thermodynamics of the inclusion complex formation. Graphical Abstract Topology, thermodynamic and (1)H NMR analysis of NFX@β-CD host-guest complexes.

  11. Supramolecular aggregates formed by sulfadiazine and sulfisomidine inclusion complexes with α- and β-cyclodextrins

    NASA Astrophysics Data System (ADS)

    Rajendiran, N.; Venkatesh, G.; Saravanan, J.

    2014-08-01

    Sulfadiazine (SDA) and sulfisomidine (SFM) inclusion complexes with two cyclodextrins (α-CD and β-CD) are studied in aqueous as well as in solid state. The inclusion complexes are characterized by UV-visible, fluorescence, time correlated single photon counting, FTIR, DSC, PXRD and 1H NMR techniques. The self assembled SDA/CD and SFM/CD inclusion complexes form different types of nano and microstructures. The self assembled nanoparticle morphologies are studied using SEM and TEM techniques. SDA/α-CD complex is formed hierarchal morphology, SDA/β-CD and SFM/β-CD complexes form the nanosheet self assembly. However, SFM/α-CD complex forms nanoporous sheet self assembly. van der Waals, hydrophobic and hydrogen bonding interaction play a vital role in the self assembling process.

  12. Synthesis and Characterization of the Inclusion Complex of β-cyclodextrin and Azomethine

    PubMed Central

    Sambasevam, Kavirajaa Pandian; Mohamad, Sharifah; Sarih, Norazilawati Muhamad; Ismail, Nor Atiqah

    2013-01-01

    A β-cyclodextrin (β-Cyd) inclusion complex containing azomethine as a guest was prepared by kneading method with aliquot addition of ethanol. The product was characterized by Fourier Transform Infrared (FTIR) spectrometer, 1H Nuclear Magnetic Resonance (1H NMR) and Thermogravimetric Analyzer (TGA), which proves the formation of the inclusion complex where the benzyl part of azomethine has been encapsulated by the hydrophobic cavity of β-Cyd. The interaction of β-Cyd and azomethine was also analyzed by means of spectrometry by UV-Vis spectrophotometer to determine the formation constant. The formation constant was calculated by using a modified Benesi-Hildebrand equation at 25 °C. The apparent formation constant obtained was 1.29 × 104 L/mol. Besides that, the stoichiometry ratio was also determined to be 1:1 for the inclusion complex of β-Cyd with azomethine. PMID:23434664

  13. Pharmacokinetic characterization of hydroxylpropyl-beta-cyclodextrin-included complex of cryptotanshinone, an investigational cardiovascular drug purified from Danshen (Salvia miltiorrhiza).

    PubMed

    Pan, Y; Bi, H-C; Zhong, G-P; Chen, X; Zuo, Z; Zhao, L-Z; Gu, L-Q; Liu, P-Q; Huang, Z-Y; Zhou, S-F; Huang, M

    2008-04-01

    1. The study aimed to investigate the pharmacokinetics of cryptotanshinone in a hydroxylpropyl-beta-cyclodextrin-included complex in dogs and rats. 2. Animals were administrated the inclusion complex of cryptotanshinone and the concentrations of cryptotanshinone and its major metabolite tanshinone IIA were determined by a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. 3. Cryptotanshinone in inclusion complex was absorbed slowly after an oral dose, and the C(max) and AUC(0-)(t) were dose-proportional. The bioavailability of cryptotanshinone in rats was (6.9% +/- 1.9%) at 60 mg kg(-1) and (11.1% +/- 1.8%) in dogs at 53.4 mg kg(-1). The t(1/2) of the compound in rats and dogs was 5.3-7.4 and 6.0-10.0 h, respectively. Cryptotanshinone showed a high accumulation in the intestine, lung and liver after oral administration, while the lung, liver and heart had the highest level following intravenous dose. Excretion data in rats showed that cryptotanshinone and its metabolites were mainly eliminated from faeces and bile, and the dose recovery rate was 0.02, 2.2, and 14.9% in urine, bile, and faeces, respectively. 4. The disposition of cryptotanshinone in an inclusion complex was dose-independent and the bioavailability was increased compared with that without cyclodextrin used to formulate the drug. Cryptotanshinone was distributed extensively into different organs. Excretion of cryptotanshinone and its metabolites into urine was extremely low, and they were mainly excreted into faeces and bile. PMID:18340563

  14. Dissolution behavior of β-cyclodextrin molecular inclusion complexes of aceclofenac

    PubMed Central

    Dua, Kamal; Pabreja, Kavita; Ramana, M. V.; Lather, Vinny

    2011-01-01

    The objective of the present investigation was to study the effect of β-cyclodextrin (β-CD) on the in vitro dissolution of aceclofenac (AF) from molecular inclusion complexes. Aceclofenac molecular inclusion complexes in 1:1 and 1:2 M ratio were prepared using a kneading method. The in vitro dissolution of pure drug, physical mixtures, and cyclodextrin inclusion complexes was carried out. Molecular inclusion complexes of AF with β-CD showed a considerable increase in the dissolution rate in comparison with the physical mixture and pure drug in 0.1 N HCl, pH 1.2, and phosphate buffer, pH 7.4. Inclusion complexes with a 1:2 M ratio showed the maximum dissolution rate in comparison to other ratios. Fourier transform infrared spectroscopy and differential scanning calorimetry studies indicated no interaction between AF and β-CD in complexes in solid state. Molecular modeling results indicated the relative energetic stability of the β-CD dimer-AF complex as compared to β-CD monomer-AF. Dissolution enhancement was attributed to the formation of water soluble inclusion complexes with β-CD. The in vitro release from all the formulations was best described by first-order kinetics (R2 = 0.9826 and 0.9938 in 0.1 N HCl and phosphate buffer, respectively) followed by the Higuchi release model (R2 = 0.9542 and 0.9686 in 0.1 N HCl and phosphate buffer, respectively). In conclusion, the dissolution of AF can be enhanced by the use of a hydrophilic carrier like β-CD. PMID:21966164

  15. A spectroscopic study of the inclusion of azulene by β- and γ-cyclodextrins

    NASA Astrophysics Data System (ADS)

    Abou-Zied, Osama K.

    2005-11-01

    The inclusion of azulene (AZ) inside the cavities of β-cyclodextrin (β-CD) and γ-cyclodextrin (γ-CD) was studied using absorption, fluorescence and induced-circular dichroism spectroscopy. The inclusion of AZ into the cavity of β-CD has a stoichiometry of 1:1, whereas that of AZ/γ-CD complex is 1:2. The equilibrium constants for the formation of the two complexes were calculated to be 780 ± 150 M -1 for AZ:β-CD and (4.5 ± 0.86) × 10 5 M -2 for AZ:(γ-CD) 2. The latter is due to a stepwise equilibrium mechanism in which a 1:1 complex is formed with a binding constant of 775 M -1, followed by the formation of a 1:2 complex with a binding constant of 580 M -1. The difference between the two binding constant values is slight, indicating an almost equal contribution from each of the γ-CD molecules to the overall binding in AZ:(γ-CD) 2. From the induced-circular dichroism spectra, the inclusion of AZ was found to be axial in AZ:β-CD and nearly axial in AZ:(γ-CD) 2.

  16. Stereoselective analysis of herbicides by capillary electrophoresis using sulfobutyl ether beta-cyclodextrin as chiral selector.

    PubMed

    Desiderio, C; Polcaro, C M; Fanali, S

    1997-02-01

    Capillary zone electrophoresis has been used for the enantiomeric separation of several herbicides. Different beta-cyclodextrin (CD) derivatives have been investigated for chiral separations and among them the negatively charged sulfobutyl ether beta-cyclodextrin (SBE-beta-CD) proved to be effective for the stereo-selective resolutions of the investigated herbicides. The effect of CD concentration, buffer pH and organic modifier on effective mobilities, resolution and selectivity of the analytes have been studied. Addition of SBE-beta-CD (5-50 mg/mL) to the buffer at pH 9 resulted in a general increase of migration times as well as resolution. A CD concentration as low as 5 mg/mL was effective to completely resolve napropamide and ethofumesate enantiomers. Buffer solutions containing 40 mg/mL of SBE-beta-CD were chosen to study the effect of buffer pH (7, 8, and 9) on chiral separation of the herbicides. No great differences in resolution and effective mobilities have been found in the pH 7-9 range. The addition of different organic modifiers to the background electrolyte at pH 9, containing 20 mg/mL of SBE-beta-CD, showed different effects. Methanol was the most effective in improving resolution but in some cases total loss in enantiomeric separation was observed. The qualitative analysis of an enantiomerically pure herbicide (flamprop isopropyl) commercial preparation is also shown.

  17. Stereoselective analysis of herbicides by capillary electrophoresis using sulfobutyl ether beta-cyclodextrin as chiral selector.

    PubMed

    Desiderio, C; Polcaro, C M; Fanali, S

    1997-02-01

    Capillary zone electrophoresis has been used for the enantiomeric separation of several herbicides. Different beta-cyclodextrin (CD) derivatives have been investigated for chiral separations and among them the negatively charged sulfobutyl ether beta-cyclodextrin (SBE-beta-CD) proved to be effective for the stereo-selective resolutions of the investigated herbicides. The effect of CD concentration, buffer pH and organic modifier on effective mobilities, resolution and selectivity of the analytes have been studied. Addition of SBE-beta-CD (5-50 mg/mL) to the buffer at pH 9 resulted in a general increase of migration times as well as resolution. A CD concentration as low as 5 mg/mL was effective to completely resolve napropamide and ethofumesate enantiomers. Buffer solutions containing 40 mg/mL of SBE-beta-CD were chosen to study the effect of buffer pH (7, 8, and 9) on chiral separation of the herbicides. No great differences in resolution and effective mobilities have been found in the pH 7-9 range. The addition of different organic modifiers to the background electrolyte at pH 9, containing 20 mg/mL of SBE-beta-CD, showed different effects. Methanol was the most effective in improving resolution but in some cases total loss in enantiomeric separation was observed. The qualitative analysis of an enantiomerically pure herbicide (flamprop isopropyl) commercial preparation is also shown. PMID:9080130

  18. Recognition ability and cytotoxicity of some oligosaccharidyl substituted beta-cyclodextrins.

    PubMed

    Attioui, F; al-Omar, A; Leray, E; Parrot-Lopez, H; Finance, C; Bonaly, R

    1994-01-01

    This paper reports a chemico-enzymatic synthesis of beta-CD derivatives. The recognition properties of these derivatives were tested using flocculating yeast and isolated lectins. It was observed that the substitution of beta-cyclodextrins with galactose end arms induces the better recognition by a cell-linked galactose-specific lectin. The physicochemical effects of the beta-CD derivatives on membranes were estimated using red blood cells and the effects on the viability of yeast and human rectal tumor cells were appreciated by measuring the mitochondrial deshydrogenase activity. The substitutions of the beta-CD ring by sugar antennae decrease the negative physicochemical effects of the beta-CD, ie their hemolytic properties. However, these substitutions induce significant modifications of the biological properties of the molecules, particularly the cytotoxicity and the growth of eukaryotic cells. PMID:7606211

  19. "Back to the Future": A New Look at Hydroxypropyl Beta-Cyclodextrins.

    PubMed

    Malanga, Milo; Szemán, Julianna; Fenyvesi, Éva; Puskás, István; Csabai, Katalin; Gyémánt, Gyöngyi; Fenyvesi, Ferenc; Szente, Lajos

    2016-09-01

    Since the discovery about 30 years ago (2-hydroxypropyl) beta-cyclodextrin, a highly soluble derivative of beta-cyclodextrin, has become an approved excipient of drug formulations included both in the United States and European Pharmacopoeias. It is recommended to use as solubilizer and stabilizer for oral and parenteral formulations. Recently, its pharmacological activity has been recognized in various diseases. The increasing applications require a closer look to the structure-activity relationship. As (2-hydroxypropyl) beta-cyclodextrin (HPBCD) is always a mixture of isomers with various degrees and pattern of hydroxypropylation, no wonder that the products of different manufacturers are often different. Several HPBCDs were compared applying a battery of analytical tools including thin layer chromatography, high performance liquid chromatography (HPLC), HPLC-mass spectrometry (MS), and matrix-assisted laser desorption MS. We studied how the average degree of substitution affects the aggregation behavior, the toxicity, and the solubilizing effect on poorly soluble drugs. We found that the products with low average degree of substitution are more prone to aggregation. The samples studied are nontoxic to Caco-2 cells and have low hemolytic activity. The solubility enhancement of poorly soluble drugs decreases or increases with increasing degree of substitution or shows a maximum curve depending on the properties of the guest. PMID:27317368

  20. Inclusion of riboflavin in β-cyclodextrin: A fluorimetric and absorption spectrometric study

    NASA Astrophysics Data System (ADS)

    Roy, Dalim Kumar; Deb, Nipamanjari; Ghosh, Bankim Chandra; Mukherjee, Asok K.

    2009-07-01

    Formation of inclusion complexes between riboflavin and β-cyclodextrin (β-CD) with both 1:1 and 1:2 stoichiometry has been established by fluorimetric titration. However, in absorption spectrometric experiment, spectral change of riboflavin in the visible range could be observed only by taking β-CD at a much higher concentration (about 100 times) than riboflavin and under such condition only 1:2 complexes could be detected. Its formation constant ( K) was determined by a multiple linear regression analysis of the absorption data. The reliability of the K value was confirmed by the consistency achieved on analyzing the data at two different wavelengths.

  1. Spectroscopic study and antioxidant properties of the inclusion complexes of rosmarinic acid with natural and derivative cyclodextrins.

    PubMed

    Celik, Saliha Esin; Ozyürek, Mustafa; Tufan, Ayşe Nur; Güçlü, Kubilay; Apak, Reşat

    2011-05-01

    Measurement of total antioxidant activity/capacity of polyphenols in various solvent media necessitates the use of cyclodextrins to solubilize lipophilic antioxidants of poor aqueous solubility. The inclusion complexes of the slightly water soluble antioxidant, rosmarinic acid (RA), with α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), 2-hydroxyethyl-β-cyclodextrin (HE-β-CD), and methyl-β-cyclodextrin (M-β-CD) were investigated for the first time. The effect of cyclodextrins (CDs) on the spectral features of RA was measured in aqueous medium using UV-vis and steady-state fluorescence techniques by varying the concentrations of CDs. The molar stoichiometry of RA-CD inclusion complexes was verified as 1:1, and the formation constants of the complexes were determined from Benesi-Hildebrand equation using fluorescence spectroscopic data. Among the CDs, maximum inclusion ability was measured in the case of M-β-CD followed by HP-β-CD, HE-β-CD, β-CD and α-CD. Solid inclusion complexes were prepared by freeze drying, and their functional groups were analyzed by IR spectroscopy. Antioxidant capacity of CD-complexed rosmarinic acid was measured to be higher than that of the lone hydroxycinnamic acid by the CUPric Reducing Antioxidant Capacity (CUPRAC) method. The mechanism of the TAC increase was interpreted as the stabilization of the 1-e oxidized o-catechol moiety of RA by enhanced intramolecular H-bonding in a hydrophobic environment provided by CDs, mostly by M-β-CD.

  2. Spectroscopic study and antioxidant properties of the inclusion complexes of rosmarinic acid with natural and derivative cyclodextrins

    NASA Astrophysics Data System (ADS)

    Çelik, Saliha Esin; Özyürek, Mustafa; Tufan, Ayşe Nur; Güçlü, Kubilay; Apak, Reşat

    2011-05-01

    Measurement of total antioxidant activity/capacity of polyphenols in various solvent media necessitates the use of cyclodextrins to solubilize lipophilic antioxidants of poor aqueous solubility. The inclusion complexes of the slightly water soluble antioxidant, rosmarinic acid (RA), with α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), 2-hydroxyethyl-β-cyclodextrin (HE-β-CD), and methyl-β-cyclodextrin (M-β-CD) were investigated for the first time. The effect of cyclodextrins (CDs) on the spectral features of RA was measured in aqueous medium using UV-vis and steady-state fluorescence techniques by varying the concentrations of CDs. The molar stoichiometry of RA-CD inclusion complexes was verified as 1:1, and the formation constants of the complexes were determined from Benesi-Hildebrand equation using fluorescence spectroscopic data. Among the CDs, maximum inclusion ability was measured in the case of M-β-CD followed by HP-β-CD, HE-β-CD, β-CD and α-CD. Solid inclusion complexes were prepared by freeze drying, and their functional groups were analyzed by IR spectroscopy. Antioxidant capacity of CD-complexed rosmarinic acid was measured to be higher than that of the lone hydroxycinnamic acid by the CUPric Reducing Antioxidant Capacity (CUPRAC) method. The mechanism of the TAC increase was interpreted as the stabilization of the 1 - e oxidized o-catechol moiety of RA by enhanced intramolecular H-bonding in a hydrophobic environment provided by CDs, mostly by M-β-CD.

  3. Fluorometric study of the inclusion interaction of β-cyclodextrin derivatives with tetraphenylporphyrin and its analytical application

    NASA Astrophysics Data System (ADS)

    Yang, Ronghua; Wang, Kemin; Xiao, Dan; Yang, Xiaohai

    2001-07-01

    The effects of native β-cyclodextrin (β-CD) and four kinds of alkylated β-cyclodextrin (β-CDs), i.e. heptakis (2,6-di-O-isobutyl-β-cyclodextrin) (I), heptakis (2,6-di-O-octyl-β-cyclodextrin) (II), heptakis (2,6-di-O-dodecyl-β-cyclodextrin) (III), and heptakis (2,6-di-O-hexadecyl-β-cyclodextrin) (IV), on the fluorescence behaviors of tetraphenylporphyrin (TPP) are investigated. An obvious fluorescence enhancement is observed from TPP by using alkylated derivatives compared to that obtained in β-CD aqueous or in water. A 114-N fluorescence emission intensity enhancement is found for the complex with 2,6-di-O-octyl-β-cyclodextrin relative to the free analyte. The exact stoichiometric ratios and the formation constants of the inclusion complexes have been examined by application of curve fitting method. The linear calibration plots between fluorescence intensity and TPP concentration are determined in the 1.14×10 -8-5.06×10 -6 mol l -1 range.

  4. Binding geometry, stoichiometry, and thermodynamics of cyclomalto-oligosaccharide (cyclodextrin) inclusion complex formation with chlorogenic acid, the major substrate of apple polyphenol oxidase.

    PubMed

    Irwin, P L; Pfeffer, P E; Doner, L W; Sapers, G M; Brewster, J D; Nagahashi, G; Hicks, K B

    1994-03-18

    The inclusion complexes of cyclomaltohexaose (alpha-CD), cyclomaltoheptaose (beta-CD), cyclomaltooctaose (gamma-CD), and polymerized beta-CD (beta-CDn) with chlorogenic acid (CA), the major substrate of apple fruit polyphenol oxidase (PPO), were studied with regard to pH, ionic strength, and temperature in model buffer systems and apple juice. The thermodynamics of CD.CA inclusion complex formation, which were studied in solution using UV spectrophotometry, displayed enthalpy-entropy compensation typical of processes driven by solvation phenomena. We also found that the apparent association constants (K) of the CD.CA equilibrium were relatively insensitive to pH for beta-CD, compared to alpha- and gamma-CDs, but were subject to substantial enhancement at low ionic strengths. The beta-CD.CA inclusion complex was also characterized for binding geometry and stoichiometry at 9.4 T and 25 degrees C in 0.05 M Na phosphate buffer by 1H NMR spectroscopy. A 1:1 stoichiometric ratio for the complex was found using the method of continuous variations. 1H Spin-lattice relaxation and chemical-shift data indicate that the phenolic ring of CA docks within the cavity of beta-CD. The Ks for beta-, alpha-, and gamma-CD determined in apple juice, which contains a mixture of PPO substrates, were found to correlate with PPO activity-related data. Apple juice, treated with beta-CDn, did not brown until CA was added back. These latter findings strongly argue that the mechanism for inhibition of juice browning with cyclodextrins was mainly due to the binding of PPO substrates and not some other means such as enzyme inactivation via sequestration of Cu2+ by CDs. PMID:8194069

  5. Host-guest system of hesperetin and β-cyclodextrin or its derivatives: Preparation, characterization, inclusion mode, solubilization and stability.

    PubMed

    Yang, Li-Juan; Xia, Sha; Ma, Shui-Xian; Zhou, Shu-Ya; Zhao, Xue-Qiu; Wang, Shu-Hui; Li, Min-Yan; Yang, Xiao-Dong

    2016-02-01

    The inclusion complexation behavior, characterization and binding ability of hesperetin with β-cyclodextrin and its derivatives were investigated in both the solution and solid state by means of XRD, DSC, SEM, (1)H and 2D NMR and UV-vis spectroscopy. The results showed that the water solubility and stability of hesperetin were obviously increased in the inclusion complex with cyclodextrins. This satisfactory water solubility and high stability of the hesperetin/CD complexes will be potentially useful for their application as herbal medicines or healthcare products.

  6. Correlation and in vitro studies on radioactive and nonradioactive albendazole-beta-cyclodextrin complex tablets.

    PubMed

    Cetin, E O; Ilem, D; Gundogdu, E; Asikoglu, M; Kirilmaz, L

    2011-09-01

    The work aims to confirm the complexation of albendazole (ABZ) by beta-cyclodextrin (beta-CD), and to compare them with pure ABZ tablets using radioactive and nonradioactive dissolution studies. The complex tablets were prepared by kneading a binary mixture of ABZ and beta-CD and a direct compression method. Nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were examined to prove the formation of complexes in the final products. The radiolabelled tablets were labelled with 99mTc-DTPA. Dissolution studies were performed with radiolabelled and nonradiolabelled tablets in two dissolution media (pH 1.2 and pH 7.4). The tablets were added to an acidic solution (pH = 1.2) to quantify the concentration of the drug inside the beta-CD cavity. The other medium (pH = 7.4) was used to prove the existence of non-complexed drug in each powder, as the drug's solubility increases with pH. It was observed that complexation occurred in all tablets, and beta-cyclodextrin (beta-CD) could increase the aqueous solubility. Further, a correlation was shown between dissolution results for radiolabelled and nonradiolabelled tablets. This study shows that the characterization studies were a good indicator for the ABZ: beta-CD complex. According to the phase solubility studies, the solubility of ABZ increased when the amount of beta-CD increased, and drug release from tablets in pH 7.4 and pH 1.2 media was dramatically improved by the addition of beta-CD compared with the pure ABZ tablet. PMID:22026122

  7. Capillary electrophoretic behaviors of pharmacologically active xanthones from Securidaca inappendiculata with beta-cyclodextrin as a buffer additive.

    PubMed

    Bo, Tao; Huang, Yongfa; Yang, Xuedong; Li, Ke An; Liu, Huwei; Xu, Lizhen

    2003-04-01

    The capillary electrophoretic (CE) behaviors of ten xanthones in the presence of beta-cyclodextrin (CD) are investigated, and apparent analyte-selector binding constants between beta-CD and the xanthones in the CE running buffer are calculated to elucidate the migration order. Also, the separation selectivity with beta-CD additive is compared with that of sulfated beta-CD additive. It is indicated that beta-CD can greatly change the separation selectivity of xanthones, and the electrophoretic behaviors of xanthones are rather different when using beta-CD from that when using sulfated beta-CD as an additive. PMID:12803804

  8. Physicochemical and molecular modeling studies of cefixime-L-arginine-cyclodextrin ternary inclusion compounds.

    PubMed

    Jadhav, Priyanka; Petkar, Bhushan; Pore, Yogesh; Kulkarni, Anita; Burade, Kishorkumar

    2013-11-01

    In an attempt to improve the physicochemical properties of cefixime (CEF), its supramolecular inclusion compounds were prepared with β-cyclodextrin (βCD) and hydroxypropyl-β-cyclodextrin (HPβCD) in presence and/or absence of ternary component L-arginine (ARG) using spray drying technique. Initially, the phase solubility studies revealed a stoichiometry of 1:1 molar ratio with an AL-type of phase solubility curve. The stability constants of binary systems were remarkably improved in presence of ARG, indicating positive effect of its addition. The inclusion complexes were characterized by FTIR, XRPD, DSC, SEM, particle size analysis, and dissolution studies. Further, molecular mechanic (MM) calculations were performed to investigate the possible orientations of CEF inside βCD cavity in presence and/or absence of ternary component. In case of physicochemical studies, the ternary systems performed well as a result of comprehensive effect of ternary complexation and particle size reduction achieved by a spray drying technology.

  9. Fluorescence enhancement of 1-napthol-5-sulfonate by forming inclusion complex with β-cyclodextrin in aqueous solution

    NASA Astrophysics Data System (ADS)

    Abdel-Shafi, Ayman A.; Al-Shihry, Shar S.

    2009-04-01

    Fluorescence enhancement of 1-naphthol-5-sulfonate (1N5S) upon inclusion in β-cyclodextrin is studied by spectrophotometry and spectrofluorimetery techniques. The spectral shifts were only observed in the emission spectra in different solvents and were found to be directly correlated to the solvent's hydrogen-bond donor strength (α). Spectral changes in the absorption spectra upon the addition of β-cyclodextrin to 1N5S in aqueous medium were too small to allow for the determination of the binding constant. On the other hand; fluorescence measurements show that the emission of both the anionic and neutral forms of 1N5S increase upon the addition of β-cyclodextrin with an increase in the quantum yield by about 60%. Fluorescence measurements show 1:1 inclusion of 1N5S in the β-cyclodextrin cavity with an association constant of 88 ± 10 M -1. 1H NMR studies are used to confirm the inclusion and to provide information on the geometry of 1N5S inside the cavity of β-cyclodextrin.

  10. Characterization, phase solubility and molecular modeling of α-cyclodextrin/pyrimethamine inclusion complex

    NASA Astrophysics Data System (ADS)

    Araujo, Marcia Valeria Gaspar de; Macedo, Osmir F. L.; Nascimento, Cristiane da Cunha; Conegero, Leila Souza; Barreto, Ledjane Silva; Almeida, Luis Eduardo; Costa, Nivan Bezerra da; Gimenez, Iara F.

    2009-02-01

    An inclusion complex between the dihydrofolate reductase inhibitor pyrimethamine (PYR) and α-cyclodextrin (α-CD) was prepared and characterized. From the phase-solubility diagram, a linear increase of PYR solubility was verified as a function of α-CD concentration, suggesting the formation of a soluble complex. A 1:1 host-guest stoichiometry can be proposed according to the Job's plot, obtained from the difference of PYR fluorescence intensity in the presence and absence of α-CD. Differential scanning calorimetry (DSC) measurements provided additional evidences of complexation such as the absence of the endothermic peak assigned to the melting of the drug. The inclusion mode characterized by two-dimensional 1H NMR spectroscopy (ROESY) involves penetration of the p-chlorophenyl ring into the α-CD cavity, in agreement to the orientation optimized by molecular modeling methods.

  11. Study of inclusion complex of β-cyclodextrin and diphenylamine: Photophysical and electrochemical behaviors

    NASA Astrophysics Data System (ADS)

    Srinivasan, K.; Kayalvizhi, K.; Sivakumar, K.; Stalin, T.

    2011-06-01

    The photophysical, electrochemical and photoprototropic behaviors of diphenylamine (DPA) in aqueous β-cyclodextrin (β-CD) solution have been investigated using absorption spectroscopy and cyclic voltammetric techniques. Absorption of the neutral and cationic form of DPA is enhanced due to the formation of a 1:1 complex with β-CD. The formation of this complex has been confirmed by Benesi-Hildebrand plot and docking studies by RasMol tool methods. The solid complex of β-CD with DPA is investigated by FT-IR, XRD and AFM methods. The thermodynamic parameters (Δ G, Δ H and Δ S) of inclusion process are also determined. The p Ka values of neutral-monocation equilibria have been determined with absorption (conjugate acid-base) titrations. A mechanism is proposed to explain the inclusion process.

  12. Microwave induced beta-cyclodextrin modification of chitosan for lead sorption.

    PubMed

    Sharma, A K; Mishra, A K

    2010-10-01

    Microwave induced copolymerization of beta-cyclodextrin (beta-CD) and chitosan (Ch) resulted in copolymer Ch-g-beta-CD synthesized without any radical initiator or catalyst. Copolymer samples of different performances in terms of Pb(II) binding were synthesized by changing beta-CD concentration at fixed microwave power and exposure time. To understand the advantage of using microwaves in the adsorbent synthesis, the copolymer synthesized using a K(2)S(2)O(8)/ascorbic acid redox pair at identical beta-CD and Chitosan concentrations (% G 103) was also evaluated as Pb(II) sorbent, and the results obtained were compared with that of microwave synthesized copolymer. A representative sample of microwave synthesized adsorbent was characterized using FTIR spectroscopy, X-ray diffraction, TGA, SEM analysis and using this sample adsorption of lead (II) was studied as a function of pH, initial Pb(II) concentration. The adsorption data followed both Freundlich and Langmuir isotherms. On the basis of the Langmuir model, Q(max) was calculated to be 434.78mg/g for microwave synthesized copolymer (Ch-g-beta-CD) in comparison to 294.11mg/g for conventionally synthesized copolymer (Ch-g-beta-CD). In order to investigate dynamic behaviour of Ch-g-beta-CD as an adsorbent, the kinetic data were modelled using pseudo-second-order and second-order. The regeneration experiments revealed that the Ch-g-beta-CD can be successfully reused for seven cycles.

  13. Use of liquid crystals for imaging different inclusion abilities of α-cyclodextrin and β-cyclodextrin toward cetyltrimethyl ammonium bromide

    NASA Astrophysics Data System (ADS)

    Liao, Zhijian; Du, Sinan; Qin, Zhenli; Wang, Jinyan; Zuo, Fang; Luo, Jianbin

    2015-09-01

    We herein report a method for the imaging of different inclusion abilities of α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD) toward cetyltrimethyl ammonium bromide (CTAB) using liquid crystals (LCs). The optical transition from the dark to the bright state was caused by the inclusion interaction between CTAB and CDs. It was confirmed that α-CD formed more stable CTAB complexes than β-CD, leading to different optical responses of the LCs from the α-CD/CTAB and β-CD/CTAB systems. This method could be used to provide a visual method for selection of the correct CD molecules for interaction with surfactant molecules in recognition systems.

  14. Correlation of the solubility of several aromatics and terpenes in aqueous hydroxypropyl-beta-cyclodextrin with steric and hydrophobicity parameters.

    PubMed

    Demian, B A

    2000-10-01

    The solubility isotherms of nineteen aromatics and terpenes in aqueous hydroxypropyl-beta-cyclodextrin were determined to be straight lines. This is explained by the host-guest complexation which is characteristic for the whole class of cyclodextrins and derivatives. The slopes of the solubility isotherms correlate with Sterimol L and log P(ow) as descriptors of the steric fit and hydrophobicity match, in accord with the qualitative representation of the phenomenon.

  15. Correlation of the solubility of several aromatics and terpenes in aqueous hydroxypropyl-beta-cyclodextrin with steric and hydrophobicity parameters.

    PubMed

    Demian, B A

    2000-10-01

    The solubility isotherms of nineteen aromatics and terpenes in aqueous hydroxypropyl-beta-cyclodextrin were determined to be straight lines. This is explained by the host-guest complexation which is characteristic for the whole class of cyclodextrins and derivatives. The slopes of the solubility isotherms correlate with Sterimol L and log P(ow) as descriptors of the steric fit and hydrophobicity match, in accord with the qualitative representation of the phenomenon. PMID:11093722

  16. Inclusion of Paracetamol into β-cyclodextrin nanocavities in solution and in the solid state

    NASA Astrophysics Data System (ADS)

    El-Kemary, Maged; Sobhy, Saffaa; El-Daly, Samy; Abdel-Shafi, Ayman

    2011-09-01

    We report on steady-state UV-visible absorption and emission characteristics of Paracetamol, drug used as antipyretic agent, in water and within cyclodextrins (CDs): β-CD, 2-hydroxypropyl- β-CD (HP- β-CD) and 2,6-dimethyl- β-CD (Me- β-CD). The results reveal that Paracetamol forms a 1:1 inclusion complex with CD. Upon encapsulation, the emission intensity enhances, indicating a confinement effect of the nanocages on the photophysical behavior of the drug. Due to its methyl groups, the Me- β-CD shows the largest effect for the drug. The observed binding constant showing the following trend: Me- β-CD > HP- β-CD > β-CD. The less complexing effectiveness of HP- β-CD is due to the steric effect of the hydroxypropyl-substituents, which can hamper the inclusion of the guest molecules. The solid state inclusion complex was prepared by co-precipitation method and its characterization was investigated by Fourier transform infrared spectroscopy, 1H NMR and X-ray diffractometry. These approaches indicated that Paracetamol was able to form an inclusion complex with CDs, and the inclusion compounds exhibited different spectroscopic features and properties from Paracetamol.

  17. Study to explore the mechanism to form inclusion complexes of β-cyclodextrin with vitamin molecules

    PubMed Central

    Saha, Subhadeep; Roy, Aditi; Roy, Kanak; Roy, Mahendra Nath

    2016-01-01

    Host–guest inclusion complexes of β-cyclodextrin with two vitamins viz., nicotinic acid and ascorbic acid in aqueous medium have been explored by reliable spectroscopic, physicochemical and calorimetric methods as stabilizer, carrier and regulatory releaser of the guest molecules. Job’s plots have been drawn by UV-visible spectroscopy to confirm the 1:1 stoichiometry of the host-guest assembly. Stereo-chemical nature of the inclusion complexes has been explained by 2D NMR spectroscopy. Surface tension and conductivity studies further support the inclusion process. Association constants for the vitamin-β-CD inclusion complexes have been calculated by UV-visible spectroscopy using both Benesi–Hildebrand method and non-linear programme, while the thermodynamic parameters have been estimated with the help of van’t Hoff equation. Isothermal titration calorimetric studies have been performed to determine the stoichiometry, association constant and thermodynamic parameters with high accuracy. The outcomes reveal that there is a drop in ΔSo, which is overcome by higher negative value of ΔHo, making the overall inclusion process thermodynamically favorable. The association constant is found to be higher for ascorbic acid than that for nicotinic acid, which has been explained on the basis of their molecular structures. PMID:27762346

  18. 2,6-Dinitroaniline and β-cyclodextrin inclusion complex properties studied by different analytical methods.

    PubMed

    Srinivasan, Krishnan; Sivakumar, Krishnamoorthy; Stalin, Thambusamy

    2014-11-26

    The formation of supramolecular host-guest inclusion complex of 2,6-Dinitroaniline (2,6-DNA) with nano-hydrophobic cavity of β-cyclodextrin (β-CD) in solution phase were studied by UV-visible spectrophotometer and electrochemical method (cyclic voltammetry, CV). The prototropic behaviors of 2,6-DNA with and without β-CD and the ground state acidity constant (pKa) of host-guest inclusion complex (2,6-DNA-β-CD) was studied by Spectrophotometrically. The binding constant of inclusion complex at 303 K was calculated using Benesi-Hildebrand plot and thermodynamic parameter (ΔG) were also calculated. The solid inclusion complex formation between β-CD and 2,6-DNA was confirmed by (1)H NMR, FT-IR, XRD and SEM analysis. The β-CD:2,6-DNA inclusion complex obtained by molecular docking studies is in good correlation with the results obtained through experimental methods. PMID:25256521

  19. Thermodynamic study on the effects of β-cyclodextrin inclusion with berberine

    NASA Astrophysics Data System (ADS)

    Yu, Jun-Sheng; Wei, Fang-Di; Gao, Wei; Zhao, Chang-Chun

    2002-01-01

    The fluorescence enhancement of berberine (Berb) as a result of complex with β-cyclodextrin (β-CD) is investigated. The association constants of α-CD and β-CD with Berb are 60 and 137 M -1 at 20 °C in pH 7.20 aqueous solution. Effects of temperature on the forming inclusion complexes of β-CD with Berb have been examined through using fluorescence titration. Enthalpy and entropy values calculated from fluorescence data are -33.7·kJ mol -1 and 74.3 J·mol -1·K -1, respectively. It was found that the dielectric constant of β-CD cavity is about 24 in a rough analogy with absolute alcohol. These results suggest that the extrusion of 'high energy water' molecules from the cavity of β-CD and hydrophobic interaction upon the inclusion complex formation are the main forces of the inclusion reaction. Effect of pH on the association of β-CD with Berb was also studied. Mechanism of the inclusion of β-CD with Berb is further studied by absorption and NMR measurements. Results show that β-CD forms a 1:1 inclusion complex with Berb.

  20. Use of principal component analysis for the evaluation of the retention behaviour of monoamine oxidase inhibitory drugs on beta-cyclodextrin column.

    PubMed

    Forgács, E

    1995-04-01

    The retention of 17 monoamine oxidase inhibitory drugs (proparlgylamine derivatives) were determined on a beta-cyclodextrin polymer (beta CDP)-coated silica column using ethanol-0.05 M K2HPO4 (6:4 v/v) as the eluent. The relative strength of interaction between the drugs and a water soluble beta-cyclodextrin polymer was determined by charge-transfer chromatography carried out on reversed-phase TLC layers. The relationship between capacity factors, physicochemical parameters and inclusion complex forming capacity of the monoamine oxidase inhibitory drugs were evaluated by stepwise regression analysis and by principal component analysis (PCA) followed by two-dimensional nonlinear mapping and varimax rotation. Calculations indicated that the retention of monoamine oxidase inhibitory drugs on beta CDP column is mainly governed by their steric and lipophylic parameters. Significant linear correlations were found between the corresponding coordinates of varimax rotation and two-dimensional nonlinear maps proving the suitability of both methods for the reduction of dimensionality of complicated data matrices.

  1. Electronic structure and normal vibrations in (+)-catechin and (-)-epicatechin encapsulated beta-cyclodextrin.

    PubMed

    Khedkar, Jayshree K; Gobre, Vivekanand V; Pinjari, Rahul V; Gejji, Shridhar P

    2010-07-29

    Host-guest interactions between beta-cyclodextrin (beta-CD) and flavan-3-Ol enantiomers (guest) namely, (+)-catechin (CA) or (-)-epicatechin (EC), have been analyzed within the framework of density functional theory. Both CA and EC consist of two phenol rings, I and II, and a pyran ring, III, which facilitate a variety of binding patterns with the host, beta-CD. The minimum energy beta-CD-CA complex reveals that ring II of CA interacts with primary hydroxyls of the upper rim and the phenol ring I engenders hydrogen-bonded interactions with secondary hydroxyl from the lower rim of CD. On the other hand, the O-H...O interactions between ring I and primary hydroxyls of beta-CD along with those between one of hydroxyl of ring II and secondary hydroxyl of the host render large stability to the beta-CD-EC complex. Structures of both beta-CD-CA and beta-CD-EC complexes thus obtained are in consonant with those inferred from the experimental NMR data and exhibit distinct features in infrared spectra. The frequency shifts of characteristic vibrations in infrared spectra of these complexes compared to the unbound individual host or guest in its free state have been analyzed with the use of natural bond orbital analyses and combining difference electron density maps with bond critical points in molecular electron density topography.

  2. Interaction of native alpha-cyclodextrin, beta-cyclodextrin and gamma-cyclodextrin and their hydroxypropyl derivatives with selected organic low molecular mass compounds at elevated and subambient temperature under RP-HPLC conditions.

    PubMed

    Zarzycki, P K; Ohta, H; Saito, Y; Jinno, K

    2008-08-01

    The main focus of this study was to explore the capability of native alpha-cyclodextrin, beta-cyclodextrin and gamma-cyclodextrin and their hydroxypropyl derivatives for host-guest interaction with 7,8-dimethoxyflavone, selected steroids (estetrol, estriol, estradiol, estrone, testosterone, cortisone, hydrocortisone, progesterone and 17alpha-hydroxyprogesterone) and polycyclic aromatic hydrocarbons (toluene, naphthalene, 1,8-dimethylnaphthalene, 1-acenaphthenol, acenaphthylene and acenaphthene) under reversed-phase liquid-chromatography conditions. The study revealed that native cyclodextrins interact more efficiently with the analytes investigated than do their hydroxypropyl counterparts. In the low-temperature region, enormously high ratios were observed for polycyclic aromatic hydrocarbons, particularly 1,8-dimethylnaphthalene, acenaphthene and acenaphthylene chromatographed on a beta-cyclodextrin-modified mobile phase. In such a case, the retention times of the polycyclic aromatic hydrocarbons were strongly reduced (e.g. from 127 to 1.2 min for 1,8-dimethylnaphthalene) and were close to the hold-up time of the high-performance liquid chromatography (HPLC) system (0.7 min). Moreover, chiral separation of 1-acenaphthenol optical isomers was observed and the elution order of the enantiomers was determined. Within the steroids group, strong interaction was observed for estradiol and testosterone. The results of cluster analysis indicate that beta-cyclodextrin as well as gamma-cyclodextrin and its hydroxypropyl derivative can be most effective mobile-phase additives under reversed-phase HPLC conditions for 3D-shape-recognition-driven separation, performed at subambient and elevated temperatures, respectively. PMID:18563397

  3. Theoretical and Experimental Study of Inclusion Complexes of β-Cyclodextrins with Chalcone and 2',4'-Dihydroxychalcone.

    PubMed

    Sancho, Matias I; Andujar, Sebastian; Porasso, Rodolfo D; Enriz, Ricardo D

    2016-03-31

    The inclusion complexes formed by chalcone and 2',4'-dihydroxychalcone with β-cyclodextrin have been studied combining experimental (phase solubility diagrams, Fourier transform infrared spectroscopy) and molecular modeling (molecular dynamics, quantum mechanics/molecular mechanics calculations) techniques. The formation constants of the complexes were determined at different temperatures, and the thermodynamic parameters of the process were obtained. The inclusion of chalcone in β-cyclodextrin is an exothermic process, while the inclusion of 2',4'-dihydroxychalcone is endothermic. Free energy profiles, derived from umbrella sampling using molecular dynamics simulations, were constructed to analyze the binding affinity and the complexation reaction at a molecular level. Hybrid QM/MM calculations were also employed to obtain a better description of the energetic and structural aspects of the complexes. The intermolecular interactions that stabilize both inclusion complexes were characterized by means of quantum atoms in molecules theory and reduce density gradient method. The calculated interactions were experimentally observed using FTIR. PMID:26950264

  4. Studies on the Preparation, Characterization, and Solubility of 2-HP-β-Cyclodextrin-Meclizine HCl Inclusion Complexes.

    PubMed

    George, Sj; Vasudevan, Dt

    2012-10-01

    Meclizine HCl is a poorly water-soluble drug having a very slow-onset of action. The effect of 2-hydroxypropyl-β-cyclodextrins and β-cyclodextrins on its aqueous solubility and dissolution rate was investigated. The phase solubility profile indicated that the solubility of Meclizine HCl was significantly increased in the presence of both 2-hydroxypropyl-β-cyclodextrin and β- cyclodextrin; an extend of increase being more for 2-hydroxypropyl-β-cyclodextrin. It was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. The complexes formed were quite stable. The solid complexes prepared by physical mixtures, kneading methods, and co-precipitation methods were characterized using differential scanning calorimetry and FTIR. An in vitro study showed that the solubility and dissolution rate of Meclizine HCl were significantly improved by complexation with 2-hydroxypropyl-β-cyclodextrin. Tablet formulation using 1:1 kneading complex of Meclizine HCl and 2-hydroxypropyl-β-cyclodextrin with drug equivalent to 25 mg was prepared by a direct compression method. A dissolution study of prepared tablets was performed in 0.5% SLS in water (pH 7.0). Almost 96% drug was released from the formulation at the end of 30min. A comparison study of prepared tablets was done with marketed a Meclizine HCl 25 mg conventional tablet. From the results of dissolution study, it was found that the prepared formulation was showing better release, which was statistically significant P < 0.01 than a marketed tablet (paired t-test). Only 54% drug release was observed from the marketed tablet at the end of 30 min. Hence this study concludes that the solubility enhancement of Meclizine HCl could be successfully achieved using the inclusion complexation technique. PMID:23493156

  5. Formulation of cyclodextrin inclusion complex-based orally disintegrating tablet of eslicarbazepine acetate for improved oral bioavailability.

    PubMed

    Desai, Samixa; Poddar, Aditi; Sawant, Krutika

    2016-01-01

    The present investigation was aimed towards developing a beta-cyclodextrin (β-CD) solid dispersion (SD) based orally disintegrating tablet (ODT) of eslicarbazepine acetate (ESL), for improving the dissolution and providing fast onset of anti-epileptic action. Optimum ratio of ESL and β-CD was determined by Job's plot. Thereafter, solid dispersions were prepared by solvent evaporation method and evaluated for yield, assay, Differential scanning calorimetry (DSC), Fourier transform infra red spectroscopy (FTIR), X-ray diffraction (XRD), and in vitro dissolution. Optimized SD was compressed into ODT by direct compression using super disintegrants and evaluated for wetting time, drug content, in vitro drug release and in vivo studies. The results of DSC, FTIR and XRD analysis supported the formation of inclusion complex. An improved dissolution with 99.95 ± 2.80% drug release in 60 min was observed in comparison to 24.85 ± 2.96% release from a plain drug suspension. Tablets with crosspovidone as a super disintegrant showed the least disintegration time of 24.66 ± 1.52 s and higher in vitro drug release against marketed tablets. In vivo studies indicated that the formulated tablets had 2 times higher bioavailability than marketed tablets. Thus, the developed β-CD-ESL SD-ODT could provide faster onset of action and higher bioavailability, which would be beneficial in case of epileptic seizures. PMID:26478377

  6. β-Cyclodextrin inclusion complex: preparation, characterization, and its aspirin release in vitro

    NASA Astrophysics Data System (ADS)

    Zhou, Hui-Yun; Jiang, Ling-Juan; Zhang, Yan-Ping; Li, Jun-Bo

    2012-09-01

    In this work, the optimal clathration condition was investigated for the preparation of aspirin-β-cyclodextrin (Asp-β-CD) inclusion complex using design of experiment (DOE) methodology. A 3-level, 3-factor Box-Behnken design with a total of 17 experimental runs was used. The Asp-β-CD inclusion complex was prepared by saturated solution method. The influence on the embedding rate was investigated, including molar ratio of β-CD to Asp, clathration temperature and clathration time, and the optimum values of such three test variables were found to be 0.82, 49°C and 2.0 h, respectively. The embedding rate could be up to 61.19%. The formation of the bonding between -COOH group of Asp and O-H group of β-CD might play an important role in the process of clathration according to FT-IR spectra. Release kinetics of Asp from inclusion complex was studied for the evaluation of drug release mechanism and diffusion coefficients. The results showed that the drug release from matrix occurred through Fickian diffusion mechanism. The cumulative release of Asp reached only 40% over 24 h, so the inclusion complex could potentially be applied as a long-acting delivery system.

  7. Neutron diffraction of. cap alpha. ,. beta. and. gamma. cyclodextrins: hydrogen bonding patterns

    SciTech Connect

    Hingerty, B.E.; Klar, B.; Hardgrove, G.; Betzel, C.; Saenger, W.

    1983-01-01

    Cyclodextrins (CD's) are torus-shaped molecules composed of six (..cap alpha..), seven (..beta..) or eight (..gamma..) (1 ..-->.. 4) linked glucoses. ..cap alpha..-CD has been shown to have two different structures with well-defined hydrogen bonds, one tense and the other relaxed. An induced-fit-like mechanism for ..cap alpha..-CD complex formation has been proposed. Circular hydrogen bond networks have also been found for ..cap alpha..-CD due to the energetically favored cooperative effect. ..beta..-CD with a disordered water structure possesses an unusual flip-flop hydrogen bonding system of the type O-H H-O representing an equilibrium between two states; O-H O reversible H-O. ..gamma..-CD with a disordered water structure similar to ..beta..-CD also possesses the flip-flop hydrogen bond. This study demonstrates that hydrogen bonds are operative in disordered systems and display dynamics even in the solid state.

  8. Spectroscopic characterization of both aqueous and solid-state diacerhein/hydroxypropyl-β-cyclodextrin inclusion complexes

    NASA Astrophysics Data System (ADS)

    Petralito, Stefania; Zanardi, Iacopo; Spera, Romina; Memoli, Adriana; Travagli, Valter

    2014-06-01

    Diacerhein, a poorly water soluble antirheumatic prodrug, was spectroscopically characterized to form inclusion complexes with hydroxypropyl-β-cyclodextrin (HPβCD) in both aqueous solution and in solid phase. Complexation with the hydrophilic carriers was used to improve the solubility and dissolution rate of the compound. The kinetics of the prodrug degradation to the active rhein in aqueous buffer solution were also investigated as a function of HPβCD concentration. The solid complexes prepared by different methods such as physical mixture, kneading, co-evaporation method and freeze dried method in 1:1 M ratio, were characterized by DSC and FTIR. The dissolution profiles of solid complexes were determined and compared with diacerhein alone and their physical mixture, in the simulated intestinal fluid at 37 °C. The accurate molecular spectroscopic characterization of diacerhein in the presence of different amounts of aqueous cyclodextrins was essential to determine the correct binding constants for the diacerhein/HPβCD system. The binding constants were also validated by UV spectrometry and HPLC procedure in order to compare the values from the different methods. Higuchi-Connors phase solubility method has proved not suitable when either the free or/and the complexed prodrug degrade in aqueous solution.

  9. [Preparation and investigation of gemfibrozil + dimethyl-beta-cyclodextrin products and solid dosage forms].

    PubMed

    Hassan, Bin Hassan; Aigner, Zoltán; Kása, Péter; Hódi, Klára; Eros, István

    2005-01-01

    Gemfibrozil is a lipid-regulating active substance. Dimethyl-beta-cyclodextrin products were prepared from this sparingly soluble pharmacon by means of methods such as physical mixing, kneading, spray drying and ultrasonication. Solid dosage forms (hydroxypropylmethyl cellulose /HPMC/ capsules and tablets) were prepared from the selected products on the basis of their dissolution profile and the in vitro membrane diffusion results. This publication details the results of electronmicroscopic morphological studies, particle size analysis and wetting contact angle determinations, and also the preparation and examination of the resulting solid dosage forms. PMID:16318236

  10. Spectral and photophysical studies of inclusion complexes of 2-amino-4,6-dimethyl pyrimidine with β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    El-Kemary, M. A.; El-Gezawy, H. S.; El-Baradie, H. Y.; Issa, R. M.

    2002-02-01

    The interaction of 2-amino-4,6-dimethyl pyrimidine (ADMP) with β-cyclodextrin (β-CD) has been studied by means of UV absorption, steady state and time resolved fluorescence techniques. Spectral characteristics, bandwidths and photophysical parameters indicating that ADMP experience two different environments in aqueous solutions: bulk water and 1:1 (ADMP:β-CD) inclusion complexation. The size restriction of the upper rim of β-CD partially include ADMP and prevent the possibility of formation of 1:2 complex. The effective polarity of the cyclodextrin cavity experienced by the induced ADMP is equivalent with the polarity of an 80:20 methanol-water mixture.

  11. Effect of water molecules on the fluorescence enhancement of Aflatoxin B1 mediated by Aflatoxin B1:beta-cyclodextrin complexes. A theoretical study.

    PubMed

    Ramírez-Galicia, Guillermo; Garduño-Juárez, Ramón; Gabriela Vargas, M

    2007-01-01

    In order to explain the observed fluorescence enhancement of Aflatoxin B1 (AFB1) when forming AFB1:beta-cyclodextrin (AFB1:beta-CD) inclusion complexes, we have performed a theoretical (quantum chemistry calculations) study of AFB1 and AFB1:beta-CD in vacuum and in the presence of aqueous solvent. The AM1 method was used to calculate the absorption and emission wavelengths of these molecules. With the help of density functional theory (DFT) and time-dependent DFT (TDDFT) vibrational frequencies and related excitation energies of AFB1 and AFB1.(H2O)m = 4,5,6,11 were calculated. On the basis of these calculations we propose a plausible mechanism for the fluorescence enhancement of AFB1 in the presence of beta-CD: (1) before photoexcitation of AFB1 to its S1 excited state, there is a vibrational coupling between the vibrational modes involving the AFB1 carbonyl groups and the bending modes of the nearby water molecules (CG + WM); (2) these interactions allow a thermal relaxation of the excited AFB1 molecules that results in fluorescence quenching; (3) when the AFB1 molecules form inclusion complexes with beta-CD the CG + WM interaction decreases; and (4) this gives rise to a fluorescence enhancement.

  12. Comparative study on the inclusion behavior between meso-tetrakis(4- N-ethylpyridiniurmyl)porphyrin and β-cyclodextrin derivatives

    NASA Astrophysics Data System (ADS)

    Xiliang, Guo; Shaomin, Shuang; Chuan, Dong; Feng, Feng; Wong, M. S.

    2005-01-01

    5,10,15,20-Tetrakis(4- N-ethylpyridiniurmyl)porphyrin (TEPyP) formed 1:1 stoichiometry inclusion complexes with β-cyclodextrin (β-CD) and its derivatives including hydroxypropyl-β-cyclodextrin (HP-β-CD), sulfobutylether-β-cyclodextrin (SBE-β-CD) in basic aqueous solution. The supramolecular system was investigated by the methods of fluorescence, UV-vis absorption spectroscopy, nuclear magnetic resonance (NMR) technique. The inclusion ability of cyclodextrins exhibited remarkable difference for β-CD, HP-β-CD and SBE-β-CD. Association constants as high as K=1.1×10 4 M -1 in the case of HP-β-CD/TEPyP and 2.0×10 5 M -1 in the case of SBE-β-CD/TEPyP complexes were determined, whereas a lower value ( K=550 M -1) was given in the case of β-CD/TEPyP. The results showed that hydrogen bonding and charge attraction play important roles in the processes of host-guest interaction. The interaction mechanism of inclusion processes could be explained by the analysis of NMR spectroscopy. The supramolecular assembly was formed. β-CD and HP-β-CD approached from the primary face of cavities of CDs.

  13. Determinations of the inclusion complex between gossypol and β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Shen, Ying-lin; Ying, Wei; Yang, Sheng-hua; Wu, Long-min

    2006-09-01

    Features of the inclusion complex between gossypol (Gos) and β-cyclodextrin (CD), such as its aqueous solubility, association constant, characteristics in the solid state and crystalline morphology, as well as the stoichiometry of this complex have been determined. The phase-solubility diagram drawn using UV detections belongs to an AN-type. Fluorescence detection and calculation with the modified Benesi-Hidebrond equation provide an 1:2 stoichiometry for the complex. Its apparent stability constant has been determined to be 3203 M -1 by fluorescence technique and confirmed by the calculation from UV spectroscopy. X-ray powder diffractions (XRD) and Scanning Electron Microscopy (SEM) observations showed a clear difference in the crystal morphology of the complex from those of both Gos and β-CD.

  14. Two-photon absorption properties of cationic 1,4-bis(styryl)benzene derivative and its inclusion complexes with cyclodextrins.

    PubMed

    Nag, Okhil Kumar; Nayak, Rati Ranjan; Lim, Chang Su; Kim, In Hong; Kyhm, Kwangseuk; Cho, Bong Rae; Woo, Han Young

    2010-07-29

    Two-photon absorption properties of 1,4-bis{4'-[N,N-bis(6''-trimethylammoniumhexyl)amino]styryl}benzene tetrabromide (C1) and its inclusion complexes (ICs) with cyclodextrins (CDs) have been studied. Upon complexation with CDs, the absorption spectra of C1 showed a slight red shift, whereas the emission spectra showed a blue shift with concomitant increase in the fluorescence quantum efficiency. A Stern-Volmer study using K(3)Fe(CN)(6) as a quencher revealed significant reduction in the photoinduced charge transfer quenching, in accord with the IC formation. Comparison of the spectroscopic results reveals that C1 forms increasingly more stable ICs in the order C1/beta-CD < C1/gamma-CD < C1/(3gamma:beta)-CD (gamma-CD/beta-CD 3:1, mole ratio). Moreover, the two-photon action cross section of C1 increased from 200 GM for C1 to 400 GM for C1/beta-CD, 460 GM for C1/gamma-CD, and 650 GM for C1/(3gamma:beta)-CD, respectively. Furthermore, the two-photon microscopy images of HeLa cells stained with C1 emitted strong two-photon excited fluorescence in the plasma membrane. These results provide a useful guideline for the development of efficient two-photon materials for bioimaging applications.

  15. Lipophilic beta-cyclodextrin cyclic-nitrone conjugate: synthesis and spin trapping studies.

    PubMed

    Han, Yongbin; Liu, Yangping; Rockenbauer, Antal; Zweier, Jay L; Durand, Grégory; Villamena, Frederick A

    2009-08-01

    Nitrone spin traps are commonly employed as probes for the identification of transient radicals in chemical and biological systems using electron paramagnetic resonance (EPR) spectroscopy. Nitrones have also found applications as therapeutic agent in the treatment of radical-mediated diseases. Therefore, a spin trap that incorporates high reactivity to superoxide radical anion (O2(*-)), more persistent superoxide adduct, enhanced bioavailability, and selective targeting in one molecular design is desirable. In this work, the synthesis of a nitrone spin trap, 4, that is tethered via amide bonds to a beta-cyclodextrin (beta-CD) and a dodecyl chain was achieved with the expectation that the beta-cyclodextrin would lead to increased reactivity to O2(*-) and persistent O2(*-) adduct while the lipophilic chain would impart membrane targeting property. The two constitutional racemic isomers, 4a and 4b, were separated using preparative HPLC, and structural analysis and self-aggregation properties were carried out using NMR, induced circular dichroism, dynamic light scattering, transmission electron microscopy, and computational approach. EPR spin trapping of O2(*-) by 4a and 4b was only successful in DMSO and not in an aqueous system, due most likely to the amphiphilic character of 4 that can favor conformations (or aggregation) hindering radical addition to nitrone. Kinetics of formation and decay of the 4a-O2H adduct in polar aprotic solvents show faster reactivity to O2(*-) and more persistent O2(*-) adduct compared to nitrones not conjugated to beta-CD. Computational analysis of 4a and 4b as well as 4a-OOH and 4b-OOH adducts were carried out, and results show that isomerism, both constitutional and stereochemical, affects the orientations of aminoxyl-NO and/or hydroperoxyl groups relative to the beta-CD annulus for optimal H-bond interaction and stability. PMID:19530689

  16. Quercetin/β-cyclodextrin inclusion complex embedded nanofibres: Slow release and high solubility.

    PubMed

    Aytac, Zeynep; Kusku, Semran Ipek; Durgun, Engin; Uyar, Tamer

    2016-04-15

    Electrospinning of polyacrylic acid (PAA) nanofibres (NF) incorporating β-cyclodextrin inclusion complex (β-CD-IC) of quercetin (QU) was performed. Here, β-CD was used as not only the crosslinking agent for PAA nanofibres but also as a host molecule for inclusion of QU. The phase solubility test showed enhanced solubility of QU due to the inclusion complexation; in addition, the stoichiometry of QU/β-CD-IC was determined to be 1:1. Computational modelling studies confirmed that 1:1 and 1:2 complex formation are desirable; 1:1 complex formation was chosen to have higher weight loading of QU. SEM images showed that PAA/QU/β-CD-IC-NF were bead-free and uniform. XRD indicated that PAA/QU/β-CD-IC-NF were amorphous in nature without the crystalline peaks of QU. Comparative results revealed that the release profile of QU from PAA/QU/β-CD-IC-NF was much slower but greater in total than from PAA/QU/β-CD-IC-film. Moreover, high antioxidant activity and photostability of QU was achieved in PAA/QU/β-CD-IC-NF. PMID:26617028

  17. Novel water-soluble fisetin/cyclodextrins inclusion complexes: Preparation, characterization, molecular docking and bioavailability.

    PubMed

    Zhang, Jian-qiang; Jiang, Kun-ming; An, Kun; Ren, Si-hao; Xie, Xiao-guang; Jin, Yi; Lin, Jun

    2015-12-11

    Novel water-soluble inclusion complexes for fisetin (FIT) were developed by introducing β-cyclodextrin (β-CD) and γ-CD. Properties of the obtained complexes, as well as the interactions between each component, were systematically investigated in both solution and solid states by means of ESI-MS, NMR, FT-IR, XRD, DSC, SEM etc. All characterization information demonstrated that FIT/CDs inclusion complexes were formed, and exhibited different spectroscopic features and properties from FIT. A complex with 1:1 stoichiometry of FIT and CDs was confirmed with Job's method. Meanwhile, as supported by molecular modeling calculations, we suggested that phenyl group (C ring) of FIT molecule was included in the CDs cavity from the wide side. Moreover, the water solubility of FIT/CDs was successfully improved from 2.8 mg/mL (in ethanol aqueous solution) to 4.5 mg/mL (FIT/β-CD complex) and 7.8 mg/mL (FIT/γ-CD complex), and higher thermal stability results were shown by thermal analysis for those complexes. Notably, the inclusion complexes displayed almost two times higher cytotoxicity compared to free FIT against Hela and MCF-7 cells. These results suggested that FIT/CDs complexes could be potentially useful in food industry and healthcare area.

  18. Investigation on the inclusion and toxicity of acriflavine with cyclodextrins: A spectroscopic approach

    NASA Astrophysics Data System (ADS)

    Manivannan, C.; Meenakshi Sundaram, K.; Sundararaman, M.; Renganathan, R.

    2014-03-01

    Acriflavine hydrochloride (AFN) is a prospective drug worn in the eradication of HIV1 infection. The toxicity and adverse side effects renders the potent drug to limits its usage. However, to overcome the dilemma we have aimed to select carriers with great complexation efficiencies in different cyclodextrins (CDs) of varying cavity size. The interaction of AFN with α, β and γ-CDs were investigated using absorption and steady state as well as lifetime measurements. From the obtained data it was found that AFN fits in the cavity of α and β-CDs but unable to form inclusion complex with γ-CD. The effect of quencher molecules during the inclusion phenomena of AFN with CDs was explored via steady state measurements. The nature of binding forces responsible for the inclusion of AFN with CDs was discussed by using thermodynamic parameters. Using Benesi-Hildebrand equation the stoichiometry of AFN with CDs was predominantly found to be 1:1. To get deeper in situ, the in vitro toxicity of AFN and its complexation product were probed by Artemia salina sp. The toxicity of AFN was reduced when complexed with α and β-CDs.

  19. Spectroscopic studies of inclusion complexes of methyl- p-dimethylaminobenzoate and its ortho derivative with α- and β-cyclodextrins

    NASA Astrophysics Data System (ADS)

    Lazarowska, Agata; Józefowicz, Marek; Heldt, Janina R.; Heldt, Józef

    2012-02-01

    The effects of α- and β-cyclodextrins (CDs) on the both emission modes (LE - locally excited and TICT - twisted intramolecular charge transfer) of the fluorescence spectrum of methyl- p-dimethylaminobenzoate (I) and its o-methoxy (II) derivative in aqueous solution have been investigated using steady-state and time-resolved fluorescence techniques. It is found that the intensity of both fluorescence bands increases with increasing concentration of α- and β-CD. The stoichiometries and equilibrium constants of the fluorophore-cyclodextrin inclusion complexes have been determined by steady-state fluorescence measurements. Performed spectroscopic studies demonstrate that in the case of I in α-CD and β-CD, both 1:1 and 1:2 inclusion complexes are formed, whereas only 1:1 inclusion complex is formed between II and β-CD.

  20. Molecularly imprinted poly beta-cyclodextrin polymer: application in protein refolding.

    PubMed

    Ali Esmaeili, Mohammad; Yazdanparast, Razieh

    2007-06-01

    Regarding our previous report on refolding of alkaline phosphatase [Yazdanparast and Khodagholi, 2005 Arch. Biochem. Biophys] it was found that in spite of the anti-aggregatory effect of 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS), a zwitteronic detergent, the recovered activity was almost the same as the recovered activity obtained through the unassisted approach. The low recovery yield is probably due to the bulky groups of the detergent that interfere with its entrance into the small cavity of the stripping agent, cyclodextrin, implying that the stripping of detergent molecules from the detergent-protein complexes plays a major role in successful refolding processes. To improve the efficiency of CHAPS stripping, we evaluated, for the first time, the stripping potential of a molecular imprinting polymer designed to replace beta-CD. In this approach, CHAPS was used as the template and the refolding of GuHCl denatured alkaline phosphatase was studied. Our results indicated that under the optimally developed refolding environment and similar to stripping by soluble beta-CD, a refolding yield of 79% was obtained for denatured alkaline phosphatase using 20 mg/ml of the molecularly imprinted poly (beta-CD) polymer. The major advantage of the new stripping agent, besides of its recycling option and ease of separation from the finished product, is its high potential of preventing aggregate formation. Based on these results, it seems that the new stripping strategy can constitute an ideal approach for refolding of proteins at much lower industrial costs compared to stripping with soluble beta-cyclodextrin.

  1. Beta-cyclodextrins as carriers of monoterpenes into the hemolymph of the honey bee (Apis mellifera) for integrated pest management.

    PubMed

    LeBlanc, Blaise W; Boué, Stephen; De-Grandi Hoffman, Gloria; Deeby, Thomas; McCready, Holly; Loeffelmann, Kevin

    2008-09-24

    The Varroa mite ( Varroa destructor) is becoming ubiquitous worldwide and is a serious threat to honey bees. The cultivation of certain food crops are at risk. The most noted acaricides against Varroa mites are tau-fluvaninate and coumaphos, but the mites are showing resistance. Since these insecticides are used in the proximity of honey, it is desirable to use natural alternatives. Monoterpenoids such as thymol and carvacrol, that are constituents of oil of thyme and oil of origanum, show promise as acaricides against the Varroa mite ( Varroa destructor), but the delivery of these compounds remains a challenge due to the low water solubility and uncontrolled release into the colony. Beta-cyclodextrin (beta-CD) inclusion complexes of thymol, oil of origanum, and carvacrol were prepared on a preparative scale. Competitive binding was studied by fluorescence spectroscopy by using 6- p-toluidinylnaphthalene-2-sulfonate as a fluorescent probe. The complexes were characterized, and the competitive binding described by (1)H and (13)C NMR spectroscopy chemical shifts. The toxicity of beta-CD and the prepared complexes in enriched sucrose syrup was studied by conducting caged honey bee ( Apis mellifera) feeding trials. After the first and second weeks of feeding, hemolymph and gut tissue samples were acquired from the caged bee study. The levels of thymol and carvacrol were quantified by solid-phase microextraction gas chromatography mass spectroscopy, using an optimized procedure we developed. High (mM) levels of thymol and carvacrol were detected in bee tissues without any imposed toxicity to the bees, in an effort to deter Varroa mites from feeding on honey bee hemolymph.

  2. Synthesis of anatase TiO2 nanoparticles with beta-cyclodextrin as a supramolecular shell.

    PubMed

    Li, Landong; Sun, Xiaohong; Yang, Yali; Guan, Naijia; Zhang, Fuxiang

    2006-11-20

    We report a novel, green hydrothermal-synthesis route to well-dispersed anatase TiO2 nanoparticles with particle sizes of 9-16 nm in the presence of beta-CD (beta-cyclodextrin). During the synthesis process, the CD-containing synthesis mixture assembled in both longitudinal and latitudinal directions. Driven by the interaction between molecules, the beta-CDs assembled in the longitudinal direction to form long-chain compounds, whereas in the latitudinal direction, they tended to form regular aggregates through coordination with the Ti species from the hydrolysis of tetrabutyl titanate. In view of the effect of the coordination and the steric hindrance of beta-CDs as a supramolecular shell, homogeneous nuclei and slow growth of TiO2 crystals during the synthesis process was observed, which was responsible for the formation of uniform TiO2 nanoparticles. The low beta-CD dosage and the high product yield (>90%) demonstrated well the potential of this synthesis route in the large-scale industrial production of anatase nanoparticles.

  3. Fluorometric and theoretical studies on inclusion complexes of β-cyclodextrin and D-, L-phenylalanine.

    PubMed

    Aree, Thammarat; Arunchai, Rungthiwa; Koonrugsa, Narongsak; Intasiri, Amarawan

    2012-10-01

    Inclusion complexes of β-cyclodextrin (β-CD) with L- and D-phenylalanine (Phe) have been characterized in solution by fluorometry and in gas phase by semiempirical PM3 calculations. The unimolar stoichiometric ratio of both β-CD-L-Phe and β-CD-D-Phe complexes and the stability constants (K) were deduced from fluorometric titrations. The β-CD-L-Phe complex is more stable than the β-CD-D-Phe complex as indicated by the larger K values, 21.1 vs. 6.86 M(-1). This is consistent with the stabilization energies (ΔE(stb)) and inclusion geometries obtained from PM3 calculations. The β-CD-L-Phe complex with L-Phe residing in the central β-CD cavity and pointing its COOH group downwards to the O6 end has ΔE(stb)=-62.7 kJ mol(-1), whereas the β-CD-D-Phe complex with D-Phe placing at 3Å beneath the β-CD O4-plane and pointing its COOH group upwards to the O2/O3 end has ΔE(stb)=-53.3 kJ mol(-1). The unison of host-guest intermolecular hydrogen bonds, hydrophobic interactions and molecular deformations plays an essential role in forming and stabilizing the inclusion complexes. Our results show that the β-CD-L-Phe and β-CD-D-Phe inclusion complexes are relatively stable and differentiable, suggesting the applications of CDs in foods and drugs.

  4. Fluorometric and theoretical studies on inclusion complexes of β-cyclodextrin and D-, L-phenylalanine

    NASA Astrophysics Data System (ADS)

    Aree, Thammarat; Arunchai, Rungthiwa; Koonrugsa, Narongsak; Intasiri, Amarawan

    2012-10-01

    Inclusion complexes of β-cyclodextrin (β-CD) with L- and D-phenylalanine (Phe) have been characterized in solution by fluorometry and in gas phase by semiempirical PM3 calculations. The unimolar stoichiometric ratio of both β-CD-L-Phe and β-CD-D-Phe complexes and the stability constants (K) were deduced from fluorometric titrations. The β-CD-L-Phe complex is more stable than the β-CD-D-Phe complex as indicated by the larger K values, 21.1 vs. 6.86 M-1. This is consistent with the stabilization energies (ΔEstb) and inclusion geometries obtained from PM3 calculations. The β-CD-L-Phe complex with L-Phe residing in the central β-CD cavity and pointing its COOH group downwards to the O6 end has ΔEstb = -62.7 kJ mol-1, whereas the β-CD-D-Phe complex with D-Phe placing at 3 Å beneath the β-CD O4-plane and pointing its COOH group upwards to the O2/O3 end has ΔEstb = -53.3 kJ mol-1. The unison of host-guest intermolecular hydrogen bonds, hydrophobic interactions and molecular deformations plays an essential role in forming and stabilizing the inclusion complexes. Our results show that the β-CD-L-Phe and β-CD-D-Phe inclusion complexes are relatively stable and differentiable, suggesting the applications of CDs in foods and drugs.

  5. Study on β-cyclodextrin inclusion of Zn(II) aromatic complex and its analytical application

    NASA Astrophysics Data System (ADS)

    Ding, Lixiu; He, Jiang; Fu, Junkai; Zhang, Jinlong

    2010-02-01

    A new β-cyclodextrin (β-CD) inclusion compound Zn(2H1NA) 2·2β-CD (2H1NA = 2-hydroxy-1-naphthoic acid) was prepared. The structure was characterized by 1H NMR, IR, the fluorescence spectra, thermogravimetric analysis (TG-DTA) and elementary analysis. Meanwhile, the mechanism of the formation of the supramolecular system (2H1NA:Zn(II):β-CD) was studied and discussed by spectrofluorimetry. The results showed that the naphthalene rings of the Zn(II) aromatic complex Zn(2H1NA) 2 were encapsulated within the β-CD's cavity to form a 2:1 stoichiometry host-guest compound. The inclusion constant calculated was 1.27 × 10 4 (L/mol) 2. A spectrofluorimetric method for the determination of 2H1NA in bulk aqueous solution in the presence of β-CD was developed based on the great enhancement of the fluorescence intensity of 2H1NA. The linear relationship was obtained in the range of 9.00 × 10 -7 to 2.50 × 10 -5 mol/L and the detection limit was 8.00 × 10 -7 mol/L. The proposed method was successfully applied to determine 2H1NA in waste water with recoveries of 97-104%.

  6. An inclusion complex of eugenol into β-cyclodextrin: Preparation, and physicochemical and antifungal characterization.

    PubMed

    Gong, Liang; Li, Taotao; Chen, Feng; Duan, Xuewu; Yuan, Yunfei; Zhang, Dandan; Jiang, Yueming

    2016-04-01

    The inclusion of eugenol (EG) into β-cyclodextrin (βCD), its structural characterization and antifungal activity, and mode of action for control of Peronophythora litchii in postharvest fresh litchi fruits is described. Nuclear magnetic resonance spectra revealed chemical shifts in H-3 and H-5 protons of βCD, indicating EG inclusion into the lipophilic cavity of βCD. In vitro assays showed βCD-EG significantly inhibited P. litchii colony growth in a concentration- and time-dependent manner (MIC100=0.2g). In vivo assays showed βCD-EG significantly (p<0.05) reduced the decay index of treated fresh litchi fruits. After exposure to βCD-EG, the surface of P. litchii hyphae and/or sporangiophores became wrinkled, with folds and breakage observed by scanning electron microscopy. Damage to hyphal and/or sporangiophore cell walls and membrane structures post-treatment with βCD-EG was confirmed by transmission electron microscopy. Therefore, βCD-EG shows great potential as a controlled-release agent against P. litchii.

  7. Antibacterial electrospun poly(lactic acid) (PLA) nanofibrous webs incorporating triclosan/cyclodextrin inclusion complexes.

    PubMed

    Kayaci, Fatma; Umu, Ozgun C O; Tekinay, Turgay; Uyar, Tamer

    2013-04-24

    Solid triclosan/cyclodextrin inclusion complexes (TR/CD-IC) were obtained and then incorporated in poly(lactic acid) (PLA) nanofibers via electrospinning. α-CD, β-CD, and γ-CD were tested for the formation of TR/CD-IC by a coprecipitation method; however, the findings indicated that α-CD could not form an inclusion complex with TR, whereas β-CD and γ-CD successfully formed TR/CD-IC crystals, and the molar ratio of TR to CD was found to be 1:1. The structural and thermal characteristics of TR/CD-IC were investigated by (1)H NMR, FTIR, XRD, DSC, and TGA studies. Then, the encapsulation of TR/β-CD-IC and TR/γ-CD-IC in PLA nanofibers was achieved. Electrospun PLA and PLA/TR nanofibers obtained for comparison were uniform, whereas the aggregates of TR/CD-IC crystals were present and distributed within the PLA fiber matrix as confirmed by SEM and XRD analyses. The antibacterial activity of these nanofibrous webs was investigated. The results indicated that PLA nanofibers incorporating TR/CD-IC showed better antibacterial activity against Staphylococcus aureus and Escherichia coli bacteria compared to PLA nanofibers containing only TR without CD-IC. Electrospun nanofibrous webs incorporating TR/CD-IC may be applicable in active food packaging due to their very high surface area and nanoporous structure as well as efficient antibacterial property.

  8. An inclusion complex of eugenol into β-cyclodextrin: Preparation, and physicochemical and antifungal characterization.

    PubMed

    Gong, Liang; Li, Taotao; Chen, Feng; Duan, Xuewu; Yuan, Yunfei; Zhang, Dandan; Jiang, Yueming

    2016-04-01

    The inclusion of eugenol (EG) into β-cyclodextrin (βCD), its structural characterization and antifungal activity, and mode of action for control of Peronophythora litchii in postharvest fresh litchi fruits is described. Nuclear magnetic resonance spectra revealed chemical shifts in H-3 and H-5 protons of βCD, indicating EG inclusion into the lipophilic cavity of βCD. In vitro assays showed βCD-EG significantly inhibited P. litchii colony growth in a concentration- and time-dependent manner (MIC100=0.2g). In vivo assays showed βCD-EG significantly (p<0.05) reduced the decay index of treated fresh litchi fruits. After exposure to βCD-EG, the surface of P. litchii hyphae and/or sporangiophores became wrinkled, with folds and breakage observed by scanning electron microscopy. Damage to hyphal and/or sporangiophore cell walls and membrane structures post-treatment with βCD-EG was confirmed by transmission electron microscopy. Therefore, βCD-EG shows great potential as a controlled-release agent against P. litchii. PMID:26593497

  9. Characterization of the Supermolecular Structure of Polydatin/6-O-α-Maltosyl-β-cyclodextrin Inclusion Complex.

    PubMed

    Liu, Benguo; Li, Yun; Xiao, Huizhi; Liu, Yonglan; Mo, Haizhen; Ma, Hanjun; Liang, Guizhao

    2015-06-01

    Polydatin is the main bioactive ingredient in many medicinal plants, such as Hu-zhang (Polygonum cuspidatum), with many bioactivities. However, its poor aqueous solubility restricts its application in functional food. In this work, 6-O-α-Maltosyl-β-cyclodextrin (Malt-β-CD), a new kind of β-CD derivative was used to enhance the aqueous solubility and stability of polydatin by forming the inclusion complex. The phase solubility study showed that polydatin and Malt-β-CD could form the complex with the stoichiometric ratio of 1:1. The supermolecular structure of the polydatin/Malt-β-CD complex was characterized by ultraviolet-visible spectroscopy (UV), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), thermogravimetric/differential scanning calorimetry (TG/DSC), and proton nuclear magnetic resonance ((1) H-NMR) spectroscopy. The changes of the characteristic spectral and thermal properties of polydatin suggested that polydatin could entrap inside the cavity of Malt-β-CD. Furthermore, to reasonably understand the complexation mode, the supermolecular structure of polydatin/Malt-β-CD inclusion complex was postulated by a molecular docking method based on Autodock 4.2.3. It was clearly observed that the ring B of polydatin oriented toward the narrow rim of Malt-β-CD with ring A and glucosyl group practically exposed to the wide rim by hydrogen bonding, which was in a good agreement with the spectral data. PMID:25916244

  10. Enantiomers resolution in capillary zone electrophoresis by using cyclodextrins.

    PubMed

    Schutzner, W; Fanali, S

    1992-01-01

    Cyclodextrins added to the background electrolyte are shown to be useful for the resolution of racemic compounds in their enantiomers. Several parameters have to be controlled in order to achieve resolution, e.g., cyclodextrin type, concentration, analyte shape, as well as column temperature. The resolution of nor-epinephrine, epinephrine and isoproterenol in their enantiomers decreased by increasing the column temperature. Octopamine and ketamine have been resolved by supporting the background electrolyte with 2, 6-di-O-methyl-beta-cyclodextrin. In spite of the stronger inclusion-complex of ketamine than octopamine with the modified cyclodextrin its resolution was not satisfactory.

  11. [Solubilization Specificities Interferon beta-1b from Inclusion Bodies].

    PubMed

    Zhuravko, A S; Kononova, N V; Bobruskin, A I

    2015-01-01

    A new solubilization method of recombinant interferon beta-1b (IFNβ-1b) from the inclusion bodies was developed. This method allows to extract the target protein selectively in the solutions of different alcohols, such as ethanol, propanol and isopropanol. It was shown that the more effective IFNβ-1b solubilization was achieved in the 55% propanol solution. This method allowed to extract the target protein from inclusion bodies around 85-90%, and significantly reduced Escherichia coli content in the solubilizate, in comparison with standard methods.

  12. Beta-cyclodextrin induced room temperature phosphorescence from 1-bromonaphthalene in the presence of naphthalene and 1-butanol

    NASA Astrophysics Data System (ADS)

    Du, Xin-Zhen; Zhang, Yong; Huang, Xian-Zhi; Li, Yao-Qun; Jiang, Yun-Bao; Chen, Guo-Zhen

    1996-10-01

    Intense room temperature phosphorescence (RTP) from host-guest inclusion complex of beta-cyclodextrin (β-CD) with 1-bromonaphthalene (1-BrN), stabilized by naphthalene (N) and 1-butanol (B), has been investigated. The spectral characteristics of luminescence emission and optimal conditions involved are reported. It has been confirmed that N and B are incorporated into the nonpolar cavity of β-CD as the second and third guests. The extra space inside the cavity is more filled by N and B, and δ-CD more effectively shields 1-BrN from quencher in aqueous solution. B completely hinders the formation of N excimer. Greater rigidity of the complex was achieved. Consequently, much more intense fluorescence and phosphorescence appear in comparison with the ternary β-CD:1-BrN:B complex. The limit of detection is 7.38 × 10 -8mol 1 -1 for 1-BrN and 1.36 × 10 -6mol 1 -1 for N.

  13. Preparation and application of poly(dimethylsiloxane)/beta-cyclodextrin solid-phase microextraction fibers.

    PubMed

    Fu, Yue-Li; Hu, Yu-Ling; Zheng, Yan-Jie; Li, Gong-Ke

    2006-11-01

    A novel poly(dimethylsiloxane)/beta-cyclodextrin (PDMS/beta-CD) coating was prepared for solid-phase microextraction (SPME). The PDMS/beta-CD coating proved to have a porous structure, providing high surface areas and allowing for high extraction efficiency. The coating had a high thermal stability (340 degrees C) and a long lifetime due to its chemical binding to the fiber surface. Polar phenols and amines were used to evaluate the character of the coating fiber by headspace (HS) extraction and thermal desorption, followed by GC-FID analysis. Parameters that affected the extraction process were investigated; these include extraction time and temperature, desorption time, pH, and ionic strength of the solution. For phenols, the range of linearity of the method was 4-500 microg/L and the LOD was 1.3-2.1 microg/L. For amines, the range of linearity was 1-1000 microg/L and the LOD was 1.2-2.8 microg/L. The presence of beta-CD not only increases the thermal stability of the fiber coating, but also enhances its selectivity. Compared with commercially available SPME fibers, the new phases show better selectivity and sensitivity towards polar compounds. PMID:17313110

  14. Host-guest inclusion complex of mesalazine and β-cyclodextrin and spectrofluorometric determination of mesalazine.

    PubMed

    Elbashir, Abdalla A; Altayib Alasha Abdalla, Fatima; Aboul-Enein, Hassan Y

    2015-06-01

    The supramolecular interaction of mesalazine (MSZ) and β-cyclodextrin (β-CD) has been examined by ultraviolet-visible (UV-vis) light, infra-red (IR) light and fluorescence spectroscopy. The formation of an inclusion complex has been confirmed based on the changes of the spectral properties. MSZ-β-CD host-guest complex was formed in (1:1) stoichiometry and the inclusion constant (K = 1.359 × 10(2)  L mol(-1) ) was ascertained by typical double reciprocal plots. Furthermore, the thermodynamic parameters (ΔG°, ΔH° and ΔS°) of (MSZ-β-CD) were obtained. Based on the remarkable enhancement of the fluorescence intensity of MSZ produced through complex formation, a simple, accurate, rapid and highly sensitive spectrofluorometric method for the determination of MSZ in aqueous solution in the presence of β-CD was developed. The measurement of relative fluorescence intensity was carried with excitation at 330 nm and emission 493 nm. All variables affecting the reactions were studied and optimized. Beer's law was obeyed in the concentration range 0.1-0.45 µg/mL. Absorbance was found to increase linearly with increasing concentration of MSZ, which is corroborated by the calculated correlation coefficient values of 0.99989. The molar absorptivity, Sandell's sensitivity, detection and quantification limits were calculated. The validity of the described methods was assessed, and the method was successfully applied to the determination of MSZ in its pharmaceutical formulation. In addition, a solid inclusion complex was synthesized by co-precipitation method.

  15. Inclusion complexes of quercetin with three β-cyclodextrins derivatives at physiological pH: spectroscopic study and antioxidant activity.

    PubMed

    Liu, Min; Dong, Lina; Chen, Aiju; Zheng, Yan; Sun, Dezhi; Wang, Xu; Wang, Bingquan

    2013-11-01

    Properties of the inclusion complexes of quercetin (QUE) with sulfobutyl ether-β-cyclodextrin (SBE-β-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD), and methylated-β-cyclodextrin (M-β-CD) in tris-HCl buffer solutions of pH 7.40 were investigated. The stoichiometry and thermodynamic parameters for the complexation process (stability constants K, Gibbs free energy change ΔG, enthalpy change ΔH and entropy change ΔS) were determined using phase-solubility and fluorescence spectra analysis. The thermodynamic studies indicated that the inclusion reactions between QUE and the three β-CDs are enthalpy-driven processes. Proton nuclear magnetic resonance spectroscopy indicated that B-ring, C-ring, and part of A-ring of QUE interact with the cavity of β-CDs. The antioxidant activity of QUE and its inclusion complexes were determined by the scavenging of stable radical DPPH(*). The results showed that the complexed QUE/CDs were more effective than free QUE, with the QUE/SBE-β-CD complex as the best form.

  16. Nanosuspensions Containing Oridonin/HP-β-Cyclodextrin Inclusion Complexes for Oral Bioavailability Enhancement via Improved Dissolution and Permeability.

    PubMed

    Zhang, Xingwang; Zhang, Tianpeng; Lan, Yali; Wu, Baojian; Shi, Zhihai

    2016-04-01

    Chemotherapy via oral route of anticancer drugs offers much convenience and compliance to patients. However, oral chemotherapy has been challenged by limited absorption due to poor drug solubility and intestinal efflux. In this study, we aimed to develop a nanosuspension formulation of oridonin (Odn) using its cyclodextrin inclusion complexes to enhance oral bioavailability. Nanosuspensions containing Odn/2 hydroxypropyl-β-cyclodextrin inclusion complexes (Odn-CICs) were prepared by a solvent evaporation followed by wet media milling technique. The nanosuspensions were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and dissolution. The resulting nanosuspensions were approximately 313.8 nm in particle size and presented a microcrystal morphology. Nanosuspensions loading Odn-CICs dramatically enhanced the dissolution of Odn. Further, the intestinal effective permeability of Odn was markedly enhanced in the presence of 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and poloxamer. Bioavailability studies showed that nanosuspensions with Odn-CICs can significantly promote the oral absorption of Odn with a relative bioavailability of 213.99% (Odn suspensions as reference). Odn itself possesses a moderate permeability and marginal intestinal metabolism. Thus, the enhanced bioavailability for Odn-CIC nanosuspensions can be attributed to improved dissolution and permeability by interaction with absorptive epithelia and anti-drug efflux. Nanosuspensions prepared from inclusion complexes may be a promising approach for the oral delivery of anticancer agents.

  17. In Situ Visualization of the Local Photothermal Effect Produced on α-Cyclodextrin Inclusion Compound Associated with Gold Nanoparticles.

    PubMed

    Silva, Nataly; Muñoz, Camila; Diaz-Marcos, Jordi; Samitier, Josep; Yutronic, Nicolás; Kogan, Marcelo J; Jara, Paul

    2016-12-01

    Evidence of guest migration in α-cyclodextrin-octylamine (α-CD-OA) inclusion compound (IC) generated via plasmonic heating of gold nanoparticles (AuNPs) has been studied. In this report, we demonstrate local effects generated by laser-mediated irradiation of a sample of AuNPs covered with inclusion compounds on surface-derivatized glass under liquid conditions by atomic force microscopy (AFM). Functionalized AuNPs on the glass and covered by the ICs were monitored by recording images by AFM during 5 h of irradiation, and images showed that after irradiation, a drastic decrease in the height of the AuNPs occurred. The absorption spectrum of the irradiated sample showed a hypsochromic shift from 542 to 536 nm, evidence suggesting that much of the population of nanoparticles lost all of the parts of the overlay of ICs due to the plasmonic heat generated by the irradiation. Mass spectrometry matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) performed on a sample containing a collection of drops obtained from the surface of the functionalized glass provided evidence that the irradiation lead to disintegration of the ICs and therefore exit of the octylamine molecule (the guest) from the cyclodextrin cavity (the matrix). Graphical Abstract Atomic Force Microscopy observation of the disintegration of a cyclodextrin inclusion compound by gold nanoparticles photothermal effect. PMID:27053258

  18. Inclusion complexes of quercetin with three β-cyclodextrins derivatives at physiological pH: Spectroscopic study and antioxidant activity

    NASA Astrophysics Data System (ADS)

    Liu, Min; Dong, Lina; Chen, Aiju; Zheng, Yan; Sun, Dezhi; Wang, Xu; Wang, Bingquan

    2013-11-01

    Properties of the inclusion complexes of quercetin (QUE) with sulfobutyl ether-β-cyclodextrin (SBE-β-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD), and methylated-β-cyclodextrin (M-β-CD) in tris-HCl buffer solutions of pH 7.40 were investigated. The stoichiometry and thermodynamic parameters for the complexation process (stability constants K, Gibbs free energy change ΔG, enthalpy change ΔH and entropy change ΔS) were determined using phase-solubility and fluorescence spectra analysis. The thermodynamic studies indicated that the inclusion reactions between QUE and the three β-CDs are enthalpy-driven processes. Proton nuclear magnetic resonance spectroscopy indicated that B-ring, C-ring, and part of A-ring of QUE interact with the cavity of β-CDs. The antioxidant activity of QUE and its inclusion complexes were determined by the scavenging of stable radical DPPH*. The results showed that the complexed QUE/CDs were more effective than free QUE, with the QUE/SBE-β-CD complex as the best form.

  19. In Situ Visualization of the Local Photothermal Effect Produced on α-Cyclodextrin Inclusion Compound Associated with Gold Nanoparticles.

    PubMed

    Silva, Nataly; Muñoz, Camila; Diaz-Marcos, Jordi; Samitier, Josep; Yutronic, Nicolás; Kogan, Marcelo J; Jara, Paul

    2016-12-01

    Evidence of guest migration in α-cyclodextrin-octylamine (α-CD-OA) inclusion compound (IC) generated via plasmonic heating of gold nanoparticles (AuNPs) has been studied. In this report, we demonstrate local effects generated by laser-mediated irradiation of a sample of AuNPs covered with inclusion compounds on surface-derivatized glass under liquid conditions by atomic force microscopy (AFM). Functionalized AuNPs on the glass and covered by the ICs were monitored by recording images by AFM during 5 h of irradiation, and images showed that after irradiation, a drastic decrease in the height of the AuNPs occurred. The absorption spectrum of the irradiated sample showed a hypsochromic shift from 542 to 536 nm, evidence suggesting that much of the population of nanoparticles lost all of the parts of the overlay of ICs due to the plasmonic heat generated by the irradiation. Mass spectrometry matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) performed on a sample containing a collection of drops obtained from the surface of the functionalized glass provided evidence that the irradiation lead to disintegration of the ICs and therefore exit of the octylamine molecule (the guest) from the cyclodextrin cavity (the matrix). Graphical Abstract Atomic Force Microscopy observation of the disintegration of a cyclodextrin inclusion compound by gold nanoparticles photothermal effect.

  20. Inclusion complex of erlotinib with sulfobutyl ether-β-cyclodextrin: Preparation, characterization, in silico, in vitro and in vivo evaluation.

    PubMed

    Devasari, Naresh; Dora, Chander Parkash; Singh, Charan; Paidi, Sharan Reddy; Kumar, Vivek; Sobhia, Masilamani Elizabeth; Suresh, Sarasija

    2015-12-10

    The aim of the study was to investigate the impact of erlotinib sulfobutyl ether beta-cyclodextrin complex (ERL-SBE-β-CD) on ERL dissolution rate and oral bioavailability. Preliminary comparative phase solubility study indicated ERL exhibited maximum solubility in SBE-β-CD solution. Optimal experimental design confirmed freeze drying of SBE-β-CD:ERL in 1:1.05 molar ratio as the optimum method. Differential scanning calorimetry (DSC), Fourier transformation infrared spectroscopy (FT-IR), powder X-ray diffractometry (PXRD), proton nuclear magnetic resonance ((1)H NMR) and two-dimensional rotating-frame Overhauser effect spectroscopy (2D ROESY NMR) confirmed the inclusion complexation. The in silico computational study, employed to analyze the comparative interactions of ERL with SBE-β-CD and β-CD, indicated ease of ERL-SBE-β-CD complexation. In vitro dissolution and in vivo bioavailability studies further confirmed the ERL-SBE-β-CD as a valuable approach to enhance ERL oral bioavailability with 3.6-fold increase in relative oral bioavailability with higher Cmax (134.29 ± 36.51 vs. 42.36 ± 1.75 μg/ml) and AUC0-∞ (2103.47 ± 156.75 vs.580.43 ± 71.91 μg/ml h) over the free drug. The complex exhibited 3.2-fold increase in Cmax with 5.4-fold decrease in Tmax (0.5 ± 0.2 vs. 2.7 ± 0.8h) in comparison to pure ERL. Thus, ERL-SBE-β-CD complexation exhibits a potential to enhance oral bioavailability of ERL leading to reduce dose and dose-related side effects. PMID:26428157

  1. Separation of chiral polychlorinated biphenyls by micellar electrokinetic chromatography using beta- and gamma-cyclodextrin mixtures in the separation buffer.

    PubMed

    Marina, M L; Benito, I; Díez-Masa, J C; González, M J

    1996-11-01

    Chiral polychlorinated biphenyls (PCBs) 45, 84, 88, 91, 95, 132, 136, 139, 149, 171, 183 and 196 were separated each in its two enantiomers by cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC). Mixtures of beta- and gamma-cyclodextrins were used as chiral modifiers in a 2-(N-cyclohexylamino)ethanesulphonic acid (CHES) buffer containing urea and sodium dodecyl sulphate (SDS) micelles. Separations of multicomponent mixtures of PCBs into their enantiomers were also performed. A mixture of PCBs 45, 88, 91, 95, 136, 139, 149 and 196 was separated into all sixteen enantiomers in an analysis time of approx. 35 min.

  2. Biquinolino-modified beta-cyclodextrin dimers and their metal complexes as efficient fluorescent sensors for the molecular recognition of steroids.

    PubMed

    Liu, Yu; Song, Yun; Chen, Yong; Li, Xue-Qing; Ding, Fei; Zhong, Rui-Qin

    2004-08-01

    A series of bridged beta-cyclodextrin (beta-CyD) dimers possessing functional tethers of various lengths was synthesized in moderate yield by the treatment of 2,2'-biquinoline- 4,4'-dicarboxylic dichloride with beta-CyD or mono[6-oligo(ethylenediamino)-6-deoxy]-beta-CyDs. The products were 2,2'-biquinoline-4,4'-dicarboxy-bridged bis(6-O-beta-CyD) (8), N,N'-bis(2-aminoethyl)-2,2'-biquinoline-4,4'-dicarboxamide-bridged bis(6-amino-6-deoxy-beta-CyD) (9), and N,N'-bis(5-amino-3-azapentyl)-2,2'-biquinoline-4,4'-dicarboxamide-bridged bis(6-amino-6-deoxy-beta-CyD) (10). The reaction of 8-10 with copper perchlorate give their copper(II) complexes 11-13 in satisfactory yields of over 77 %. All the bis(beta-CyD)s 8-13 act as efficient fluorescent sensors and display remarkable fluorescence enhancement upon addition of optically inert steroids. The inclusion complexation behaviors of 8-13 when treated with the representative steroids cholate (14), deoxycholate (15), and glycocholate (16) in aqueous solution at 25 degrees C were investigated by means of UV/Vis spectroscopy, conductivity and fluorescence measurements, circular dichroism spectroscopy, and 2D NMR spectroscopy. The tether length of bis(beta-CyD) 9 allows it to adopt a cooperative host-tether-guest binding mode in which the spacer and guest are co-included in the two CyD cavities. As a result of this cooperation, 9 has a stability constant (K(s)) about 2x10(2) times higher than that of monomodified beta-CyD 4 for inclusion complexation with cholate. Metallooligo(beta-CyD)s with four beta-CyD units have enhanced binding abilities compared with monomodified beta-CyDs. These metallo compounds have binding affinities for guest steroids that are up to 50-4.1x10(3) times higher than those of CyDs 2-4. The guest-induced fluorescence enhancement of bis(CyD)s opens a new channel for the design of sensor materials. The complex stability constants of these compounds are discussed from the viewpoint of induced-fit interaction

  3. Solid inclusion complexes of vanillin with cyclodextrins: their formation, characterization, and high-temperature stability.

    PubMed

    Kayaci, Fatma; Uyar, Tamer

    2011-11-01

    This study reports the formation of solid vanillin/cyclodextrin inclusion complexes (vanillin/CD ICs) with the aim to enhance the thermal stability and sustained release of vanillin by inclusion complexation. The solid vanillin/CD ICs with three types of CDs (α-CD, β-CD, and γ-CD) were prepared using the freeze-drying method; in addition, a coprecipitation method was also used in the case of γ-CD. The presence of vanillin in CD ICs was confirmed by FTIR and (1)H NMR studies. Moreover, (1)H NMR study elucidated that the complexation stoichiometry for both vanillin/β-CD IC and vanillin/γ-CD IC was a 1:1 molar ratio, whereas it was 0.625:1 for vanillin/α-CD IC. XRD studies have shown channel-type arrangement for CD molecules, and no diffraction peak for free vanillin was observed for vanillin/β-CD IC and vanillin/γ-CD IC, indicating that complete inclusion complexation was successfully achieved for these CD ICs. In the case of vanillin/α-CD IC, the sample was mostly amorphous and some uncomplexed vanillin was present, suggesting that α-CD was not very effective for complexation with vanillin compared to β-CD and γ-CD. Furthermore, DSC studies for vanillin/β-CD IC and vanillin/γ-CD IC have shown no melting point for vanillin, elucidating the true complex formation, whereas a melting point for vanillin was recorded for vanillin/α-CD IC, confirming the presence of some uncomplexed vanillin in this sample. TGA thermograms indicated that thermal evaporation/degradation of vanillin occurred over a much higher temperature range (150-300 °C) for vanillin/CD ICs samples when compared to pure vanillin (80-200 °C) or vanillin/CD physical mixtures, signifying that the thermal stability of vanillin was increased due to the inclusion complexation with CDs. Moreover, headspace GC-MS analyses indicated that the release of vanillin was sustained at higher temperatures in the case of vanillin/CD ICs due to the inclusion complexation when compared to vanillin

  4. Stability and spatial arrangement of the 2,4-dichlorophenoxyacetic acid and β-cyclodextrin inclusion compound: A theoretical study

    NASA Astrophysics Data System (ADS)

    Pereira, Robson A.; Anconi, Cleber P. A.; Nascimento, Clebio S.; De Almeida, Wagner B.; Dos Santos, Hélio F.

    2015-07-01

    The present letter reports results from a comprehensive theoretical analysis of the inclusion process involving 2,4-dichlorophenoxyacetic acid (2,4-D) and β-cyclodextrin (β-CD) for which the experimental data of formation is available. Spatial arrangement and stabilization energies were evaluated in gas phase and aqueous solution through density functional theory (DFT) and through the use of SMD implicit solvation approach. The discussed methodology was applied to predict the stability and identify the most favorable form (deprotonated or neutral) as well as the most probable spatial arrangement of the studied inclusion compound.

  5. Beta-cyclodextrins conjugated magnetic Fe3O4 colloidal nanoclusters for the loading and release of hydrophobic molecule

    NASA Astrophysics Data System (ADS)

    Lv, Shaonan; Song, Yubei; Song, Yaya; Zhao, Zhigang; Cheng, Changjing

    2014-06-01

    Herein, we report a facile method to prepare beta-cyclodextrin (β-CD)-conjugated magnetic Fe3O4 colloidal nanocrystal clusters (Fe3O4@GLY-CD) using (3-glycidyloxypropyl) trimethoxysilane (GLY) as the intermediate linker. The resulting Fe3O4@GLY-CD was characterized by several methods including Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and vibrating sample magnetometer (VSM). In addition, the loading and release properties of the synthesized Fe3O4@GLY-CD for the hydrophobic molecule 8-anilino-1-naphthalenesulfonic acid ammonium salt (ANS) were also investigated. The results show that the Fe3O4@GLY-CD has a spherical structure with an average diameter of 186 nm and high saturated magnetism of 51.2 emu/g. The grafting of β-CD onto Fe3O4 colloidal nanocrystal clusters can markedly increase the loading capacity of ANS because of β-CD/ANS inclusion complex formation. The in vitro delivery profile shows that the release of ANS from the Fe3O4@GLY-CD nanosystem exhibits an initial burst followed by a slow and steady release. Moreover, Fe3O4@GLY-CD also demonstrates a temperature-dependent release behavior for ANS owing to the effect of temperature on the association constants of β-CD/ANS inclusion complexes. The developed magnetic hybrid nanomaterial is expected to find potential applications in several fields including separation science and biomedicine.

  6. Quantification of Randomly-methylated-{beta}-cyclodextrin effect on liposome: An ESR study

    SciTech Connect

    Grammenos, A.; Bahri, M.A.; Guelluy, P.H.; Piel, G.; Hoebeke, M.

    2009-12-04

    In the present work, the effect of Randomly-methylated-{beta}-cyclodextrin (Rameb) on the microviscosity of dimyristoyl-L-{alpha} phosphatidylcholine (DMPC) bilayer was investigated using the electron spin resonance (ESR) technique. The ability of Rameb to extract membrane cholesterol was demonstrated. For the first time, the percentage of cholesterol extracted by Rameb from cholesterol doped DMPC bilayer was monitored and quantified throughout a wide Rameb concentration range. The effect of cholesterol on the inner part of the membrane was also investigated using 16-doxyl stearic acid spin label (16-DSA). 16-DSA seems to explore two different membrane domains and report their respective microviscosities. ESR experiments also establish that the presence of 30% of cholesterol in DMPC liposomes suppresses the jump in membrane fluidity at lipids phase-transition temperature (23.9 {sup o}C).

  7. Cleaning efficacy of hydroxypropyl-beta-cyclodextrin for biofouling reduction on reverse osmosis membranes.

    PubMed

    Alayande, Abayomi Babatunde; Kim, Lan Hee; Kim, In S

    2016-01-01

    In this study, an environmentally friendly compound, hydroxypropyl-beta-cyclodextrin (HP-β-CD) was applied to clean reverse osmosis (RO) membranes fouled by microorganisms. The cleaning with HP-β-CD removed the biofilm and resulted in a flux recovery ratio (FRR) of 102%. As cleaning efficiency is sometimes difficult to determine using flux recovery data alone, attached bacterial cells and extracellular polymeric substances (EPS) were quantified after cleaning the biofouled membrane with HP-β-CD. Membrane surface characterization using scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared (ATR-FTIR) and atomic force microscopy (AFM) confirmed the effectiveness of HP-β-CD in removal of biofilm from the RO membrane surface. Finally, a comparative study was performed to investigate the competitiveness of HP-β-CD with other known cleaning agents such as sodium dodecyl sulfate (SDS), ethylenediaminetetraacetic acid (EDTA), Tween 20, rhamnolipid, nisin, and surfactin. In all cases, HP-β-CD was superior.

  8. Studies on the inclusion behavior of 9-Aminoacridine into cyclodextrins: Spectroscopic and theoretical evidences

    NASA Astrophysics Data System (ADS)

    Manivannan, C.; Vijay Solomon, R.; Venuvanalingam, P.; Renganathan, R.

    2013-02-01

    9-Aminoacridine (9-AA) is an important attractive pharmaceutical drug employed as chemotheraptic agent for wound dressings. However, 9-AA possesses limited solubility and rapid metabolic decomposition renders this potential drug to limit its applications. Here we propose cyclodextrins (CDs) as a drug carrier to improve the bioavailability, solubility of 9-AA. The interaction between 9-AA and CDs (α-CD and β-CD) has been studied using UV-Vis absorption, steady state time resolved fluorescence, 1H NMR and FT-IR spectroscopy techniques. The spectroscopic measurements show that 9-AA does not form stable complex with α-CD and also confirmed by DFT calculations. On the other hand, 9-AA forms inclusion complex with β-CD in a 1:1 stoichiometry ratio. Our DFT results suggest that 9-AA stabilizes inside the CD environment through hydrogen bonding that has unambiguously confirmed by AIM analysis. Thus our studies provide a useful insights in the development of Aminoacridine based drugs & its delivery through a suitable carrier like CDs.

  9. Binding mode and free energy prediction of fisetin/β-cyclodextrin inclusion complexes.

    PubMed

    Nutho, Bodee; Khuntawee, Wasinee; Rungnim, Chompoonut; Pongsawasdi, Piamsook; Wolschann, Peter; Karpfen, Alfred; Kungwan, Nawee; Rungrotmongkol, Thanyada

    2014-01-01

    In the present study, our aim is to investigate the preferential binding mode and encapsulation of the flavonoid fisetin in the nano-pore of β-cyclodextrin (β-CD) at the molecular level using various theoretical approaches: molecular docking, molecular dynamics (MD) simulations and binding free energy calculations. The molecular docking suggested four possible fisetin orientations in the cavity through its chromone or phenyl ring with two different geometries of fisetin due to the rotatable bond between the two rings. From the multiple MD results, the phenyl ring of fisetin favours its inclusion into the β-CD cavity, whilst less binding or even unbinding preference was observed in the complexes where the larger chromone ring is located in the cavity. All MM- and QM-PBSA/GBSA free energy predictions supported the more stable fisetin/β-CD complex of the bound phenyl ring. Van der Waals interaction is the key force in forming the complexes. In addition, the quantum mechanics calculations with M06-2X/6-31G(d,p) clearly showed that both solvation effect and BSSE correction cannot be neglected for the energy determination of the chosen system. PMID:25550745

  10. Binding mode and free energy prediction of fisetin/β-cyclodextrin inclusion complexes

    PubMed Central

    Nutho, Bodee; Khuntawee, Wasinee; Rungnim, Chompoonut; Pongsawasdi, Piamsook; Wolschann, Peter; Karpfen, Alfred; Kungwan, Nawee

    2014-01-01

    Summary In the present study, our aim is to investigate the preferential binding mode and encapsulation of the flavonoid fisetin in the nano-pore of β-cyclodextrin (β-CD) at the molecular level using various theoretical approaches: molecular docking, molecular dynamics (MD) simulations and binding free energy calculations. The molecular docking suggested four possible fisetin orientations in the cavity through its chromone or phenyl ring with two different geometries of fisetin due to the rotatable bond between the two rings. From the multiple MD results, the phenyl ring of fisetin favours its inclusion into the β-CD cavity, whilst less binding or even unbinding preference was observed in the complexes where the larger chromone ring is located in the cavity. All MM- and QM-PBSA/GBSA free energy predictions supported the more stable fisetin/β-CD complex of the bound phenyl ring. Van der Waals interaction is the key force in forming the complexes. In addition, the quantum mechanics calculations with M06-2X/6-31G(d,p) clearly showed that both solvation effect and BSSE correction cannot be neglected for the energy determination of the chosen system. PMID:25550745

  11. Supramolecular photochemistry in beta-cyclodextrin hosts: a TREPR, NMR, and CIDNP investigation.

    PubMed

    Krumkacheva, Olesya A; Gorelik, Vitaly R; Bagryanskaya, Elena G; Lebedeva, Natalia V; Forbes, Malcolm D E

    2010-06-01

    A systematic investigation of the photochemistry and ensuing radical chemistry of three guest ketones encapsulated in randomly methylated beta-cyclodextrin (beta-CD) hosts is reported. Dibenzyl ketone (DBK), deoxybenzoin (DOB), and benzophenone (BP) triplet states are rapidly formed after photolysis at 308 nm. Time-resolved electron paramagnetic resonance (TREPR) spectroscopy, steady-state NMR spectroscopy, and time-resolved chemically induced nuclear polarization (TR-CIDNP) experiments were performed on the ketone/CD complexes and on the ketones in free solution for comparison. The major reactivity pathways available from these excited states are either Norrish I alpha-cleavage or H-atom abstraction from the interior of the CD capsule or the solvent. The DOB triplet state undergoes both reactions, whereas the DBK triplet shows exclusively alpha-cleavage and the BP triplet shows exclusively H-atom abstraction. Radical pairs are observed in beta-CDs by TREPR, consisting of either DOB or BP ketyl radicals with sugar radicals from the CD interior. The TREPR spectra acquired in CDs are substantially broadened due to strong spin exchange. The electron spin polarization mechanism is mostly due to S-T(0) radical pair mechanism (RPM) in solution but changes to S-T(-) RPM in the CDs due to the large exchange interaction. The TR-CIDNP results confirm the reactivity patterns of all three ketones, and DOB shows strong nuclear spin polarization from a novel rearrangement product resulting from the alpha-cleavage reaction.

  12. Characterization and dynamic properties for the solid inclusion complexes of β-cyclodextrin and perfluorooctanoic acid.

    PubMed

    Karoyo, Abdalla H; Sidhu, Paul; Wilson, Lee D; Hazendonk, Paul

    2013-07-11

    The structural characterization and dynamic properties of solid-state inclusion complexes (ICs) formed between β-cyclodextrin (β-CD; host) and perfluorooctanoic acid (PFOA; guest) were investigated using (13)C NMR spectroscopy. The 1:1 and 2:1 host/guest solid-state complexes were prepared using a modified dissolution method to obtain complexes with high phase purity. These complexes were further characterized using differential scanning calorimetry (DSC), FT-IR spectroscopy, powder X-ray diffraction (PXRD), (19)F directpolarization (DP), and (13)C cross-polarization (CP) with magic-angle spinning (MAS) NMR spectroscopy. The (19)F → (13)C CP results provided unequivocal support for the formation of well-defined inclusion compounds. The phase purity of the complexes formed between β-CD and PFOA were assessed using the (19)F DP NMR technique at variable temperature (VT) and MAS at 20 kHz. The complexes were found to be of high phase purity when prepared in accordance with the modified dissolution method. The motional dynamics of the guest in the solid complexes were assessed using T1/T2/T1ρ relaxation NMR methods at ambient and VT conditions. The relaxation data revealed reliable and variable guest dynamics for the 1:1 versus 2:1 complexes at the VTs investigated. The motional dynamics of the guest molecules involve an ensemble of axial motions of the whole chain and 120° rotational jumps of the methyl (CF3) group at the termini of the perfluorocarbon chain. The axial and rotational dynamics of the guest in the 1:1 and 2:1 complexes differ in distribution and magnitude in accordance with the binding geometry of the guest within the host. PMID:23713518

  13. Fabrication of 2D nanosheet through self assembly behavior of sulfamethoxypyridazine inclusion complexes with α- and β-cyclodextrins.

    PubMed

    Rajendiran, N; Venkatesh, G; Mohandass, T

    2014-04-01

    A 2D nanosheet was fabricated through the supramolecular self assembly of sulfamethoxypyridazine (SMP) and β-cyclodextrin (β-CD) inclusion complexes. HRTEM image exhibited 2D nanosheet morphology with a length of 1200mm and the sheet thickness of 60mm. It is noted that the nanosheet did not form a single layer aggregation but a bulk aggregation of SMP/β-CD inclusion complex. The formation of this multilayer 2D nanosheet based on the self assembly of SMP/β-CD inclusion complexes is proposed by the topological transformation as well as molecular modeling calculations. But, nanorods are formed in SMP/α-CD inclusion complex indicated that the nature of the CD determined the shape of the self assembled supramolecular architecture. The formation of nanomaterial was characterized by using FT-IR, DSC, PXRD, (1)H NMR, absorption, fluorescence and lifetime measurements.

  14. Studies on inclusion complexation between 4,4‧-dihydroxybiphenyl and β-cyclodextrin by experimental and theoretical approach

    NASA Astrophysics Data System (ADS)

    Paramasivaganesh, K.; Srinivasan, K.; Manivel, A.; Anandan, S.; Sivakumar, K.; Radhakrishnan, S.; Stalin, T.

    2013-09-01

    The inclusion complex formation between 4,4‧-dihydroxybiphenyl (DHBP) and β-cyclodextrin (β-CD) in aqueous state were studied by UV-Visible spectroscopy, Fluorescence spectroscopy and electrochemical study (cyclic voltammetry, CV). The solid state complex between β-CD and DHBP were characterized by FT-IR, XRD techniques and SEM morphological studies. The β-CD: DHBP inclusion complex obtained by molecular docking studies was in good correlation with the results obtained through experimental methods. The binding constant of 'β-CD: DHBP' inclusion complex was calculated using Benesi-Hildebrand plot at 303 K. The experimental results indicated that the inclusion process is an exergonic and spontaneous process. The point energy, stabilization energy upon complexation and frontier molecular orbital's were obtained. The calculation results correlates well with the docking and experimental observations.

  15. Host-guest inclusion systems of daidzein with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD): Preparation, binding behaviors and water solubility

    NASA Astrophysics Data System (ADS)

    Deng, Yinghui; Pang, Yanhua; Guo, Yafei; Ren, Yufeng; Wang, Fen; Liao, Xiali; Yang, Bo

    2016-08-01

    Daidzein is an isoflavone of naturally abundance existing in plants and foods which has attracted much attention for its significant benefits on human health. However, its application was severely limited by its poor solubilities, instability and low bioavailability. To overcome these drawbacks, inclusion complexes of daidzein with two cyclodextrin (CD) derivatives, i.e., 2-hydropropyl-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD) were prepared and characterized both in solution and solid state by 1D and 2D NMR, XRD, SEM and elemental analyses. Fluorescence spectroscopy and the Job plot were used to demonstrate a mainly 1:1 inclusion mode between daidzein and CDs. Their thermal stabilities were evaluated with TG and DSC experiments. Moreover, water solubility of daidzein was significantly improved by inclusion complexation with CDs. These results might suggest valuable approaches to developments of new pharmaceutical formulations of daidzein.

  16. Supramolecular dye inclusion single crystals created from 2,3,6-trimethyl-β-cyclodextrin and porphyrins.

    PubMed

    Tsuchiya, Youichi; Shiraki, Tomohiro; Matsumoto, Takashi; Sugikawa, Kouta; Sada, Kazuki; Yamano, Akihito; Shinkai, Seiji

    2012-01-01

    In Nature, chromophoric groups play various roles, such as oxygen carriers, electron donors, light sensitizers, which are achieved in many cases by control of their aggregation modes in proteins. Host-guest chemistry between cyclodextrins and porphyrins has attracted great interest from supramolecular chemists because of their unique structures and functions that mimic those of proteins with chromophoric prosthetic groups. To mimic Nature's contrivances, the host-guest systems between cyclodextrins and porphyrins have frequently been studied. It is really surprising, however, that to date no detailed structural information of these complexes has been obtained from single-crystal analysis. In 2011, we reported the first successful isolation of a dye inclusion single crystal (DISC) between 2,3,6-trimethyl-β-cyclodextrin (TMβCD) and 5,10,15,20-tetrapyridylporphyrin (TPyP), and analyzed its X-ray crystal structure. The crystal structure revealed not only the real complex mode but also the attractive orientation of TPyP in the DISC. Herein, we present new strategies to prepare DISCs of TMβCD for several porphyrins and provide crystal structures, details of the complex modes, and optical properties. We believe that the present study has various important implications not only for the basic crystal analysis of inclusion complexes but also for potential applications that use these single crystals.

  17. The effect of cyclodextrins on chemical and physical stability of glucagon and characterization of glucagon/gamma-CD inclusion complexes.

    PubMed

    Matilainen, Laura; Larsen, Kim Lambertsen; Wimmer, Reinhard; Keski-Rahkonen, Pekka; Auriola, Seppo; Järvinen, Tomi; Jarho, Pekka

    2008-07-01

    The purpose of the study was to evaluate the effect of cyclodextrin (CD) complexation on the chemical and physical stability of a polypeptide hormone glucagon and to study the interactions between glucagon and gamma-cyclodextrin molecules in inclusion complexes. The chemical stability of glucagon at pH 2.0 was studied with HPLC-UV and HPLC-MS/MS. The physical stability of glucagon at pH 2.5 was studied by measuring the turbidity (A(405 nm)) and viscosity (Ostwald capillary viscosimeter) of the samples. The structure of glucagon/gamma-CD complexes at pH 2.5 was studied with 2D-NMR. The presence of various CDs increased the chemical half-life of glucagon at pH 2.0 (37 degrees C, 0.01 M HCl, ionic strength 0.15) and prolonged the lag-time before aggregation at pH 2.5 (0.9% (w/v) NaCl in 3.2 mM HCl). The NMR studies showed that the side chains of all the aromatic amino acid residues (Phe6, Tyr10, Tyr13, Phe22, Trp25) and leucines (Leu14 and Leu26) of glucagon interacted with the cavities of the gamma-CD molecules. The present study shows that glucagon forms inclusion complexes with cyclodextrins in acidic solution, resulting in an improvement in its chemical and physical stability.

  18. Encapsulation of gallic acid/cyclodextrin inclusion complex in electrospun polylactic acid nanofibers: Release behavior and antioxidant activity of gallic acid.

    PubMed

    Aytac, Zeynep; Kusku, Semran Ipek; Durgun, Engin; Uyar, Tamer

    2016-06-01

    Cyclodextrin-inclusion complexes (CD-ICs) possess great prominence in food and pharmaceutical industries due to their enhanced ability for stabilization of active compounds during processing, storage and usage. Here, CD-IC of gallic acid (GA) with hydroxypropyl-beta-cyclodextrin (GA/HPβCD-IC) was prepared and then incorporated into polylactic acid (PLA) nanofibers (PLA/GA/HPβCD-IC-NF) using electrospinning technique to observe the effect of CD-ICs in the release behavior of GA into three different mediums (water, 10% ethanol and 95% ethanol). The GA incorporated PLA nanofibers (PLA/GA-NFs) were served as control. Phase solubility studies showed an enhanced solubility of GA with increasing amount of HPβCD. The detailed characterization techniques (XRD, TGA and (1)H-NMR) confirmed the formation of inclusion complex between GA and HPβCD. Computational modeling studies indicated that the GA made an efficient complex with HPβCD at 1:1 either in vacuum or aqueous system. SEM images revealed the bead-free and uniform morphology of PLA/GA/HPβCD-IC-NF. The release studies of GA from PLA/GA/HPβCD-IC-NF and PLA/GA-NF were carried out in water, 10% ethanol and 95% ethanol, and the findings revealed that PLA/GA/HPβCD-IC-NF has released much more amount of GA in water and 10% ethanol system when compared to PLA/GA-NF. In addition, GA was released slowly from PLA/GA/HPβCD-IC-NF into 95% ethanol when compared to PLA/GA-NF. It was also observed that electrospinning process had no negative effect on the antioxidant activity of GA when GA was incorporated in PLA nanofibers.

  19. Encapsulation of gallic acid/cyclodextrin inclusion complex in electrospun polylactic acid nanofibers: Release behavior and antioxidant activity of gallic acid.

    PubMed

    Aytac, Zeynep; Kusku, Semran Ipek; Durgun, Engin; Uyar, Tamer

    2016-06-01

    Cyclodextrin-inclusion complexes (CD-ICs) possess great prominence in food and pharmaceutical industries due to their enhanced ability for stabilization of active compounds during processing, storage and usage. Here, CD-IC of gallic acid (GA) with hydroxypropyl-beta-cyclodextrin (GA/HPβCD-IC) was prepared and then incorporated into polylactic acid (PLA) nanofibers (PLA/GA/HPβCD-IC-NF) using electrospinning technique to observe the effect of CD-ICs in the release behavior of GA into three different mediums (water, 10% ethanol and 95% ethanol). The GA incorporated PLA nanofibers (PLA/GA-NFs) were served as control. Phase solubility studies showed an enhanced solubility of GA with increasing amount of HPβCD. The detailed characterization techniques (XRD, TGA and (1)H-NMR) confirmed the formation of inclusion complex between GA and HPβCD. Computational modeling studies indicated that the GA made an efficient complex with HPβCD at 1:1 either in vacuum or aqueous system. SEM images revealed the bead-free and uniform morphology of PLA/GA/HPβCD-IC-NF. The release studies of GA from PLA/GA/HPβCD-IC-NF and PLA/GA-NF were carried out in water, 10% ethanol and 95% ethanol, and the findings revealed that PLA/GA/HPβCD-IC-NF has released much more amount of GA in water and 10% ethanol system when compared to PLA/GA-NF. In addition, GA was released slowly from PLA/GA/HPβCD-IC-NF into 95% ethanol when compared to PLA/GA-NF. It was also observed that electrospinning process had no negative effect on the antioxidant activity of GA when GA was incorporated in PLA nanofibers. PMID:27040215

  20. 1H NMR spectroscopic characterization of inclusion complexes of tolfenamic and flufenamic acids with β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Floare, C. G.; Pirnau, A.; Bogdan, M.

    2013-07-01

    The complexation between the anionic forms of tolfenamic acid and flufenamic acid with β-cyclodextrin was investigated in solution by 1D and 2D proton NMR spectroscopy. The stoichiometry of the complexes was determined by the method of continuous variation using the chemical induced shifts of both the host and guest protons. An analysis of the spectroscopic data revealed that simultaneous inclusion of both rings of tolfenamic and flufenamic acids occur, giving rise each to two isomeric 1:1 complexes. The view of a bimodal binding between these two drugs and β-cyclodextrin was also supported by ROESY experiments. Using a rough approximation, we have estimated the association constants order of magnitude of the 1:1 complexes.

  1. Experimental and theoretical study of the inclusion complexes of 3-carboxycoumarin acid with β- and 2-hydroxypropyl-β-cyclodextrins

    NASA Astrophysics Data System (ADS)

    Tablet, Cristina; Minea, Liliana; Dumitrache, Luigi; Hillebrand, Mihaela

    2012-06-01

    The association process of a host-guest system, cyclodextrins (CyD) - 3-carboxycoumarin acid (3CCA) was followed by means of UV-vis, circular dichroism and steady-state fluorescence spectroscopies in buffer solution at pH = 1. The experimental data were analyzed in order to get information on the stoichiometry, the equilibrium constants and the geometry of the inclusion complexes. In the circular dichroism spectra, a positive induced signal was obtained reflecting that the guest penetrates the cavity in such a way that the transition moment of the electronic band is quasi parallel to the host main axis. The experimental data are supported by the DFT and TDDFT (B3LYP/6-31G) calculations performed on the isolated ligand and by TDDFT (ZINDO) calculations carried out on the supramolecular ligand-cyclodextrin system.

  2. Enantioseparation of mandelic acid derivatives by high performance liquid chromatography with substituted β-cyclodextrin as chiral mobile phase additive and evaluation of inclusion complex formation

    PubMed Central

    Tong, Shengqiang; Zhang, Hu; Shen, Mangmang

    2014-01-01

    The enantioseparation of ten mandelic acid derivatives was performed by reverse phase high performance liquid chromatography with hydroxypropyl-β-cyclodextrin (HP-β-CD) or sulfobutyl ether-β-cyclodextrin (SBE-β-CD) as chiral mobile phase additives, in which inclusion complex formations between cyclodextrins and enantiomers were evaluated. The effects of various factors such as the composition of mobile phase, concentration of cyclodextrins and column temperature on retention and enantioselectivity were studied. The peak resolutions and retention time of the enantiomers were strongly affected by the pH, the organic modifier and the type of β-cyclodextrin in the mobile phase, while the concentration of buffer solution and temperature had a relatively low effect on resolutions. Enantioseparations were successfully achieved on a Shimpack CLC-ODS column (150×4.6 mm i.d., 5 μm). The mobile phase was a mixture of acetonitrile and 0.10 mol L-1 of phosphate buffer at pH 2.68 containing 20 mmol L-1 of HP-β-CD or SBE-β-CD. Semi-preparative enantioseparation of about 10 mg of α-cyclohexylmandelic acid and α-cyclopentylmandelic acid were established individually. Cyclodextrin-enantiomer complex stoichiometries as well as binding constants were investigated. Results showed that stoichiomertries for all the inclusion complex of cyclodextrin-enantiomers were 1:1. PMID:24893270

  3. Shifting the Azo-hydrazone tautomeric equilibrium of methyl yellow in acidic medium by the formation of inclusion complexes with cyclodextrins

    NASA Astrophysics Data System (ADS)

    Ferreira, Ivania R.; Ando, Rômulo A.

    2012-01-01

    The protonation of methyl yellow (MY) leads to a tautomeric equilibrium involving the azo and hydrazone species, where the latter is predominant. Electronic and Raman spectroscopic data show that when MY in acidic medium is included in cyclodextrins, there is an inversion in the relative ratio of tautomers, in which the azo species become the major species. This indicates that the azo bond is included in cyclodextrin precluding its protonation. The understanding of the protonation, tautomeric and inclusion equilibria of these systems plays an important role in the designing of cyclodextrin based molecular machines controlled by light.

  4. A study of the properties of the 1:1 inclusion complex of β-cyclodextrin with cetyltrimethylammonium bromide

    NASA Astrophysics Data System (ADS)

    Lin, Li-Rong; Jiang, Yun-Bao; Du, Xin-zhen; Huang, Xian-Zhi; Chen, Guo-zhen

    1997-02-01

    The properties of the 1:1 inclusion complex of β-cyclodextrin (β-CD) with cetyltrimethylammonium bromide (CTAB) were investigated by pyrene and 1-pyrene butyric acid fluorescence. It is shown that in the 1:1 CTAB/β-CD inclusion complex the hydrophobic alkyl chain is included in the β-CD cavity, with the majority of the chain protruding into the bulk phase with the counterion binding to the polar head. In aqueous solution this 1:1 CTAB/β-CD inclusion complex aggregates and micellizes into micelles of which the interior hydrophobic region (the Stern layer and micelle core) is less polar than that of CTAB and its critical micelle concentration is 2.05 × 10 -3 mol l -1, which is in agreement with the value determined by surface tension.

  5. Excimer formation in inclusion complexes of β-cyclodextrin with salbutamol, sotalol and atenolol: spectral and molecular modeling studies.

    PubMed

    Antony Muthu Prabhu, A; Subramanian, V K; Rajendiran, N

    2012-10-01

    The inclusion complexation behavior of salbutamol, sotalol and atenolol drugs with β-cyclodextrin (β-CD) were investigated by UV-visible, fluorometry, time resolved fluorescence, FT-IR, (1)H NMR, SEM and PM3 methods. The above drugs gave a single emission maximum in water where as dual emission in β-CD. In β-CD solutions the shorter wavelength fluorescence intensity was regularly decreased and longer wavelength fluorescence intensity increased. Addition of β-CD to aqueous solutions of drugs resulted into excimer emission. The excimer emission is concluded to be due to a 1:2 inclusion complex between β-CD and drug. Nanosecond time-resolved studies indicated that all drugs exhibited biexponential decay in solvents and triexponential decay in CD. Investigations of thermodynamic and electronic properties confirmed the stability of the inclusion complex.

  6. Excimer formation in inclusion complexes of β-cyclodextrin with salbutamol, sotalol and atenolol: Spectral and molecular modeling studies

    NASA Astrophysics Data System (ADS)

    Antony Muthu Prabhu, A.; Subramanian, V. K.; Rajendiran, N.

    2012-10-01

    The inclusion complexation behavior of salbutamol, sotalol and atenolol drugs with β-cyclodextrin (β-CD) were investigated by UV-visible, fluorometry, time resolved fluorescence, FT-IR, 1H NMR, SEM and PM3 methods. The above drugs gave a single emission maximum in water where as dual emission in β-CD. In β-CD solutions the shorter wavelength fluorescence intensity was regularly decreased and longer wavelength fluorescence intensity increased. Addition of β-CD to aqueous solutions of drugs resulted into excimer emission. The excimer emission is concluded to be due to a 1:2 inclusion complex between β-CD and drug. Nanosecond time-resolved studies indicated that all drugs exhibited biexponential decay in solvents and triexponential decay in CD. Investigations of thermodynamic and electronic properties confirmed the stability of the inclusion complex.

  7. Inclusion complexation of phenoxyaliphatic acid derivatives of 3,3'-bis(indolyl)methanes with β-cyclodextrin.

    PubMed

    Antony Muthu Prabhu, A; Suresh Kumar, G S

    2014-05-01

    The inclusion complexation behavior of phenoxyaliphatic acid derivatives of 3,3'-bis(indolyl)methane (BIMs 1-5) with β-cyclodextrin (β-CD) were investigated in both solution and solid state by means of UV-Visible, fluorescence spectroscopy, FT-IR and (1)H NMR techniques. The nature of the host-guest inclusion complex between BIMs and β-CD has been elucidated. The experimental results confirmed the existence of 1:1 inclusion complex of BIMs with β-CD. The binding constants describing the extent of formation of the complexes have been determined using Benesi-Hildebrand plots using UV-Vis and fluorescence spectroscopy. BIMs exhibited an affinity for β-CD. The spectral studies suggested the phenyl ring along with alkyl substitutions of BIMs is present inside of β-CD cavity.

  8. Biological activity of water-soluble inclusion complexes of 1'-acetoxychavicol acetate with cyclodextrins.

    PubMed

    Azuma, Hideki; Aizawa, Yui; Higashitani, Nao; Tsumori, Takashi; Kojima-Yuasa, Akiko; Matsui-Yuasa, Isao; Nagasaki, Takeshi

    2011-06-15

    1'-Acetoxychavicol acetate (ACA), isolated from the rhizomes and the seeds of the Zingiberaceae plant, has a variety of biological activities such as antitumor, antiallergic and repellent effects. However, ACA seems to have some disadvantages which may limit for future possible clinical applications, for example, its poor water solubility. Furthermore, ACA is not stable in aqueous solutions and undergoes hydrolysis and/or isomerization. To improve the solubility and stability of ACA in water, we prepared the inclusion complexes with various β-cyclodextrins (β-CDs).In aqueous solution, the association constants of ACA with various CDs were estimated at 662±95 (β-CD), 336±70 (methyl-β-CD, Meβ-CD), and 322±44M(-1) (hydroxypropyl-β-CD, HPβ-CD), respectively, by a spectrofluorometric displacement method based on competition between a guest and a fluorescent probe for CDs. It was revealed that almost all ACAs existed as a free molecule in the CD-containing aqueous solution. However, in the case of preparing the inclusion complexes of CDs with ACA by a solid phase 'high-speed vibration milling' technique, the average inclusion rates of the obtained water-soluble complexes were calculated as 88±13% (β-CD), 70±1% (Meβ-CD), and 63±2% (HPβ-CD), respectively, by (1)H NMR analysis. To characterize the structures of the CD·ACA complexes, 2,3,6-trimethyl-β-CD (TMeβ-CD)·ACA complex was prepared as a model compound (inclusion rate: 40%). As a result of 2D ROESY experiments, it was considered that the aromatic ring of ACA is located in the narrow side of the hydrophobic cavity of the TMeβ-CD and both 1'- and 4-acetoxy groups of ACA positioned in the vicinity of the secondary and primary methoxy groups of TMeβ-CD, respectively. Furthermore, we examined the apoptogenic activity of CD·ACA complexes to evaluate whether or not the bioactivities of ACA were affected by their inclusion. Although the cytotoxicity of all CD·ACA complexes in human epithelial carcinoma

  9. Enhanced bioavailability of raloxifene hydrochloride via dry suspensions prepared from drug/HP-β-cyclodextrin inclusion complexes.

    PubMed

    Lu, Rong; Liu, Shan; Wang, Qilin; Li, Xia

    2015-12-01

    This study aimed to develop a dry suspension formulation of raloxifene (RLX) using its HP-β-cyclodextrin inclusion complexes to enhance the oral bioavailability. Dry suspensions loading RLX/HP-β-cyclodextrin inclusion complexes (RLX-HICs) were prepared by solvent evaporation followed by a standard wet granulation process. The inclusion complexes were characterized by scanning electron microscopy, differential scanning calorimetry, and Fourier transform infrared spectroscopy. The features of dry suspensions such as dispersibility, flowability and dissolution were compared with conventional suspensions. Dry suspensions containing RLX-HICs dramatically increased the dissolution of RLX. Pharmacokinetic studies in rats showed that dry suspensions with RLX-HICs significantly enhanced the oral bioavailabilities of RLX. The absolute and relative bioavailabilities were up to 13.04% and 413.97% compared with the solution formulation (i.v.) and conventional suspensions (i.g.), respectively. The bioavailability improvement for dry suspensions with RLX-HICs can be attributed to improved dissolution and physiochemical properties of RLX, by which the overall absorption was enhanced. Dry suspensions prepared from RLX-HICs may be an attractive formulation for the oral delivery of RLX. PMID:26817276

  10. Experimental and molecular docking investigations on the inclusion mechanism of the complex of phloridzin and hydroxypropyl-β-cyclodextrin.

    PubMed

    Zhang, Chun-Ling; Liu, Jie-Chao; Yang, Wen-Bo; Chen, Da-Lei; Jiao, Zhong-Gao

    2017-01-15

    Phloridzin is a nutraceutical. Its use in food, medicine and cosmetics is limited because of its low aqueous solubility and stability limits, but it can be improved by complexing with cyclodextrins. In this study, we investigated the inclusion mechanism between phloridzin and hydroxylpropyl-β-cyclodextrin (HP-β-CD) using isothermal titration calorimetry (ITC), ultraviolet-visible spectrometry (UV), infrared spectrometry (IR), proton nuclear magnetic resonance spectroscopy ((1)H NMR) and molecular docking simulations. The ITC results found that the equilibrium binding constant of HP-β-CD with phloridzin was higher than that of β-CD. Their inclusion was a spontaneous process with negative ΔG, ΔH and ΔS values. UV spectra showed that the aqueous solubility of phloridzin was enhanced by HP-β-CD. Our IR analysis verified the inclusion complexation of phloridzin into the HP-β-CD cavity. The Autodock determined that the substitution distribution of HP-β-CD influenced not only the orientation and depth degree of phloridzin within the cavity, but also the binding energies. PMID:27542458

  11. Inclusion complex of ellagic acid with β-cyclodextrin: Characterization and in vitro anti-inflammatory evaluation

    NASA Astrophysics Data System (ADS)

    Bulani, Vipin D.; Kothavade, Pankaj S.; Kundaikar, Harish S.; Gawali, Nitin B.; Chowdhury, Amrita A.; Degani, Mariam S.; Juvekar, Archana R.

    2016-02-01

    Freeze-dried inclusion complex of ellagic acid/β-cyclodextrin (EACD) was investigated both in solution and solid state by means of aqueous solubility, in vitro dissolution, absorption, fluorescence, Fourier transform infrared spectroscopy (FTIR), powder X-ray diffractometry (XRD), scanning electron microscopy (SEM), nuclear magnetic resonance (NMR) and molecular modeling methods. The phase solubility study showed that ellagic acid formed 1:2 stoichiometric inclusion complex with β-cyclodextrin (β-CD). The FTIR study indicates that carbonyl group of ellagic acid interact with β-CD. The NMR results demonstrate that ellagic acid was partly included into the β-CD from the wider side of the cavity. Molecular modeling studies revealed that hydrogen bonding interactions played an important role in the inclusion process and higher negative values for the complexation energies imply that 1:2 complex was more stable than 1:1 complex. The solubility and in vitro dissolution of ellagic acid was significantly enhanced by complexation with β-CD as compared to the free ellagic acid. Additionally, the complexation of EACD positively influences it's in vitro anti-inflammatory activity by protecting from protein denaturation and lysis of erythrocyte membrane.

  12. Effects of Two Surfactants and Beta-Cyclodextrin on Beta-Cypermethrin Degradation by Bacillus licheniformis B-1.

    PubMed

    Zhao, Jiayuan; Chi, Yuanlong; Liu, Fangfang; Jia, Dongying; Yao, Kai

    2015-12-23

    The biodegradation efficiency of beta-cypermethrin (β-CY) is low especially at high concentrations mainly due to poor contact between this hydrophobic pesticide and microbial cells. In this study, the effects of two biodegradable surfactants (Tween-80 and Brij-35) and β-cyclodextrin (β-CD) on the growth and cell surface hydrophobicity (CSH) of Bacillus licheniformis B-1 were studied. Furthermore, their effects on the solubility, biosorption, and degradation of β-CY were investigated. The results showed that Tween-80 could slightly promote the growth of the strain while Brij-35 and β-CD exhibited little effect on its growth. The CSH of strain B-1 and the solubility of β-CY were obviously changed by using Tween-80 and Brij-35. The surfactants and β-CD could enhance β-CY biosorption and degradation by the strain, and the highest degradation was obtained in the presence of Brij-35. When the surfactant or β-CD concentration was 2.4 g/L, the degradation rate of β-CY in Brij-35, Tween-80, and β-CD treatments was 89.4%, 50.5%, and 48.1%, respectively. The half-life of β-CY by using Brij-35 was shortened by 69.1 h. Beta-CY content in the soil with both strain B-1 and Brij-35 decreased from 22.29 mg/kg to 4.41 mg/kg after incubation for 22 d. This work can provide a promising approach for the efficient degradation of pyrethroid pesticides by microorganisms.

  13. Effect of inclusion complexation on the photophysical behavior of diphenylamine in β-cyclodextrin medium: A study by electronic spectra

    NASA Astrophysics Data System (ADS)

    Rajamohan, Rajaram; Swaminathan, Meenakshisundaram

    2011-12-01

    Spectral characteristics of diphenylamine (DPA) have been investigated in β-cyclodextrin (β-CDx) solution. The formation of the complex was revealed by UV, steady state and time-resolved fluorescence spectroscopy. The stoichiometry of DPA:β-CDx complex, determined using Benesi-Hildebrand equation and Job's continuous variation method is 1:1. The binding constants calculated from various methods are reported. This inclusion complex formation from DPA and β-CDx was also confirmed by the FT-IR spectral study and SEM image analysis of solid complex prepared by co-precipitation method.

  14. The enhancement of fluorescence quantum yields of anilino naphthalene sulfonic acids by inclusion of various cyclodextrins and cucurbit[7]uril

    NASA Astrophysics Data System (ADS)

    Sueishi, Yoshimi; Fujita, Tomonori; Nakatani, Shinichiro; Inazumi, Naoya; Osawa, Yoshihiro

    2013-10-01

    The association constants (K) for the inclusion complexation of four kinds of cyclodextrins (CDs (β- and γ-), 2,6-di-O-methylated β-CD, and 2,3,6-tri-O-methylated β-CD) and cucurbit[7]uril (CB[7]) with 1,8- and 2,6-anilinonaphthalene sulfonic acids (ANSs) were determined from fluorescence spectra enhanced by inclusion. Various CDs and CB[7] form stable 1:1 inclusion complexes with 1,8- and 2,6-ANSs: K = 80-11 700 M-1 for 2,6-ANS and 50-195 M-1 for 1,8-ANS. The high stability of the inclusion complexes of 2,6-ANS with CB[7] and 2,6-di-O-methylated β-CD is shown. Further, we determined the fluorescence quantum yields (Φ values) for the inclusion complexes of ANSs by using a fluorescence spectrophotometer equipped with a half-moon unit. The Φ values of 1,8- and 2,6-ANSs were largely enhanced by the inclusion of methylated β-CDs and did not correlate with the degree of stability (K) of the inclusion complexes. We characterized the structures of the inclusion complexes by 2D ROESY-NMR measurements. In addition, the microenvironmental polarity inside the hydrophobic CD and CB[7] cavities was evaluated using the fluorescence probe 2,6-ANS. Based on the emission mechanism and the aspect of inclusion in a hydrophobic cavity, we have suggested that the microenvironmental polarity and viscosity for the excited state of ANS plays an important role for the Φ values of inclusion complexes.

  15. The enhancement of fluorescence quantum yields of anilino naphthalene sulfonic acids by inclusion of various cyclodextrins and cucurbit[7]uril.

    PubMed

    Sueishi, Yoshimi; Fujita, Tomonori; Nakatani, Shinichiro; Inazumi, Naoya; Osawa, Yoshihiro

    2013-10-01

    The association constants (K) for the inclusion complexation of four kinds of cyclodextrins (CDs (β- and γ-), 2,6-di-O-methylated β-CD, and 2,3,6-tri-O-methylated β-CD) and cucurbit[7]uril (CB[7]) with 1,8- and 2,6-anilinonaphthalene sulfonic acids (ANSs) were determined from fluorescence spectra enhanced by inclusion. Various CDs and CB[7] form stable 1:1 inclusion complexes with 1,8- and 2,6-ANSs: K=80-11700 M(-1) for 2,6-ANS and 50-195 M(-1) for 1,8-ANS. The high stability of the inclusion complexes of 2,6-ANS with CB[7] and 2,6-di-O-methylated β-CD is shown. Further, we determined the fluorescence quantum yields (Φ values) for the inclusion complexes of ANSs by using a fluorescence spectrophotometer equipped with a half-moon unit. The Φ values of 1,8- and 2,6-ANSs were largely enhanced by the inclusion of methylated β-CDs and did not correlate with the degree of stability (K) of the inclusion complexes. We characterized the structures of the inclusion complexes by 2D ROESY-NMR measurements. In addition, the microenvironmental polarity inside the hydrophobic CD and CB[7] cavities was evaluated using the fluorescence probe 2,6-ANS. Based on the emission mechanism and the aspect of inclusion in a hydrophobic cavity, we have suggested that the microenvironmental polarity and viscosity for the excited state of ANS plays an important role for the Φ values of inclusion complexes.

  16. Inclusion complexes of HP-β-cyclodextrin with agomelatine: Preparation, characterization, mechanism study and in vivo evaluation.

    PubMed

    Liao, Yunhui; Zhang, Xuefei; Li, Chenglin; Huang, Yanjuan; Lei, Ming; Yan, Mina; Zhou, Yuefang; Zhao, Chunshun

    2016-08-20

    Agomelatine (AGM), is efficacious in both the acute phase and the continuation phase of depression. However, its poor water-solubility, low bioavailability and polymorphism limit its pharmacological effects. To address these problems, agomelatine-hydroxypropyl-β-cyclodextrin inclusion complex (AGM/HPβ-CD) was prepared successfully by freeze-drying. The products was evaluated by structural characterization, solubilization test, in-situ absorption of rat intestinal tract and pharmacokinetic study. In addition, thermodynamic studies were performed, the results indicated that the inclusion process was enthalpy-determined and exothermic nature of complexation, signifying the role of steric interactions in complex formation. Molecular docking of AGM with HPβ-CD has been conducted as well to verify the experimental findings and predict the stable molecular structure of the inclusion complex. The in vivo data showed that, AGM was mainly absorbed in duodenum and jejunum by passive diffusion. AGM/HPβ-CD inclusion complex displayed earlier Tmax and higher Cmax, and the AUC0-12h was approximately twice larger than its physical mixture. These results suggested that AGM/HPβ-CD inclusion complex was established with 1:1 stoichiometry through the naphthalene group of AGM and it was deeply inserted into the cavity of HPβ-CD, and the inclusion complex could significantly enhance the oral bioavailability of AGM. PMID:27178948

  17. Effect of γ-Cyclodextrin Inclusion Complex on the Absorption of R-α-Lipoic Acid in Rats

    PubMed Central

    Uchida, Ryota; Iwamoto, Kosuke; Nagayama, Suetada; Miyajima, Atsushi; Okamoto, Hinako; Ikuta, Naoko; Fukumi, Hiroshi; Terao, Keiji; Hirota, Takashi

    2015-01-01

    R-α-lipoic acid (RLA) is an endogenous organic acid, and works as a cofactor for mitochondrial enzymes and as a kind of antioxidant. Inclusion complexes of RLA with α-, β- or γ-cyclodextrins (CD) were prepared and orally administered as a suspension to rats. Among them, RLA/γ-CD showed the highest plasma exposure, and its area under the plasma concentration-time curve (AUC) of RLA was 2.2 times higher than that after oral administration of non-inclusion RLA. On the other hand, the AUC after oral administration of non-inclusion RLA and RLA/γ-CD to pylorus-ligated rats did not differ. However, the AUC after intraduodenal administration of RLA/γ-CD was 5.1 times higher than that of non-inclusion RLA, and was almost comparable to the AUC after intraduodenal administration of RLA-Na solution. Furthermore, the AUC after intraduodenal administration of RLA/γ-CD was not affected by biliary ligation or co-administration of an amylase inhibitor. These findings demonstrated that RLA was absorbed from the small intestine effectively when orally administered as a γ-CD inclusion complex, which could be easily dissolved in the lumen of the intestine. In conclusion, γ-CD inclusion complex is an appropriate formulation for supplying RLA as a drug or nutritional supplement with respect to absorption. PMID:25946345

  18. A joint structural, kinetic, and thermodynamic investigation of substituent effects on host-guest complexation of bicyclic azoalkanes by beta-cyclodextrin.

    PubMed

    Zhang, Xiangyang; Gramlich, Gabriela; Wang, Xiaojuan; Nau, Werner M

    2002-01-16

    Derivatives of the azoalkane 2,3-diazabicyclo[2,2,2]oct-2-ene (1a) with bridgehead 1,4-dialkyl (1b), 1,4-dichloro (1c), 1-hydroxymethyl (1d), 1-aminomethyl (1e), and 1-ammoniummethyl (1f) substituents form host-guest inclusion complexes with beta-cyclodextrin. They were employed as probes to assess substituent effects on the kinetics and thermodynamics of this complexation by using time-resolved and steady-state fluorimetry, UV spectrophotometry, induced circular dichroism (ICD) measurements, and (1)H NMR spectroscopy. The kinetic analysis based on quenching of the long-lived fluorescence of the azoalkanes by addition of host provided excited-state association rate constants between 2.6 x 10(8) and 7.0 x 10(8) M(-)(1) s(-)(1). The binding constants for 1a (1100 M(-1)), 1b (900 M(-1)), 1c (1900 M(-1)), 1d (180 M(-1)), 1e (250 M(-1)), and 1f (ca. 20 M(-1)) were obtained by UV, NMR, and ICD titrations. A positive ICD signal of the azo absorption around 370 nm was observed for the beta-cyclodextrin complexes of 1a, 1d, and 1f with the intensity order 1a > 1d approximately 1f, and a negative signal was measured for those of 1b, 1c, and 1e with the intensity order 1c < 1b approximately 1e. The ICD was employed for the assignment of the solution structures of the complexes, in particular the relative orientation of the guest in the host (co-conformation).

  19. Formulation studies and in vivo evaluation of a flurbiprofen-hydroxypropyl beta-cyclodextrin system.

    PubMed

    Govindarajan, Ramprakash; Nagarsenker, Mangal S

    2005-01-01

    The purpose of this study was 1) to investigate in vivo advantages of a flurbiprofen (FPN)-hydroxypropyl beta-cyclodextrin (HPbetaCD) solid dispersion (SD) in rats, 2) to study factors affecting the drug release from SD formulations, and 3) to evaluate the pharmacokinetic profile of the drug when administered as SD, in humans. The solubility of FPN in water and dissolution media was evaluated as a function of HPbetaCD concentration. The SD was prepared by coevaporation from dilute aqueous NH3 and evaluated in rats. The release of the drug from tablet formulations and capsules of SD was studied in simulated gastric fluid and phosphate buffer, pH 7.2. The bioavailability of drug when administered as SD was evaluated in humans. HPbetaCD enhanced the solubility of the drug, and SD improved bioavailability and reduced ulcerogenicity of the drug in rats. The type of excipient used affected drug release from tablets. Presence of microcrystalline cellulose, a hydrophilic polymeric excipient, resulted in uptake of water and stabilization of the resulting gels-like structure of HPbetaCD-containing tablets. This adversely affected drug release. The release from capsules filled with SD was comparable to that obtained from plain SD powder. The drug-HPbetaCD association constant in water was much lower than the values reported in literature. The bioavailability (which could suffer in case of higher association constant) was enhanced on administration of SD-filled capsules to humans.

  20. Sorption of agrochemical model compounds by sorbent materials containing beta-cyclodextrin.

    PubMed

    Wilson, Lee D; Mohamed, Mohamed H; Guo, Rui; Pratt, Dawn Y; Kwon, Jae Hyuck; Mahmud, Sarker T

    2010-04-01

    Polymeric sorbent materials that incorporate beta-cyclodextrin (CD) have been prepared and their sorption behavior toward two model agrochemical contaminant compounds, p-nitrophenol (PNP) and methyl chloride examined. The sorption of PNP was studied in aqueous solution using ultraviolet-visible (UV-Vis) spectroscopy, whereas the sorption of methyl chloride from the gas phase was studied using a Langmuir adsorption method. The sorption results for PNP in solution were compared between granular activated carbon (GAC), modified GAC, CD copolymers, and CD-based mesoporous silica hybrid materials. Nitrogen porosimetry at 77 K was used to estimate the surface area and pore structure properties of the sorbent materials. The sorbents displayed variable surface areas as follows: copolymers (36.2-157 m(2)/g), CD-silica materials (307-906 m(2)/g), surface modified GAC (657 m(2)/g), and granular activated carbon (approximately 10(3) m(2)/g). The sorption capacities for PNP and methyl chloride with the different sorbents are listed in descending order as follows: GAC > copolymers > surface modified GAC > CD-silica hybrid materials. In general, the differences in the sorption properties of the sorbents were related to the following: (i) surface area of the sorbent, (ii) CD content and accessibility, (iii) and the chemical nature of the sorbent material. PMID:20407992

  1. Cleaning efficacy of hydroxypropyl-beta-cyclodextrin for biofouling reduction on reverse osmosis membranes.

    PubMed

    Alayande, Abayomi Babatunde; Kim, Lan Hee; Kim, In S

    2016-01-01

    In this study, an environmentally friendly compound, hydroxypropyl-beta-cyclodextrin (HP-β-CD) was applied to clean reverse osmosis (RO) membranes fouled by microorganisms. The cleaning with HP-β-CD removed the biofilm and resulted in a flux recovery ratio (FRR) of 102%. As cleaning efficiency is sometimes difficult to determine using flux recovery data alone, attached bacterial cells and extracellular polymeric substances (EPS) were quantified after cleaning the biofouled membrane with HP-β-CD. Membrane surface characterization using scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared (ATR-FTIR) and atomic force microscopy (AFM) confirmed the effectiveness of HP-β-CD in removal of biofilm from the RO membrane surface. Finally, a comparative study was performed to investigate the competitiveness of HP-β-CD with other known cleaning agents such as sodium dodecyl sulfate (SDS), ethylenediaminetetraacetic acid (EDTA), Tween 20, rhamnolipid, nisin, and surfactin. In all cases, HP-β-CD was superior. PMID:26923225

  2. Solubility enhancement of seven metal contaminants using carboxymethyl-beta-cyclodextrin (CMCD).

    PubMed

    Skold, Magnus E; Thyne, Geoffrey D; Drexler, John W; McCray, John E

    2009-07-21

    Carboxymethyl-beta-cyclodextrin (CMCD) has been suggested as a complexing agent for remediation of sites co-contaminated with metals and organic pollutants. As part of an attempt to construct a geochemical complexation model for metal-CMCD interactions, conditional formation constants for the complexes between CMCD and 7 metal ions (Ba, Ca, Cd, Ni, Pb, Sr, and Zn) are estimated from experimental data. Stable metal concentrations were reached after approximately 1 day and estimated logarithmic conditional formation constants range from -3.2 to -5.1 with confidence intervals within +/-0.08 log units. Experiments performed at 10 degrees C and 25 degrees C show that temperature affects the solubility of the metal salts but the strength of CMCD-metal complexes are not affected by this temperature variation. The conditional stability constants and complexation model presented in this work can be used to screen CMCD as a potential remediation agent for clean-up of contaminated soil and groundwater.

  3. Enhanced Solubilisation of Six PAHs by Three Synthetic Cyclodextrins for Remediation Applications: Molecular Modelling of the Inclusion Complexes

    PubMed Central

    Morillo, Esmeralda; Sánchez-Trujillo, María Antonia; Moyano, José Ramón; Villaverde, Jaime; Gómez-Pantoja, María Eulalia; Pérez-Martínez, José Ignacio

    2012-01-01

    Solubilisation of six polycyclic aromatic hydrocarbons (PAHs) (acenaphthene, anthracene, fluoranthene, fluorene, phenanthrene and pyrene) by three synthetic cyclodextrins (CDs) (2-hydroxypropyl-β-CD, hydroxypropyl-γ-CD and ramdomly methylated-β-CD) was investigated in order to select the CD which presents the greatest increase in solubility and better complexation parameters for its use in contaminated scenarios. The presence of the three cyclodextrins greatly enhanced the apparent water solubility of all the PAHs through the formation of inclusion complexes of 1∶1 stoichiometry. Anthracene, fluoranthene, fluorene and phenanthrene clearly presented a higher solubility when β-CD derivatives were used, and especially the complexes with the ramdomly methylated-β-CD were favoured. On the contrary, pyrene presented its best solubility results when using 2-hydroxypropyl-γ-CD, but for acenaphthene the use of any of the three CDs gave the same results. Complementary to experimental phase-solubility studies, a more in-depth estimation of the inclusion process for the different complexes was carried out using molecular modelling in order to find a correlation between the degree of solubilisation and the fit of PAH molecules within the cavity of the different CDs and to know the predominant driving forces of the complexation. PMID:23028493

  4. In Situ Visualization of the Local Photothermal Effect Produced on α-Cyclodextrin Inclusion Compound Associated with Gold Nanoparticles

    NASA Astrophysics Data System (ADS)

    Silva, Nataly; Muñoz, Camila; Diaz-Marcos, Jordi; Samitier, Josep; Yutronic, Nicolás; Kogan, Marcelo J.; Jara, Paul

    2016-04-01

    Evidence of guest migration in α-cyclodextrin-octylamine (α-CD-OA) inclusion compound (IC) generated via plasmonic heating of gold nanoparticles (AuNPs) has been studied. In this report, we demonstrate local effects generated by laser-mediated irradiation of a sample of AuNPs covered with inclusion compounds on surface-derivatized glass under liquid conditions by atomic force microscopy (AFM). Functionalized AuNPs on the glass and covered by the ICs were monitored by recording images by AFM during 5 h of irradiation, and images showed that after irradiation, a drastic decrease in the height of the AuNPs occurred. The absorption spectrum of the irradiated sample showed a hypsochromic shift from 542 to 536 nm, evidence suggesting that much of the population of nanoparticles lost all of the parts of the overlay of ICs due to the plasmonic heat generated by the irradiation. Mass spectrometry matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) performed on a sample containing a collection of drops obtained from the surface of the functionalized glass provided evidence that the irradiation lead to disintegration of the ICs and therefore exit of the octylamine molecule (the guest) from the cyclodextrin cavity (the matrix).

  5. Spectroscopic studies of inclusion of 4H-1-benzopyran-4-thione in a β-cyclodextrin cavity

    NASA Astrophysics Data System (ADS)

    Milewski, Marek; Maciejewski, Andrzej; Augustyniak, Włodzimierz

    1997-06-01

    Spectral and photophysical properties of 4H-1-benzopyran-4-thione (BFT) in aqueous solutions of β-cyclodextrin (β-CD) and in some solvents have been investigated by stationary methods. Both fluorescence and phosphorescence of BPT are observable at room temperature. Results indicate the formation of an inclusion complex. Spectral shifts in the absorption spectrum and the shape of the phosphorescence spectrum mostly depend on the polarity of environment whereas the photophysical properties of the second excited singlet state depend on other structural properties of the medium, which allows us to investigate interactions between water molecules and complexed molecules. These properties make BFT a very convenient probe in the investigation of photophysics of inclusion complexes.

  6. Improving ITC studies of cyclodextrin inclusion compounds by global analysis of conventional and non-conventional experiments

    PubMed Central

    Bertaut, Eléonore

    2014-01-01

    Summary The study of 1:1 cyclodextrin inclusion compounds by isothermal titration calorimetry was explored in a theoretical and experimental point of view to compare the efficiency of conventional and non-conventional experiments. All direct and competitive protocols were described and evaluated in terms of accuracy on both binding constant and inclusion enthalpy. Significant improvement in the calorimetric characterization may be obtained by means of the global analysis of non-conventional experiments coupled to the standard titration protocol. While the titration-release approach proved to be the most accurate strategy for classical complexations, the valuable contribution of other non-conventional experiments was demonstrated for issues concerning weak stability, enthalpy, or solubility. PMID:25550724

  7. The preparation, characterization, and pharmacokinetic studies of chitosan nanoparticles loaded with paclitaxel/dimethyl-β-cyclodextrin inclusion complexes

    PubMed Central

    Ye, Ya-Jing; Wang, Yun; Lou, Kai-Yan; Chen, Yan-Zuo; Chen, Rongjun; Gao, Feng

    2015-01-01

    A novel biocompatible and biodegradable drug-delivery nanoparticle (NP) has been developed to minimize the severe side effects of the poorly water-soluble anticancer drug paclitaxel (PTX) for clinical use. PTX was loaded into the hydrophobic cavity of a hydrophilic cyclodextrin derivative, heptakis (2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD), using an aqueous solution-stirring method followed by lyophilization. The resulting PTX/DM-β-CD inclusion complex dramatically enhanced the solubility of PTX in water and was directly incorporated into chitosan (CS) to form NPs (with a size of 323.9–407.8 nm in diameter) using an ionic gelation method. The formed NPs had a zeta potential of +15.9–23.3 mV and showed high colloidal stability. With the same weight ratio of PTX to CS of 0.7, the loading efficiency of the PTX/DM-β-CD inclusion complex-loaded CS NPs was 30.3-fold higher than that of the PTX-loaded CS NPs. Moreover, it is notable that PTX was released from the DM-β-CD/CS NPs in a sustained-release manner. The pharmacokinetic studies revealed that, compared with reference formulation (Taxol®), the PTX/DM-β-CD inclusion complex-loaded CS NPs exhibited a significant increase in AUC0→24h (the area under the plasma drug concentration–time curve over the period of 24 hours) and mean residence time by 2.7-fold and 1.4-fold, respectively. Therefore, the novel drug/DM-β-CD inclusion complex-loaded CS NPs have promising applications for the significantly improved delivery and controlled release of the poorly water-soluble drug PTX or its derivatives, thus possibly leading to enhanced therapeutic efficacy and less severe side effects. PMID:26170666

  8. Inclusion excluded: Chiroptical sensing of the external surface of sulfated cyclodextrins.

    PubMed

    Zsila, Ferenc

    2015-05-01

    It is shown that the heparin antagonist bis-aminoquinoline derivative surfen interacts with sulfated cyclodextrins in a unique fashion. Analysis of the UV spectroscopic data revealed exceptionally strong association (K(a) ∼ 10(7) M(-1)) of several surfen molecules to the external surface of the cyclodextrin hosts. H-bonded to the sulfate groups in 1:1 stoichiometry, the drug molecules form a chiral layer around the macrocycles. Due to the steric proximity, dipole-dipole coupling occurs between the adjacent aminoquinoline rings that accounts for the large UV hypochromism and the induced exciton couplet in the circular dichroism spectra.

  9. Host-guest inclusion system of oleanolic acid with methyl-β-cyclodextrin: Preparation, characterization and anticancer activity

    NASA Astrophysics Data System (ADS)

    Ren, Yufeng; Liu, Ying; Niu, Raomei; Liao, Xiali; Zhang, Jihong; Yang, Bo

    2016-08-01

    In this study, the solid inclusion complex of oleanolic acid (OA) with methyl-β-cyclodextrin (M-β-CD) was prepared and characterized by nuclear magnetic resonance (NMR), X-ray diffraction (XRD), scanning electron microscope (SEM) and differential scanning calorimetry (DSC). The inclusion behaviors of OA/M-β-CD complex were studied by fluorescence spectroscopy and the Job plot, which indicated a 1:1 inclusion mode between OA and M-β-CD. The stability constant (Ks) of the complex was 1072.30 ± 20 M-1 determined by spectral titration at 25 °C. Besides, the water solubility of OA was significantly increased to 8.2 mg/mL by inclusion complexation, compared to only ca. 0.012 μg/mL of free OA. The in vitro cytotoxicity of the inclusion complex was noticeably better than that of native OA with the IC50 values of 8.89, 7.89 and 5.77 μM on human cancer cell lines HepG2, HT29 and HCT116, respectively, by MTT assay.

  10. Preparation of inclusion complex of apigenin-hydroxypropyl-β-cyclodextrin by using supercritical antisolvent process for dissolution and bioavailability enhancement.

    PubMed

    Huang, Yannian; Zu, Yuangang; Zhao, Xiuhua; Wu, Mingfang; Feng, Ziqi; Deng, Yiping; Zu, Chang; Wang, Lingling

    2016-09-25

    In this study, an inclusion complex of apigenin (AP)-hydroxypropyl-β-cyclodextrin (HP-β-CD) was prepared via supercritical antisolvent (SAS) method using N, N-dimethylformamide (DMF) as solvent and carbon dioxide as antisolvent. The mole ratio of AP and HP-β-CD (1:1) was established by phase solubility equilibrium experiment. The optimal conditions were determined through single-factor experiments; these conditions included precipitation pressure of 22.5MPa, precipitation temperature of 50°C, and AP concentration of 20mg/ml. The load efficiency and encapsulation efficiency of the AP-HP-β-CD inclusion complex, with a mean particle size of 392.13±7.56nm, were 13.97%±0.17% and 93.22%±1.17%, respectively, under the optimal conditions. FTIR, (1)H NMR, SEM, XRD, DSC, and TG analyses were also conducted. Results showed that the inclusion complex was formed because of the interaction between AP and HP-β-CD. DMF residue in the inclusion complex was 0.033% lower than the ICH limit for class II solvents. The solubility of the inclusion complex was approximately 152.43 times higher than that of the raw AP. In the in vitro study, the dissolution rate of the AP-HP-β-CD inclusion complex was about 7.60 times higher than that of the raw AP. In the in vivo study, the bioavailability of the inclusion complex increased by 6.45 times compared with that of the raw AP. Hence, the prepared AP-HP-β-CD inclusion complex exhibits potential as a new oral therapeutic agent formulation for clinical applications. PMID:27515291

  11. Preparation of inclusion complex of apigenin-hydroxypropyl-β-cyclodextrin by using supercritical antisolvent process for dissolution and bioavailability enhancement.

    PubMed

    Huang, Yannian; Zu, Yuangang; Zhao, Xiuhua; Wu, Mingfang; Feng, Ziqi; Deng, Yiping; Zu, Chang; Wang, Lingling

    2016-09-25

    In this study, an inclusion complex of apigenin (AP)-hydroxypropyl-β-cyclodextrin (HP-β-CD) was prepared via supercritical antisolvent (SAS) method using N, N-dimethylformamide (DMF) as solvent and carbon dioxide as antisolvent. The mole ratio of AP and HP-β-CD (1:1) was established by phase solubility equilibrium experiment. The optimal conditions were determined through single-factor experiments; these conditions included precipitation pressure of 22.5MPa, precipitation temperature of 50°C, and AP concentration of 20mg/ml. The load efficiency and encapsulation efficiency of the AP-HP-β-CD inclusion complex, with a mean particle size of 392.13±7.56nm, were 13.97%±0.17% and 93.22%±1.17%, respectively, under the optimal conditions. FTIR, (1)H NMR, SEM, XRD, DSC, and TG analyses were also conducted. Results showed that the inclusion complex was formed because of the interaction between AP and HP-β-CD. DMF residue in the inclusion complex was 0.033% lower than the ICH limit for class II solvents. The solubility of the inclusion complex was approximately 152.43 times higher than that of the raw AP. In the in vitro study, the dissolution rate of the AP-HP-β-CD inclusion complex was about 7.60 times higher than that of the raw AP. In the in vivo study, the bioavailability of the inclusion complex increased by 6.45 times compared with that of the raw AP. Hence, the prepared AP-HP-β-CD inclusion complex exhibits potential as a new oral therapeutic agent formulation for clinical applications.

  12. Inclusion complexes of 2-methoxyestradiol with dimethylated and permethylated β-cyclodextrins: models for cyclodextrin–steroid interaction

    PubMed Central

    Bourne, Susan A; Samsodien, Halima; Smith, Vincent J

    2015-01-01

    Summary The interaction between the potent anticancer agent 2-methoxyestradiol (2ME) and a series of cyclodextrins (CDs) was investigated in the solid state using thermal analysis and X-ray diffraction, while the possibility of enhancing its poor aqueous solubility with CDs was probed by means of equilibrium solubility and dissolution rate measurements. Single crystal X-ray diffraction studies of the inclusion complexes between 2ME and the derivatised cyclodextrins heptakis(2,6-di-O-methyl)-β-CD (DIMEB) and heptakis(2,3,6-tri-O-methyl)-β-CD (TRIMEB) revealed for the first time the nature of the encapsulation of a bioactive steroid by representative CD host molecules. Inclusion complexation invariably involves insertion of the D-ring of 2ME from the secondary side of each CD molecule, with the 17-OH group generally hydrogen bonding to a host glycosidic oxygen atom within the CD cavity, while the A-ring and part of the B-ring of 2ME protrude from the secondary side. In the case of the TRIMEB·2ME complex, there is evidence that complexation proceeds with mutual conformational adaptation of host and guest molecules. The aqueous solubility of 2ME was significantly enhanced by CDs, with DIMEB, TRIMEB, randomly methylated β-CD and hydroxypropyl-β-CD being the most effective hosts. The 2:1 host–guest β-CD inclusion complex, prepared by two methods, yielded very rapid dissolution in water at 37 °C relative to untreated 2ME, attaining complete dissolution within 15 minutes (co-precipitated complex) and 45 minutes (complex from kneading). PMID:26734107

  13. Effect of different polymers on avanafil-β-cyclodextrin inclusion complex: in vitro and in vivo evaluation.

    PubMed

    Soliman, Kareem AbuBakr; Ibrahim, Howida Kamal; Ghorab, Mahmoud Mohammed

    2016-10-15

    In this study, we examined the effect of different polymers on the chemical, physical and pharmacokinetic properties of avanafil-β-cyclodextrin (β-CD) inclusion complex. Equimolar mixtures of drug and β-CD were used to prepare 25 ternary drug-β-CD-polymer inclusion complexes using five different polymers, polyethylene glycol (PEG 4000), polyvinyl pyrrolidone (PVP K-30), chitosan, hydroxypropylmethyl cellulose, and hydroxyethyl cellulose, each in five different concentrations, 1, 3, 5, 7, and 10% (w/w). The addition of 10% (w/w) PEG 4000 resulted in a significant decrease of drug solubility, where the infrared spectra and differential scanning thermograms revealed an interaction between PEG 4000 and avanafil which hindered drug inclusion. In contrast, addition of 7% (w/w) PVP K-30 facilitated drug inclusion as concluded from differential scanning thermograms, X-ray diffraction patterns and scanning electron micrographs. This resulted in a subsequent improvement in drug solubility and in vitro dissolution. This ‎formula was chemically and physically stable for 6 ‎months under accelerated storage conditions. The formula had a relative bioavailability of 125.56% in rabbits as compared to conventional commercially available avanafil‎ tablets (Spedra(®)).

  14. Effect of different polymers on avanafil-β-cyclodextrin inclusion complex: in vitro and in vivo evaluation.

    PubMed

    Soliman, Kareem AbuBakr; Ibrahim, Howida Kamal; Ghorab, Mahmoud Mohammed

    2016-10-15

    In this study, we examined the effect of different polymers on the chemical, physical and pharmacokinetic properties of avanafil-β-cyclodextrin (β-CD) inclusion complex. Equimolar mixtures of drug and β-CD were used to prepare 25 ternary drug-β-CD-polymer inclusion complexes using five different polymers, polyethylene glycol (PEG 4000), polyvinyl pyrrolidone (PVP K-30), chitosan, hydroxypropylmethyl cellulose, and hydroxyethyl cellulose, each in five different concentrations, 1, 3, 5, 7, and 10% (w/w). The addition of 10% (w/w) PEG 4000 resulted in a significant decrease of drug solubility, where the infrared spectra and differential scanning thermograms revealed an interaction between PEG 4000 and avanafil which hindered drug inclusion. In contrast, addition of 7% (w/w) PVP K-30 facilitated drug inclusion as concluded from differential scanning thermograms, X-ray diffraction patterns and scanning electron micrographs. This resulted in a subsequent improvement in drug solubility and in vitro dissolution. This ‎formula was chemically and physically stable for 6 ‎months under accelerated storage conditions. The formula had a relative bioavailability of 125.56% in rabbits as compared to conventional commercially available avanafil‎ tablets (Spedra(®)). PMID:27576665

  15. Interaction Mode between Inclusion Complex of Vitamin K3 with γ- Cyclodextrin and Herring-Sperm DNA.

    PubMed

    Tang, Yan; Cai, Li; Xue, Kang; Wang, Chunling; Xiong, Xiaoli

    2016-05-01

    Methods including spectroscopy, electronic chemistry and thermodynamics were used to study the inclusion effect between γ-cyclodextrin (CD) and vitamin K3(K3), as well as the interaction mode between herring-sperm DNA (hsDNA) and γ-CD-K3 inclusion complex. The results from ultraviolet spectroscopic method indicated that VK3 and γ-CD formed 1:1 inclusion complex, with the inclusion constant Kf = 1.02 × 10(4) L/mol, which is based on Benesi-Hildebrand's viewpoint. The outcomes from the probe method and Scatchard methods suggested that the interaction mode between γ-CD-K3 and DNA was a mixture mode, which included intercalation and electrostatic binding effects. The binding constants were K (θ)25°C = 2.16 × 10(4) L/mol, and K(θ)37°C = 1.06 × 10(4) L/mol. The thermodynamic functions of the interaction between γ-CD-K3 and DNA were ΔrHm(θ) = -2.74 × 10(4) J/mol, ΔrSm(θ) = 174.74 J·mol(-1)K(-1), therefore, both ΔrHm(θ) (enthalpy) and ΔrSm(θ) (entropy) worked as driven forces in this action.

  16. Solid-state flurbiprofen and methyl-β-cyclodextrin inclusion complexes prepared using a single-step, organic solvent-free supercritical fluid process.

    PubMed

    Rudrangi, Shashi Ravi Suman; Kaialy, Waseem; Ghori, Muhammad U; Trivedi, Vivek; Snowden, Martin J; Alexander, Bruce David

    2016-07-01

    The aim of this study was to enhance the apparent solubility and dissolution properties of flurbiprofen through inclusion complexation with cyclodextrins. Especially, the efficacy of supercritical fluid technology as a preparative technique for the preparation of flurbiprofen-methyl-β-cyclodextrin inclusion complexes was evaluated. The complexes were prepared by supercritical carbon dioxide processing and were evaluated by solubility, differential scanning calorimetry, X-ray powder diffraction, scanning electron microscopy, practical yield, drug content estimation and in vitro dissolution studies. Computational molecular docking studies were conducted to study the possibility of molecular arrangement of inclusion complexes between flurbiprofen and methyl-β-cyclodextrin. The studies support the formation of stable molecular inclusion complexes between the drug and cyclodextrin in a 1:1 stoichiometry. In vitro dissolution studies showed that the dissolution properties of flurbiprofen were significantly enhanced by the binary mixtures prepared by supercritical carbon dioxide processing. The amount of flurbiprofen dissolved into solution alone was very low with 1.11±0.09% dissolving at the end of 60min, while the binary mixtures processed by supercritical carbon dioxide at 45°C and 200bar released 99.39±2.34% of the drug at the end of 30min. All the binary mixtures processed by supercritical carbon dioxide at 45°C exhibited a drug release of more than 80% within the first 10min irrespective of the pressure employed. The study demonstrated the single step, organic solvent-free supercritical carbon dioxide process as a promising approach for the preparation of inclusion complexes between flurbiprofen and methyl-β-cyclodextrin in solid-state.

  17. Preparation, release and physicochemical characterisation of ethyl butyrate and hexanal inclusion complexes with β- and γ-cyclodextrin.

    PubMed

    Zhang, Yang; Zhou, Yibin; Cao, Shengnan; Li, Songnan; Jin, Shanshan; Zhang, Shu

    2015-01-01

    Complexes of ethyl butyrate and hexanal encapsulated by β-cyclodextrin (β-CD) and γ-cyclodextrin (γ-CD) were prepared by coprecipitation, and gas chromatography was used to quantity the flavour compounds in the complexes. The ethyl butyrate-γ-CD complex had the highest inclusion ratio (12.20%) followed by the ethyl butyrate-β-CD, hexanal-β-CD and hexanal-γ-CD complexes (11.29, 4.41 and 3.33%, respectively). Release experiments were performed under different relative humidities (RH 93, 75 and 52%) and temperatures (4 and 25 °C). The flavour release behaviours of the complexes were described by the Avrami equation. The rate of flavour release was enhanced with both increasing temperature and RH, although the effect of RH was stronger. Physicochemical characterisation using FT-IR, XRD, DSC and SEM analyses demonstrated that crystalline complexes were formed. Both β-CD and γ-CD were able to encapsulate ethyl butyrate and hexanal, and lower RH and temperature were more suitable for the storage of these complexes.

  18. Improved thermal stability of polylactic acid (PLA) composite film via PLA-β-cyclodextrin-inclusion complex systems.

    PubMed

    Byun, Youngjae; Rodriguez, Katia; Han, Jung H; Kim, Young Teck

    2015-11-01

    The effects of the incorporation of PLA-β-cyclodextrin-inclusion complex (IC) and β-cyclodextrin (β-CD) on biopolyester PLA films were investigated. Thermal stability, surface morphology, barrier, and mechanical properties of the films were measured at varying IC (1, 3, 5, and 7%) and β-CD (1 and 5%) concentrations. The PLA-IC-composite films (IC-PLA-CFs) showed uniform morphological structure, while samples containing β-CD (β-CD-PLA-CFs) showed high agglomeration of β-CD due to poor interfacial interaction between β-CD and PLA moieties. According to the thermal property analysis, the 5% IC-PLA-CFs showed 6.6 times lower dimensional changes (6.5%) at the temperature range of 20-80°C than that of pure PLA film (43.0%). The increase of IC or β-CD content in the PLA-composite films shifted the glass transition and crystallization temperature to higher temperature regions. The crystallinity of both composite films improved by increasing IC or β-CD content. Both composite films had higher oxygen and water vapor permeability as IC or β-CD content increased in comparison to pure PLA film. All the composite films had less flexibility and lower tensile strength than the pure PLA film. In conclusion, this study shows that the IC technique is valuable to improve the thermal expansion stability of PLA-based films.

  19. Improved thermal stability of polylactic acid (PLA) composite film via PLA-β-cyclodextrin-inclusion complex systems.

    PubMed

    Byun, Youngjae; Rodriguez, Katia; Han, Jung H; Kim, Young Teck

    2015-11-01

    The effects of the incorporation of PLA-β-cyclodextrin-inclusion complex (IC) and β-cyclodextrin (β-CD) on biopolyester PLA films were investigated. Thermal stability, surface morphology, barrier, and mechanical properties of the films were measured at varying IC (1, 3, 5, and 7%) and β-CD (1 and 5%) concentrations. The PLA-IC-composite films (IC-PLA-CFs) showed uniform morphological structure, while samples containing β-CD (β-CD-PLA-CFs) showed high agglomeration of β-CD due to poor interfacial interaction between β-CD and PLA moieties. According to the thermal property analysis, the 5% IC-PLA-CFs showed 6.6 times lower dimensional changes (6.5%) at the temperature range of 20-80°C than that of pure PLA film (43.0%). The increase of IC or β-CD content in the PLA-composite films shifted the glass transition and crystallization temperature to higher temperature regions. The crystallinity of both composite films improved by increasing IC or β-CD content. Both composite films had higher oxygen and water vapor permeability as IC or β-CD content increased in comparison to pure PLA film. All the composite films had less flexibility and lower tensile strength than the pure PLA film. In conclusion, this study shows that the IC technique is valuable to improve the thermal expansion stability of PLA-based films. PMID:26299710

  20. Conjugates of methylated cyclodextrin derivatives and hydroxyethyl starch (HES): Synthesis, cytotoxicity and inclusion of anaesthetic actives

    PubMed Central

    Markenstein, Lisa; Appelt-Menzel, Antje; Metzger, Marco

    2014-01-01

    Summary The mono-6-deoxy-6-azides of 2,6-di-O-methyl-β-cyclodextrin (DIMEB) and randomly methylated-β-cyclodextrin (RAMEB) were conjugated to propargylated hydroxyethyl starch (HES) by Cu+-catalysed [2 + 3] cycloaddition. The resulting water soluble polymers showed lower critical solution temperatures (LCST) at 52.5 °C (DIMEB-HES) and 84.5 °C (RAMEB-HES), respectively. LCST phase separations could be completely avoided by the introduction of a small amount of carboxylate groups at the HES backbone. The methylated CDs conjugated to the HES backbone exhibited significantly lower cytotoxicities than the corresponding monomeric CD derivatives. Since the binding potentials of these CD conjugates were very high, they are promising candidates for new oral dosage forms of anaesthetic actives. PMID:25670977

  1. Supramolecular inclusion complexes between a coumarin dye and β-cyclodextrin, and attachment kinetics of thiolated β-cyclodextrin to gold surface

    NASA Astrophysics Data System (ADS)

    Velic, Dusan; Knapp, Martin; Köhler, Gottfried

    2001-10-01

    Supramolecular host-guest complexes formed between dye molecules, which are absorbing and fluorescing in the visible range, and cyclodextrin molecules are studied with the aim to generate a self-assembled nanostructured layer on a surface. Studies in solution show that an aminocoumarin dye, i.e. coumarin-6, binds strongly to β-cyclodextrin and yields fluorescent structures. The complex formation is substantiated by 17 nm blue shift of the fluorescence spectrum. The binding of thiolated cyclodextrin, 6-monodeoxy-6-monothio-β-cyclodextrin, to gold surface is then studied by induced change in the second-harmonic signal intensity generated from the surface. The saturation times of surface adsorption, as a measure of binding kinetics, are estimated for thiolated cyclodextrin as well as hexadecanethiol. The results support formation of self-assembled layers of the host molecules, which can serve as basis for the formation of supramolecular host-guest surface layers.

  2. Synthesis and surface grafting of a β-cyclodextrin dimer facilitating cooperative inclusion of 2,6-ANS.

    PubMed

    Städe, Lars W; Nielsen, Thorbjørn T; Duroux, Laurent; Wimmer, Reinhard; Shimizu, Kyoko; Larsen, Kim L

    2015-01-01

    A novel β-cyclodextrin (β-CD) dimer was synthesized and surface-grafted by click chemistry onto azide-functionalized quartz surfaces in order to introduce the cooperative features of the β-CD dimer to solid surfaces. Using NMR and fluorescence spectroscopy, it is shown that the free β-CD dimer forms a 1:1 complex with the fluorescent guest molecule, 2-anilinonaphthalene-6-sulfonic acid (otherwise known not to form 1:2 complexes with parent β-CD), with an apparent association constant of 7300 M(-1). Further, it is shown using total internal reflection fluorescence spectroscopy that the inclusion of the fluorescent guest into both cavities of the β-CD dimer is maintained when grafted onto a solid surface.

  3. Synthesis and surface grafting of a β-cyclodextrin dimer facilitating cooperative inclusion of 2,6-ANS

    PubMed Central

    Städe, Lars W; Nielsen, Thorbjørn T; Duroux, Laurent; Wimmer, Reinhard; Shimizu, Kyoko

    2015-01-01

    Summary A novel β-cyclodextrin (β-CD) dimer was synthesized and surface-grafted by click chemistry onto azide-functionalized quartz surfaces in order to introduce the cooperative features of the β-CD dimer to solid surfaces. Using NMR and fluorescence spectroscopy, it is shown that the free β-CD dimer forms a 1:1 complex with the fluorescent guest molecule, 2-anilinonaphthalene-6-sulfonic acid (otherwise known not to form 1:2 complexes with parent β-CD), with an apparent association constant of 7300 M−1. Further, it is shown using total internal reflection fluorescence spectroscopy that the inclusion of the fluorescent guest into both cavities of the β-CD dimer is maintained when grafted onto a solid surface. PMID:25977726

  4. Study on inclusion complexation between plant growth regulator 6-benzylaminopurine and β-cyclodextrin: Preparation, characterization and molecular modeling

    NASA Astrophysics Data System (ADS)

    Ge, Xia; He, Jiang; Yang, Ying; Qi, Fengming; Huang, Zheng; Lu, Ruihua; Huang, Lizhen; Yao, Xiaojun

    2011-05-01

    An inclusion complex between the plant growth regulator 6-benzylaminopurine (6-BA) and β-cyclodextrin (β-CD) was prepared. A 1:1 host-guest stoichiometry was conformed by elemental analysis and Job's plot. From phase solubility diagram, a calculated apparent stability constant was 259.49 L/mol. The obtained complex was found to significantly improve the water solubility of 6-BA, and there was a 4.1-fold increase in the presence of 12 mmol/L β-CD as compared with the free 6-BA. Thermoanalysis, NMR and IR spectra were applied to characterize the complex. 1H NMR and ROESY results indicated that the benzene ring of 6-BA was included into the β-CD cavity, which was in agreement with the most predominant configuration optimized by molecular modeling.

  5. Computational study on the conformations of CD38 and inclusion complexes of some lower-size large-ring cyclodextrins

    NASA Astrophysics Data System (ADS)

    Ivanov, Petko; Atanassov, Emanouil; Jaime, Carlos

    2014-01-01

    The conformations of CD38 were examined by conformational search with molecular dynamics simulations using the Glycam04 force field. The results were compared with previous ones for CD26, the largest cyclodextrin for which crystal data are available. Principal component analysis (PCA) was applied for post-processing of the simulation trajectories. Limited number of modes determine the overall deformations of the macroring of CD38. The longer perimeter of the macroring allowed the formation of a form not observed so far - a three-turn helix shaped as a short tube. In analogy with CD26, significant participation was monitored for conformations of CD38 with one-turn spirals at the opposite sides of the macroring linked together from the 'bottom' and from the 'top' with extended bridge spacers. Computationally were examined for the first time inclusion complexes of some lower-size LR-CDs, namely complexes of CDn (n = 13, 14, 26) with adamantane and of CD14 with 1-hydroxyadamantane. The macroring conformation of CD13 was not altered by the inclusion of the substrate molecule which acquired preferred positioning not in the middle of the cavity but rather close to the glucose residues at one of the sides. The same positioning of the small molecule in the cavity of the more flexible CD14 macroring enhanced the appearance of bent onto two conformation of this cyclodextrin. The most interesting behaviour presented the complex of CD26 with adamantane in which case the small molecule acts as a 'nucleation center' for the formation of a second helical turn about the substrate molecule.

  6. Assessment of ternary iron-cyclodextrin-2-naphthol complexes using NMR and fluorescence spectroscopies.

    PubMed

    Zheng, Weixi; Tarr, Matthew A

    2006-12-01

    Recent research has indicated that ternary complexes can be formed among carboxymethyl-beta-cyclodextrin, certain polycyclic aromatic hydrocarbons (PAHs) (e.g. anthracene and 2-naphthol), and Fe(2+) in aqueous solution. The formation of these ternary complexes has been suggested as the reason for improved reaction efficiency in iron catalyzed Fenton degradation (H(2)O(2)+Fe(2+)-->*OH+OH(-)+Fe(3+)) of PAHs and other pollutants. In the present work, several other cyclodextrins were examined to determine their ability to form similar ternary complexes with 2-naphthol and Fe(2+). Fluorescence and NMR techniques were employed in this study. Results showed that hydroxypropyl-beta-cyclodextrin, beta-cyclodextrin, and alpha-cyclodextrin were able to encapsulate 2-naphthol molecules, but their binding with Fe(2+) was weak. On the contrary, sulfated-beta-cyclodextrin has significant binding with Fe(2+), but it showed little inclusion of 2-naphthol molecules. Consequently, none of these four cyclodextrins formed significant amounts of ternary complexes in aqueous solution. The techniques used in this study provide useful methods for assessing the ability of cyclodextrins to form ternary complexes with guest compounds and metal ions.

  7. Host-guest inclusion complex of propafenone hydrochloride with α- and β-cyclodextrins: Spectral and molecular modeling studies

    NASA Astrophysics Data System (ADS)

    Siva, S.; Thulasidhasan, J.; Rajendiran, N.

    2013-11-01

    Host-guest inclusion complexes of cyclodextrins (CDs) with a potential cardiovascular drug propafenone hydrochloride (PFO), were prepared and characterized using absorption, fluorescence, time-resolved fluorescence, SEM, FT-IR, DSC, 1H NMR, XRD and PM3 methods. The spectral studies suggested the phenyl ring along with carbonyl group is present inside of CD cavity. Solvent studies revealed that the normal Stokes shifted band originates from the locally excited state and the large Stokes shifted band occurs due to the emission from ICT. Nanosecond time-resolved studies indicated that PFO exhibits biexponential decay in water and triexponential decay in CD, indicating the formation of 1:1 inclusion complex. The results from solid state studies showed important modifications in the physicochemical properties of free PFO. The ΔH, ΔG and ΔS of the complexation process were determined and it was found that the complexation processes were spontaneous. Investigations of thermodynamic and electronic properties confirmed the stability of the inclusion complex.

  8. Preparation, characterisation and antitumour activity of β-, γ- and HP-β-cyclodextrin inclusion complexes of oxaliplatin.

    PubMed

    Zhang, Da; Zhang, Jianqiang; Jiang, Kunming; Li, Ke; Cong, Yangwei; Pu, Shaoping; Jin, Yi; Lin, Jun

    2016-01-01

    Three water-soluble oxaliplatin complexes were prepared by inclusion complexation with β-cyclodextrin (β-CD), γ-CD and HP-β-CD. The structures of oxaliplatin/CDs were confirmed by NMR, FTIR, TGA, XRD as well as SEM analysis. The results show that the water solubility of oxaliplatin was increased in the complex with CDs in 1:1 stoichiometry inclusion modes, and the cyclohexane ring of oxaliplatin molecule was deeply inserted into the cavity of CDs. Moreover, the stoichiometry was established by a Job plot and the water stability constant (Kc) of oxaliplatin/CDs was calculated by phase solubility studies, all results show that the oxaliplatin/β-CD complex is more stable than free oxaliplatin, oxaliplatin/HP-β-CD and oxaliplatin/γ-CD. Meanwhile, the inclusion complexes displayed almost twice as high cytotoxicity compared to free oxaliplatin against HCT116 and MCF-7 cells. This satisfactory water solubility and higher cytotoxic activity of the oxaliplatin/CD complexes will potentially be useful for their application in anti-tumour therapy.

  9. Preparation, characterisation and antitumour activity of β-, γ- and HP-β-cyclodextrin inclusion complexes of oxaliplatin

    NASA Astrophysics Data System (ADS)

    Zhang, Da; Zhang, Jianqiang; Jiang, Kunming; Li, Ke; Cong, Yangwei; Pu, Shaoping; Jin, Yi; Lin, Jun

    2016-01-01

    Three water-soluble oxaliplatin complexes were prepared by inclusion complexation with β-cyclodextrin (β-CD), γ-CD and HP-β-CD. The structures of oxaliplatin/CDs were confirmed by NMR, FTIR, TGA, XRD as well as SEM analysis. The results show that the water solubility of oxaliplatin was increased in the complex with CDs in 1:1 stoichiometry inclusion modes, and the cyclohexane ring of oxaliplatin molecule was deeply inserted into the cavity of CDs. Moreover, the stoichiometry was established by a Job plot and the water stability constant (Kc) of oxaliplatin/CDs was calculated by phase solubility studies, all results show that the oxaliplatin/β-CD complex is more stable than free oxaliplatin, oxaliplatin/HP-β-CD and oxaliplatin/γ-CD. Meanwhile, the inclusion complexes displayed almost twice as high cytotoxicity compared to free oxaliplatin against HCT116 and MCF-7 cells. This satisfactory water solubility and higher cytotoxic activity of the oxaliplatin/CD complexes will potentially be useful for their application in anti-tumour therapy.

  10. Analysis of the microcrystalline inclusion compounds of triclosan with β-cyclodextrin and its tris-O-methylated derivative.

    PubMed

    Ramos, Ana I; Braga, Teresa M; Fernandes, José A; Silva, Patrícia; Ribeiro-Claro, Paulo J; Almeida Paz, Filipe A; de Fátima Silva Lopes, Maria; Braga, Susana S

    2013-06-01

    Solid 1:1 inclusion compounds of triclosan with native and permethylated β-cyclodextrin (β-CD and TRIMEB) were prepared by co-crystallisation and co-evaporation, respectively, and studied by FT-IR and (13)C{(1)H} CP/MAS NMR spectroscopies, thermogravimetric analysis, X-ray diffraction and theoretical calculations. Results showed that triclosan inclusion into TRIMEB afforded an amorphous solid, whilst β-CD·triclosan is composed of microcrystals belonging to two different phases. In the phase featuring larger crystals, X-ray diffraction was carried out and the β-CD host units, packing head-to-head in infinite channels, were refined; the geometry for the included but highly disordered triclosan molecules was assessed by theoretical calculations. The bacterial growth inhibitory action of the inclusion compounds was studied in comparison to that of pure triclosan on Gram-negative (Salmonella, Escherichia) and Gram-positive strains (Bacillus, Listeria, Enterococcus and Staphylococcus) typically associated with human pathologies, and also on environmental bacteria isolated from different soil and water sources. The antimicrobial activities obtained in the present work showed that, of the two CD hosts, TRIMEB brings the most favourable carrier effect: it reduced the toxicity of triclosan against some of the environmental strains and afforded slightly higher action against virulent strains. PMID:23523864

  11. Co-solvation effect on the binding mode of the α-mangostin/β-cyclodextrin inclusion complex.

    PubMed

    Rungnim, Chompoonut; Phunpee, Sarunya; Kunaseth, Manaschai; Namuangruk, Supawadee; Rungsardthong, Kanin; Rungrotmongkol, Thanyada; Ruktanonchai, Uracha

    2015-01-01

    Cyclodextrins (CDs) have been extensively utilized as host molecules to enhance the solubility, stability and bioavailability of hydrophobic drug molecules through the formation of inclusion complexes. It was previously reported that the use of co-solvents in such studies may result in ternary (host:guest:co-solvent) complex formation. The objective of this work was to investigate the effect of ethanol as a co-solvent on the inclusion complex formation between α-mangostin (α-MGS) and β-CD, using both experimental and theoretical studies. Experimental phase-solubility studies were carried out in order to assess complex formation, with the mechanism of association being probed using a mathematical model. It was found that α-MGS was poorly soluble at low ethanol concentrations (0-10% v/v), but higher concentrations (10-40% v/v) resulted in better α-MGS solubility at all β-CD concentrations studied (0-10 mM). From the equilibrium constant calculation, the inclusion complex is still a binary complex (1:1), even in the presence of ethanol. The results from our theoretical study confirm that the binding mode is binary complex and the presence of ethanol as co-solvent enhances the solubility of α-MGS with some effects on the binding affinity with β-CD, depending on the concentration employed. PMID:26734079

  12. Co-solvation effect on the binding mode of the α-mangostin/β-cyclodextrin inclusion complex

    PubMed Central

    Rungnim, Chompoonut; Phunpee, Sarunya; Kunaseth, Manaschai; Namuangruk, Supawadee; Rungsardthong, Kanin

    2015-01-01

    Summary Cyclodextrins (CDs) have been extensively utilized as host molecules to enhance the solubility, stability and bioavailability of hydrophobic drug molecules through the formation of inclusion complexes. It was previously reported that the use of co-solvents in such studies may result in ternary (host:guest:co-solvent) complex formation. The objective of this work was to investigate the effect of ethanol as a co-solvent on the inclusion complex formation between α-mangostin (α-MGS) and β-CD, using both experimental and theoretical studies. Experimental phase-solubility studies were carried out in order to assess complex formation, with the mechanism of association being probed using a mathematical model. It was found that α-MGS was poorly soluble at low ethanol concentrations (0–10% v/v), but higher concentrations (10–40% v/v) resulted in better α-MGS solubility at all β-CD concentrations studied (0–10 mM). From the equilibrium constant calculation, the inclusion complex is still a binary complex (1:1), even in the presence of ethanol. The results from our theoretical study confirm that the binding mode is binary complex and the presence of ethanol as co-solvent enhances the solubility of α-MGS with some effects on the binding affinity with β-CD, depending on the concentration employed. PMID:26734079

  13. Co-solvation effect on the binding mode of the α-mangostin/β-cyclodextrin inclusion complex.

    PubMed

    Rungnim, Chompoonut; Phunpee, Sarunya; Kunaseth, Manaschai; Namuangruk, Supawadee; Rungsardthong, Kanin; Rungrotmongkol, Thanyada; Ruktanonchai, Uracha

    2015-01-01

    Cyclodextrins (CDs) have been extensively utilized as host molecules to enhance the solubility, stability and bioavailability of hydrophobic drug molecules through the formation of inclusion complexes. It was previously reported that the use of co-solvents in such studies may result in ternary (host:guest:co-solvent) complex formation. The objective of this work was to investigate the effect of ethanol as a co-solvent on the inclusion complex formation between α-mangostin (α-MGS) and β-CD, using both experimental and theoretical studies. Experimental phase-solubility studies were carried out in order to assess complex formation, with the mechanism of association being probed using a mathematical model. It was found that α-MGS was poorly soluble at low ethanol concentrations (0-10% v/v), but higher concentrations (10-40% v/v) resulted in better α-MGS solubility at all β-CD concentrations studied (0-10 mM). From the equilibrium constant calculation, the inclusion complex is still a binary complex (1:1), even in the presence of ethanol. The results from our theoretical study confirm that the binding mode is binary complex and the presence of ethanol as co-solvent enhances the solubility of α-MGS with some effects on the binding affinity with β-CD, depending on the concentration employed.

  14. Analysis of the microcrystalline inclusion compounds of triclosan with β-cyclodextrin and its tris-O-methylated derivative.

    PubMed

    Ramos, Ana I; Braga, Teresa M; Fernandes, José A; Silva, Patrícia; Ribeiro-Claro, Paulo J; Almeida Paz, Filipe A; de Fátima Silva Lopes, Maria; Braga, Susana S

    2013-06-01

    Solid 1:1 inclusion compounds of triclosan with native and permethylated β-cyclodextrin (β-CD and TRIMEB) were prepared by co-crystallisation and co-evaporation, respectively, and studied by FT-IR and (13)C{(1)H} CP/MAS NMR spectroscopies, thermogravimetric analysis, X-ray diffraction and theoretical calculations. Results showed that triclosan inclusion into TRIMEB afforded an amorphous solid, whilst β-CD·triclosan is composed of microcrystals belonging to two different phases. In the phase featuring larger crystals, X-ray diffraction was carried out and the β-CD host units, packing head-to-head in infinite channels, were refined; the geometry for the included but highly disordered triclosan molecules was assessed by theoretical calculations. The bacterial growth inhibitory action of the inclusion compounds was studied in comparison to that of pure triclosan on Gram-negative (Salmonella, Escherichia) and Gram-positive strains (Bacillus, Listeria, Enterococcus and Staphylococcus) typically associated with human pathologies, and also on environmental bacteria isolated from different soil and water sources. The antimicrobial activities obtained in the present work showed that, of the two CD hosts, TRIMEB brings the most favourable carrier effect: it reduced the toxicity of triclosan against some of the environmental strains and afforded slightly higher action against virulent strains.

  15. Determination of formation constants and structural characterization of cyclodextrin inclusion complexes with two phenolic isomers: carvacrol and thymol

    PubMed Central

    Kfoury, Miriana; Landy, David; Ruellan, Steven; Auezova, Lizette; Greige-Gerges, Hélène

    2016-01-01

    Summary Carvacrol and thymol have been widely studied for their ability to control food spoilage and to extend shelf-life of food products due to their antimicrobial and antioxidant activities. However, they suffer from poor aqueous solubility and pronounced flavoring ability that limit their application in food systems. These drawbacks could be surpassed by encapsulation in cyclodextrins (CDs). Applications of their inclusion complexes with CDs were reported without investigating the inclusion phenomenon in deep. In this study, inclusion complexes were characterized in terms of formation constants (K f), complexation efficiency (CE), CD:guest molar ratio and increase in bulk formulation by using an UV–visible competitive method, phase solubility studies as well as 1H and DOSY 1H NMR titration experiments. For the first time, a new algorithmic treatment that combines the chemical shifts and diffusion coefficients variations for all guest protons was applied to calculate K f. The position of the hydroxy group in carvacrol and thymol did not affect the stoichiometry of the inclusion complexes but led to a different binding stability with CDs. 2D ROESY NMR experiments were also performed to prove the encapsulation and illustrate the stable 3D conformation of the inclusion complexes. The structural investigation was accomplished with molecular modeling studies. Finally, the radical scavenging activity of carvacrol and thymol was evaluated by the ABTS radical scavenging assay. An improvement of this activity was observed upon encapsulation. Taken together, these results evidence that the encapsulation in CDs could be valuable for applications of carvacrol and thymol in food. PMID:26877806

  16. Continuous lifetime distributions of β-cyclodextrin-anilinonaphthalene sulfonic acid inclusion complexes.

    PubMed

    Catena, G C; Bright, F V

    1991-03-01

    Fluorescence lifetimes are reported for a series of anilinonaphthalene sulfonate (ANS) probe molecules complexed with β-cyclodextrin (β-CD). The fluorescence decay kinetics are recovered by multifrequency phase and modulation measurements in concert with a global analysis scheme. In all cases studied, a continuous Lorentzian distribution of lifetimes is observed, resulting from the dynamical nature of the ANS-β-CD complex and free ANS. Trends are discussed and comparisons made between bound and free fluorophore and between different isomeric ANS structures.

  17. Evaluation of norbornene- beta-cyclodextrin-based monomers and oligomers as chiral selectors by means of nonaqueous capillary electrophoresis.

    PubMed

    Eder, K; Sinner, F; Mupa, M; Huber, C G; Buchmeiser, M R

    2001-01-01

    Norbornen-5-yl carboxylic acid and norbornen-5-ylmethylsilyl ether-based beta-cyclodextrins (beta-CDs) containing up to three norbornene ester and up to five norbornene silyl ether units have been prepared from beta-CD and norbornen-5-carboxylic chloride and norbornen-5-ylmethyldichlorosilane, respectively. Oligomers (n = 2-4) were prepared therefrom using ring-opening metathesis polymerization (ROMP). Monomeric and oligomeric substituted beta-CDs were evaluated as chiral selectors in nonaqueous capillary zone electrophoresis using 35 mM sodium bicarbonate in N-methylformamide (NMF) as background electrolyte. Both monomeric and oligomeric norbornene ester- and norbornene silyl ether-type selectors showed good enantioresolution for dansylated (DNS-) amino acids using concentrations of the chiral selector of up to 4% w/v. A significant improvement in resolution was observed upon the introduction of up to five norbornene silyl ether units into a beta-CD molecule, whereas higher degrees of substitution with norbornen-5-yl-carboxyl groups lead to a reduction in enantioresolution of DNS-amino acids. Thus, pentakis(norbornen-5-ylmethylhydroxysiloxyl)-beta-CD turned out to be superior to mono(norbornen-5-ylmethylhydroxysiloxyl)-beta-CD in terms of enantioresolution. Moreover, norbornene silyl ether-type selectors were found to be more efficient than norbornene ester-type selectors. Finally, oligomeric selectors were found to possess superior or at least comparable enantioselectivity in the separation of DNS-amino acids compared to the parent monomers. A maximum in enantioresolution was obtained with oligo(pentakis(norbornen-5-ylmethylhydroxysiloxyl)beta-CD).

  18. Mild oxidation of alcohols with o-iodoxybenzoic acid (IBX) in water/acetone mixture in the presence of beta-cyclodextrin.

    PubMed

    Surendra, K; Krishnaveni, N Srilakshmi; Reddy, M Arjun; Nageswar, Y V D; Rao, K Rama

    2003-03-01

    A mild and efficient oxidation of alcohols with o-iodoxybenzoic acid (IBX) catalyzed by beta-cyclodextrin in a water/acetone mixture (86:14) has been developed. A series of alcohols were oxidized at room temperature in excellent yields.

  19. Entropy-controlled supramolecular photochirogenesis: enantiodifferentiating Z-E photoisomerization of cyclooctene included and sensitized by permethylated 6-O-benzoyl-beta-cyclodextrin.

    PubMed

    Fukuhara, Gaku; Mori, Tadashi; Wada, Takehiko; Inoue, Yoshihisa

    2005-09-01

    In contrast to the photosensitization with a non-methylated analogue, supramolecular photochirogenesis with a novel permethylated mono(6-O-benzoyl)-beta-cyclodextrin exhibited a critical dependence of the product's enantiomeric excess upon temperature, and possessed a large differential entropy of activation (-11 J K(-1) mol(-1)) for which the flexible host skeleton is likely to be responsible.

  20. Efficacy of attractive toxic sugar baits (ATSB) against Aedes albopictus with garlic oil encapsulated in beta-Cyclodextrin as the active ingredient

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We tested the efficacy of attractive toxic sugar bait (ATSB) with garlic oil microencapsulated in beta-cyclodextrin as active ingredient against Aedes albopictus in suburban Haifa, Israel. Two three-acre gardens with high numbers of Ae. albopictus were chosen for perimeter spray treatment with ATSB ...

  1. Formation of nanoparticles by cooperative inclusion between (S)-camptothecin-modified dextrans and β-cyclodextrin polymers.

    PubMed

    Nielsen, Thorbjørn Terndrup; Amiel, Catherine; Duroux, Laurent; Larsen, Kim Lambertsen; Städe, Lars Wagner; Wimmer, Reinhard; Wintgens, Véronique

    2015-01-01

    Novel (S)-camptothecin-dextran polymers were obtained by "click" grafting of azide-modified (S)-camptothecin and alkyne-modified dextrans. Two series based on 10 kDa and 70 kDa dextrans were prepared with a degree of substitution of (S)-camptothecin between 3.1 and 10.2%. The binding properties with β-cyclodextrin and β-cyclodextrin polymers were measured by isothermal titration calorimetry and fluorescence spectroscopy, showing no binding with β-cyclodextrin but high binding with β-cyclodextrin polymers. In aqueous solution nanoparticles were formed from association between the (S)-camptothecin-dextran polymers and the β-cyclodextrin polymers.

  2. Genistein in 1:1 inclusion complexes with ramified cyclodextrins: theoretical, physicochemical and biological evaluation.

    PubMed

    Danciu, Corina; Soica, Codruta; Oltean, Mircea; Avram, Stefana; Borcan, Florin; Csanyi, Erzsebet; Ambrus, Rita; Zupko, Istvan; Muntean, Delia; Dehelean, Cristina A; Craina, Marius; Popovici, Ramona A

    2014-01-27

    Genistein is one of the most studied phytocompound in the class of isoflavones, presenting a notable estrogenic activity and in vitro and/or in vivo benefits in different types of cancer such as those of the bladder, kidney, lung, pancreatic, skin and endometrial cancer. A big inconvenience for drug development is low water solubility, which can be solved by using hydrophilic cyclodextrins. The aim of this study is to theoretically analyze, based on the interaction energy, the possibility of a complex formation between genistein (Gen) and three different ramified cyclodextrins (CD), using a 1:1 molar ratio Gen:CD. Theoretical data were correlated with a screening of both in vitro and in vivo activity. Proliferation of different human cancer cell lines, antimicrobial activity and angiogenesis behavior was analyzed in order to see if complexation has a beneficial effect for any of the above mentioned activities and if so, which of the three CDs is the most suitable for the incorporation of genistein, and which may lead to future improved pharmaceutical formulations. Results showed antiproliferative activity with different IC50 values for all tested cell lines, remarkable antimicrobial activity on Bacillus subtilis and antiangiogenic activity as revealed by CAM assay. Differences regarding the intensity of the activity for pure and the three Gen complexes were noticed as explained in the text. The data represent a proof that the three CDs can be used for furtherer research towards practical use in the pharmaceutical and medical field.

  3. Inclusion complex of a new propiconazole derivative with β-cyclodextrin: NMR, ESI–MS and preliminary pharmacological studies

    PubMed Central

    Marangoci, Narcisa; Mares, Mihai; Silion, Mihaela; Fifere, Adrian; Varganici, Cristian; Nicolescu, Alina; Deleanu, Calin; Coroaba, Adina; Pinteala, Mariana; Simionescu, Bogdan C.

    2011-01-01

    A novel inclusion complex of the propiconazole nitrate (NO3PCZ) with β-cyclodextrin (β-CD) was prepared by treatment of propiconazole (PCZ) with an acidic nitrating agent. The formation of NO3PCZ and its inclusion complex with β-CD has been studied by NMR, ESI–MS, TGA, DSC methods. Using the undecoupled signal in the HMBC correlation spectra, almost identical coupling constants of CH from trizolic ring of PCZ and NO3PCZ compounds (1J(HC)3=207 Hz, 1J(CH)5=214 Hz, for PCZ; 1J(HC)3=208 Hz and 1J(CH)5=215 Hz, for NO3PCZ) were determined, confirming that the geometry of the heterocyclic skeleton is identical in both the forms. The 1:1 stoichiometry of the complex was determined by ESI–MS and was confirmed using Scott's equation in DMSO and Higuchi and Connors equation in water. The solubility curve obtained for NO3PCZ in presence of β-CD in distilled water was constructed, resulting in a solubility diagram of AL type. Solubility of NO3PCZ in water was determined by DLS studies. The results showed that NO3PCZ was encapsulated within the β-CD cavity with a binding constant of 330 M-1 in DMSO and 975 M-1 in water. Preliminary pharmacological studies showed higher antifungal activities for NO3PCZ and its inclusion complex, compared with its PCZ analog. The acute toxicity of the complex is smaller than the pure or modified drug, recommending the inclusion complex as future promising therapeutic agents. PMID:25755979

  4. Inclusion complex of a new propiconazole derivative with β-cyclodextrin: NMR, ESI-MS and preliminary pharmacological studies.

    PubMed

    Marangoci, Narcisa; Mares, Mihai; Silion, Mihaela; Fifere, Adrian; Varganici, Cristian; Nicolescu, Alina; Deleanu, Calin; Coroaba, Adina; Pinteala, Mariana; Simionescu, Bogdan C

    2011-05-01

    A novel inclusion complex of the propiconazole nitrate (NO3PCZ) with β-cyclodextrin (β-CD) was prepared by treatment of propiconazole (PCZ) with an acidic nitrating agent. The formation of NO3PCZ and its inclusion complex with β-CD has been studied by NMR, ESI-MS, TGA, DSC methods. Using the undecoupled signal in the HMBC correlation spectra, almost identical coupling constants of CH from trizolic ring of PCZ and NO3PCZ compounds ((1)J(HC)3=207 Hz, (1)J(CH)5=214 Hz, for PCZ; (1)J(HC)3=208 Hz and (1)J(CH)5=215 Hz, for NO3PCZ) were determined, confirming that the geometry of the heterocyclic skeleton is identical in both the forms. The 1:1 stoichiometry of the complex was determined by ESI-MS and was confirmed using Scott's equation in DMSO and Higuchi and Connors equation in water. The solubility curve obtained for NO3PCZ in presence of β-CD in distilled water was constructed, resulting in a solubility diagram of AL type. Solubility of NO3PCZ in water was determined by DLS studies. The results showed that NO3PCZ was encapsulated within the β-CD cavity with a binding constant of 330 M-1 in DMSO and 975 M-1 in water. Preliminary pharmacological studies showed higher antifungal activities for NO3PCZ and its inclusion complex, compared with its PCZ analog. The acute toxicity of the complex is smaller than the pure or modified drug, recommending the inclusion complex as future promising therapeutic agents.

  5. Inclusion complex of 2-naphthylamine-6-sulfonate with β-cyclodextrin: Intramolecular charge transfer versus hydrogen bonding effects

    NASA Astrophysics Data System (ADS)

    Abdel-Shafi, Ayman Ayoub

    2007-04-01

    The photophysical characteristics of the ground and excited states of 2-naphthylamine-6-sulfonate (2-NA-6-S) were investigated in different solvents and in β-cyclodextrin (β-CD). The spectral shifts are well correlated with Kamlet-Taft relationship. Multiple linear regression analysis indicated that both non-specific dipolar interaction and specific hydrogen bonding interactions play competitive roles in determining the position of the absorption maximum, while the dipolar interaction is the dominating parameter in determining the emission maximum. For the Stokes shift, both the nonspecific interaction and the hydrogen donation property of the solvent are participating equally. The molecular encapsulation of 2-NA-6-S by β-CD in aqueous solution has been studied by different spectroscopic techniques. Fluorescence measurements show that the dielectric constant of β-CD experienced by the included 2-NA-6-S is intermediate between water and methanol. The changes observed in the absorption and fluorescence spectra of 2-NA-6-S upon inclusion in β-CD allowed the association constant to be calculated and found to be 465 ± 100 and 495 ± 100 M -1, respectively. The changes observed for the chemical shifts of 2-NA-6-S and β-CD 1H NMR spectra and the corresponding 1H NMR spectra of their mixture confirmed the formation of the inclusion complex and showed that 2-NA-6-S is encapsulated in β-CD cavity in a tilted equatorial approach.

  6. Sol-gel technique for the preparation of beta-cyclodextrin derivative stationary phase in open-tubular capillary electrochromatography.

    PubMed

    Wang, Y; Zeng, Z; Guan, N; Cheng, J

    2001-07-01

    A novel open-tubular capillary electrochromatography (OT-CEC) column coated with 2,6-dibutyl-beta-cyclodextrin (DB-beta-CD) was prepared using sol-gel technique. In the sol-gel approach, owing to the three-dimensional network of sol-gel and the strong chemical bond between the stationary phase and the surface of capillary columns, good chromatographic characteristics and unique selectivity in separating isomers were shown. We achieved high efficiencies of 5-14 x 10(4) plates/m for the isomeric nitrophenols using the sol-gel-derived DB-beta-CD columns. The migration time reproducibility of the separation of the isomeric nitrophenols was better than 2.2% over five runs and 4.5% from column to column. These sol-gel-coated DB-beta-CD columns have shown improved separations of isomeric aminophenols, isomeric dihydroxybenzenes and isomeric nitrophenols, in comparison with the sol-gel matrix capillary column. The influences of buffer pH and methanol solvent on separation were investigated. The chiral resolution of enantiomers such as ibuprofen and binaphthol was explored primarily.

  7. Removal of organic compounds from water via cloud-point extraction with permethyl hydroxypropyl-[beta]-cyclodextrin

    SciTech Connect

    Warner-Schmid, D.; Hoshi, Suwaru; Armstrong, D.W. )

    1993-03-01

    Aqueous solutions of nonionic surfactants are known to undergo phase separations at elevated temperatures. This phenomenon is known as clouding,' and the temperature at which it occurs is refereed to as the cloud point. Permethylhydroxypropyl-[beta]-cyclodextrin (PMHP-[beta]-CD) was synthesized and aqueous solutions containing it were found to undergo similar cloud-point behavior. Factors that affect the phase separation of PMHP-[beta]-CD were investigated. Subsequently, the cloud-point extractions of several aromatic compounds (i.e., acetanilide, aniline, 2,2[prime]-dihydroxybiphenyl, N-methylaniline, 2-naphthol, o-nitroaniline, m-nitroaniline, p-nitroaniline, nitrobenzene, o-nitrophenol, m-nitrophenol, p-nitrophenol, 4-phenazophenol, 3-phenylphenol, and 2-phenylbenzimidazole) from dilute aqueous solution were evaluated. Although the extraction efficiency of the compounds varied, most can be quantitatively extracted if sufficient PMHP-[beta]-CD is used. For those few compounds that are not extracted (e.g., o-nitroacetanilide), the cloud-point procedure may be an effective one-step isolation or purification method. 18 refs., 2 figs., 3 tabs.

  8. Sorption of Ochratoxin A from aqueous solutions using beta-cyclodextrin-polyurethane polymer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ability of a cyclodextrin-polyurethane polymer to remove ochratoxin A from aqueous solutions, including wine, was examined by batch rebinding assays and equilibrium sorption isotherms. The results were fit to two parameter models. Freundlich analysis of the sorption isotherm indicates the polyme...

  9. Study of β-cyclodextrin inclusion complexes with volatile molecules geraniol and α-terpineol enantiomers in solid state and in solution

    NASA Astrophysics Data System (ADS)

    Ceborska, Magdalena; Szwed, Kamila; Asztemborska, Monika; Wszelaka-Rylik, Małgorzata; Kicińska, Ewa; Suwińska, Kinga

    2015-11-01

    Geraniol and α-terpineol are insoluble in water volatile compounds. α-Terpineol is a potentially important agent for medical applications. Formation of molecular complexes with β-cyclodextrin would lead to the increase of water solubility and bioavailability. β-Cyclodextrin forms 2:2 inclusion complexes with both enantiomers of α-terpineol and their precursor geraniol. Solid state complexes are thoroughly characterized by single X-ray crystallography and their stability over vast range of temperatures is proven by TG analysis. Intermolecular host-guest, host-host and guest-guest interactions give good insight into the nature of formed inclusion complexes. Stability constants of the complexes in solution are determined by HPLC.

  10. NMR, surface tension and conductance study to investigate host-guest inclusion complexes of three sequential ionic liquids with β-cyclodextrin in aqueous media

    NASA Astrophysics Data System (ADS)

    Barman, Siti; Ekka, Deepak; Saha, Subhadeep; Roy, Mahendra Nath

    2016-08-01

    Host-guest inclusion complexes of three sequential cationic room temperature surface active ionic liquids, benzyltrialkylammonium chloride [(C6H5CH2)N(CnH2n+1)3Cl; where n = 1, 2, 4] with β-cyclodextrin in aqueous media have been studied using surface tension, conductance and NMR spectroscopy. All the studies have suggested that the hydrophobic benzyl group of ionic liquids is encapsulated inside into the cavity of β-cyclodextrin and played a crucial role in supporting the formation of inclusion complexes. The variation of the thermodynamic parameters with guest size, shape is used to draw inferences about contributions to the overall binding by means of the driving forces, viz., hydrophobic effect, steric hindrance, van der Waal force, and electrostatic force.

  11. Sustained inhibition of intimal thickening. In vitro and in vivo effects of polymeric beta-cyclodextrin sulfate.

    PubMed Central

    Bachinsky, W B; Barnathan, E S; Liu, H; Okada, S S; Kuo, A; Raghunath, P N; Muttreja, M; Caron, R J; Tomaszewski, J E; Golden, M A

    1995-01-01

    Intimal thickening after vascular injury may be modulated in part by heparin binding growth factors. We hypothesized that placement of a therapeutic polymer in the periadventitial space capable of tightly binding growth factors might alter the vascular response to injury. We first demonstrated that incubation of rat aortic smooth muscle cells with an insoluble, sulfated polymer of beta-cyclodextrin (P-CDS) was associated with a dose-dependent inhibition of proliferation induced by fetal calf serum, fibroblast growth factor-2 (FGF-2), platelet-derived growth factor BB, or epidermal growth factor. Preincubation studies of P-CDS with FGF-2 revealed a very rapid removal of mitogenic activity. Using radiolabeled FGF-2 (0.25 microg/ml), we observed a very rapid association rate (0.34 +/- 0.07 min-1, n=4) and a very slow dissociation rate (3.3 +/- 0.2 X 10(-7) min-1) at 37 degrees C, suggesting a high affinity interaction. Using both Transwell and linear under-agarose assays, we demonstrated a significant inhibition of random migration (chemokinesis) by P-CDS. Unsulfated polymeric beta-cyclodextrin (P-CD) had little if any of these effects, suggesting that the high negative charge density of P-CDS was important for the effects. Finally, rats undergoing carotid artery balloon injury were randomized to treatment with periadventitial P-CDS or no treatment, and were killed at 4 (n=20), 14 (n=59), and 88 d (n=14). Morphometric analysis demonstrated significant and sustained inhibition of intimal thickening in P-CDS-treated rats at 14 (P < 0.01) and 88 d (P < 0.05) using absolute intimal area or intima/media area ratios. No inhibition was seen in a group of rats treated with P-CD. In P-CDS-treated rats, bromodeoxyuridine labeling studies revealed fewer labeled smooth muscle cells in the intima at 14 d (P=0.01), while staining with Evans blue revealed enhanced late endothelial cell regrowth. Thus, periadventitially applied sulfated beta-cyclodextrin polymer, which can tightly

  12. Linkage of α-cyclodextrin-terminated poly(dimethylsiloxanes) by inclusion of quasi bifunctional ferrocene.

    PubMed

    Ritter, Helmut; Knudsen, Berit; Durnev, Valerij

    2013-01-01

    We report the noncovalent linkage of terminally substituted oligo(dimethylsiloxanes) bearing α-cyclodextrins (α-CD) as host end groups for the cyclopentadienyl rings of ferrocene. This double complexation of unsubstituted ferrocene leads to a supramolecuar formation of the siloxane strands. Structural characterization was performed by the use of (1)H NMR and IR spectroscopy and by mass spectrometry. Electron microscopy studies and dynamic light scattering measurements show a significant decrease of the derivative size after the complexation with ferrocene. In addition, further evidence for the successful complexation of the end groups was verified by the shifts of the protons in the (1)H NMR spectra and in the correlation signals of the 2D ROESY NMR spectra.

  13. Poly-dopamine-beta-cyclodextrin: A novel nanobiopolymer towards sensing of some amino acids at physiological pH.

    PubMed

    Hasanzadeh, Mohammad; Sadeghi, Sattar; Bageri, Leyla; Mokhtarzadeh, Ahad; Karimzadeh, Ayub; Shadjou, Nasrin; Mahboob, Soltanali

    2016-12-01

    A novel nanobiopolymer film was electrodeposited on the surface of glassy carbon through cyclic voltammetry from dopamine, β-cyclodextrin, and phosphate buffer solution in physiological pH (7.40). The electrochemical behavior of polydopamine-Beta-cyclodextrin modified glassy carbon electrode was investigated for electro-oxidation and determination of some amino acids (l-Cysteine, l-Tyrosine, l-Glycine, and l-Phenylalanine). The modified electrode was applied for selected amino acid detection at physiological pH using cyclic voltammetry, differential pulse voltammetry and chronoamperometry, chronocoulometery. The linear concentration range of the proposed sensor for the l-Glycine, l-Cysteine, l-Tyrosine, and l-Phenylalanine were 0.2-70, 0.06-0.2, 0.01-0.1, and 0.2-10μM, while low limit of quantifications were 0.2, 0.06, 0.01, and 0.2μM, respectively. The modified electrode shows many advantages as an amino acid sensor such as simple preparation method without using any specific electron transfer mediator or specific reagent, good sensitivity, short response time, and long term stability. PMID:27612722

  14. Poly-dopamine-beta-cyclodextrin: A novel nanobiopolymer towards sensing of some amino acids at physiological pH.

    PubMed

    Hasanzadeh, Mohammad; Sadeghi, Sattar; Bageri, Leyla; Mokhtarzadeh, Ahad; Karimzadeh, Ayub; Shadjou, Nasrin; Mahboob, Soltanali

    2016-12-01

    A novel nanobiopolymer film was electrodeposited on the surface of glassy carbon through cyclic voltammetry from dopamine, β-cyclodextrin, and phosphate buffer solution in physiological pH (7.40). The electrochemical behavior of polydopamine-Beta-cyclodextrin modified glassy carbon electrode was investigated for electro-oxidation and determination of some amino acids (l-Cysteine, l-Tyrosine, l-Glycine, and l-Phenylalanine). The modified electrode was applied for selected amino acid detection at physiological pH using cyclic voltammetry, differential pulse voltammetry and chronoamperometry, chronocoulometery. The linear concentration range of the proposed sensor for the l-Glycine, l-Cysteine, l-Tyrosine, and l-Phenylalanine were 0.2-70, 0.06-0.2, 0.01-0.1, and 0.2-10μM, while low limit of quantifications were 0.2, 0.06, 0.01, and 0.2μM, respectively. The modified electrode shows many advantages as an amino acid sensor such as simple preparation method without using any specific electron transfer mediator or specific reagent, good sensitivity, short response time, and long term stability.

  15. On the use of dynamic fluorescence measurements to determine equilibrium and kinetic constants. The inclusion of pyrene in β-cyclodextrin cavities

    NASA Astrophysics Data System (ADS)

    De Feyter, Steven; van Stam, Jan; Boens, Noël; De Schryver, Fans C.

    1996-01-01

    An analysis of the kinetic identifiability of two-state excited-state processes goves the conditions which have to be fulfilled to make it possible to estimate the ground-state equilibrium constant from dynamic fluorescence data. For the aqueous system β-cyclodextrin:pyrene it turns out that the only kinetic parameters which can be estimated are (i) the deactivation rate constant of pyrene dissolved in the aqeuous mbulk, (ii) the rate of formation of a β-cyclodextrin:pyrene inclusion complex in the excited-state, which is negligibly slow, and (iii) the sum of the rate constats for deactivation to the ground-state and for exclusion into the aqueous bulk of the excited pyrene participating in inclusion complex formation. This sum cannot be separated into its individual rate constant contributions, and it is impossible to determine the ground-state equilibrium constant for the formation of β-cyclodextrin:pyrene inclusion complexes solely from fluorescence decay data, a fact not taken into account in the literature.

  16. N-phenyl-1-naphthylamine/β-cyclodextrin inclusion complex as a new fluorescent probe for rapid and visual detection of Pd2+

    NASA Astrophysics Data System (ADS)

    Maniyazagan, Munisamy; Mohandoss, Sonaimuthu; Sivakumar, Krishnamoorthy; Stalin, Thambusamy

    2014-12-01

    Inclusion complex between N-phenyl-1-naphthylamine (NPN) and β-cyclodextrin (β-CD) was studied by FT-IR, 1H and 2D NMR, XRD, FT-Raman, SEM and DSC techniques. The formation of 1:1 stoichiometric inclusion complex of NPN with β-CD was proposed based on the Nuclear magnetic resonance spectroscopy and Molecular docking study. The molecular encapsulation of host-guest inclusion complex based on simple chemosensor has high selectivity and sensitivity for the determination of Pd2+ ion. Host-guest inclusion complex as a spectroscopic probe is used for the detection of transition metal cation Pd2+. Coordination of this Pd2+ with (NPN/β-CD) inclusion complex exhibited a noticeable color change in the solution state it used for naked-eye detection.

  17. Kinetic study of the activation of banana juice enzymatic browning by the addition of maltosyl-beta-cyclodextrin.

    PubMed

    López-Nicolás, José M; Pérez-López, Antonio J; Carbonell-Barrachina, Angel; García-Carmona, Francisco

    2007-11-14

    In recent years, the use of cyclodextrins (CDs) as antibrowning agents in fruit juices has received growning attention. However, there has been no detailed study of the behavior of these molecules as substances, which can lead to the darkening of foods. In this paper, when the color of fresh banana juice was evaluated in the presence of different CDs, the evolution of several color parameters was the opposite of that observed in other fruit juices. Moreover, a kinetic model based on the complexation by CDs of the natural browning inhibitors present in banana is developed for the first time to clarify the enzymatic browning activation of banana juice. Finally, the apparent complexation constant between the natural polyphenoloxidase inhibitors present in banana juice and maltosyl-beta-CD was calculated (Kci = 27.026 +/- 0.212 mM (-1)). PMID:17929887

  18. Migration behavior of alkylphenols, bisphenol A and bisphenol S studied by capillary electrophoresis using sulfated beta-cyclodextrin.

    PubMed

    Mori, M; Naraoka, H; Tsue, H; Morozumi, T; Kaneta, T; Tanaka, S

    2001-06-01

    An application of capillary electrophoresis (CE) using sulfated beta-cyclodextrin (SCD) has been investigated for separating alkylphenols with different chain lengths, as well as bisphenol A and bisphenol S. In the absence of SCD in running buffer, all the phenols migrated at the same velocity as the electroosmotic flow (EOF), whereas the addition of SCD effectively led to the baseline separation of alkylphenols on the basis of the difference in the abilities to bind into the hydrophobic cavity of CD. The host-guest binding constants between analyte phenols and SCD were evaluated from Benesi-Hildebrand plots of the data obtained by two independent methods, CE and UV-visible measurements, demonstrating that the greater the hydrophobicity of the phenols, the larger the binding constants. The effects of organic solvents on the resolution for alkylphenols and bisphenols were also examined. This system using SCD was effective for the separation of 4-octylphenol and 4-nonylphenol isomers having longer alkyl chains.

  19. High shear mixing granulation of ibuprofen and beta-cyclodextrin: effects of process variables on ibuprofen dissolution.

    PubMed

    Ghorab, Mohamed K; Adeyeye, Moji Christianah

    2007-01-01

    The aims of the study were to evaluate the effect of high shear mixer (HSM) granulation process parameters and scale-up on wet mass consistency and granulation characteristics. A mixer torque rheometer (MTR) was employed to evaluate the granulating solvents used (water, isopropanol, and 1:1 vol/vol mixture of both) based on the wet mass consistency. Gral 25 and mini-HSM were used for the granulation. The MTR study showed that the water significantly enhanced the beta-cyclodextrin (beta CD) binding tendency and the strength of liquid bridges formed between the particles, whereas the isopropanol/water mixture yielded more suitable agglomerates. Mini-HSM granulation with the isopropanol/water mixture (1:1 vol/vol) showed a reduction in the extent of torque value rise by increasing the impeller speed as a result of more breakdown of agglomerates than coalescence. In contrast, increasing the impeller speed of the Gral 25 resulted in higher torque readings, larger granule size, and consequently, slower dissolution. This was due to a remarkable rise in temperature during Gral granulation that reduced the isopropanol/water ratio in the granulating solvent as a result of evaporation and consequently increased the beta CD binding strength. In general, the HSM granulation retarded ibuprofen dissolution compared with the physical mixture because of densification and agglomeration. However, a successful HSM granulation scale-up was not achieved due to the difference in the solvent mixture's effect from 1 scale to the other. PMID:18181545

  20. Kinetics of inhibition of polyphenol oxidase mediated browning in apple juice by beta-cyclodextrin and L-ascorbate-2-triphosphate.

    PubMed

    Gacche, R N; Zore, G B; Ghole, V S

    2003-02-01

    Polyphenol Oxidase (PPO) mediated browning in raw fruits and vegetables is a major cause of quality deterioration in fruits and vegetables and derived food products. Here the rate of browning reaction in apple juice treated individually and in combination (1:1) of beta-Cyclodextrin (beta-CD) and L-Ascorbate-2-triphosphate (L-AATP) is described. It was observed that the rate of quinone formation can be minimized using a combination of beta-CD and L-AATP as compared to individual treatment with these agents. Kinetic experiments revealed that both compounds are non-competitive inhibitors of PPO.

  1. [Effect of β-cyclodextrin inclusion complex on transport of major components of Xiangfu Siwu decoction essential oil in Caco-2 cell monolayer model].

    PubMed

    Xi, Jun-zuan; Qian, Da-wei; Duan, Jin-ao; Liu, Pei; Zhu, Yue; Zhu, Zhen-hua; Zhang, Li

    2015-08-01

    Although the essential oil of Xiangfu Siwu decoction (XFSWD) has strong pharmacological activity, its special physical and chemical properties restrict the clinical application and curative effect. In this paper, Xiangfu Siwu decoction essential oil (XFS-WO) was prepared by forming inclusion complex with β-cyclodextrin (β-CD). The present study is to investigate the effect of β-CD inclusion complex on the transport of major components of XFSWO using Caco-2 cell monolayer model, thus to research the effect of this formation on the absorption of drugs with low solubility and high permeability, which belong to class 2 in biopharmaceutics classification system. A sensitive and rapid UPLC-MS/MS method was developed for simultaneous quantification of senkyunolide A, 3-n-butylphthalide, Z-ligustilide, dehydrocostus lactone and α-cyperone, which are active compounds in XFSWO. The transport parameters were analyzed and compared in free oil and its β-CD inclusion complex. The result revealed that the formation of XFSWO/β-CD inclusion complex has significantly increased the transportation and absorption of major active ingredients than free oil. Accordingly, it can be speculated that cyclodextrin inclusion complex can improve bioavailability of poorly water-soluble drugs. Above all these mentioned researches, it provided foundation and basis for physiological disposition and pharmaceutical study of XFSWD. PMID:26677694

  2. [Effect of β-cyclodextrin inclusion complex on transport of major components of Xiangfu Siwu decoction essential oil in Caco-2 cell monolayer model].

    PubMed

    Xi, Jun-zuan; Qian, Da-wei; Duan, Jin-ao; Liu, Pei; Zhu, Yue; Zhu, Zhen-hua; Zhang, Li

    2015-08-01

    Although the essential oil of Xiangfu Siwu decoction (XFSWD) has strong pharmacological activity, its special physical and chemical properties restrict the clinical application and curative effect. In this paper, Xiangfu Siwu decoction essential oil (XFS-WO) was prepared by forming inclusion complex with β-cyclodextrin (β-CD). The present study is to investigate the effect of β-CD inclusion complex on the transport of major components of XFSWO using Caco-2 cell monolayer model, thus to research the effect of this formation on the absorption of drugs with low solubility and high permeability, which belong to class 2 in biopharmaceutics classification system. A sensitive and rapid UPLC-MS/MS method was developed for simultaneous quantification of senkyunolide A, 3-n-butylphthalide, Z-ligustilide, dehydrocostus lactone and α-cyperone, which are active compounds in XFSWO. The transport parameters were analyzed and compared in free oil and its β-CD inclusion complex. The result revealed that the formation of XFSWO/β-CD inclusion complex has significantly increased the transportation and absorption of major active ingredients than free oil. Accordingly, it can be speculated that cyclodextrin inclusion complex can improve bioavailability of poorly water-soluble drugs. Above all these mentioned researches, it provided foundation and basis for physiological disposition and pharmaceutical study of XFSWD.

  3. Inclusion complexation of sulfapyridine with α- and β-cyclodextrins: Spectral and molecular modeling study

    NASA Astrophysics Data System (ADS)

    Rajendiran, N.; Siva, S.; Saravanan, J.

    2013-12-01

    The inclusion complexes of sulfapyridine (SFP) with α-CD and β-CD were investigated by absorption, fluorescence, time-resolved fluorescence, FTIR, DSC, XRD, 1H NMR, SEM, TEM and molecular modeling methods. The normal fluorescence takes place from locally excited (LE) state while twisted intramolecular charge transfer (TICT) is responsible for highly Stokes shifted fluorescence. The enhancement of TICT emission in both CDs suggesting that the inclusion process plays the major role in this emission. The spectral shifts revealed that part of pyridine ring of SFP is entrapped in the CDs cavities. TEM images confirmed round shaped nanoparticles with the average size about 20-50 nm were observed in SFP with α-CD and β-CD inclusion complexes. PM3 calculations have suggested that the large stabilization of excited singlet state of SFP with twisted conformation occurring at the amide SN bond between the electron donor group (aniline ring) and the electron acceptor group (pyridine ring).

  4. pH and temperature stability of (-)-epigallocatechin-3-gallate-β-cyclodextrin inclusion complex-loaded chitosan nanoparticles.

    PubMed

    Liu, Fei; Majeed, Hamid; Antoniou, John; Li, Yue; Ma, Yun; Yokoyama, Wallace; Ma, Jianguo; Zhong, Fang

    2016-09-20

    The oxidative stability of (-)-epigallocatechin-3-gallate (EGCG) incorporated as inclusion complexes (ICs) in sulfobutylether-β-cyclodextrin sodium (SBE-β-CD) and then ionotropically crosslinked with chitosan hydrochloride (CSH) into nanoparticles were investigated. EGCG-loaded CSH-SBE-β-CD nanoparticles (CSNs) were physically unstable at higher pH and temperature. The particle size of CSNs was unchanged in the pH range of 3-5, but the microenvironment of EGCG-IC appeared to be intact until the pH increased to 6.5 by fluorescence spectroscopy. The physical structure of EGCG-ICs was also affected during storage in addition to CSNs, which was further affected as temperature increased from 25 to 55°C. The decrease in antioxidant activities of EGCG-ICs and free EGCG with increasing pH, storage time and temperature were modest compared to the prominent decreases in antioxidant activities of EGCG-loaded CSNs. The extreme entrapment of EGCG-ICs and/or free EGCG in the aggregated CSNs restricted the release of EGCG, thus inhibiting the antioxidant activities.

  5. Biodiesel fuel production from waste cooking oil by the inclusion complex of heteropoly acid with bridged bis-cyclodextrin.

    PubMed

    Zou, Changjun; Zhao, Pinwen; Shi, Lihong; Huang, Shaobing; Luo, Pingya

    2013-10-01

    The inclusion complex of Cs2.5H0.5PW12O40 with bridged bis-cyclodextrin (CsPW/B) is prepared as a highly efficient catalyst for the direct production of biodiesel via the transesterification of waste cooking oil. CsPW/B is characterized by X-ray diffraction, and the biodiesel is analyzed by Gas Chromatography-Mass Spectrometer. The conversion rate of waste cooking oil is up to 94.2% under the optimum experimental conditions that are methanol/oil molar ratio of 9:1, catalyst dosage of 3 wt%, temperature of 65 °C and reaction time of 180 min. The physical properties of biodiesel sample satisfy the requirement of ASTM D6751 standards. The novel CsPW/B catalyst used for the transesterification can lead to 96.9% fatty acid methyl esters and 86.5% of the biodiesel product can serve as the ideal substitute for diesel fuel, indicating its excellent potential application in biodiesel production.

  6. Release studies of trans-anethole from β-cyclodextrin solid inclusion complexes by Multiple Headspace Extraction.

    PubMed

    Kfoury, Miriana; Auezova, Lizette; Greige-Gerges, Hélène; Larsen, Kim L; Fourmentin, Sophie

    2016-10-20

    This study aimed to evaluate the effect of the preparation method, temperature and humidity on the release of aroma from β-cyclodextrin (β-CD) solid inclusion complexes (IC). Therefore β-CD/trans-anethole (β-CD/AN) IC were prepared by freeze-drying (FD) and co-precipitation coupled to FD (Cop-FD). Release experiments were performed at various temperatures and relative humidities (RH). Multiple headspace extraction-gas chromatography (MHE) was used to determine the loading capacity (LC) and encapsulation efficiency (EE%) and perform release studies. Results underlined that the quantification of encapsulated AN by MHE requires the IC dissolution. The release of AN was accelerated by increases in RH and temperature. However, it was quite negligible below 75% RH. The release behavior of AN was well simulated by Avrami's equation. Cop-FD IC retained more efficiently AN and the release depended on the preparation method and treatment conditions. Thus, the preparation method could be chosen based on the application. PMID:27474677

  7. Fabrication of electrospun polylactic acid nanofilm incorporating cinnamon essential oil/β-cyclodextrin inclusion complex for antimicrobial packaging.

    PubMed

    Wen, Peng; Zhu, Ding-He; Feng, Kun; Liu, Fang-Jun; Lou, Wen-Yong; Li, Ning; Zong, Min-Hua; Wu, Hong

    2016-04-01

    A novel antimicrobial packaging material was obtained by incorporating cinnamon essential oil/β-cyclodextrin inclusion complex (CEO/β-CD-IC) into polylacticacid (PLA) nanofibers via electrospinning technique. The CEO/β-CD-IC was prepared by the co-precipitation method and SEM and FT-IR spectroscopy analysis indicated the successful formation of CEO/β-CD-IC, which improved the thermal stability of CEO. The CEO/β-CD-IC was then incorporated into PLA nanofibers by electrospinning and the resulting PLA/CEO/β-CD nanofilm showed better antimicrobial activity compared to PLA/CEO nanofilm. The minimum inhibitory concentration (MIC) of PLA/CEO/β-CD nanofilm against Escherichia coli and Staphylococcus aureus was approximately 1 mg/ml (corresponding CEO concentration 11.35 μg/ml) and minimum bactericidal concentration (MBC) was approximately 7 mg/ml (corresponding CEO concentration 79.45 μg/ml). Furthermore, compared with the casting method, the mild electrospinning process was more favorable for maintaining greater CEO in the obtained film. The PLA/CEO/β-CD nanofilm can effectively prolong the shelf life of pork, suggesting it has potential application in active food packaging.

  8. Preparation and tribological properties of inclusion complex of β-cyclodextrin/dialkyl pentasulfide as additive in PEG-600 aqueous solution

    NASA Astrophysics Data System (ADS)

    Guan, Jiju; Xu, Xuefeng; Li, Gan; Peng, Wei

    2014-01-01

    The inclusion complex of β-cyclodextrin (β-CD) and dialkyl pentasulfide (DPS), in which DPS was incorporated into β-CD cavities, was prepared by a co-precipitation method. The tribological properties of the complex used as lubricant additive in PEG 600 aqueous solution were investigated by a four-ball tester. The complex exhibited better tribological properties than β-CD under different loads, and also showed better anti-friction performance than DPS in the latter half of the test duration. The tribological action mechanism of the complex on a steel surface was studied according to the X-ray photoelectron spectroscopy (XPS) analyses. The β-CD molecules of the complexes were decomposed into various molecular fragments and the DPS molecules were released under the friction condition. It revealed that thiolate and ferrous sulfide (FeS) films formed by DPS played a major role, and iron alkoxide and carbon deposition films formed by the friction fragments of β-CD mainly exhibited anti-friction property on FeS-to-FeS interface. The interactions among different films led to the formation of a mixed boundary lubrication film.

  9. Fabrication of electrospun polylactic acid nanofilm incorporating cinnamon essential oil/β-cyclodextrin inclusion complex for antimicrobial packaging.

    PubMed

    Wen, Peng; Zhu, Ding-He; Feng, Kun; Liu, Fang-Jun; Lou, Wen-Yong; Li, Ning; Zong, Min-Hua; Wu, Hong

    2016-04-01

    A novel antimicrobial packaging material was obtained by incorporating cinnamon essential oil/β-cyclodextrin inclusion complex (CEO/β-CD-IC) into polylacticacid (PLA) nanofibers via electrospinning technique. The CEO/β-CD-IC was prepared by the co-precipitation method and SEM and FT-IR spectroscopy analysis indicated the successful formation of CEO/β-CD-IC, which improved the thermal stability of CEO. The CEO/β-CD-IC was then incorporated into PLA nanofibers by electrospinning and the resulting PLA/CEO/β-CD nanofilm showed better antimicrobial activity compared to PLA/CEO nanofilm. The minimum inhibitory concentration (MIC) of PLA/CEO/β-CD nanofilm against Escherichia coli and Staphylococcus aureus was approximately 1 mg/ml (corresponding CEO concentration 11.35 μg/ml) and minimum bactericidal concentration (MBC) was approximately 7 mg/ml (corresponding CEO concentration 79.45 μg/ml). Furthermore, compared with the casting method, the mild electrospinning process was more favorable for maintaining greater CEO in the obtained film. The PLA/CEO/β-CD nanofilm can effectively prolong the shelf life of pork, suggesting it has potential application in active food packaging. PMID:26593582

  10. Fluorimetric and prototropic studies on the inclusion complexation of 3,3'-diaminodiphenylsulphone with β-cyclodextrin and its unusual behavior

    NASA Astrophysics Data System (ADS)

    Enoch, Muthu Vijayan; Rajamohan, Rajaram; Swaminathan, Meenakshisundaram

    2010-10-01

    The photophysical and photoprototropic properties of 3,3'-diaminodiphenylsulphone (3DADPS) in aqueous β-cyclodextrin (β-CDx) solution have been investigated using absorption and fluorescence spectral techniques. β-CDx forms 1:1 inclusion complex with 3DADPS as revealed by steady state and time-resolved fluorescence spectroscopy. This inclusion complex formation was also confirmed by the FT-IR and SEM image analysis of solid complex prepared by co-precipitation method. The existence of twisted intramolecular charge transfer state and the unusual red shift observed during inclusion complexation were analyzed and discussed. The ground and excited state acidity constants in β-CDx are reported. Based on the photophysical and photoprototropic characteristics of 3DADPS in β-CDx, the structure of the 1:1 inclusion complex is proposed.

  11. Using inclusion complexes with cyclodextrins to explore the aggregation behavior of a ruthenium metallosurfactant.

    PubMed

    Iza, Nerea; Guerrero-Martínez, Andrés; Tardajos, Gloria; Ortiz, María José; Palao, Eduardo; Montoro, Teresa; Radulescu, Aurel; Dreiss, Cécile A; González-Gaitano, Gustavo

    2015-03-10

    The aggregation behavior of a chiral metallosurfactant, bis(2,2'-bipyridine)(4,4'-ditridecyl-2,2'-bipyridine)ruthenium(II) dichloride (Ru2(4)C13), synthesized as a racemic mixture was characterized by small-angle neutron scattering, light scattering, NMR, and electronic spectroscopies. The analysis of the SANS data indicates that micelles are prolate ellipsoids over the range of concentrations studied, with a relatively low aggregation number, and the micellization takes place gradually with increasing concentration. The presence of cyclodextrins (β-CD and γ-CD) induces the breakup of the micelles and helps to establish that micellization occurs at a very slow exchange rate compared to the NMR time scale. The open structure of this metallosurfactant enables the formation of very stable complexes of 3:1 stoichiometry, in which one CD threads one of the hydrocarbon tails and two CDs the other, in close contact with the polar head. The complex formed with β-CD, more stable than the one formed with the wider γ-CD, is capable of resolving the Δ and Λ enantiomers at high CD/surfactant molar ratios. The chiral recognition is possible due to the very specific interactions taking place when the β-CD covers-via its secondary rim-part of the diimine moiety connected to the hydrophobic tails. A SANS model comprising a binary mixture of hard spheres (complex + micelles) was successfully used to study quantitatively the effect of the CDs on the aggregation of the surfactant.

  12. Formation of nanoparticles by cooperative inclusion between (S)-camptothecin-modified dextrans and β-cyclodextrin polymers

    PubMed Central

    Amiel, Catherine; Duroux, Laurent; Larsen, Kim Lambertsen; Städe, Lars Wagner; Wimmer, Reinhard; Wintgens, Véronique

    2015-01-01

    Summary Novel (S)-camptothecin–dextran polymers were obtained by “click” grafting of azide-modified (S)-camptothecin and alkyne-modified dextrans. Two series based on 10 kDa and 70 kDa dextrans were prepared with a degree of substitution of (S)-camptothecin between 3.1 and 10.2%. The binding properties with β-cyclodextrin and β-cyclodextrin polymers were measured by isothermal titration calorimetry and fluorescence spectroscopy, showing no binding with β-cyclodextrin but high binding with β-cyclodextrin polymers. In aqueous solution nanoparticles were formed from association between the (S)-camptothecin–dextran polymers and the β-cyclodextrin polymers. PMID:25670998

  13. Enzymatic synthesis of dimaltosyl-{beta}-cyclodextrin via a transglycosylation reaction using TreX, a Sulfolobus solfataricus P2 debranching enzyme

    SciTech Connect

    Kang, Hee-Kwon; Cha, Hyunju; Yang, Tae-Joo; Park, Jong-Tae; Lee, Seungjae; Kim, Young-Wan; Auh, Joong-Hyuck; Okada, Yasuyo; Kim, Jung-Wan; Cha, Jaeho; Kim, Chung Ho; Park, Kwan-Hwa

    2008-02-01

    Di-O-{alpha}-maltosyl-{beta}-cyclodextrin ((G2){sub 2}-{beta}-CD) was synthesized from 6-O-{alpha}-maltosyl-{beta}-cyclodextrin (G2-{beta}-CD) via a transglycosylation reaction catalyzed by TreX, a debranching enzyme from Sulfolobus solfataricus P2. TreX showed no activity toward glucosyl-{beta}-CD, but a transfer product (1) was detected when the enzyme was incubated with maltosyl-{beta}-CD, indicating specificity for a branched glucosyl chain bigger than DP2. Analysis of the structure of the transfer product (1) using MALDI-TOF/MS and isoamylase or glucoamylase treatment revealed it to be dimaltosyl-{beta}-CD, suggesting that TreX transferred the maltosyl residue of a G2-{beta}-CD to another molecule of G2-{beta}-CD by forming an {alpha}-1,6-glucosidic linkage. When [{sup 14}C]-maltose and maltosyl-{beta}-CD were reacted with the enzyme, the radiogram showed no labeled dimaltosyl-{beta}-CD; no condensation product between the two substrates was detected, indicating that the synthesis of dimaltosyl-{beta}-CD occurred exclusively via transglycosylation of an {alpha}-1,6-glucosidic linkage. Based on the HPLC elution profile, the transfer product (1) was identified to be isomers of 6{sup 1},6{sup 3}- and 6{sup 1},6{sup 4}-dimaltosyl-{beta}-CD. Inhibition studies with {beta}-CD on the transglycosylation activity revealed that {beta}-CD was a mixed-type inhibitor, with a K{sub i} value of 55.6 {mu}mol/mL. Thus, dimaltosyl-{beta}-CD can be more efficiently synthesized by a transglycosylation reaction with TreX in the absence of {beta}-CD. Our findings suggest that the high yield of (G2){sub 2}-{beta}-CD from G2-{beta}-CD was based on both the transglycosylation action mode and elimination of the inhibitory effect of {beta}-CD.

  14. Growth, shrinking, and breaking of pluronic micelles in the presence of drugs and/or beta-cyclodextrin, a study by small-angle neutron scattering and fluorescence spectroscopy.

    PubMed

    Valero, Margarita; Dreiss, Cécile A

    2010-07-01

    The associative structures between F127 Pluronic micelles and four drugs, namely, lidocaine (LD), pentobarbital sodium salt (PB), sodium naproxen (NP), and sodium salicylate (SAL), were studied by small-angle neutron scattering (SANS). Different outcomes for the micellar aggregates are observed, which are dependent on the chemical nature of the drug and the presence of charge or otherwise: the micelles grow with LD, are hardly modified with PB, and decrease in size with both NP and SAL. The partition coefficient, determined by fluorescence spectroscopy, is directly correlated to the amount of charge, following NP approximately SAL < PB < LD. All drugs are found to lie at the interfacial layer, with a slightly deeper localization of LD and more superficial for PB. All drugs can form inclusion complexes with heptakis(2,6-di-O-methyl) beta-cyclodextrin (hep2,6 beta-CD). Hep2,6 beta-CD, as shown in previous studies (Joseph, J.; Dreiss, C. A.; Cosgrove, T. Langmuir, 2008, 24, 10005-10010; Dreiss, C. A.; Nwabunwanne, E.; Liu, R.; Brooks, N. J. Soft Matter, 2009, 5, 1888-1896), is also able to form a complex with F127, resulting in micellar breakup. In the ternary mixtures, a fine balance of forces is involved, which results in drastic micellar changes, as observed from the SANS patterns. Depending on the ratio of drug, polymer, and hep2,6 beta-CD and the nature of the interactions (which is directly linked to the drug chemical structure), the presence of drug either hinders micellar breakup by beta-CD (at high enough concentration of LD or PB) or leads to micellar growth (NP). These effects are mainly attributed to a preferential drug/beta-CD interaction (except for PB), which, at least in the conditions studied here, explains the higher beta-CD concentration needed for micellar breakup to occur.

  15. Cholesterol depletion by methyl-beta-cyclodextrin enhances myoblast fusion and induces the formation of myotubes with disorganized nuclei.

    PubMed

    Mermelstein, Cláudia S; Portilho, Débora M; Medeiros, Rommel B; Matos, Aline R; Einicker-Lamas, Marcelo; Tortelote, Giovane G; Vieyra, Adalberto; Costa, Manoel L

    2005-02-01

    The formation of a skeletal muscle fiber begins with the withdrawal of committed mononucleated precursors from the cell cycle. These myoblasts elongate while aligning with each other, guided by recognition between their membranes. This step is followed by cell fusion and the formation of long striated multinucleated myotubes. We used methyl-beta-cyclodextrin (MCD) in primary cultured chick skeletal muscle cells to deplete membrane cholesterol and investigate its role during myogenesis. MCD promoted a significant increase in the expression of troponin T, enhanced myoblast fusion, and induced the formation of large multinucleated myotubes with nuclei being clustered centrally and not aligned at the cell periphery. MCD myotubes were striated, as indicated by sarcomeric alpha-actinin staining, and microtubule and desmin filament distribution was not altered. Pre-fusion MCD-treated myoblasts formed large aggregates, with cadherin and beta-catenin being accumulated in cell adhesion contacts. We also found that the membrane microdomain marker GM1 was not present as clusters in the membrane of MCD-treated myoblasts. Our data demonstrate that cholesterol is involved in the early steps of skeletal muscle differentiation.

  16. Enantiodifferentiating photoisomerization of cyclooctene included and sensitized by aroyl-beta-cyclodextrins: a critical enantioselectivity control by substituents.

    PubMed

    Lu, Runhua; Yang, Cheng; Cao, Yujuan; Tong, Linhui; Jiao, Wei; Wada, Takehiko; Wang, Zhizhong; Mori, Tadashi; Inoue, Yoshihisa

    2008-10-01

    A series of 6-O-benzoyl-beta-cyclodextrins (CDs) with methyl, methoxy, methoxycarbonyl, and bromo substituent(s) at the ortho-, meta-, and/or para-position(s) were synthesized as chiral sensitizing hosts for the use in supramolecular enantiodifferentiating photoisomerization of (Z)-cyclooctene (1Z) to its chiral (E)-isomer (1E). The complex stability constants (K(S)) of the modified beta-CDs with 1Z in aqueous methanol solutions were highly sensitive to the substituent(s) introduced to the benzoate moiety, and the log K(S) values decreased linearly with slightly different slopes with increasing methanol content. The enantiomeric excess (ee) of 1E obtained upon photosensitization with these hosts was a critical function of the size and position of the substituent, varying from almost zero to 46% ee. This indicates that even an apparently small structural difference between methyl and methoxy can critically affect the enantiodifferentiating photoisomerization of a guest included in the chiral cavity, probably through manipulation of both the orientation of ground-state 1Z and the subsequent rotational relaxation of excited 1Z inside the chiral cavity.

  17. Processing polymers with cyclodextrins

    NASA Astrophysics Data System (ADS)

    Williamson, Brandon Robert

    Cyclodextrins (CDs) are cyclic starch molecules that have the unique ability to include a variety of small molecules and polymers inside their cavities, forming "Inclusion Complexes" (ICs). While much work has been done to understand the formation and behavior of these ICs, far less is known about the fundamental property changes that can occur when CD is used to alter polymer chain morphology. The goal of my graduate research has been to discover different ways to improve upon existing polymer properties through CD processing, as well as explore the possibility of creating a novel type of IC using non-traditional forms of cyclodextrin. Poly(ε-caprolactone) (PCL) was processed with alpha-CD to form an IC. The cyclodextrin was then stripped away to yield a PCL with elongated, unentangled, and constrained polymer chains, a process referred to as coalescence. The physical and rheological property changes resulting from this coalescence were then examined. It was found that reorganizing PCL in this manner resulted in an increase in the melt crystallization temperature of up to 25°C. Coalescence also decreased the tan delta of the material and increased the average hardness and Young's modulus by 33 and 53%, respectively. Non-stoichiometric ICs (NS-ICs), or ICs with at least parts of some polymer chains uncovered, were formed between poly (methyl methacrylate) (PMMA) and gamma-CD as well as a synthesized poly(ε-caprolactone)-poly(propylene glycol)-poly(ε-caprolactone) (PCL-PPG-PCL) triblock copolymer and beta-CD. The property changes of the non-complexed polymer chains were then studied. The PMMA/gamma-CD NS-IC samples were determined to be extremely heterogeneous, however glass transition temperature increases of up to 27°C above that of as-received PMMA were observed. Diffraction data for the PMMA NS-ICs suggests slight crystallinity at partial coverage, with a similar crystal structure to that of the fully covered IC. XRD, DSC and FTIR data revealed an almost

  18. Polymer-free nanofibers from vanillin/cyclodextrin inclusion complexes: high thermal stability, enhanced solubility and antioxidant property.

    PubMed

    Celebioglu, Asli; Kayaci-Senirmak, Fatma; İpek, Semran; Durgun, Engin; Uyar, Tamer

    2016-07-13

    Vanillin/cyclodextrin inclusion complex nanofibers (vanillin/CD-IC NFs) were successfully obtained from three modified CD types (HPβCD, HPγCD and MβCD) in three different solvent systems (water, DMF and DMAc) via an electrospinning technique without using a carrier polymeric matrix. Vanillin/CD-IC NFs with uniform and bead-free fiber morphology were successfully produced and their free-standing nanofibrous webs were obtained. The polymer-free CD/vanillin-IC-NFs allow us to accomplish a much higher vanillin loading (∼12%, w/w) when compared to electrospun polymeric nanofibers containing CD/vanillin-IC (∼5%, w/w). Vanillin has a volatile nature yet, after electrospinning, a significant amount of vanillin was preserved due to complex formation depending on the CD types. Maximum preservation of vanillin was observed for vanillin/MβCD-IC NFs which is up to ∼85% w/w, besides, a considerable amount of vanillin (∼75% w/w) was also preserved for vanillin/HPβCD-IC NFs and vanillin/HPγCD-IC NFs. Phase solubility studies suggested a 1 : 1 molar complexation tendency between guest vanillin and host CD molecules. Molecular modelling studies and experimental findings revealed that vanillin : CD complexation was strongest for MβCD when compared to HPβCD and HPγCD in vanillin/CD-IC NFs. For vanillin/CD-IC NFs, water solubility and the antioxidant property of vanillin was improved significantly owing to inclusion complexation. In brief, polymer-free vanillin/CD-IC NFs are capable of incorporating a much higher loading of vanillin and effectively preserve volatile vanillin. Hence, encapsulation of volatile active agents such as flavor, fragrance and essential oils in electrospun polymer-free CD-IC NFs may have potential for food related applications by integrating the particularly large surface area of NFs with the non-toxic nature of CD and inclusion complexation benefits, such as high temperature stability, improved water solubility and an enhanced

  19. Polymer-free nanofibers from vanillin/cyclodextrin inclusion complexes: high thermal stability, enhanced solubility and antioxidant property.

    PubMed

    Celebioglu, Asli; Kayaci-Senirmak, Fatma; İpek, Semran; Durgun, Engin; Uyar, Tamer

    2016-07-13

    Vanillin/cyclodextrin inclusion complex nanofibers (vanillin/CD-IC NFs) were successfully obtained from three modified CD types (HPβCD, HPγCD and MβCD) in three different solvent systems (water, DMF and DMAc) via an electrospinning technique without using a carrier polymeric matrix. Vanillin/CD-IC NFs with uniform and bead-free fiber morphology were successfully produced and their free-standing nanofibrous webs were obtained. The polymer-free CD/vanillin-IC-NFs allow us to accomplish a much higher vanillin loading (∼12%, w/w) when compared to electrospun polymeric nanofibers containing CD/vanillin-IC (∼5%, w/w). Vanillin has a volatile nature yet, after electrospinning, a significant amount of vanillin was preserved due to complex formation depending on the CD types. Maximum preservation of vanillin was observed for vanillin/MβCD-IC NFs which is up to ∼85% w/w, besides, a considerable amount of vanillin (∼75% w/w) was also preserved for vanillin/HPβCD-IC NFs and vanillin/HPγCD-IC NFs. Phase solubility studies suggested a 1 : 1 molar complexation tendency between guest vanillin and host CD molecules. Molecular modelling studies and experimental findings revealed that vanillin : CD complexation was strongest for MβCD when compared to HPβCD and HPγCD in vanillin/CD-IC NFs. For vanillin/CD-IC NFs, water solubility and the antioxidant property of vanillin was improved significantly owing to inclusion complexation. In brief, polymer-free vanillin/CD-IC NFs are capable of incorporating a much higher loading of vanillin and effectively preserve volatile vanillin. Hence, encapsulation of volatile active agents such as flavor, fragrance and essential oils in electrospun polymer-free CD-IC NFs may have potential for food related applications by integrating the particularly large surface area of NFs with the non-toxic nature of CD and inclusion complexation benefits, such as high temperature stability, improved water solubility and an enhanced

  20. SUPRAMOLECULAR COMPOSITE MATERIALS FROM CELLULOSE, CHITOSAN AND CYCLODEXTRIN: FACILE PREPARATION AND THEIR SELECTIVE INCLUSION COMPLEX FORMATION WITH ENDOCRINE DISRUPTORS

    PubMed Central

    Duri, Simon; Tran, Chieu D.

    2013-01-01

    We have successfully developed a simple and one step method to prepare high performance supramolecular polysaccharide composites from cellulose (CEL), chitosan (CS) and (2,3,6-tri-O-acetyl)-α-, β- and γ-cyclodextrin (α-, β- and γ-TCD). In this method, [BMIm+Cl−], an ionic liquid (IL), was used as a solvent to dissolve and prepare the composites. Since majority (>88%) of the IL used was recovered for reuse, the method is recyclable. XRD, FT-IR, NIR and SEM were used to monitor the dissolution process and to confirm that the polysaccharides were regenerated without any chemical modifications. It was found that unique properties of each component including superior mechanical properties (from CEL), excellent adsorbent for pollutants and toxins (from CS) and size/structure selectivity through inclusion complex formation (from TCDs) remain intact in the composites. Specifically, results from kinetics and adsorption isotherms show that while CS-based composites can effectively adsorb the endocrine disruptors (polychlrophenols, bisphenol-A), its adsorption is independent on the size and structure of the analytes. Conversely, the adsorption by γ-TCD-based composites exhibits strong dependency on size and structure of the analytes. For example, while all three TCD-based composites (i.e., α-, β- and γ-TCD) can effectively adsorb 2-, 3- and 4-chlorophenol, only γ-TCD-based composite can adsorb analytes with bulky groups including 3,4-dichloro- and 2,4,5-trichlorophenol. Furthermore, equilibrium sorption capacities for the analytes with bulky groups by γ-TCD-based composite are much higher than those by CS-based composites. Together, these results indicate that γ-TCD-based composite with its relatively larger cavity size can readily form inclusion complexes with analytes with bulky groups, and through inclusion complex formation, it can strongly adsorb much more analytes and with size/structure selectivity compared to CS-based composites which can adsorb the

  1. Differentiating inclusion complexes from host molecules by tapping-mode atomic force microscopy.

    PubMed Central

    Muñoz-Botella, S; Martin, M A; del Castillo, B; Vázquez, L

    1996-01-01

    Tapping-mode atomic force microscopy imaging under different cantilever vibration amplitudes has been used to differentiate the host beta-cyclodextrin nanotubes from retinal/beta-cyclodextrin inclusion complex nanotubes. It was observed that both compounds were deformed differently by the applied probe force because of their different local rigidity. This change in the elasticity properties can be explained as a consequence of the inclusion process. This method shows that tapping-mode atomic force microscopy is an useful tool to map soft sample elasticity properties and to distinguish inclusion complexes from their host molecules on the basis of their different mechanical response. Images FIGURE 1 FIGURE 2 FIGURE 3 PMID:8804591

  2. Thermodynamic study of β-cyclodextrin-dye inclusion complexes using gradient flow injection technique and molecular modeling.

    PubMed

    Izadmanesh, Y; Ghasemi, Jahan B

    2016-08-01

    Gradient flow injection technique-diode array spectrophotometry was applied for β-cyclodextrin (β-CD)-dye inclusion complex studies. A single injection of a small amount of mixed β-CD-dye solution (100μl) into the carrier solution of the dye and recording the spectra gave the titration data. The mole ratio data were calculated by calibrating the dispersion pattern using a calibrator dye (rose bengal). Model-based multivariate methods were used to analyze the spectral-mole ratio data and, as a result, estimate stability constants and concentration-spectral profiles. Reliability was tested by applying this method to study the β-CD host-guest complexes with several dyes as guest molecules. Singular value decomposition (SVD) was used to select the chemical model and reduce noise. Molecular modeling provided the ability to predict the guest conformation-orientation (posing) within the cavity of β-CD and the nature of the involved interactions. Among those dyes showing observable spectral variation, the stoichiometric ratio of β-CD: dye (and log Kf) of methyl orange, fluorescein, phenol red, 4-(2-pyridylazo) resorcinol (PAR), and crystal violet were calculated to be 1:1 (4.26±0.01), 1:1 (1.53±0.08), 1:1 (3.11±0.04), 1:1 (1.06±0.12), and 2:1 (5.27±0.03), respectively. Compared with the classical method of titration, this method is simple and fast and has the advantage of needing reduced human interference. Molecular modeling facilitates a better understanding of the type of interactions and conformation of guest molecules in the β-CD cavity. The details of the proposed method are discussed in this paper.

  3. β-Cyclodextrin-Based Inclusion Complexation Bridged Biodegradable Self-Assembly Macromolecular Micelle for the Delivery of Paclitaxel.

    PubMed

    Chen, Yanzuo; Huang, Yukun; Qin, Dongdong; Liu, Wenchao; Song, Chao; Lou, Kaiyan; Wang, Wei; Gao, Feng

    2016-01-01

    In this study, a novel adamantanamine-paclitaxel (AD-PTX) incorporated oligochitosan- carboxymethyl-β-cyclodextrin (CSO-g-CM-β-CD) self-assembly macromolecular (CSO-g-CM-β-CD@AD-PTX) micelle was successfully prepared in water through sonication. The formed molecules were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance (NMR) spectroscopy, two-dimensional NMR, elemental analysis, and liquid chromatography-mass spectrometry, while the correspondent micelles were characterized by dynamic light scattering and transmission electron microscopy. We showed that the macromolecular micelle contained a spherical core-shell structure with a diameter of 197.1 ± 3.3 nm and zeta potential of -19.1 ± 4.3 mV. The CSO-g-CM-β-CD@AD-PTX micelle exhibited a high drug-loading efficacy up to 31.3%, as well as a critical micelle concentration of 3.4 × 10-7 M, which indicated good stability. Additionally, the in vitro release profile of the CSO-g-CM-β-CD@AD-PTX micelle demonstrated a long-term release pattern, 63.1% of AD-PTX was released from the micelle during a 30-day period. Moreover, the CSO-g-CM-β-CD@AD-PTX micelle displayed cytotoxicity at a sub-μM scale similar to PTX in U87 MG cells, and CSO-g-CM-β-CD exhibited a good safety profile by not manifesting significant toxicity at concentrations up to 100 μM. These results indicated that β-CD-based inclusion complexation resulting in biodegradable self-assembled macromolecular micelles can be utilized as nanocarrier, and may provide a promising platform for drug delivery in the future medical applications. PMID:26964047

  4. Thermodynamic study of β-cyclodextrin-dye inclusion complexes using gradient flow injection technique and molecular modeling

    NASA Astrophysics Data System (ADS)

    Izadmanesh, Y.; Ghasemi, Jahan B.

    2016-08-01

    Gradient flow injection technique-diode array spectrophotometry was applied for β-cyclodextrin (β-CD)-dye inclusion complex studies. A single injection of a small amount of mixed β-CD-dye solution (100 μl) into the carrier solution of the dye and recording the spectra gave the titration data. The mole ratio data were calculated by calibrating the dispersion pattern using a calibrator dye (rose bengal). Model-based multivariate methods were used to analyze the spectral-mole ratio data and, as a result, estimate stability constants and concentration-spectral profiles. Reliability was tested by applying this method to study the β-CD host-guest complexes with several dyes as guest molecules. Singular value decomposition (SVD) was used to select the chemical model and reduce noise. Molecular modeling provided the ability to predict the guest conformation-orientation (posing) within the cavity of β-CD and the nature of the involved interactions. Among those dyes showing observable spectral variation, the stoichiometric ratio of β-CD: dye (and log Kf) of methyl orange, fluorescein, phenol red, 4-(2-pyridylazo) resorcinol (PAR), and crystal violet were calculated to be 1:1 (4.26 ± 0.01), 1:1 (1.53 ± 0.08), 1:1 (3.11 ± 0.04), 1:1 (1.06 ± 0.12), and 2:1 (5.27 ± 0.03), respectively. Compared with the classical method of titration, this method is simple and fast and has the advantage of needing reduced human interference. Molecular modeling facilitates a better understanding of the type of interactions and conformation of guest molecules in the β-CD cavity. The details of the proposed method are discussed in this paper.

  5. Thermodynamic study of β-cyclodextrin-dye inclusion complexes using gradient flow injection technique and molecular modeling.

    PubMed

    Izadmanesh, Y; Ghasemi, Jahan B

    2016-08-01

    Gradient flow injection technique-diode array spectrophotometry was applied for β-cyclodextrin (β-CD)-dye inclusion complex studies. A single injection of a small amount of mixed β-CD-dye solution (100μl) into the carrier solution of the dye and recording the spectra gave the titration data. The mole ratio data were calculated by calibrating the dispersion pattern using a calibrator dye (rose bengal). Model-based multivariate methods were used to analyze the spectral-mole ratio data and, as a result, estimate stability constants and concentration-spectral profiles. Reliability was tested by applying this method to study the β-CD host-guest complexes with several dyes as guest molecules. Singular value decomposition (SVD) was used to select the chemical model and reduce noise. Molecular modeling provided the ability to predict the guest conformation-orientation (posing) within the cavity of β-CD and the nature of the involved interactions. Among those dyes showing observable spectral variation, the stoichiometric ratio of β-CD: dye (and log Kf) of methyl orange, fluorescein, phenol red, 4-(2-pyridylazo) resorcinol (PAR), and crystal violet were calculated to be 1:1 (4.26±0.01), 1:1 (1.53±0.08), 1:1 (3.11±0.04), 1:1 (1.06±0.12), and 2:1 (5.27±0.03), respectively. Compared with the classical method of titration, this method is simple and fast and has the advantage of needing reduced human interference. Molecular modeling facilitates a better understanding of the type of interactions and conformation of guest molecules in the β-CD cavity. The details of the proposed method are discussed in this paper. PMID:27111153

  6. β-Cyclodextrin-Based Inclusion Complexation Bridged Biodegradable Self-Assembly Macromolecular Micelle for the Delivery of Paclitaxel

    PubMed Central

    Chen, Yanzuo; Huang, Yukun; Qin, Dongdong; Liu, Wenchao; Song, Chao; Lou, Kaiyan; Wang, Wei; Gao, Feng

    2016-01-01

    In this study, a novel adamantanamine-paclitaxel (AD-PTX) incorporated oligochitosan- carboxymethyl-β-cyclodextrin (CSO-g-CM-β-CD) self-assembly macromolecular (CSO-g-CM-β-CD@AD-PTX) micelle was successfully prepared in water through sonication. The formed molecules were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance (NMR) spectroscopy, two-dimensional NMR, elemental analysis, and liquid chromatography-mass spectrometry, while the correspondent micelles were characterized by dynamic light scattering and transmission electron microscopy. We showed that the macromolecular micelle contained a spherical core-shell structure with a diameter of 197.1 ± 3.3 nm and zeta potential of −19.1 ± 4.3 mV. The CSO-g-CM-β-CD@AD-PTX micelle exhibited a high drug-loading efficacy up to 31.3%, as well as a critical micelle concentration of 3.4 × 10-7 M, which indicated good stability. Additionally, the in vitro release profile of the CSO-g-CM-β-CD@AD-PTX micelle demonstrated a long-term release pattern, 63.1% of AD-PTX was released from the micelle during a 30-day period. Moreover, the CSO-g-CM-β-CD@AD-PTX micelle displayed cytotoxicity at a sub-μM scale similar to PTX in U87 MG cells, and CSO-g-CM-β-CD exhibited a good safety profile by not manifesting significant toxicity at concentrations up to 100 μM. These results indicated that β-CD-based inclusion complexation resulting in biodegradable self-assembled macromolecular micelles can be utilized as nanocarrier, and may provide a promising platform for drug delivery in the future medical applications. PMID:26964047

  7. Synthesis of the novel β-cyclodextrin-chromophore inclusion compound and research on the electro-optic activity of its systems

    NASA Astrophysics Data System (ADS)

    Bo, Shuhui; Chen, Zhuo; Zhen, Zhen; Liu, Xinhou

    2011-10-01

    In the second order nonlinear (NLO) optics, interchromophore electrostatic interactions have been suggested as a major challenge of the poor efficiency in the poling induced polar order. In this article, we formed a β-cyclodextrinchromophore inclusion compound by embedding a dumb-bell shape chromophore in a β-cyclodextrin. Compared to hyperbranched chromophores, this inclusion compound could create a 360° steric hindrance and pull the distance between molecules. Then this inclusion compound could prevent chromophore aggregation and minimize the interactions which hamper higher nonlinear optical activity. The method of the refractive index for electro-optic materials which can determine the degree of chromophore aggregation in polymers was first proposed and confirmed in this work. These properties have provided a great promise in the fabrication of EO materials and devices.

  8. Characterization of aspartame-cyclodextrin complexation.

    PubMed

    Sohajda, Tamás; Béni, Szabolcs; Varga, Erzsébet; Iványi, Róbert; Rácz, Akos; Szente, Lajos; Noszál, Béla

    2009-12-01

    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. PMID:19586735

  9. Characterization of aspartame-cyclodextrin complexation.

    PubMed

    Sohajda, Tamás; Béni, Szabolcs; Varga, Erzsébet; Iványi, Róbert; Rácz, Akos; Szente, Lajos; Noszál, Béla

    2009-12-01

    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.

  10. New enzymatically polymerized copolymers from 4-tert-butylphenol and 4-ferrocenylphenol and their modification and inclusion complexes with β-cyclodextrin.

    PubMed

    Mondrzyk, Adam; Mondrzik, Beate; Gingter, Sabrina; Ritter, Helmut

    2012-01-01

    The enzymatically catalyzed synthesis of a copolymer of 4-tert-butylphenol and 4-ferrocenylphenol by horse radish peroxidase (HRP) in the presence of H(2)O(2) in a 1,4-dioxane/water system is described. Furthermore, polymer-analogous alkylation of the free hydroxy groups and subsequent click reaction with mono-6-azido-6-desoxy-β-cyclodextrin (N(3)-β-CD) was carried out. The formation of inter- and intramolecular inclusion complexes was investigated by DLS measurement. PMID:23243473

  11. Enantioselective determination of chlorpheniramine in various formulations by HPLC using carboxymethyl-beta-cyclodextrin as a chiral additive.

    PubMed

    Chen, Quan Cheng; Jeong, Su Jin; Hwang, Gwi Seo; Kim, Kyeong Ho; Kang, Jong Seong

    2008-04-01

    A chiral mobile phase HPLC method is described for chiral separation and determination of chlorpheniramine (CP) enantiomers in various commercial preparations. Chromatographic separation was achieved on a conventional ODS column with a mixture of aqueous sodium phosphate (5 mM) containing 0.5 mM carboxymethyl-beta-cyclodextrin, methanol and triethylamine (73:25:2, v/v/v, pH 4.3) as the mobile phase. The flow rate of isocratic elution was 0.24 mL/min and peaks were detected at 224 nm. The method was applied to nine commercial CP preparations in six dosage forms and CP enantiomers were well separated without any disturbance of other ingredients or impurities present. The results showed that only one preparation was d-CP and the others were dl-CP preparations. The contents of all the preparations were found to be in the range of 97%-104% of labeled contents. This method was economical and convenient, affording sufficient accuracy, precision and reproducibility, as well as sensitivity and selectivity.

  12. [Pharmacological studies on the clathrate compound of mobenzoxamine with beta-cyclodextrin. (I). Effects on the digestive system].

    PubMed

    Yokochi, E; Kohno, S; Ohata, K

    1988-11-01

    Effects of the clathrate compound of mobenzoxamine (MBX) with beta-cyclodextrin (MBX-CD), a new gastro-intestinal function modulator, on the digestive system were studied in comparison with those of metoclopramide, domperidone and trimebutine. MBX-CD showed inhibitory effects that were approximately 1/4 times as potent as metoclopramide on both apomorphine- and copper sulfate-induced emesis and about 1/40 times as potent as domperidone on apomorphine-induced emesis in dogs. In rats, MBX-CD enhanced gastric emptying as potently as metoclopramide, and only MBX-CD showed a clear amelioration of the delayed gastric emptying induced by BaCl2. Similarly, only MBX-CD showed an ameliorative effect on small intestinal transport accelerated by BaCl2 in mice. Though both MBX and trimebutine inhibited spontaneous contractions of the isolated guinea pig stomach and rabbit intestine, it seemed that the properties of these effects were different from those of papaverine. On isolated guinea pig ileum, MBX inhibited contractions induced by various agonists equally to or more potently than trimebutine or papaverine. The results suggest that MBX-CD or MBX acts extensively on the gastro-intestinal system for the reason that it has not only the respective properties of the gastro-intestinal function modulators used as the standards, but also its own characteristic effects. PMID:3243512

  13. Antiproliferative effect of methyl-beta-cyclodextrin in vitro and in human tumour xenografted athymic nude mice.

    PubMed Central

    Grosse, P. Y.; Bressolle, F.; Pinguet, F.

    1998-01-01

    The anti-tumour activity of methyl-beta-cyclodextrin (MEBCD), a cyclic oligosaccharide known for its interaction with the plasma membrane, was investigated in vitro and in vivo and compared with that of doxorubicin (DOX) in the human tumour models MCF7 breast carcinoma and A2780 ovarian carcinoma. In vitro proliferation was assessed using the MTT assay. In vivo studies were carried out using xenografted Swiss nude mice injected weekly i.p. with MEBCD at 300 or 800 mg kg(-1) or DOX at 2 mg kg(-1), during 2 months. Under these conditions, MEBCD was active against MCF7 and A2780 cell lines and tumour xenografts. For each tumour model, the tumoral volume of the xenografted mice treated with MEBCD was at least twofold reduced compared with the control group. In the MCF7 model, MEBCD (800 mg kg(-1)) was more active than DOX (2 mg kg(-1)). After 56 days of treatment with MEBCD, no toxicologically meaningful differences were observed in macroscopic and microscopic parameters compared with controls. The accumulation of MEBCD in normal and tumour tissues was also assessed using a chromatographic method. Results indicated that after a single injection of MEBCD, tumour, liver and kidneys accumulated the highest concentrations of MEBCD. These results provided a basis for the potential therapeutic application of MEBCD in cancer therapy. PMID:9820174

  14. Inclusion of chrysin in β-cyclodextrin nanocavity and its effect on antioxidant potential of chrysin: A spectroscopic and molecular modeling approach

    NASA Astrophysics Data System (ADS)

    Chakraborty, Sandipan; Basu, Soumalee; Lahiri, Ansuman; Basak, Soumen

    2010-08-01

    Chrysin is a naturally occurring flavone that possesses a wide range of important biological activities. β-Cyclodextrin (β-CD) on the other hand due to its property of encapsulating molecules that are hydrophobic in nature is widely applied as drug delivery vehicle. Here, we have investigated the inclusion of chrysin within β-CD in aqueous solution using spectroscopic and theoretical methods. The stoichiometry of this inclusion complex was established to be equimolar (1:1) and its equilibrium constant was determined. Estimation of the thermodynamic parameters of the inclusion complex showed that it is an enthalpy driven process. Our observations also inferred that van der Waal's interaction and hydrogen bonding are the key interactions that prevail in the complex. The process of inclusion not only increased the solubility of chrysin but also its antioxidant potential, as inferred from ABTS radical scavenging assay. Theoretical calculations show that destabilization of HOMO energies account for the higher antioxidant potential of chrysin upon inclusion. Molecular docking of chrysin with β-CD followed by molecular modeling of the obtained complexes yielded results consistent with our experimental observation. Combining our studies on solvatochromicity with cluster and interaction analyses, we suggest the preferred mode of inclusion to be through the A-ring of chrysin.

  15. Enhanced dissolution, stability and physicochemical characterization of ATRA/2-hydroxypropyl-β-cyclodextrin inclusion complex pellets prepared by fluid-bed coating technique.

    PubMed

    Chen, Zhongjian; Lu, Yi; Qi, Jianping; Wu, Wei

    2013-02-01

    The aim of this work was to prepare stable all-trans-retinoic acid (ATRA)/2-hydroxypropyl-β-cyclodextrin (HPCD) inclusion complex pellets with industrial feasible technology, the fluid-bed coating technique, using PVP K30 simultaneously as binder and reprecipitation retarder. The coating process was fluent with high coating efficiency. In vitro dissolution of the inclusion complex pellets in 5% w/v Cremopher EL solution was dramatically enhanced with no reprecipitation observed, and significantly improved stability against humidity (92.5% and 75% RH) and illumination (4500 lx ± 500 lx) was achieved by HPCD inclusion. Differential scanning calorimetry and powder X-ray diffractometry confirmed the absence of crystallinity of ATRA. Fourier transform-infrared spectrometry revealed interaction between ATRA and HPCD adding evidence on inclusion of ATRA moieties into HPCD cavities. Solid-state (13)C NMR spectrometry indicated possible inclusion of ATRA through the polyene chain, which was the main reason for the enhanced photostability. It is concluded that the fluid-bed coating technique has the potential use in the industrial preparation of ATRA/HPCD inclusion complex pellets. PMID:22304703

  16. Folate-conjugated beta-cyclodextrin-based polymeric micelles with enhanced doxorubicin antitumor efficacy.

    PubMed

    Zhang, Lu; Lu, Jiafei; Jin, Yangmin; Qiu, Liyan

    2014-10-01

    In order to enhance the antitumor effects of doxorubicin (DOX), a novel micellar vector with high DOX loading and tumor targeting function based on folate-conjugated amphiphilic copolymer folate-poly(ethylene glycol)-poly(d,l-lactide)-β-cyclodextrin (FA-PEL-CD) was constructed. Cytotoxicity and cellular uptake experiments were performed in HeLa, KB, and A549 cell lines expressing different amounts of folate receptors in order to evaluate the targeting effect of the folate modification. The antitumor experiments performed in a KB cell-xenografted nude mouse model showed that the treatment with 10mg/kg DOX loaded FA-PEL-CD micelles achieved approximately 86% of tumor growth inhibition compared to the control. Ex vivo fluorescence imaging experiments and histological examination confirmed that folate modification can enhance the antitumorigenesis efficacy and reduce the cardiotoxicity of DOX. These results suggest that FA-PEL-CD copolymer-based micelles are promising nanocarriers for targeted doxorubicin delivery, with improved antitumor efficacy and reduced toxicity in normal tissues. PMID:25058857

  17. Electrochemical and surface plasmon resonance characterization of β-cyclodextrin-based self-assembled monolayers and evaluation of their inclusion complexes with glucocorticoids

    NASA Astrophysics Data System (ADS)

    Frasconi, Marco; Mazzei, Franco

    2009-07-01

    This paper describes the characterization of a self-assembled β-cyclodextrin (β-CD)-derivative monolayer (β-CD-SAM) on a gold surface and the study of their inclusion complexes with glucocorticoids. To this aim the arrangement of a self-assembled β-cyclodextrin-derivative monolayer on a gold surface was monitored in situ by means of surface plasmon resonance (SPR) spectroscopy and double-layer capacitance measurements. Film thickness and dielectric constant were evaluated for a monolayer of β-CD using one-color-approach SPR. The selectivity of the β-CD host surface was verified by using electroactive species permeable and impermeable in the β-CD cavity. The redox probe was selected according to its capacity to permeate the β-CD monolayer and its electrochemical behavior. In order to evaluate the feasibility of an inclusion complex between β-CD-SAM with some steroids such as cortisol and cortisone, voltammetric experiments in the presence of the redox probes as molecules competitive with the steroids have been performed. The formation constant of the surface host-guest by β-CD-SAM and the steroids under study was calculated.

  18. Preparation, physicochemical analysis and molecular modeling investigation of 2,2‧-Bipyridine: β-Cyclodextrin inclusion complex in solution and solid state

    NASA Astrophysics Data System (ADS)

    Periasamy, R.; Kothainayaki, S.; Sivakumar, K.

    2015-11-01

    Supramolecular interaction between 2,2‧-Bipyridine (BPY) and β-Cyclodextrin (β-CD) has been investigated in solution and solid state. Non-covalent interaction between BPY and β-CD was studied in solution using absorption and fluorescence spectroscopy. Inclusion complex of BPY and β-CD was prepared in solid state by co-precipitation method and it was characterized using Fourier Transform Infra-red spectroscopy (FT-IR), Thermal analysis, Scanning Electron Microscopy (SEM), Powder X-ray diffractometry (XRD) and Atomic Force Microscopy (AFM). Binding constant values and 1:1 stoichiometry of the inclusion complex were calculated using Benesi-Hildebrand plots at 303 K. Using continuous variation method the 1:1 stoichiometry has been confirmed for BPY: β-CD complex. Thermodynamic parameter, ΔG of inclusion complex formation was determined and the negative value indicated that the inclusion process was an exergonic and spontaneous process. The most probable model of BPY: β-CD inclusion complex suggested by molecular docking studies was in good agreement with the results obtained by experimental methods.

  19. Use of cyclodextrins as a cosmetic delivery system for fragrance materials: linalool and benzyl acetate.

    PubMed

    Numanoğlu, Ulya; Sen, Tangül; Tarimci, Nilüfer; Kartal, Murat; Koo, Otilia M Y; Onyüksel, Hayat

    2007-01-01

    The aim of this study was to increase the stability and water solubility of fragrance materials, to provide controlled release of these compounds, and to convert these substances from liquid to powder form by preparing their inclusion complexes with cyclodextrins (CDs). For this purpose, linalool and benzyl acetate were chosen as the fragrance materials. The use of beta-cyclodextrin (beta CD) and 2-hydroxypropyl-beta-cyclodextrin (2-HP beta CD) for increasing the solubility of these 2 fragrance materials was studied. Linalool and benzyl acetate gave a B-type diagram with beta CD, whereas they gave an A(L)-type diagram with 2-HP beta CD. Therefore, complexes of fragrance materials with 2-HP beta CD at 1:1 and 1:2 molar ratios (guest:host) were prepared. The formation of inclusion complexes was confirmed using proton nuclear magnetic resonance ((1)H-NMR) spectroscopy and circular dichroism spectroscopy. The results of the solubility studies showed that preparing the inclusion complex with 2-HP beta CD at a 1:1 molar ratio increased the solubility of linalool 5.9-fold and that of benzyl acetate 4.2-fold, whereas the complexes at a 1:2 molar ratio increased the solubility 6.4- and 4.5-fold for linalool and benzyl acetate, respectively. The stability and in vitro release studies were performed on the gel formulations prepared using uncomplexed fragrance materials or inclusion complexes of fragrance materials at a 1:1 molar ratio. It was observed that the volatility of both fragrance materials was decreased by preparing the inclusion complexes with 2-HP beta CD. Also, in vitro release data indicated that controlled release of fragrances could be possible if inclusion complexes were prepared.

  20. Ionic cluster size distributions of swollen nafion/sulfated beta-cyclodextrin membranes characterized by nuclear magnetic resonance cryoporometry.

    PubMed

    Jeon, Jae-Deok; Kwak, Seung-Yeop

    2007-08-16

    Nafion/sb-CD membranes were prepared by mixing 5 wt% Nafion solution with H+-form sulfated beta-cyclodextrin (sb-CD), and their water uptakes, ion exchange capacities (IECs), and ionic cluster size distributions were measured. Gravimetric and thermogravimetric measurements showed that the water uptake of the membranes increased with increases in their sb-CD content. The IECs of the membrane were measured with acid-base titration and found to increase with increases in the sb-CD content, reaching 0.96 mequiv/g for NC5 ("NCx" denotes a Nafion/sb-CD composite membrane containing x wt% of sb-CD). The cluster-correlation peaks and ionic cluster size distributions of the water-swollen membranes were determined using small-angle X-ray scattering (SAXS) and 1H nuclear magnetic resonance (NMR) cryoporometry, respectively. The SAXS experiments confirmed that increases in the sb-CD content of the membranes shifted the maximum SAXS peaks to lower angles, indicating an increase in the cluster correlation peak. NMR cryoporometry is based on the theory of the melting point depression, Delta Tm, of a liquid confined within a pore, which is dependent on the pore diameter. The melting point depression was determined by analyzing the variation of the NMR signal intensity with temperature. Our analysis of the intensity-temperature (IT) curves showed that the ionic cluster size distribution gradually became broader with increases in the membrane sb-CD content due to the increased water content, indicating an increase in the ionic cluster size. This result indicates that the presence of sb-CD with its many sulfonic acid sites in the Nafion membranes results in increases in the ionic cluster size as well as in the water uptake and the IEC. We conclude that NMR cryoporometry provides a method for determining the ionic cluster size on the nanometer scale in an aqueous environment, which cannot be obtained using other methods.

  1. The influence of dissolved H2O content in supercritical carbon dioxide to the inclusion complexes formation of ketoprofen/β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Goenawan, Joshua; Trisanti, P. N.; Sumarno

    2015-12-01

    This work studies the relation between dissolved H2O content in supercritical carbon dioxide (SC-CO2) with the formation of ketoprofen (KP)/β-cyclodextrin(CD) inclusion complexes. The process involves a physical mixture of these two compounds into contact with the supercritical carbon dioxide which had been previously saturated with H2O over a certain duration. The pressure used for saturation process is 130 bar and saturation temperature was ranged between 30 °C to 50 °C. The inclusion process was achieved by keeping it for 2 hours at 160 bar and 200 bar with inclusion temperature of 50 °C. The results enable us to suggest explanations for the inclusion formation. The inclusion complexes can be formed by contacting the dissolved H2O in SC-CO2 to the physical mixture of KP and CD. An increase in the temperature of saturation process resulted in an increase of dissolved H2O content in the supercritical carbon dioxide. The increasing levels of this water soluble resulted an increase in the inclusion complexes that has been formed. The formation of inclusion complexes includes the water molecules enhancing the emptying of the CD cavities and being replaced by KP, towards a more stable energy state. The drug release used for analyzing the dissolution rate of the KP/CD complexes. The results vary from 79,85% to 99,98% after 45 minutes which is above the rate that has been assigned by Farmakope Indonesia at 70% dissolution rate for KP. The use of SC-CO2 offers a new methods for increasing the rate of dissolution of drugs that are hydrophobic such as KP. CO2 used as a supercritical fluid because of its relatively low cost, easily obtainable supercritical conditions, and lack of toxicity. The material samples were characterized by DSC and Spectrophotometer UV-vis technique.

  2. Solid inclusion complexes of oleanolic acid with amino-appended β-cyclodextrins (ACDs): Preparation, characterization, water solubility and anticancer activity.

    PubMed

    Ren, Yufeng; Liu, Ying; Yang, Zhikuan; Niu, Raomei; Gao, Kai; Yang, Bo; Liao, Xiali; Zhang, Jihong

    2016-12-01

    Oleanolic acid (OA) is a pentacyclic triterpenoid acid of natural abundance in plants which possesses important biological activities. However, its medicinal applications were severely impeded by the poor water solubility and resultant low bioavailability and potency. In this work, studies on solid inclusion complexes of OA with a series of amino-appended β-cyclodextrins (ACDs) were conducted in order to address this issue. These complexes were prepared by suspension method and were well characterized by NMR, SEM, XRD, TG, DSC and Zeta potential measurement. The 2:1 inclusion mode of ACDs/OA complexes was elucidated by elaborate 2D NMR (ROESY). Besides, water solubility of OA was dramatically promoted by inclusion complexation with ACDs. Moreover, in vitro anticancer activities of OA against human cancer cell lines HepG2, HT29 and HCT116 were significantly enhanced after formation of inclusion complexes, while the apoptotic response results indicated their induction of apoptosis of cancer cells. This could provide a novel approach to development of novel pharmaceutical formulations of OA. PMID:27612690

  3. Entropy-controlled supramolecular photochirogenesis: enantiodifferentiating Z-E photoisomerization of cyclooctene included and sensitized by permethylated 6-O-modified beta-cyclodextrins.

    PubMed

    Fukuhara, Gaku; Mori, Tadashi; Wada, Takehiko; Inoue, Yoshihisa

    2006-10-13

    Permethylated 6-O-modified beta-cyclodextrins 2a-2d were synthesized as novel photosensitizing hosts with a flexible skeleton. Circular dichroism (CD) and 2D NMR spectral examinations of benzoate 2a revealed that the benzoate moiety is deeply included into its own cavity in aqueous solution. Upon addition of (Z)-cyclooctene (1Z) to a 50% aqueous methanol solution of 2a at 25 degrees C, the benzoate moiety of 2a was gradually excluded from the cavity as indicated by the CD spectral changes; the Job's plot revealed the formation of a 1:1 complex of 2a with 1Z. The binding constants for the complexation of 1Z by 2a were determined by CD spectral titration in 50% aqueous methanol at various temperatures. The van't Hoff analysis of the obtained data afforded the thermodynamic parameters (DeltaH degrees = -3.1 kJ mol(-1), DeltaS degrees = 48.5 J mol(-1) K(-1)), demonstrating the entropy-driven complexation by the permethylated cyclodextrin. This is in sharp contrast to the complexation of 1Z by nonmethylated beta-cyclodextrin benzoate that is driven by enthalpy (DeltaH degrees = -31.8 kJ mol(-1) and DeltaS degrees = -51.1 J mol(-1) K(-1)). Upon supramolecular photosensitization with 2a-2d, 1Z isomerized to the (E)-isomer (1E) in moderate enantiomeric excesses (ee's), which however displayed significant temperature dependence with accompanying switching of the product's chirality in an extreme case. Such dynamic behavior of ee is very different from that reported for the photosensitization with nonmethylated cyclodextrin benzoate, where the product's ee is controlled by host occupancy. Eyring treatment of the ee obtained at various temperatures (<0 degrees C) gave the differential activation parameters for the enantiodifferentiation process occurring in the supramolecular exciplex, revealing the crucial role of entropy, as indicated by the DeltaDeltaS(++) value changing dynamically from +4 to -24 J K(-1) mol(-1). The origin of the contrasting behavior of permethylated

  4. beta-Cyclodextrin derivatives as carriers to enhance the antiviral activity of an antisense oligonucleotide directed toward a coronavirus intergenic consensus sequence.

    PubMed

    Abdou, S; Collomb, J; Sallas, F; Marsura, A; Finance, C

    1997-01-01

    The ability of cyclodextrins to enhance the antiviral activity of a phosphodiester oligodeoxynucleotide has been investigated. A 18-mer oligodeoxynucleotide complementary to the initiation region of the mRNA coding for the spike protein and containing the intergenic consensus sequence of an enteric coronavirus has been tested for antiviral action against virus growth in human adenocarcinoma cells. The phosphodiester oligodeoxynucleotide only showed a limited effect on virus growth rate (from 12 to 34% viral inhibition in cells treated with 7.5 to 25 microM oligodeoxynucleotide, respectively, at a multiplicity of infection of 0.1 infectious particle per cell). In the same conditions, the phosphorothioate analogue exhibited stronger antiviral activity, the inhibition increased from 56 to 90%. The inhibitory effect of this analogue was antisense and sequence-specific. Northern blot analysis showed that the sequence-dependent mechanism of action appears to be the inhibition of mRNA transcription. We conclude that the coronavirus intergenic consensus sequence is a good target for an antisense oligonucleotide antiviral action. The properties of the phosphodiester oligonucleotide was improved after its complexation with cyclodextrins. The most important increase of the antiviral activity (90% inhibition) was obtained with only 7.5 microM oligonucleotide complexed to a cyclodextrin derivative, 6-deoxy-6-S-beta-D-galactopyranosyl-6-thio-cyclomalto-heptaose+ ++ in a molar ratio of 1:100. These studies suggest that the use of cyclodextrin derivatives as carrier for phosphodiester oligonucleotides delivery may be an effective method for increasing the therapeutic potential of these compounds in viral infections. PMID:9672621

  5. Computer-aided molecular modeling techniques for predicting the stability of drug cyclodextrin inclusion complexes in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Faucci, Maria Teresa; Melani, Fabrizio; Mura, Paola

    2002-06-01

    Molecular modeling was used to investigate factors influencing complex formation between cyclodextrins and guest molecules and predict their stability through a theoretical model based on the search for a correlation between experimental stability constants ( Ks) and some theoretical parameters describing complexation (docking energy, host-guest contact surfaces, intermolecular interaction fields) calculated from complex structures at a minimum conformational energy, obtained through stochastic methods based on molecular dynamic simulations. Naproxen, ibuprofen, ketoprofen and ibuproxam were used as model drug molecules. Multiple Regression Analysis allowed identification of the significant factors for the complex stability. A mathematical model ( r=0.897) related log Ks with complex docking energy and lipophilic molecular fields of cyclodextrin and drug.

  6. Effect of cyclodextrin complexation on the aqueous solubility and solubility/dose ratio of praziquantel.

    PubMed

    Maragos, Stratos; Archontaki, Helen; Macheras, Panos; Valsami, Georgia

    2009-01-01

    Praziquantel (PZQ), the primary drug of choice in the treatment of schistosomiasis, is a highly lipophilic drug that possesses high permeability and low aqueous solubility and is, therefore, classified as a Class II drug according to the Biopharmaceutics Classification System (BCS). In this work, beta-cyclodextrin (beta-CD) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) were used in order to determine whether increasing the aqueous solubility of a drug by complexation with CDs, a BCS-Class II compound like PZQ could behave as BCS-Class I (highly soluble/highly permeable) drug. Phase solubility and the kneading and lyophilization techniques were used for inclusion complex preparation; solubility was determined by UV spectroscopy. The ability of the water soluble polymer polyvinylpyrolidone (PVP) to increase the complexation and solubilization efficiency of beta-CD and HP-beta-CD for PZQ was examined. Results showed significant improvement of PZQ solubility in the presence of both cyclodextrins but no additional effect in the presence of PVP. The solubility/dose ratios values of PZQ-cyclodextrin complexes calculated considering the low (150 mg) and the high dose (600 mg) of PZQ, used in practice, indicate that PZQ complexation with CDs may result in drug dosage forms that would behave as a BCS-Class I depending on the administered dose.

  7. Influence of Single Skimmer Versus Dual Funnel Transfer on the Appearance of ESI-Generated LiCl Cluster/ß-Cyclodextrin Inclusion Complexes

    NASA Astrophysics Data System (ADS)

    Kellner, Ina D.; Drewello, Thomas

    2015-08-01

    Singly and doubly charged adducts of LiCl with β-cyclodextrin (βCD) of the type (βCD)(LiCl)nLi+ and (βCD)2(LiCl)pLi2 2+ were studied using electrospray ionization mass spectrometry (ESI-MS). Insight into their structural composition was gained by analysis of their collision-induced dissociation (CID) mass spectra. The conditions the ions experience in the transfer region interfacing the ESI source and the mass analyzer were found to have a marked influence on the nature of the detected ions. In one instrument incorporating a single skimmer, individually attached LiCl ion pairs were observed, whereas the dual funnel ion guides of the second instrument allow the detection of previously unknown labile inclusion complexes of (LiCl)n clusters in βCD.

  8. Antiviral activity against the hepatitis C virus (HCV) of 1-indanone thiosemicarbazones and their inclusion complexes with hydroxypropyl-β-cyclodextrin.

    PubMed

    Glisoni, Romina J; Cuestas, María L; Mathet, Verónica L; Oubiña, José R; Moglioni, Albertina G; Sosnik, Alejandro

    2012-10-01

    The hepatitis C virus (HCV) is a major cause of acute and chronic hepatitis in humans. Approximately 5% of the infected people die from cirrhosis or hepatocellular carcinoma. The current standard therapy comprises a combination of pegylated-interferon alpha and ribavirin. Due to the relatively low effectiveness, the prohibitive costs and the extensive side effects of the treatment, an intense research for new direct-acting anti-HCV agents is taking place. Furthermore, NS3 protease inhibitors recently introduced into the market are not effective against all HCV subgenotypes. Thiosemicarbazones (TSCs) have shown antiviral activity against a wide range of DNA and RNA viruses. However, their extremely low aqueous solubility and high self-aggregation tendency often preclude their reliable biological evaluation in vitro. In this work, we investigated and compared for the first time the anti-HCV activity of two 1-indanone TSCs, namely 5,6-dimethoxy-1-indanone TSC and 5,6-dimethoxy-1-indanone N4-allyl TSC, and their inclusion complexes with hydroxypropyl-β-cyclodextrin (HPβ-CD) in Huh-7.5 cells containing the full-length and the subgenomic subgenotype 1b HCV replicon system. Studies of physical stability in culture medium showed that free TSCs precipitated rapidly and formed submicron aggregates. Conversely, TSC complexation with HPβ-CD led to more stable systems with minimal size growth and drug concentration loss. More importantly, both TSCs and their inclusion complexes displayed a potent suppression of the HCV replication in both cell lines with no cytotoxic effects. The mechanism likely involves the inhibition of non-structural proteins of the virus. In addition, findings suggested that the cyclodextrin released the drug to the culture medium over time. This platform could be exploited for the study of the drug toxicity and pharmacokinetics animal models.

  9. Antiviral activity against the hepatitis C virus (HCV) of 1-indanone thiosemicarbazones and their inclusion complexes with hydroxypropyl-β-cyclodextrin.

    PubMed

    Glisoni, Romina J; Cuestas, María L; Mathet, Verónica L; Oubiña, José R; Moglioni, Albertina G; Sosnik, Alejandro

    2012-10-01

    The hepatitis C virus (HCV) is a major cause of acute and chronic hepatitis in humans. Approximately 5% of the infected people die from cirrhosis or hepatocellular carcinoma. The current standard therapy comprises a combination of pegylated-interferon alpha and ribavirin. Due to the relatively low effectiveness, the prohibitive costs and the extensive side effects of the treatment, an intense research for new direct-acting anti-HCV agents is taking place. Furthermore, NS3 protease inhibitors recently introduced into the market are not effective against all HCV subgenotypes. Thiosemicarbazones (TSCs) have shown antiviral activity against a wide range of DNA and RNA viruses. However, their extremely low aqueous solubility and high self-aggregation tendency often preclude their reliable biological evaluation in vitro. In this work, we investigated and compared for the first time the anti-HCV activity of two 1-indanone TSCs, namely 5,6-dimethoxy-1-indanone TSC and 5,6-dimethoxy-1-indanone N4-allyl TSC, and their inclusion complexes with hydroxypropyl-β-cyclodextrin (HPβ-CD) in Huh-7.5 cells containing the full-length and the subgenomic subgenotype 1b HCV replicon system. Studies of physical stability in culture medium showed that free TSCs precipitated rapidly and formed submicron aggregates. Conversely, TSC complexation with HPβ-CD led to more stable systems with minimal size growth and drug concentration loss. More importantly, both TSCs and their inclusion complexes displayed a potent suppression of the HCV replication in both cell lines with no cytotoxic effects. The mechanism likely involves the inhibition of non-structural proteins of the virus. In addition, findings suggested that the cyclodextrin released the drug to the culture medium over time. This platform could be exploited for the study of the drug toxicity and pharmacokinetics animal models. PMID:22885176

  10. Cationic-modified cyclodextrin nanosphere/anionic polymer as flocculation/sorption systems.

    PubMed

    Xiao, Huining; Cezar, Norlito

    2005-03-15

    Simultaneous removal of dissolved and colloidal substances has been a challenging task. The cationic-modified beta-cyclodextrin nanospheres synthesized in this work, in conjunction with a water-soluble polyacrylamide-based anionic polymer, potentially provide a novel approach to address the problem. The cyclodextrin was rendered cationic using (2,3-epoxypropyl)trimethylammonium chloride as a reagent. The cationicity of the modified cyclodextrin and the reaction between cyclodextrin and the reagent were characterized by electrophoresis measurement, polyelectrolyte titration, and NMR. As a dual-component flocculation system, the cationic cyclodextrin/anionic polymer significantly induced clay flocculation, lowering the relative turbidity of the clay suspension over a wide pH range. Meanwhile, as a nanospherical absorbent, the modified cyclodextrins exhibited strong affinity toward aromatic compounds via inclusion complex formation in the hydrophobic cavities, which was monitored by UV spectroscopy. These systems facilitated the simultaneous removal of dissolved and colloidal substances, which was unachievable previously. In addition, the interaction between anionic polymers and the clay particles pretreated with cationic cyclodextrin was investigated in order to reveal the flocculation mechanism.

  11. Cationic-modified cyclodextrin nanosphere/anionic polymer as flocculation/sorption systems.

    PubMed

    Xiao, Huining; Cezar, Norlito

    2005-03-15

    Simultaneous removal of dissolved and colloidal substances has been a challenging task. The cationic-modified beta-cyclodextrin nanospheres synthesized in this work, in conjunction with a water-soluble polyacrylamide-based anionic polymer, potentially provide a novel approach to address the problem. The cyclodextrin was rendered cationic using (2,3-epoxypropyl)trimethylammonium chloride as a reagent. The cationicity of the modified cyclodextrin and the reaction between cyclodextrin and the reagent were characterized by electrophoresis measurement, polyelectrolyte titration, and NMR. As a dual-component flocculation system, the cationic cyclodextrin/anionic polymer significantly induced clay flocculation, lowering the relative turbidity of the clay suspension over a wide pH range. Meanwhile, as a nanospherical absorbent, the modified cyclodextrins exhibited strong affinity toward aromatic compounds via inclusion complex formation in the hydrophobic cavities, which was monitored by UV spectroscopy. These systems facilitated the simultaneous removal of dissolved and colloidal substances, which was unachievable previously. In addition, the interaction between anionic polymers and the clay particles pretreated with cationic cyclodextrin was investigated in order to reveal the flocculation mechanism. PMID:15721912

  12. Ternary inclusion complex formation and stabilization of limaprost, a prostaglandin E1 derivative, in the presence of α- and β-cyclodextrins in the solid state.

    PubMed

    Inoue, Yasuo; Iohara, Daisuke; Sekiya, Noboru; Yamamoto, Masanobu; Ishida, Hiroyuki; Sakiyama, Yoko; Hirayama, Fumitoshi; Arima, Hidetoshi; Uekama, Kaneto

    2016-07-25

    Limaprost/α-cyclodextrin (CD)/β-CD ternary inclusion complex was prepared by freeze-drying a solution containing all three components. Under humid conditions, limaprost was more stable in the ternary α-/β-CD inclusion complex than in the binary α- or β-CD complex. Specifically, during storage at 30°C/75% relative humidity (R.H.) for 4 weeks, about 19% of limaprost degraded into 17S,20-dimethyl-trans-Δ(2)-prostaglandin A1 (referred as 11-deoxy-Δ(10)) in the β-CD complex, 8.1% degraded in the α-CD complex, and only 2.2% degraded in the α-/β-CD complex. The mechanism of limaprost stabilization in the presence of both CDs was investigated by Raman and solid-state NMR spectroscopy and powder X-ray diffractometry. The fast degradation of limaprost to 11-deoxy-Δ(10) in the β-CD complex was due to the rapid crystallization of β-CD from the complex, liberating the free amorphous drug, which is susceptible to degradation. The dissociation and crystallization of β-CD from the inclusion complex were suppressed by freeze-drying limaprost in the presence of both α- and β-CDs. In addition, the interaction between limaprost and the two CDs was reinforced by inclusion of different moieties of limaprost: α-CD predominantly included the alkyl ω-chain, whereas β-CD included the five-membered ring. Thus, a stable ternary inclusion complex was formed that included limaprost, maintaining the amorphous state of the complex and dramatically stabilizing the drug under humid conditions. PMID:27286633

  13. Combination of β-cyclodextrin inclusion complex and self-microemulsifying drug delivery system for photostability and enhanced oral bioavailability of methotrexate: novel technique.

    PubMed

    Bourkaib, Nadia; Zhou, Jianping; Yao, Jing; Fang, Zhengjie; Mezghrani, Omar

    2013-06-01

    In the present study, we prepared an inclusion complex of methotrexate (MTX) with β-cyclodextrin (β-CD) in order to decrease its photosensitivity and enhance its aqueous solubility. Then we incorporated this inclusion complex in a self-microemulsifying drug delivery system (SMEDDS) overall to increase its oral bioavailability. The inclusion complex has been prepared by freeze drying method and characterized by differential scanning calorimetry (DSC), ultraviolet (UV), and infrared (IR) spectroscopy assays. The proper molecular ratio of MTX/β-CD was found to be of 1:7, and the water-solubility of MTX was increased in an average of 10-fold. The photostability studies showed that the MTX became stable on exposure to light. Construction of pseudoternary diagrams were investigated to prepare a MTX/β-CD inclusion complex loaded SMEDDS which was characterized by measuring the particle size and the zeta-potential. The optimum formulation of SMEDDS was a system consisting of ethyl oleate, tween 80, and propylene glycol with a mean droplet size of 39.42 nm. In vitro drug release in different pH media showed that the release profile of MTX from the MTX/β-CD loaded SMEDDS was influenced by the pH of the release medium and presented the characteristics of a sustained release profile. Finally, in-vivo studies showed an enhancement of the bioavailability of MTX from the MTX/β-CD loaded SMEDDS form of 1.57-fold. We concluded that the β-CD inclusion complex loaded SMEDDS improved the chemical and physiological properties of MTX and could be a promising means for the delivery of MTX and other unstable and lipophilic drugs by oral route. PMID:22998295

  14. Experimental and Theoretical Investigations on the Supermolecular Structure of Isoliquiritigenin and 6-O-α-d-Maltosyl-β-cyclodextrin Inclusion Complex

    PubMed Central

    Li, Bin; Liu, Benguo; Li, Jiaqi; Xiao, Huizhi; Wang, Junyi; Liang, Guizhao

    2015-01-01

    Isoliquiritigenin (ILTG) possesses many pharmacological properties. However, its poor solubility and stability in water hinders its wide applications. The solubility of bioactive compounds can often be enhanced through preparation and delivery of various cyclodextrin (CD) inclusion complexes. The 6-O-α-d-maltosyl-β-CD (G2-β-CD), as one of the newest developments of CDs, has high aqueous solubility and low toxicity, especially stable inclusion characteristics with bioactive compounds. In this work, we for the first time construct and characterize the supermolecular structure of ILTG/G2-β-CD by scanning electron microscopy (SEM), ultraviolet-visible spectroscopy (UV), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffractometry (XRD). The solubility of ILTG in water at 25 °C rises from 0.003 to 0.717 mg/mL by the encapsulation with G2-β-CD. Our experimental observations on the presence of the ILTG/G2-β-CD inclusion complex are further supported by the ONIOM(our Own N-layer Integrated Orbital molecular Mechanics)-based QM/MM (Quantum Mechanics/Molecular Mechanics) calculations, typically substantiating these supermolecular characteristics, such as detailed structural assignments, preferred binding orientations, selectivity, solvent effects, interaction energies and forces of the ILTG/G2-β-CD inclusion complex. Our results have elucidated how ILTG interacts with G2-β-CD, demonstrating the primary host-guest interactions between ILTG and G2-β-CD, characterized by hydrogen bonds, hydrophobic interactions, electrostatic forces, and conformational effects, are favored for the formation of the ILTG/G2-β-CD inclusion. PMID:26247946

  15. Ternary inclusion complex formation and stabilization of limaprost, a prostaglandin E1 derivative, in the presence of α- and β-cyclodextrins in the solid state.

    PubMed

    Inoue, Yasuo; Iohara, Daisuke; Sekiya, Noboru; Yamamoto, Masanobu; Ishida, Hiroyuki; Sakiyama, Yoko; Hirayama, Fumitoshi; Arima, Hidetoshi; Uekama, Kaneto

    2016-07-25

    Limaprost/α-cyclodextrin (CD)/β-CD ternary inclusion complex was prepared by freeze-drying a solution containing all three components. Under humid conditions, limaprost was more stable in the ternary α-/β-CD inclusion complex than in the binary α- or β-CD complex. Specifically, during storage at 30°C/75% relative humidity (R.H.) for 4 weeks, about 19% of limaprost degraded into 17S,20-dimethyl-trans-Δ(2)-prostaglandin A1 (referred as 11-deoxy-Δ(10)) in the β-CD complex, 8.1% degraded in the α-CD complex, and only 2.2% degraded in the α-/β-CD complex. The mechanism of limaprost stabilization in the presence of both CDs was investigated by Raman and solid-state NMR spectroscopy and powder X-ray diffractometry. The fast degradation of limaprost to 11-deoxy-Δ(10) in the β-CD complex was due to the rapid crystallization of β-CD from the complex, liberating the free amorphous drug, which is susceptible to degradation. The dissociation and crystallization of β-CD from the inclusion complex were suppressed by freeze-drying limaprost in the presence of both α- and β-CDs. In addition, the interaction between limaprost and the two CDs was reinforced by inclusion of different moieties of limaprost: α-CD predominantly included the alkyl ω-chain, whereas β-CD included the five-membered ring. Thus, a stable ternary inclusion complex was formed that included limaprost, maintaining the amorphous state of the complex and dramatically stabilizing the drug under humid conditions.

  16. Inhibition of ruminal microbial methane production by beta-cyclodextrin iodopropane, malate and their combination in vitro.

    PubMed

    Mohammed, N; Lila, Z A; Ajisaka, N; Hara, K; Mikuni, K; Hara, K; Kanda, S; Itabashi, H

    2004-06-01

    The objective of this study was to evaluate the effects of different concentrations of l-malate (0, 5, 10 and 20 mm), 2-iodopropane-beta-cyclodextrin complex (CD-IP) (0, 0.1, 0.2 and 0.4 mm) and a combination of malate (10 and 20 mm) plus CD-IP (0.2 and 0.4 mm) on methane production from corn starch. Ruminal fluid was collected from dairy cows, mixed with phosphate buffer (1 : 2) and incubated (30 ml) anaerobically at 38 degrees C for 6 h with or without additives. Fermentation of corn starch in the presence of malate resulted in an increase (p < 0.05) in pH of the medium, total volatile fatty acid (VFA), total gas production and molar proportion of propionate. Acetate and ammonia-N concentration were unchanged. Methane production was decreased (p < 0.05) (15.5 to 20.4%). Addition of CD-IP in corn starch resulted in an increase (p < 0.05) in total VFA and molar proportion of propionate. Acetate, pH and ammonia-N concentration of the medium were decreased (p < 0.05). Total gas production was unchanged. Methane production was decreased (p < 0.05) (25.2 to 97.1%) and hydrogen production was increased (p < 0.05). Addition of l-malate to CD-IP resulted in an increase (p < 0.05) in total VFA, total gas production and molar proportion of propionate. Acetate and ammonia-N concentration were decreased (p < 0.05). No effects were observed on medium pH. Methane production was decreased (p < 0.05) (49.5 to 97.1%). Hydrogen production was also decreased (p < 0.05) (54.5 to 64.1%) compared with those of CD-IP alone. Therefore, these additives may be used as supplements to inhibit methane production as well as to improve rumen fermentation and animal performance.

  17. Preparation of alpha-cyclodextrin-terminated polyrotaxane consisting of beta-cyclodextrins and pluronic as a building block of a biodegradable network.

    PubMed

    Ooya, Tooru; Ito, Akihiro; Yui, Nobuhiko

    2005-05-23

    A beta-CD-based biodegradable polyrotaxane was prepared by capping both terminals of polypseudorotaxane consisting of hydrazide-terminated PEG-block-PPG-block-PEG (Pluronic P-105) and beta-CD-succinates with mono-aldehyde alpha-CDs. By decreasing pH, the fluorescent intensity of TNS was increased with time, indicating cleavage of the terminal hydrazone bonds followed by beta-CD-succinate release. The terminal alpha-CD moieties of the polyrotaxane are useful for self-assembled formation with some guest molecules. [Diagram: see text

  18. Hydrogels composed of cyclodextrin inclusion complexes with PLGA-PEG-PLGA triblock copolymers as drug delivery systems.

    PubMed

    Khodaverdi, Elham; Mirzazadeh Tekie, Farnaz Sadat; Hadizadeh, Farzin; Esmaeel, Haydar; Mohajeri, Seyed Ahmad; Sajadi Tabassi, Sayyed A; Zohuri, Gholamhossein

    2014-02-01

    Although conventional pharmaceuticals have many drug dosage forms on the market, the development of new therapeutic molecules and the low efficacy of instant release formulations for the treatment of some chronic diseases and specific conditions encourage scientists to invent different delivery systems. To this purpose, a supramolecular hydrogel consisting of the tri-block copolymer PLGA-PEGPLGA and α-cyclodextrin was fabricated for the first time and characterised in terms of rheological, morphological, and structural properties. Naltrexone hydrochloride and vitamin B12 were loaded, and their release profiles were determined.

  19. Host-Guest Inclusion Complexation of α-Cyclodextrin and Triiodide Examined Using UV-Vis Spectrophotometry.

    PubMed

    Pursell, Janet L; Pursell, Christopher J

    2016-04-01

    The historically relevant host-guest complexation of α-cyclodextrin (α-CD) and triiodide (I3(-)) in aqueous solution was examined using a systematic UV-vis spectrophotometric approach. This particular system is experimentally challenging because of the coupled equilibria, namely, I2 + I(-) ⇌ I3(-) and α-CD + I3(-) ⇌ α-CD·I3(-). We therefore developed a unique experimental approach that allowed us to determine the concentration of all iodine species. This enabled us to unequivocally demonstrate that the large increase in the UV absorbance with added α-cyclodextrin is due to an increase in the overall triiodide concentration as α-CD essentially converts iodine to triiodide according to the coupled equilibria. Herein we report (a) the complexation stoichiometry is 1:1 (i.e., the host-guest complex is α-CD·I3(-)), (b) the binding constant is KH-G = (1.35 ± 0.05) × 10(5) M(-1) at room temperature, and PMID:26997285

  20. Proparacaine complexation with beta-cyclodextrin and p-sulfonic acid calix[6]arene, as evaluated by varied (1)H-NMR approaches.

    PubMed

    Arantes, Lucas Micquéias; Scarelli, Camilla; Marsaioli, Anita Jocelyne; de Paula, Eneida; Fernandes, Sergio Antonio

    2009-09-01

    This study focused on the use of NMR techniques as a tool for the investigation of complex formation between proparacaine and cyclodextrins (CDs) or p-sulfonic acid calix[6]arene. The pH dependence of the complexation of proparacaine with beta-CD and p-sulfonic acid calix[6]arene was studied and binding constants were determined by (1)H NMR spectroscopy [diffusion-ordered spectroscopy (DOSY)] for the charged and uncharged forms of the local anesthetic in beta-CD and p-sulfonic acid calix[6]arene. The stoichiometries of the complexes was determined and rotating frame Overhauser enhancement spectroscopy (ROESY) 1D experiments revealed details of the molecular insertion of proparacaine into the beta-CD and p-sulfonic acid calix[6]arene cavities. The results unambiguously demonstrate that pH is an important factor for the development of supramolecular architectures based on beta-CD and p-sulfonic acid calix[6]arene as the host molecules. Such host-guest complexes were investigated in view of their potential use as new therapeutic formulations, designed to increase the bioavailability and/or to decrease the systemic toxicity of proparacaine in anesthesia procedures.

  1. Quantitative Analysis of Norfloxacin in β-Cyclodextrin Inclusion Complexes--Development and Validation of a Stability-indicating HPLC Method.

    PubMed

    Mendes, Cassiana; Buttchevitz, Aline; Kruger, Jéssica Henriques; Bernardi, Larissa Sakis; Oliveira, Paulo Renato; Silva, Marcos Antônio Segatto

    2015-01-01

    The aim of this study was to develop and validate a simple liquid-chromatography method, with good accuracy, reproducibility and sensitivity, for the quantification of norfloxacin in β-cyclodextrin inclusion complexes. In the method validation, the parameters evaluated were linearity, limits of detection and quantification, specificity, accuracy, precision and robustness. The stability-indication property of the method was evaluated through studies on the degradation under stress conditions. A method employing a simple mobile phase consisting of phosphate buffer (pH 3.0) and acetonitrile (86:14 v/v) was developed. Fluorescence detection was employed to minimize the influence of degradation products, due to its high sensitivity, selectivity and specificity. The method was specific, linear in the concentration range of 1 - 30 μg/mL, robust, precise and accurate. The proposed method was successfully applied in the determination of norfloxacin in inclusion complexes, thus aiding quality-control analysis in the future development of drug delivery systems.

  2. A DFT study of infrared spectra and Monte Carlo predictions of the solvation shell of Praziquantel and β-cyclodextrin inclusion complex in liquid water

    NASA Astrophysics Data System (ADS)

    de Oliveira, C. X.; Ferreira, N. S.; Mota, G. V. S.

    2016-01-01

    In this paper, we report a theoretical study of the inclusion complexes of Praziquantel (PZQ) and β-cyclodextrin (β-CD) in liquid water. The starting geometry has been carried out by molecular mechanics simulations, and afterwards optimized in B3LYP level with a 6-311G(d) basis set. Monte Carlo simulations have been used to calculate the solvation shell of the PZQ/β-CD inclusion complexes. Moreover, the vibrational frequencies and the infrared intensities for the PZQ/β-CD complex were computed using the B3LYP method. It is demonstrated that this combined model can yield well-converged thermodynamic data even for a modest number of sample configurations, which makes the methodology particularly adequate for understanding the solute-solvent interaction used for generating the liquid structures of one solute surrounded by solvent molecules. The complex solvation shell showed an increase of the water molecule level in relation to the isolated PZQ molecule because of the hydrophilic effect of the CD molecule. The infrared spectra showed that the contribution that originated in the PZQ molecule was not predominant in the upper-wave number region in the drug/β-CD. The movement that purely originated in the PZQ molecule was localized in the absorption band, ranging from 1328 to 1688 cm- 1.

  3. Inclusion compounds between α-, β- and γ-cyclodextrins: iron II lactate: a theoretical and experimental study using diffusion coefficients and molecular mechanics

    NASA Astrophysics Data System (ADS)

    Leite, Rosiley A.; Lino, Antonio C. S.; Takahata, Yuji

    2003-01-01

    The inclusion compounds between iron II lactate and three different cyclodextrins (CDs) were studied by means of experimental and theoretical data. The importance of iron II in the human metabolism effort the necessity of a minimum concentration to the human life. Malnutrition is one great problem in social politics of many countries on the world. The possibility to the development of novel medicines with the iron II species stable look for an increase on the efficiency for this kind of aid. Kinetics measurements confirm the possibility to stop the oxidation reaction. It was the first indication of efficient molecular encapsulation. Diffusion coefficient measurements were carried out by Taylor-Aris diffusion technique. The decrease of diffusion coefficients measured for iron II lactate when alone and forming the inclusion complexes was obtained for all hosts molecules used. Molecular Mechanics calculations were performed to elucidate the perfect arrange of iron II lactate inside CDs cavity. No great differences were obtained to the binding energy for the different hosts. Using the software HyperChem6.03v MM+, AMBER94 and OPLS Forced Fields for iron atom in two chemical environments (a) vacuum and (b) with addition of 250 water molecules (MM+). The solvent treatment was decisive to the order of stability. This order was β-CD>γ-CD>α-CD, the same order of solubility in water. The results contained in this work confirm the possibility to protect iron II lactate against oxidation.

  4. A DFT study of infrared spectra and Monte Carlo predictions of the solvation shell of Praziquantel and β-cyclodextrin inclusion complex in liquid water.

    PubMed

    de Oliveira, C X; Ferreira, N S; Mota, G V S

    2016-01-15

    In this paper, we report a theoretical study of the inclusion complexes of Praziquantel (PZQ) and β-cyclodextrin (β-CD) in liquid water. The starting geometry has been carried out by molecular mechanics simulations, and afterwards optimized in B3LYP level with a 6-311G(d) basis set. Monte Carlo simulations have been used to calculate the solvation shell of the PZQ/β-CD inclusion complexes. Moreover, the vibrational frequencies and the infrared intensities for the PZQ/β-CD complex were computed using the B3LYP method. It is demonstrated that this combined model can yield well-converged thermodynamic data even for a modest number of sample configurations, which makes the methodology particularly adequate for understanding the solute-solvent interaction used for generating the liquid structures of one solute surrounded by solvent molecules. The complex solvation shell showed an increase of the water molecule level in relation to the isolated PZQ molecule because of the hydrophilic effect of the CD molecule. The infrared spectra showed that the contribution that originated in the PZQ molecule was not predominant in the upper-wave number region in the drug/β-CD. The movement that purely originated in the PZQ molecule was localized in the absorption band, ranging from 1328 to 1688cm(-1).

  5. Characterization of Albendazole-Randomly Methylated-β-Cyclodextrin Inclusion Complex and In Vivo Evaluation of Its Antihelmitic Activity in a Murine Model of Trichinellosis

    PubMed Central

    García, Agustina; Leonardi, Darío; Vasconi, María D.; Hinrichsen, Lucila I.; Lamas, María C.

    2014-01-01

    Albendazole is a benzimidazole carbamate extensively used in oral chemotherapy against intestinal parasites, due to its broad spectrum activity, good tolerance and low cost. However, the drug has the disadvantage of poor bioavailability due to its very low solubility in water; as a consequence, a very active area of research focuses on the development of new pharmaceutical formulations to increase its solubility, dissolution rate, and bioavailability. The primary objective of this study was to prepare randomly methylated β-cyclodextrins inclusion complexes to increase albendazole dissolution rate, in order to enhance its antiparasitic activity. This formulation therapeutic efficacy was contrasted with that of the pure drug by treating Trichinella spiralis infected mice during the intestinal phase of the parasite cycle, on days five and six post-infection. This protocol significantly decreased muscle larval burden measured in the parenteral stage on day 30 post-infection, when compared with the untreated control. Thus, it could be demonstrated that the inclusion complexes improve the in vivo therapeutic activity of albendazole. PMID:25406084

  6. Synthesis, Characterization, In Vitro Evaluation, and Preclinical Profiling of beta-Cyclodextrin Polyrotaxane Families for Use As Potential Niemann-Pick Type C Therapeutics

    NASA Astrophysics Data System (ADS)

    Collins, Christopher J.

    Niemann-Pick Disease Type C (NPC) is a rare, autosomal recessive genetic disorder featuring a loss of proteins responsible for unesterified cholesterol (UC) trafficking through the late endosomes/lysosomes (LE/LY) of every cell of the body. Disruption of this pathway leads to abnormal accumulation and storage of UC and other lipids. A broad range of visceral and neurological symptoms result from this accumulation exhibiting a variable age of onset and a disease progression that is ultimately fatal. The disease has an incidence of approximately 1 in 120,000 live births and has no known effective treatment. beta-Cyclodextrin (beta-CD) are natural small molecules macrocycles composed of glucose units with a hydrophobic inner cavity and hydrophilic outer rims. beta-CD derivatives have recently been shown to be effective therapeutics for NPC in cellular and animal models. In the mouse model of the disease, beta-CD therapy increases overall lifetime by as much as 50% and slows the progression of neurodegeneration. The progress has led to the initiation of a National Institutes of Health phase I clinical trial. A main drawback of beta-CD administration is the poor pharmacokinetic profile characterized by rapid renal clearance of the drug through the urine. Libraries of beta-CD derivative carrying high molecular weight polyrotaxane (PR) systems have been designed to prevent glomerular filtration of the injected beta-CD dose. An initial family of unmodified beta-CD PRs was synthesized, characterized, and their therapeutic efficacy was tested in NPC fibroblasts. This was followed by screening of PRs consisting of mixed beta-CD derivative threading featuring charged sulfobutylether beta-CD. Finally, we sought to define PR structure-property effects on in vivo pharmacokinetics, biodistribution, toxicity, immunogenicity, and protein hard corona composition. This was accomplished using a family of gadolinium carrying PRs composed of triblock Pluronic co-polymers of varying

  7. Activation of acyl-CoA cholesterol acyltransferase: redistribution in microsomal fragments of cholesterol and its facilitated movement by methyl-beta-cyclodextrin.

    PubMed

    Cheng, D; Tipton, C L

    1999-03-01

    Acyl-CoA cholesterol acyltransferase (ACAT) (EC 2.3.1.26) in the yolk sac membrane of chicken eggs plays an important role in the transport of lipids, which serve as both structural components and as an energy source during embryogenesis. ACAT from the yolk sac membrane of chicken eggs 16 d after fertilization has higher activity and better stability than its mammalian liver counterpart. During our study of the avian enzyme, ACAT was found to be activated up to twofold during storage at 4 degrees C. The activation was investigated, and data suggest that redistribution of cholesterol within microsomal vesicles leads to the increase. Methyl-beta-cyclodextrin (MbetaCD) increases activation an additional twofold, possibly by facilitating the movement of cholesterol within microsomal fragments and allowing redistribution of cholesterol in lipid bilayers to a greater extent. Treatment of microsomes with MbetaCD removes cholesterol from the membranes. Controlled amounts of cholesterol can be restored to the membranes by mixing them with cholesterol-phosphatidylcholine liposomes in the presence of MbetaCD. Under these conditions, the plot of ACAT vs. cholesterol mole fraction in the liposomes is sigmoidal. The finding that MbetaCD can enhance cholesterol transfer between liposomes and microsomes and reduce the limitation of slow movement of nonpolar molecules in aqueous media should make cyclodextrins more useful in in vitro studies of apolar molecule transport between membrane vesicles.

  8. In situ electroactive and antioxidant supramolecular hydrogel based on cyclodextrin/copolymer inclusion for tissue engineering repair.

    PubMed

    Cui, Haitao; Cui, Liguo; Zhang, Peibiao; Huang, Yubin; Wei, Yen; Chen, Xuesi

    2014-03-01

    The injectable electroactive and antioxidant hydrogels are prepared from mixing the tetraaniline functional copolymers and α-cyclodextrin (α-CD) aqueous solution. UV-vis and CV of the copolymer solution showed good electroactive properties. The antioxidant ability of the copolymer is also proved. The gelation mechanism and properties of the system are studied by WAXD, DSC, and rheometer. The encapsulated cells are highly viable in the hydrogels, suggesting that the hydrogels have excellent cytocompatibility. After subcutaneous injection, H&E staining study suggests acceptable biocompatibility of the materials in vivo. Moreover, data shows the injectable electroactive material can effectively accelerate the proliferation of encapsulated cells with electrical stimuli, and the mechanism is also elaborated. Such an injectable electroactive hydrogel would more closely mimic the native extracellular matrix, thereby combining a biomimetic environment of long-term cell survival and electrical signal to support the generation of functional tissue.

  9. Inclusion complexes of α-cyclodextrin and the cisplatin analogues oxaliplatin, carboplatin and nedaplatin: A theoretical approach

    NASA Astrophysics Data System (ADS)

    Anconi, Cleber P. A.; da Silva Delgado, Luciano; Alves dos Reis, João B.; De Almeida, Wagner B.; Costa, Luiz Antônio S.; Dos Santos, Hélio F.

    2011-10-01

    Quantum mechanics theoretical methodology has been applied in order to access and compare the relative stability of inclusion compounds formed by α-CD and the platinum (II) based drugs carboplatin, oxaliplatin and nedaplatin. The relative stability of the studied inclusion compounds has been discussed based on the number and type of hydrogen bonds identified between host and guest molecules. The evaluated energies at B3LYP/6-31G ∗ level of theory strongly indicates that α-CD forms stable supramolecular systems with all studied cisplatin analogues, being the carboplatin@α-CD found as the most favorable inclusion complex among the platinum (II) derivatives studied in the present paper.

  10. 1H NMR titration and quantum calculation for the inclusion complexes of cis-cyclooctene, cis, cis-1, 3-cyclooctadiene and cis, cis-1, 5-cyclooctadiene with β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Yujuan, Cao; Runhua, Lu

    2009-08-01

    The inclusion behavior of cis-cyclooctene, cis, cis-1, 3-cyclooctadiene and cis, cis-1, 5-cyclooctadiene with β-cyclodextrin (β-CD) was studied by using 1H NMR method in D 2O/CD 3OD solution and PM3 quantum-chemical simulation in vacuum. The experimental results indicate that each guest molecule penetrates deeply into β-CD cavity and forms equimolecular inclusion complex with the host. The association constants of the complexes were determined by non-linear least-square method on the bases of the conversion-dependent chemical shift of two protons of the host molecule. The inclusion process and the most probable structure of the inclusion complexes were simulated using PM3 energy scanning and optimization. The trend of stability of the three inclusion complexes deduced from their calculated stabilization energies agrees well with the order of their association constants obtained from NMR experiments.

  11. Inclusion complexation of isoprenaline and methyl dopa with α- and β-cyclodextrin nanocavities: Spectral and theoretical study

    NASA Astrophysics Data System (ADS)

    Rajendiran, N.; Thulasidhasan, J.; Saravanan, J.

    2014-03-01

    Inclusion complex formation of isoprenaline (ISOP) and methyldopa (MDOP) with α-CD and β-CD were investigated. Solid inclusion complex nanomaterials were characterized by SEM, TEM, FTIR, DSC, 1H NMR and XRD methods. Spectral results showed that single emission (monomer) noticed in aqueous solution where as dual emission (excimer) in CD. Both drugs formed 1:2 (CD-drug2) inclusion complexes with CDs. Time-resolved fluorescence studies show that single exponential decay observed in water whereas biexponential decay observed in CD. Nano-sized particles were found in ISOP/CD while vesicles were obtained in MDOP/CD complexes. DSC results revealed that the thermal stability of drugs was improved when it was included in the CD nanocavity. Based on PM3 calculations, the inclusion structure of ISOP/CD and MDOP/CD complexes were proposed. Thermodynamic parameters and binding affinity of complexation of CD were determined by PM3 method.

  12. Inclusion complexation of isoprenaline and methyl dopa with α- and β-cyclodextrin nanocavities: spectral and theoretical study.

    PubMed

    Rajendiran, N; Thulasidhasan, J; Saravanan, J

    2014-03-25

    Inclusion complex formation of isoprenaline (ISOP) and methyldopa (MDOP) with α-CD and β-CD were investigated. Solid inclusion complex nanomaterials were characterized by SEM, TEM, FTIR, DSC, (1)H NMR and XRD methods. Spectral results showed that single emission (monomer) noticed in aqueous solution where as dual emission (excimer) in CD. Both drugs formed 1:2 (CD-drug2) inclusion complexes with CDs. Time-resolved fluorescence studies show that single exponential decay observed in water whereas biexponential decay observed in CD. Nano-sized particles were found in ISOP/CD while vesicles were obtained in MDOP/CD complexes. DSC results revealed that the thermal stability of drugs was improved when it was included in the CD nanocavity. Based on PM3 calculations, the inclusion structure of ISOP/CD and MDOP/CD complexes were proposed. Thermodynamic parameters and binding affinity of complexation of CD were determined by PM3 method.

  13. Inclusion of an Anthracene-based Fluorophore within Molecular Containers: A Comparative Study of the Cucurbituril and Cyclodextrin Host Families.

    PubMed

    Ganguly, Aniruddha; Ghosh, Soumen; Guchhait, Nikhil

    2016-05-19

    In this paper, the binding interaction of a promising chloride channel blocker, 9-methyl anthroate (9-MA), with two different classes of molecular containers, β-cyclodextrins (β-CD and methyl-β-CD) and cucurbit[7]uril, having comparable cavity dimensions, has been thoroughly demonstrated via inspection of the modulation of the excited-state properties of the emissive molecule. Spectral data suggest that CB7 encapsulates the probe more efficiently in a 1:2 fashion, whereas the efficacies of β-CDs are relatively less and the corresponding stoichiometry is 1:1. Interestingly, despite being thermodynamically much more favorable than the probe-β-CD complexation equilibria, the fraction of probe-CB7 complex formed is appreciably smaller with respect to that of probe-β-CD complexes. This apparent inconsistency has been addressed via the proposition that since the formation of a 1:2 complex is entropically disadvantageous, it is anticipated that the activation barrier of the corresponding reaction is reasonably high, and thus only a small fraction of the reactants are able to surpass the energy barrier to form the products. This proposition has been thoroughly corroborated by fluorescence lifetime measurements at different temperatures. PMID:27119387

  14. Encapsulation of plai oil/2-hydroxypropyl-β-cyclodextrin inclusion complexes in polyvinylpyrrolidone (PVP) electrospun nanofibers for topical application.

    PubMed

    Tonglairoum, Prasopchai; Chuchote, Tudduo; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Opanasopit, Praneet

    2014-06-01

    The aim of this study was to prepare electrospun polyvinylpyrrolidone (PVP)/2-hydroxypropyl-β-cyclodextrin (HPβCD) nanofiber mats and to incorporate plai oil (Zingiber Cassumunar Roxb.). The plai oil with 10, 20 and 30% wt to polymer were incorporated in the PVP/HPβCD solution and electrospun to obtain nanofibers. The morphology and structure of the PVP and PVP/HPβCD nanofiber mats with and without the plai oil were analyzed using scanning electron microscopy (SEM). The thermal behaviors of the nanofiber mats were characterized using differential scanning calorimeter (DSC). Terpinen-4-ol was used as a marker of the plai oil. The amount of plai oil remaining in the PVP/HPβCD nanofiber mats was determined using gas chromatography-mass spectoscopy (GC-MS). The SEM images revealed that all of the fibers were smooth. The average diameter of fibers was 212-450 nm, and decreased with the increasing of plai oil content. The release characteristics of plai oil from the fiber showed the fast release followed by a sustained release over the experimental time of 24 h. The release rate ranged was in the order of 10% > 20% ∼ 30% plai oil within 24 h. Electrospun fibers with 20% plai oil loading provided the controlled release and also showed the highest plai oil content. Hence, this electrospun nanofiber has a potential for use as an alternative topical application.

  15. Changes in the Physicochemical Properties of Piperine/β-Cyclodextrin due to the Formation of Inclusion Complexes

    PubMed Central

    Ezawa, Toshinari; Inoue, Yutaka; Tunvichien, Sujimon; Suzuki, Rina; Kanamoto, Ikuo

    2016-01-01

    Piperine (PP) is a pungent component in black pepper that possesses useful biological activities; however it is practically insoluble in water. The aim of the current study was to prepare a coground mixture (GM) of PP and β-cyclodextrin (βCD) (molar ratio of PP/βCD = 1/1) and subsequently evaluate the solubility of PP and physicochemical properties of the GM. DSC thermal behavior of the GM showed the absence of melting peak of piperine. PXRD profile of the GM exhibited halo pattern and no characteristic peaks due to PP and βCD were observed. Based on Job's plot, the PP/βCD complex in solution had a stoichiometric ratio of 1/1. Raman spectrum of the GM revealed scattering peaks assigned for the benzene ring (C=C), the methylene groups (CH2), and ether groups (C-O-C) of PP that were broaden and shifted to lower frequencies. SEM micrographs showed that particles in the GM were agglomerated and had rough surface, unlike pure PP and pure βCD particles. At 15 min of dissolution testing, the amount dissolved of PP in the GM was dramatically increased (about 16 times) compared to that of pure PP. Moreover the interaction between PP and βCD cavity was detected by 1H-1H NMR nuclear Overhauser effect spectroscopy NMR spectroscopy. PMID:26998357

  16. Physicochemical characterization and analgesic effect of inclusion complexes of essential oil from Hyptis pectinata L. Poit leaves with β-cyclodextrin.

    PubMed

    Menezes, Paula dos P; Araujo, Adriano A de S; Doria, Grace Anne A; Quintans-Junior, Lucindo J; de Oliveira, Makson G B; dos Santos, Marcio R V; de Oliveira, Juliana F; Matos, Jivaldo do R; Carvalho, Flavio M de S; Alves, Pericles B; de Matos, Iara L; dos Santos, Darlisson A; Marreto, Ricardo N; da Silva, Gabriel F; Serafini, Mairim R

    2015-01-01

    The formation of inclusion complexes of Hyptis pectinata essential oil (EOHP), with potent activities such as anti-nociceptive, anti-inflammatory, among others, with β -cyclodextrin (β-CD), was obtained by slurry (SC) and paste procedures (PC). The gas chromatography coupled to the mass spectrometry (GC/MS) analysis demonstrated a total of 36.4% monoterpenes and 63.6% sesquiterpenes in the EOHP. The major components of EOHP were identified as (E)- caryophyllene (54.07%). The analysis of samples (PM, PC and SC) by GC/MS involved the surface and the total extracted oils. The GC/MS results suggested important differences between in SC and PC methods indicating the complexation of mono and sesquiterpenoids in different ratios. Furthermore, the thermal analysis techniques suggests the complexation, especially in SC, which show a thermogravimetry/derivative thermogravimetry (TG/DTG) peak at 140-270ºC, probably related to oil loss. Scanning electron microscopy (SEM) images showed reduction size of the samples mainly in the SC product. Additionally, EOHP/ β-CD improves pharmacological profile of EOHP alone in formalin-induced pain protocol in mice.

  17. Effect of inclusion of hydroxycinnamic and chlorogenic acids from green coffee bean in β-cyclodextrin on their interactions with whey, egg white and soy protein isolates.

    PubMed

    Budryn, Grażyna; Pałecz, Bartłomiej; Rachwał-Rosiak, Danuta; Oracz, Joanna; Zaczyńska, Donata; Belica, Sylwia; Navarro-González, Inmaculada; Meseguer, Josefina María Vegara; Pérez-Sánchez, Horacio

    2015-02-01

    The aim of the study was to characterise the interactions of hydroxycinnamic and chlorogenic acids (CHAs) from green coffee, with isolates of proteins from egg white (EWP), whey (WPC) and soy (SPI), depending on pH and temperature. The binding degree was determined by liquid chromatography coupled to a diode array detector and an ultrahigh resolution hybrid quadruple-time-of-flight mass spectrometer with ESI source (LC-QTOF-MS/MS). As a result of binding, the concentration of CHAs in proteins ranged from 9.44-12.2, 11.8-13.1 and 12.1-14.4g/100g for SPI, WPC and EWP, respectively. Thermodynamic parameters of protein-ligand interactions were determined by isothermal titration calorimetry (ITC) and energetics of interactions at the atomic level by molecular modelling. The amount of CHAs released during proteolytic digestion was in the range 0.33-2.67g/100g. Inclusion of CHAs with β-cyclodextrin strongly limited these interactions to a level of 0.03-0.06g/100g.

  18. Beta-amyloid protein-containing inclusions in skeletal muscle of apolipoprotein-E-deficient mice.

    PubMed Central

    Robertson, T. A.; Dutton, N. S.; Martins, R. N.; Roses, A. D.; Kakulas, B. A.; Papadimitriou, J. M.

    1997-01-01

    The tibialis anterior muscle and soleus muscle of apolipoprotein-E-deficient mice were examined by light and electron microscopy. By light microscopy, sarcoplasmic inclusions were seen in tibialis anterior muscle and 40% of type 2 myofibers were affected in all animals over 8 months of age. These inclusions reacted for nonspecific esterase, cytochrome oxidase, and myoadenylate deaminase and were also periodic acid Schiff positive and stained basophilic with hematoxylin. Moreover, they reacted immunocytochemically with an antibody specific to fragment 17 to 24 of the published sequence of Alzheimer's cerebrovascular amyloid peptide. Immunoreactivity was lost when the antibody was adsorbed with the appropriate synthetic peptide. Ultrastructurally, the inclusions consisted of tubular arrays and were similar to those observed in human muscle in several pathological conditions. In type 1 myofibers of both tibialis anterior and soleus muscle, however, mitochondrial abnormalities including an increase in their number and size were detected, but tubular aggregates were not seen. These large mitochondria possessed an electron-dense inner chamber with an increased number of tightly packed cristae. The results obtained suggest that in these mice there is a disturbed lipid metabolism in skeletal muscle fibers that manifests itself with an accumulation of phospholipid in the form of sarcoplasmic reticulum tubules in the type 2 fibers and enlarged mitochondria with tightly packed cristae in the type 1 fibers. In addition, beta-amyloid protein was closely associated with the accumulated tubules and vesicles of sarcoplasmic reticulum and may represent dysregulation of amyloid precursor protein metabolism. Images Figure 1 Figure 2 Figure 3 PMID:9033257

  19. Self-assembled supramolecular hydrogel based on PCL-PEG-PCL triblock copolymer and γ-cyclodextrin inclusion complex for sustained delivery of dexamethasone.

    PubMed

    Khodaverdi, Elham; Gharechahi, Marzieh; Alibolandi, Mona; Tekie, Farnaz Sadat Mirzazadeh; Khashyarmanesh, Bibi Zahra; Hadizadeh, Farzin

    2016-01-01

    In this study, thermosensitive, water-soluble, and biodegradable triblock copolymer PCL600-PEG6000-PCL600 was used to form supramolecular hydrogel (SMGel) by inclusion complexation with γ-cyclodextrin (γ-CD). The prepared SMGel was investigated as a carrier for sustained release of dexamethasone. The triblock copolymer PCL-PEG-PCL [where PCL = polycaprolactone, PEG = poly(ethylene glycol)] was synthesized by the ring-opening polymerization method using microwave irradiation. The polymerization reaction and the copolymer structures were evaluated by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). SMGel was prepared in aqueous solution by blending an aqueous γ-CD solution with aqueous solution of PCL-PEG-PCL triblock copolymer at room temperature. The sol-to-gel transition time was measured at various concentrations of copolymer and γ-CD. As-prepared SMGel was used to prepare a sustained, controllable drug delivery system of dexamethasone sodium phosphate. The SMGel was also characterized in terms of rheological, morphological, and structural properties. Results obtained from proton nuclear magnetic resonance ( (1)H-NMR) and GPC demonstrated that microwave irradiation is a simple and reliable method for synthesis of PEG-PCL copolymer. The SMGel with excellent syringability was prepared by mixing of 20% wt γ-CD and 10% wt of copolymer within 4 s. The SMGel containing 10% wt copolymer, 20% wt γ-CD, and 0.5% or 0.1% wt dexamethasone released approximately 100% and 45% of drug over up to 23 days, respectively. It could be concluded that SMGel based on self-assembly of inclusion complexes between PCL-PEG-PCL copolymer and γ-CD could be used as a basis for injectable drug delivery systems that provide sustained and controlled release of macromolecular drugs such as dexamethasone. PMID:27051627

  20. Self-assembled supramolecular hydrogel based on PCL-PEG-PCL triblock copolymer and γ-cyclodextrin inclusion complex for sustained delivery of dexamethasone

    PubMed Central

    Khodaverdi, Elham; Gharechahi, Marzieh; Alibolandi, Mona; Tekie, Farnaz Sadat Mirzazadeh; Khashyarmanesh, Bibi Zahra; Hadizadeh, Farzin

    2016-01-01

    In this study, thermosensitive, water-soluble, and biodegradable triblock copolymer PCL600-PEG6000-PCL600 was used to form supramolecular hydrogel (SMGel) by inclusion complexation with γ-cyclodextrin (γ-CD). The prepared SMGel was investigated as a carrier for sustained release of dexamethasone. The triblock copolymer PCL-PEG-PCL [where PCL = polycaprolactone, PEG = poly(ethylene glycol)] was synthesized by the ring-opening polymerization method using microwave irradiation. The polymerization reaction and the copolymer structures were evaluated by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). SMGel was prepared in aqueous solution by blending an aqueous γ-CD solution with aqueous solution of PCL-PEG-PCL triblock copolymer at room temperature. The sol-to-gel transition time was measured at various concentrations of copolymer and γ-CD. As-prepared SMGel was used to prepare a sustained, controllable drug delivery system of dexamethasone sodium phosphate. The SMGel was also characterized in terms of rheological, morphological, and structural properties. Results obtained from proton nuclear magnetic resonance ( 1H-NMR) and GPC demonstrated that microwave irradiation is a simple and reliable method for synthesis of PEG-PCL copolymer. The SMGel with excellent syringability was prepared by mixing of 20% wt γ-CD and 10% wt of copolymer within 4 s. The SMGel containing 10% wt copolymer, 20% wt γ-CD, and 0.5% or 0.1% wt dexamethasone released approximately 100% and 45% of drug over up to 23 days, respectively. It could be concluded that SMGel based on self-assembly of inclusion complexes between PCL-PEG-PCL copolymer and γ-CD could be used as a basis for injectable drug delivery systems that provide sustained and controlled release of macromolecular drugs such as dexamethasone. PMID:27051627

  1. Improvement of p-cymene antinociceptive and anti-inflammatory effects by inclusion in β-cyclodextrin.

    PubMed

    Quintans, Jullyana de Souza Siqueira; Menezes, Paula Passos; Santos, Márcio Roberto Viana; Bonjardim, Leonardo Rigoldi; Almeida, Jackson Roberto Guedes Silva; Gelain, Daniel Pens; Araújo, Adriano Antunes de Souza; Quintans-Júnior, Lucindo José

    2013-03-15

    Previously, we have demonstrated the analgesic-like property of p-cymene in rodents. Short half-life is a limitation for p-cymene application and several approaches have been used to improve pharmaceutical properties of monoterpenes, including the employment of drug-delivery systems. Here, we used p-cymene/β-cyclodextrin (β-CD) complex and p-cymene (PC) isolated to evaluated whether the complex formulation is able to improve the antinociceptive activity of this monoterpene. Male mice (26-30g) were pretreated with PC/β-CD (20 or 40mg/kg, p.o.), PC (20 or 40mg/kg, p.o.) or vehicle (distilled water), 0.5h before painful tests and antinociceptive effect was evaluated at times: 0.5, 1, 2, 4, 8, and 16h after treatment. We evaluated the analgesic-like effect of PC/β-CD and PC in acetic acid-induced abdominal writhes, hot-plate, carrageenan-induced paw edema and in rota-rod apparatus. Our results demonstrated that acute treatment with complex PC/β-CD produced an antinocicepitve effect (p<0.01 or p<0.001) for 8h followed whereas isolated PC produced the same effect for 2h. Similar results were obtained in hot-plate test, PC/β-CD, in all doses, significantly reduces (p<0.01 or p<0.001) nociceptive behavior for 8h while isolated PC for 1h, did so only in higher dose. Such results were unlikely to be caused by motor abnormality. Systemic pretreatment with PC/β-CD and PC inhibited the development paw edema by carrageenan 1%, but PC/β-CD did so during a longer period when compared with isolated monoterpene alone. Our results provide evidence to propose that the complex with β-CD improved analgesic and anti-inflammatory effects of p-cymene. PMID:23357360

  2. beta-Cyclodextrin-bonded silica particles as the solid-phase extraction medium for the determination of phenol compounds in water samples followed by gas chromatography with flame ionization and mass spectrometry detection.

    PubMed

    Faraji, Hakim

    2005-09-16

    A new absorbent for solid-phase extraction (SPE) was prepared by a beta-cyclodextrin bonded silica stationary phase (CDS) has been applied to determine the concentrations of phenol compounds in water samples. SPE of selected phenolic compounds from aqueous samples were performed using 250 mg CDS. The determination was subsequently carried out by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Compared with available SPE, the CDS showed high sensitivity and fast velocity of mass transfer for phenolic compound because of its porous structure of beta-cyclodextrin. The relative standard deviation (RSD) for river water sample spiked with phenolic compounds at sub-ppb level was lower than 10% and limit of detection (LOD) for these compounds were between 10 and 100 ng l(-1). PMID:16130725

  3. 2,3-di-O-methoxymethyl-6-O-tert-butyldimethylsilyl-beta-cyclodextrin, a useful stationary phase for gas chromatographic separation of enantiomers.

    PubMed

    Takahisa, Eisuke; Engel, Karl-Heinz

    2005-05-27

    Heptakis(2,3-di-O-methoxymethyl-6-O-tert-butyldimethylsilyl)-beta-cyclodextrin (2,3-MOM-6-TBDMS-beta-CD), synthesized by using methoxymethylchloride (MOM-Cl) as derivatization reagent, was used for capillary gas chromatographic separation of enantiomers. The new chiral stationary phase proved to be suitable for the enantiodifferentiation of volatiles from various chemical classes. Compared to the corresponding gamma-CD derivative (2,3-MOM-6-TBDMS-gamma-CD), the spectrum of compounds for which enantiomers could be separated was more limited and the enantioseparation achieved was generally less pronounced. Unusually high separation factors were observed for 2-alkyl esters of short chain acids (C2-C6). Phenomena underlying the enantioseparation of 2-pentyl acetate (alpha: 4.31; 35 degrees C) were investigated by determining thermodynamic parameters. Data show that only one enantiomer is retained significantly on the chiral stationary phase whereas the other one behaves like the hydrocarbons used as references. PMID:15974081

  4. Effect of n-alkyl chain length on the complexation of phenanthrene and 9-alkyl-phenanthrene with $beta;-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Rima, J.; Aoun, E.; Hanna, K.

    2004-06-01

    The characteristics of host-guest complexation between β-cyclodextrin (β-CD) and phenanthrene derivatives (phenanthrene, n-propyl, n-butyl and n-hexyl-phenanthrene) were investigated by fluorescence spectrometry. Linear and non-linear regression methods were used to estimate the formation constants ( K1). A 1:1 stoichiometric ratio and an effect of n-alkyl chain length on the formation constant were observed for the binary inclusion complex between guest and β-CD. The formation constant dramatically increases with the length of n-alkyl, it starts from the value of 140 l mol -1 for the phenanthrene to reach the value of 580 l mol -1 for hexyl-phenanthrene. The effect of the temperature on the fluorescence intensity of each complex (guest-host) was also studied; and then the thermodynamic parameters were calculated. The main inclusion site seems to be aromatic moiety for short chain molecules, and it moves toward the alkyl chain part, as the chain becomes longer.

  5. Comparative assessment of effectiveness of ketoprofen and ketoprofen/beta-cyclodextrin complex in two experimental models of inflammation in rats.

    PubMed

    Grecu, Mariana; Năstasă, Valentin; Ilie, Cornelia; Miron, Liviu; Mareş, Mihai

    2014-01-01

    Oral administration of non-steroidal anti-inflammatory drugs (NSAIDs) can lead to adverse effects such as gastrointestinal distress. The complexation of different groups of active substances with β-cyclodextrin (β-CD) has drawn considerable interest over recent years. The purpose of this study was to analyze the ketoprofen/β-cyclodextrin (K/β-CD) conjugate complex as well as to assess its anti-inflammatory effect after oral administration (doses of 30 mg/m(2) and 15 mg/m(2) of body surface), compared with ketoprofen. The studies were done on two models of experimentally-induced acute inflammation in rats (n = 48, 6/group), by means of intraplantar administration of a 10% aqueous kaolin suspension and intraperitoneal administration of a 1% sodium thioglycolate solution. The dynamics of the acute inflammatory process and the anti-inflammatory effects were monitored using plethysmometric determinations after 3, 6, 9, 12, 24 and 48 h (plantar inflammation), and the absorbance of the exudates (spectrophotometrically read) and nucleated cell counts after 24 h (peritoneal inflammation). The coupling of ketoprofen with β-CD resulted in increased solubility (100% in 60 min) of the newly-formed product, which further resulted in a higher bioavailability compared with ketoprofen (<40% in 120 min). In both models of experimentally-induced inflammation, the K/β-CD complex had a higher anti-inflammatory activity than ketoprofen.

  6. Inclusion.

    ERIC Educational Resources Information Center

    Nathanson, Jeanne H., Ed.

    1992-01-01

    This theme journal issue focuses on current activities of the Office of Special Education and Rehabilitative Services which stress inclusion of students with disabilities in the mainstream. It begins with a message from the Assistant Secretary, Robert R. Davila which examines the full meaning of an "inclusive" education. Next, Barbara Buswell and…

  7. Preparation and characterization of host-guest system between inosine and β-cyclodextrin through inclusion mode.

    PubMed

    Prabu, Samikannu; Sivakumar, Krishnamurty; Swaminathan, Meenakshisundaram; Rajamohan, Rajaram

    2015-08-01

    Inosine is a nucleoside that is formed when hypoxanthine is attached to a ribose ring (also known as a ribofuranose) via a β-N₉-glycosidic bond. Inosine is commonly found in tRNAs. Inosine (INS) has been used widely as an antiviral drug. The inclusion complex of INS with β-CDx in solution phase is studied by ground and excited state with UV-visible and fluorescence spectroscopy, respectively. A binding constant and stoichiometric ratio between INS and β-CDx are calculated by BH equation. The lifetime and relative amplitude of INS is increases with increasing the concentrations of β-CDx, confirms the formation of inclusion complex in liquid state. The solid complexes are prepared by kneading method (KM) and co-precipitation method (CP). The solid complex is characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), powder X-ray diffraction (XRD) and differential scanning colorimetry (DSC). CP method gives the solid product with good yield than that of physical mixture and KM method. The structure of complex is proposed based on the study of Patch - Dock server.

  8. Preparation and characterization of host-guest system between inosine and β-cyclodextrin through inclusion mode

    NASA Astrophysics Data System (ADS)

    Prabu, Samikannu; Sivakumar, Krishnamurty; Swaminathan, Meenakshisundaram; Rajamohan, Rajaram

    2015-08-01

    Inosine is a nucleoside that is formed when hypoxanthine is attached to a ribose ring (also known as a ribofuranose) via a β-N9-glycosidic bond. Inosine is commonly found in tRNAs. Inosine (INS) has been used widely as an antiviral drug. The inclusion complex of INS with β-CDx in solution phase is studied by ground and excited state with UV-visible and fluorescence spectroscopy, respectively. A binding constant and stoichiometric ratio between INS and β-CDx are calculated by BH equation. The lifetime and relative amplitude of INS is increases with increasing the concentrations of β-CDx, confirms the formation of inclusion complex in liquid state. The solid complexes are prepared by kneading method (KM) and co-precipitation method (CP). The solid complex is characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), powder X-ray diffraction (XRD) and differential scanning colorimetry (DSC). CP method gives the solid product with good yield than that of physical mixture and KM method. The structure of complex is proposed based on the study of Patch - Dock server.

  9. Enhanced phytoremediation potential of polychlorinated biphenyl contaminated soil from e-waste recycling area in the presence of randomly methylated-beta-cyclodextrins.

    PubMed

    Shen, Chaofeng; Tang, Xianjin; Cheema, Sardar Alam; Zhang, Congkai; Khan, Muhammad Imran; Liang, Fang; Chen, Xincai; Zhu, Youfeng; Lin, Qi; Chen, Yingxu

    2009-12-30

    The crude recycling of electronic and electric waste (e-waste) is now creating soil pollution problems with organic compounds such as polychlorinated biphenyls (PCBs). The present study aimed to compare the phytoremediation potential of four plant species (rice, alfalfa, ryegrass and tall fescue) for PCBs contaminated soil from Taizhou city, one of the largest e-waste recycling centers in China. In addition, the enhanced effects of randomly methylated-beta-cyclodextrins (RAMEB) on PCBs phytoremediation potential were evaluated. Higher PCBs removal percentages of 25.6-28.5% in rhizosphere soil were observed after 120 days, compared with those of the non-rhizosphere (10.4-16.9%) and unplanted controls (7.3%). The average PCBs removal percentages of four plant species increased from 26.9% to 37.1% in the rhizosphere soil with addition of RAMEB. Meanwhile, relatively high microbial counts and dehydrogenase activity were detected in planted soils and a stimulatory effect by RAMEB addition was found. The present study indicated that all the plant candidates were feasible for phytoremediation of PCBs contaminated soil from the e-waste recycling area, and tall fescue with RAMEB amendment seemed as a promising remediation strategy. High PCBs removal percentage was due to the increased PCBs bioavailability as well as biostimulation of microbial communities after plantation and RAMEB addition.

  10. Methyl-{beta}-cyclodextrin enhances the susceptibility of human breast cancer cells to carboplatin and 5-fluorouracil: Involvement of Akt, NF-{kappa}B and Bcl-2

    SciTech Connect

    Upadhyay, Ankur Kumar; Singh, Sandeep; Chhipa, Rishi Raj; Vijayakumar, Maleppillil Vavachan; Ajay, Amrendra Kumar; Bhat, Manoj Kumar . E-mail: manojkbhat@nccs.res.in

    2006-10-15

    The response rates of extensively used chemotherapeutic drugs, carboplatin (Carb) or 5-fluorouracil (5-FU) are relatively disappointing because of considerable side effects associated with their high-dose regimen. In the present study, we determined whether treatment with a cholesterol depleting agent, methyl-{beta}-cyclodextrin (MCD), enhances the weak efficacy of low doses of Carb or 5-FU in human breast cancer cells. Data demonstrate that pretreatment with MCD significantly potentiates the cytotoxic activity of Carb and 5-FU in both MCF-7 and MDA-MB-231. Furthermore, we explored the molecular basis of enhanced cytotoxicity, and our data revealed that low-dose treatment with these drugs in MCD pretreated cells exhibited significantly decreased Akt phosphorylation, NF-{kappa}B activity and down-regulation in expression of anti-apoptotic protein Bcl-2. In addition, MCD pretreated cells demonstrated an increased intracellular drug accumulation as compared to cells treated with drugs alone. Taken together, our data provide the basis for potential therapeutic application of MCD in combination with other conventional cytotoxic drugs to facilitate reduction of drug dosage that offers a better chemotherapeutic approach with low toxicity.

  11. Silicone elastomer uptake method for determination of free 1-alkyl-2-pyrrolidone concentration in micelle and hydroxypropyl-beta-cyclodextrin systems used in skin transport studies.

    PubMed

    Warner, Kevin S; Shaker, Dalia S; Molokhia, Sarah; Xu, Qingfang; Hao, Jinsong; Higuchi, William I; Li, S Kevin

    2008-01-01

    Previous investigations in our laboratory demonstrated how the polar head group and alkyl chain of amphiphilic chemical skin permeation enhancers contribute to enhancer potency. In those studies enhancers with n-alkyl chain lengths of eight or less were investigated. In order to investigate enhancers with longer n-alkyl chain lengths, enhancer-solubilizing agents should be considered. Corticosterone (CS) flux enhancement along the lipoidal pathway of hairless mouse skin (HMS) was determined with the enhancers 1-hexyl- (HP), 1-octyl- (OP), 1-decyl- (DP), and 1-dodecyl-2-pyrrolidone (DoP) solubilized in 1,2-distearoyl-sn-glycero-3-phosphatidylethanolamine-N-[methoxy(polyethylene glycol-2000] (DSPE) micelles or in hydroxypropyl-beta-cyclodextrin (HPbetaCD). The free CS, HP, OP, DP, and DoP aqueous concentrations in the DSPE micelle and HPbetaCD systems were determined using a partitioning method. Comparisons of the enhancer potencies based on the free concentration of the enhancers revealed a nearly semi-logarithmic linear relationship between enhancer potency and the carbon number of the alkyl chain length with a slope of approximately 0.55. The observed n-alkyl chain length dependency in the aqueous phase is consistent with the hydrophobic effect. This study shows that longer chain enhancers may be studied by employing a solubilizing system, and free enhancer concentration in these systems can be determined with the aid of the silicone elastomer uptake method.

  12. Experimental and theoretical analysis of the interaction of (+/-)-cis-ketoconazole with beta-cyclodextrin in the presence of (+)-L-tartaric acid.

    PubMed

    Redenti, E; Ventura, P; Fronza, G; Selva, A; Rivara, S; Plazzi, P V; Mor, M

    1999-06-01

    1H NMR spectroscopy was used for determining the optical purity of cis-ketoconazole enantiomers obtained by fractional crystallization. The chiral analysis was carried out using beta-cyclodextrin in the presence of (+)-L-tartaric acid. The mechanism of the chiral discrimination process, the stability of the complexes formed, and their structure in aqueous solution were also investigated by 1H and 13C chemical shift analysis, two-dimensional NOE experiments, relaxation time measurements, and mass spectrometry experiments. Theoretical models of the three-component interaction were built up on the basis of the available NMR data, by performing a conformational analysis on the relevant fragments on ketoconazole and docking studies on the components of the complex. The model derived from a folded conformation of ketoconazole turned out to be fully consistent with the molecular assembly found in aqueous solution, as inferred from NOE experiments. An explanation of the different association constants for the complexes of the two enantiomers is also provided on the basis of the interaction energies.

  13. Complex formation between benzene carboxylic acids and β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Belyakova, L. A.; Lyashenko, D. Yu.

    2008-05-01

    Complex formation between benzene carboxylic acids and β-cyclodextrin in aqueous solutions at 290 300 K was studied using UV spectroscopy. The formation of 1:1 supramolecular inclusion compounds β-cyclodextrin-benzene and β-cyclodextrin-salicylic acid was found. Stability constants (Ks) of the complexes and thermodynamic parameters for formation of the inclusion compounds (ΔG, ΔH, and ΔS) were calculated.

  14. Influence of buffer substances and urea on the beta-cyclodextrin-mediated chiral separation of dipeptides in CE.

    PubMed

    Hammitzsch-Wiedemann, Manuela; Scriba, Gerhard K E

    2007-08-01

    The influence of buffering substances and urea on the beta-CD-mediated chiral separations of the dipeptides Ala-Phe and Ala-Tyr was studied in the pH range of 2.5-3.8. Only minor effects of the buffer substances on the chiral separation selectivity alpha were observed at a beta-CD concentration of 15 mg/mL. In contrast, the selectivity improved at pH 2.5 but decreased at pH 3.8 upon the addition of 2 M urea. Complexation by beta-CD resulted in a shift of the pK(a) values toward higher values which was more pronounced for the DD-enantiomers of both dipeptides than for the LL-enantiomers. Addition of urea further increased the pK(a) shift. The consequence of this pK(a) shift is an increase of the fraction of the protonated, positively charged form of the peptides which explained the improved chiral separation at pH 2.5 and the reduced selectivity at pH 3.8. A pK(a) shift by the addition of urea was also observed for N-tert-butyloxycarbonyl phenylalanine (BOC-Phe) as a model compound that is strongly complexed by beta-CD. This effect was not stereospecific. Addition of urea resulted in a decrease of the apparent complexation constants between beta-CD and the BOC-Phe enantiomers to the same extent but this did not affect the separation selectivity alpha. For chiral separations that display strong pH dependence such as peptide enantioseparations close to the pK(a) values of the compounds, urea may not solely be regarded as a solubility enhancer for beta-CD but may also influence the separation.

  15. Study of the effects of cyclodextrins on the fluorescence detection of zearalenone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Successful applications of inclusion complexes to improve isolation and detection of small molecules have made cyclodextrins increasingly popular components in methods of detection. Studies of the effects of cyclodextrins on aflatoxins have advanced mycotoxin detection research. Recently, a capill...

  16. Predicting the binding free energy of the inclusion process of 2-hydroxypropyl-β-cyclodextrin and small molecules by means of the MM/3D-RISM method

    NASA Astrophysics Data System (ADS)

    Sugita, Masatake; Hirata, Fumio

    2016-09-01

    A protocol to calculate the binding free energy of a host–guest system is proposed based on the MM/3D-RISM method, taking cyclodextrin derivatives and their ligands as model systems. The protocol involves the procedure to identify the most probable binding mode (MPBM) of receptors and ligands by means of the umbrella sampling method. The binding free energies calculated by the MM/3D-RISM method for the complexes of the seven ligands with the MPBM of the cyclodextrin, and with the fluctuated structures around it, are in agreement with the corresponding experimental data in a semi-quantitative manner. It suggests that the protocol proposed here is promising for predicting the binding affinity of a small ligand to a relatively rigid receptor such as cyclodextrin.

  17. Purification and renaturation of recombinant human lymphotoxin (tumour necrosis factor beta) expressed in Escherichia coli as inclusion bodies.

    PubMed

    Jin, H; Uddin, M S; Huang, Y L; Teo, W K

    1994-01-01

    High level expression of recombinant human tumour necrosis factor beta (rhTNF-beta) in Escherichia coli results in the formation of two portions of protein, namely soluble active protein and insoluble protein which is inactive and aggregates in the form of inclusion bodies (IBs). In this study, a procedure for purification and renaturation of rhTNF-beta from inclusion bodies has been designed and verified experimentally with a product purity of more than 90% and a recovery of about 30%. The procedure includes washing of IBs with specific wash buffer (Triton X-100/EDTA/lysozyme/PMSF), their solubilization with 8 mol dm-3 alkaline urea, purification with ion-exchange columns, refolding with renaturation buffer and finally concentration and desalination with an ultrafiltration membrane. The characteristics of the renatured protein were identical with those of purified protein from the soluble fraction as demonstrated by (1) SDS-PAGE, (2) cytotoxic activity on mouse L929 cells, (3) N-terminal amino acid sequence, and (4) gel filtration chromatography.

  18. Efficacy of attractive toxic sugar baits (ATSB) against Aedes albopictus with garlic oil encapsulated in beta-cyclodextrin as the active ingredient.

    PubMed

    Junnila, Amy; Revay, Edita E; Müller, Gunter C; Kravchenko, Vasiliy; Qualls, Whitney A; Xue, Rui-de; Allen, Sandra A; Beier, John C; Schlein, Yosef

    2015-12-01

    We tested the efficacy of attractive toxic sugar bait (ATSB) with garlic oil microencapsulated in beta-cyclodextrin as active ingredient against Aedes albopictus in suburban Haifa, Israel. Two three-acre gardens with high numbers of Ae. albopictus were selected for perimeter spray treatment with ATSB and ASB (bait containing no active ingredient). Baits were colored with food dye to verify feeding of the mosquitoes. The mosquito population was monitored by human landing catches and sweep net catches in the surrounding vegetation. Experiments lasted for 44 days. Treatment occurred on day 13. The mosquito population collapsed about 4 days after treatment and continued to drop steadily for 27 days until the end of the study. At the experimental site the average pre-treatment landing rate was 17.2 per 5mins. Two days post-treatment, the landing rate dropped to 11.4, and continued to drop to an average of 2.6 during the following 26 days. During the same period, the control population was stable. Few sugar fed females (8-10%) approached a human bait and anthrone tests showed relatively small amounts of sugar within their crop/gut. Around 60-70 % of males caught near our human bait were sugar positive which may indicate that the males were feeding on sugar for mating related behavior. From the vegetation treated with the toxic bait, we recovered significantly fewer (about 10-14%) males and females stained by ATSB than at the ASB-treated control. This may indicate that the toxic baits alter the resting behavior of the poisoned mosquitoes within the vegetation. Almost no Ae. albopictus females (5.2±1.4) approached human bait after treatment with ATSB. It therefore appears that microencapsulated garlic oil is an effective pesticide against Ae. albopictus when used in an ATSB system. PMID:26403337

  19. Efficacy of attractive toxic sugar baits (ATSB) against Aedes albopictus with garlic oil encapsulated in beta-cyclodextrin as the active ingredient.

    PubMed

    Junnila, Amy; Revay, Edita E; Müller, Gunter C; Kravchenko, Vasiliy; Qualls, Whitney A; Xue, Rui-de; Allen, Sandra A; Beier, John C; Schlein, Yosef

    2015-12-01

    We tested the efficacy of attractive toxic sugar bait (ATSB) with garlic oil microencapsulated in beta-cyclodextrin as active ingredient against Aedes albopictus in suburban Haifa, Israel. Two three-acre gardens with high numbers of Ae. albopictus were selected for perimeter spray treatment with ATSB and ASB (bait containing no active ingredient). Baits were colored with food dye to verify feeding of the mosquitoes. The mosquito population was monitored by human landing catches and sweep net catches in the surrounding vegetation. Experiments lasted for 44 days. Treatment occurred on day 13. The mosquito population collapsed about 4 days after treatment and continued to drop steadily for 27 days until the end of the study. At the experimental site the average pre-treatment landing rate was 17.2 per 5mins. Two days post-treatment, the landing rate dropped to 11.4, and continued to drop to an average of 2.6 during the following 26 days. During the same period, the control population was stable. Few sugar fed females (8-10%) approached a human bait and anthrone tests showed relatively small amounts of sugar within their crop/gut. Around 60-70 % of males caught near our human bait were sugar positive which may indicate that the males were feeding on sugar for mating related behavior. From the vegetation treated with the toxic bait, we recovered significantly fewer (about 10-14%) males and females stained by ATSB than at the ASB-treated control. This may indicate that the toxic baits alter the resting behavior of the poisoned mosquitoes within the vegetation. Almost no Ae. albopictus females (5.2±1.4) approached human bait after treatment with ATSB. It therefore appears that microencapsulated garlic oil is an effective pesticide against Ae. albopictus when used in an ATSB system.

  20. Efficacy of attractive toxic sugar baits (ATSB) against Aedes albopictus with garlic oil encapsulated in beta-cyclodextrin as the active ingredient

    PubMed Central

    Junnila, Amy; Revay, Edita E.; Müller, Gunter C.; Kravchenko, Vasiliy; Qualls, Whitney A.; Xue, Rui-de; Allen, Sandra A.; Beier, John C.; Schlein, Yosef

    2016-01-01

    We tested the efficacy of attractive toxic sugar bait (ATSB) with garlic oil microencapsulated in beta-cyclodextrin as active ingredient against Aedes albopictus in suburban Haifa, Israel. Two three-acre gardens with high numbers of Ae. albopictus were selected for perimeter spray treatment with ATSB and ASB (bait containing no active ingredient). Baits were colored with food dye to verify feeding of the mosquitoes. The mosquito population was monitored by human landing catches and sweep net catches in the surrounding vegetation. Experiments lasted for 44 days. Treatment occurred on day 13. The mosquito population collapsed about 4 days after treatment and continued to drop steadily for 27 days until the end of the study. At the experimental site the average pre-treatment landing rate was 17.2 per 5 mins. Two days post-treatment, the landing rate dropped to 11.4, and continued to drop to an average of 2.6 during the following 26 days. During the same period, the control population was stable. Few sugar fed females (8–10%) approached a human bait and anthrone tests showed relatively small amounts of sugar within their crop/gut. Around 60–70 % of males caught near our human bait were sugar positive which may indicate that the males were feeding on sugar for mating related behavior. From the vegetation treated with the toxic bait, we recovered significantly fewer (about 10–14%) males and females stained by ATSB than at the ASB-treated control. This may indicate that the toxic baits alter the resting behavior of the poisoned mosquitoes within the vegetation. Almost no Ae. albopictus females (5.2 ± 1.4) approached human bait after treatment with ATSB. It therefore appears that microencapsulated garlic oil is an effective pesticide against Ae. albopictus when used in an ATSB system. PMID:26403337

  1. Comparative study of polymer containing beta-cyclodextrin and -COOH for adsorption toward aniline, 1-naphthylamine and methylene blue.

    PubMed

    Zhao, Dong; Zhao, Liang; Zhu, Cheng-Shen; Shen, Xiangyu; Zhang, Xiaozhuan; Sha, Baofeng

    2009-11-15

    Three different polymers P1, P2 and P3 (P1 containing both beta-CD and -COOH, P2 containing beta-CD and P3 containing -COOH) were synthesized and applied to adsorption toward aniline, 1-naphthylamine and methylene blue. The concentrations (C) before and after adsorption were determined and the adsorption capacities (q) of P1, P2 and P3 were calculated. The maximum adsorption capacities (q(max)) toward aniline: q(max) (P1)=104 micromol g(-1), q(max) (P2)=14.9 micromol g(-1) and q(max) (P3)=53.1 micromol g(-1); toward 1-naphthylamine: q(max) (P1)=184 micromol g(-1), q(max) (P2)=53.8 micromol g(-1) and q(max) (P3)=125 micromol g(-1); toward methylene blue: q(max) (P1)=200 micromol g(-1), q(max) (P2)=12.7 micromol g(-1) and q(max) (P3)=215 micromol g(-1). P1 exhibited remarkable adsorption toward all the three adsorbates. P2 was almost equal to P1 in adsorption toward methylene blue, but was less efficient than P1 in adsorption toward aniline and 1-naphthylamine. P3 also exhibited considerable adsorption toward aniline and 1-naphthylamine, but was inefficient toward methylene blue. P1 was obtained from nontoxic materials and through environment friendly procedures, so it was potentially an efficient and green adsorbent for water purification.

  2. An improved HPLC method overcoming Beer's law deviations arising from supramolecular interactions in tolfenamic acid and cyclodextrins complexes.

    PubMed

    Rozou, S; Antoniadou-Vyza, E

    1998-12-01

    Inclusion complexes of tolfenamic acid (TA), a non-steroidal anti-inflammatory drug, with methyl-beta cyclodextrin and hydroxypropyl-beta cyclodextrin were prepared and characterised. Spectrophotometric, chromatographic (RP-HPLC) and 1H NMR studies of the complexes were conducted. It was observed that cyclodextrins influence TA's molar absorptivity leading to Beer's law deviation. Consequently, the accuracy problem arose, urged for the application of specific chromatographic conditions for the determination of TA in the presence of CDs. A new HPLC method was developed and validated. TA was analysed on a C18 column 5 microm (150 x 4.6 mm), using a column thermostat regulated at 30 degrees C. The mobile phase consisted of methanol-phosphate buffer solution (pH 3.2; 0.07 M) (90:10 v/v) and the flow rate was set at 2.0 ml min(-1). The detector was operated at 286 nm. TA was successfully determined, overcoming the problems arising from the presence of cyclodextrins.

  3. A spectrofluorimetric method for determining the association constants of pyrene with cyclodextrins based on polarity variation

    NASA Astrophysics Data System (ADS)

    Kusumoto, Yoshihumi

    1987-05-01

    The association constants of pyrene inclusion complexes with β-cyclodextrin and methylated β-cyclodextrins were determined using equations which provide an accurate description of the variation in the vibronic-band-intensity ratio of pyrene monomer fluorescence in the presence of cyclodextrins.

  4. Cyclodextrin stabilised emulsions and cyclodextrinosomes.

    PubMed

    Mathapa, Baghali G; Paunov, Vesselin N

    2013-11-01

    We report the preparation of o/w emulsions stabilised by microcrystals of cyclodextrin-oil inclusion complexes. The inclusion complexes are formed by threading cyclodextrins from the aqueous phase on n-tetradecane or silicone oil molecules from the emulsion drop surface which grow further into microrods and microplatelets depending on the type of cyclodextrin (CD) used. These microcrystals remain attached on the surface of the emulsion drops and form densely packed layers which resemble Pickering emulsions. The novelty of this emulsion stabilisation mechanism is that molecularly dissolved cyclodextrin from the continuous aqueous phase is assembled into colloid particles directly onto the emulsion drop surface, i.e. molecular adsorption leads to effective Pickering stabilisation. The β-CD stabilised tetradecane-in-water emulsions were so stable that we used this system as a template for preparation of cyclodextrinosomes. These structures were produced solely through formation of cyclodextrin-oil inclusion complexes and their assembly into a crystalline phase on the drop surface retained its stability after the removal of the core oil. The structures of CD-stabilised tetradecane-in-water emulsions were characterised using optical microscopy, fluorescence microscopy, cross-polarised light microscopy and WETSEM while the cyclodextrinosomes were characterised by SEM. We also report the preparation of CD-stabilised emulsions with a range of other oils, including tricaprylin, silicone oil, isopropyl myristate and sunflower oil. We studied the effect of the salt concentration in the aqueous phase, the type of CD and the oil volume fraction on the type of emulsion formed. The CD-stabilised emulsions can be applied in a range of surfactant-free formulations with possible applications in cosmetics, home and personal care. Cyclodextrinosomes could find applications in pharmaceutical formulations as microencapsulation and drug delivery vehicles. PMID:24043288

  5. Preparation of polydimethylsiloxane/beta-cyclodextrin/divinylbenzene coated "dumbbell-shaped" stir bar and its application to the analysis of polycyclic aromatic hydrocarbons and polycyclic aromatic sulfur heterocycles compounds in lake water and soil by high performance liquid chromatography.

    PubMed

    Yu, Chunhe; Yao, Zhimin; Hu, Bin

    2009-05-01

    A "dumbbell-shaped" stir bar was proposed to prevent the friction loss of coating during the stirring process, and thus prolonged the lifetime of stir bars. The effects of the coating components, including polydimethylsiloxane (PDMS), beta-cyclodextrin (beta-CD) and divinylbenzene (DVB) were investigated according to an orthogonal experimental design, using three polycyclic aromatic hydrocarbons (PAHs) and four polycyclic aromatic sulfur heterocycles (PASHs) as model analytes. Four kinds of stir bars coated with PDMS, PDMS/beta-CD, PDMS/DVB and PDMS/beta-CD/DVB were prepared and their extraction efficiencies for the target compounds were compared. It was demonstrated that PDMS/beta-CD/DVB-coated stir bar showed the best affinity to the studied compounds. The preparation reproducibility of PDMS/beta-CD/DVB-coated stir bar ranged from 3.2% to 15.2% (n = 6) in one batch, and 5.2% to 13.4% (n = 6) among batches. The "dumbbell-shaped" stir bar could be used for about 40 times, which were 10 extractions more than a normal stir bar. The prepared PDMS/beta-CD/DVB-coated "dumbbell-shaped" stir bar was used for stir bar sorptive extraction (SBSE) of PAHs and PASHs and the desorbed solution was introduced into HPLC-UV for subsequent analysis. The limits of detection of the proposed method for seven target analytes ranged from 0.007 to 0.103 microg L(-1), the relative standard deviations were in the range of 6.3-12.9% (n = 6, c = 40 microg L(-1)), and the enrichment factors were 19-86. The proposed method was successfully applied to the analysis of seven target analytes in lake water and soil samples.

  6. Safety assessment of gamma-cyclodextrin.

    PubMed

    Munro, I C; Newberne, P M; Young, V R; Bär, A

    2004-06-01

    Gamma-cyclodextrin (gamma-CD) is a cyclic alpha-(1,4)-linked oligosaccharide consisting of eight glucose molecules. Like other cyclodextrins, gamma-CD can form inclusion complexes with a variety of organic molecules because the inner side of the torus-like molecule is less polar than the outer side. In foods, gamma-CD may be used as a carrier for flavors, vitamins, polyunsaturated fatty acids, and other ingredients. It also has useful properties as a stabilizer in different food systems. The daily intake from all its intended uses in food at highest feasible concentrations has been estimated at 4.1g/person/day for consumers of gamma-CD containing foods. The present review summarizes the safety data of gamma-CD. The toxicity studies consist of standard genotoxicity tests, subchronic rat studies with oral and intravenous administration of gamma-CD for up to 3 months, a subchronic (3-month) toxicity study in dogs, a (1-year) oral toxicity study in rats, and embryotoxicity/teratogenicity studies in rats and rabbits. In the studies with oral administration, gamma-CD was given at dietary concentrations of up to 20%. All these studies demonstrated that gamma-CD is well tolerated and elicits no toxicological effects. Metabolic studies in rats showed that gamma-CD is rapidly and essentially completely digested by salivary and pancreatic amylase. Therefore, the metabolism of gamma-CD closely resembles that of starch and linear dextrins. A human study with ingestion of single doses of 8 g gamma-CD or 8 g maltodextrin did not reveal a difference in gastrointestinal tolerance of these two products. An interaction of ingested gamma-CD with the absorption of fat-soluble vitamins or other lipophilic nutrients is not to be expected because the formation of inclusion complexes is a reversible process, gamma-CD is readily digested in the small intestine, and studies with beta-CD, a non-digestible cyclodextrin, have shown that the bioavailability of vitamins (A, D, and E) is not

  7. Preparation, Characterization, and Pharmacological Activity of Cymbopogon winterianus Jowitt ex Bor (Poaceae) Leaf Essential Oil of β-Cyclodextrin Inclusion Complexes

    PubMed Central

    Santos, Priscila L.; Araújo, Adriano A. S.; Quintans, Jullyana S. S.; Oliveira, Makson G. B.; Brito, Renan G.; Serafini, Mairim R.; Menezes, Paula P.; Santos, Marcio R. V.; Alves, Pericles B.; de Lucca Júnior, Waldecy; Blank, Arie F.; La Rocca, Viviana; Almeida, Reinaldo N.; Quintans-Júnior, Lucindo J.

    2015-01-01

    This study aimed to evaluate the orofacial antinociceptive effect of the Cymbopogon winterianus essential oil (LEO) complexed in β-cyclodextrin (LEO-CD) and to assess the possible involvement of the central nervous system (CNS). The LEO was extracted, chromatographed, and complexed in β-cyclodextrin. The complex was characterized by differential scanning calorimetry (DSC) and thermogravimetry derivative (TG/DTG). Male Swiss mice (2-3 months) were treated with LEO-CD (50–200 mg/kg, p.o.), vehicle (distilled water, p.o.), or standard drug (i.p.) and subjected to the orofacial nociception formalin-, capsaicin-, and glutamate-induced. After the formalin test, the animals were perfused and the brains subjected to immunofluorescence for Fos. The rota-rod test (7 rpm/min) was carried out. Geraniol (37.57%) was the main compound of LEO. DSC and TG/DTG proved the complexation. The orofacial nociceptive behavior was significantly (p < 0.05) reduced. The number of Fos-positive cells was significantly changed in the dorsal raphe nucleus (p < 0.01), locus coeruleus (p < 0.001), trigeminal nucleus (p < 0.05), and trigeminal thalamic tract (p < 0.05). LEO-CD did not cause changes in motor coordination in the rota-rod test. Thus, our results suggested that LEO-CD has an orofacial antinociceptive profile, probably mediated by the activation of the CNS without changing the motor coordination. PMID:26246838

  8. Preparation, Characterization, and Pharmacological Activity of Cymbopogon winterianus Jowitt ex Bor (Poaceae) Leaf Essential Oil of β-Cyclodextrin Inclusion Complexes.

    PubMed

    Santos, Priscila L; Araújo, Adriano A S; Quintans, Jullyana S S; Oliveira, Makson G B; Brito, Renan G; Serafini, Mairim R; Menezes, Paula P; Santos, Marcio R V; Alves, Pericles B; de Lucca Júnior, Waldecy; Blank, Arie F; La Rocca, Viviana; Almeida, Reinaldo N; Quintans-Júnior, Lucindo J

    2015-01-01

    This study aimed to evaluate the orofacial antinociceptive effect of the Cymbopogon winterianus essential oil (LEO) complexed in β-cyclodextrin (LEO-CD) and to assess the possible involvement of the central nervous system (CNS). The LEO was extracted, chromatographed, and complexed in β-cyclodextrin. The complex was characterized by differential scanning calorimetry (DSC) and thermogravimetry derivative (TG/DTG). Male Swiss mice (2-3 months) were treated with LEO-CD (50-200 mg/kg, p.o.), vehicle (distilled water, p.o.), or standard drug (i.p.) and subjected to the orofacial nociception formalin-, capsaicin-, and glutamate-induced. After the formalin test, the animals were perfused and the brains subjected to immunofluorescence for Fos. The rota-rod test (7 rpm/min) was carried out. Geraniol (37.57%) was the main compound of LEO. DSC and TG/DTG proved the complexation. The orofacial nociceptive behavior was significantly (p < 0.05) reduced. The number of Fos-positive cells was significantly changed in the dorsal raphe nucleus (p < 0.01), locus coeruleus (p < 0.001), trigeminal nucleus (p < 0.05), and trigeminal thalamic tract (p < 0.05). LEO-CD did not cause changes in motor coordination in the rota-rod test. Thus, our results suggested that LEO-CD has an orofacial antinociceptive profile, probably mediated by the activation of the CNS without changing the motor coordination. PMID:26246838

  9. Cooperation between two ClpB isoforms enhances the recovery of the recombinant {beta}-galactosidase from inclusion bodies

    SciTech Connect

    Guenther, Izabela; Zolkiewski, Michal; Kedzierska-Mieszkowska, Sabina

    2012-10-05

    Highlights: Black-Right-Pointing-Pointer An important role of synergistic cooperation between the two ClpB isoforms. Black-Right-Pointing-Pointer Both ClpB isoforms are associated with IBs of {beta}-galactosidase. Black-Right-Pointing-Pointer ClpB is a key chaperone in IB protein release. -- Abstract: Bacterial ClpB is a molecular chaperone that solubilizes and reactivates aggregated proteins in cooperation with the DnaK chaperone system. The mechanism of protein disaggregation mediated by ClpB is linked to translocation of substrates through the central channel within the ring-hexameric structure of ClpB. Two isoforms of ClpB are produced in vivo: the full-length ClpB95 and the truncated ClpB80 (ClpB{Delta}N), which does not contain the N-terminal domain. The functional specificity of the two ClpB isoforms and the biological role of the N-terminal domain are still not fully understood. Recently, it has been demonstrated that ClpB may achieve its full potential as an aggregate-reactivating chaperone through the functional interaction and synergistic cooperation of its two isoforms. It has been found that the most efficient resolubilization and reactivation of stress-aggregated proteins occurred in the presence of both ClpB95 and ClpB80. In this work, we asked if the two ClpB isoforms functionally cooperate in the solubilization and reactivation of proteins from insoluble inclusion bodies (IBs) in Escherichia coli cells. Using the model {beta}-galactosidase fusion protein (VP1LAC), we found that solubilization and reactivation of enzymes entrapped in IBs occurred more efficiently in the presence of ClpB95 with ClpB80 than with either ClpB95 or ClpB80 alone. The two isoforms of ClpB chaperone acting together enhanced the solubility and enzymatic activity of {beta}-galactosidase sequestered into IBs. Both ClpB isoforms were associated with IBs of {beta}-galactosidase, what demonstrates their affinity to this type of aggregates. These results demonstrate a synergistic

  10. Inclusion Complex of Zerumbone with Hydroxypropyl-β-Cyclodextrin Induces Apoptosis in Liver Hepatocellular HepG2 Cells via Caspase 8/BID Cleavage Switch and Modulating Bcl2/Bax Ratio

    PubMed Central

    Abdul, Ahmad Bustamam; Sukari, Mohd Aspollah; Abdelwahab, Siddig Ibrahim; Eid, Eltayeb E. M.; Kamalidehghan, Behnam; Anasamy, Theebaa; Ng, Kuan Beng; Syam, Suvitha; Arbab, Ismail Adam; Rahman, Heshu Sulaiman; Ali, Hapipah Mohd

    2013-01-01

    Zerumbone (ZER) isolated from Zingiber zerumbet was previously encapsulated with hydroxypropyl-β-cyclodextrin (HPβCD) to enhance ZER's solubility in water, thus making it highly tolerable in the human body. The anticancer effects of this new ZER-HPβCD inclusion complex via apoptosis cell death were assessed in this study for the first time in liver hepatocellular cells, HepG2. Apoptosis was ascertained by morphological study, nuclear stain, and sub-G1 cell population accumulation with G2/M arrest. Further investigations showed the release of cytochrome c and loss of mitochondrial membrane potential, proving mitochondrial dysfunction upon the ZER-HPβCD treatment as well as modulating proapoptotic and anti-apototic Bcl-2 family members. A significant increase in caspase 3/7, caspase 9, and caspase 8 was detected with the depletion of BID cleaved by caspase 8. Collectively, these results prove that a highly soluble inclusion complex of ZER-HPβCD could be a promising anticancer agent for the treatment of hepatocellular carcinoma in humans. PMID:23737847

  11. Molecular Inclusion Complexes of β-Cyclodextrin Derivatives Enhance Aqueous Solubility and Cellular Internalization of Paclitaxel: Preformulation and In vitro Assessments

    PubMed Central

    Shah, Milin; Shah, Vatsal; Ghosh, Anasuya; Zhang, Zheng; Minko, Tamara

    2015-01-01

    Drugs with low aqueous solubility and permeability possess substantial challenges in designing effective and safe formulations. Synergistic solubility and permeability enhancement in a simple formulation can increase bioavailability and efficacy of such drugs. To overcome limitations of the clinical formulation of Taxol®, Paclitaxel (PTX) was reformulated with various β-cyclodextrin (CD) derivatives suitable for parenteral administration. Results indicated that β-CDs can efficiently form complexes with PTX at lower molar ratios, enhance aqueous solubility up to 500 times and improved cellular internalization of PTX. All β-CD derivatives were found to be safe as excipient since none showed detectable signs of cyto-genotoxicity. As a result, the CD-PTX complexes significantly increased the cytotoxicity of the drug. The study concluded that CD-PTX formulations could substitute the current intravenous infusion of PTX obviating the use of non-inert excipient Cremophor EL. PMID:25950011

  12. AmyA, an alpha-amylase with beta-cyclodextrin-forming activity, and AmyB from the thermoalkaliphilic organism Anaerobranca gottschalkii: two alpha-amylases adapted to their different cellular localizations.

    PubMed

    Ballschmiter, Meike; Armbrecht, Martin; Ivanova, Krasimira; Antranikian, Garabed; Liebl, Wolfgang

    2005-07-01

    Two alpha-amylase genes from the thermophilic alkaliphile Anaerobranca gottschalkii were cloned, and the corresponding enzymes, AmyA and AmyB, were investigated after purification of the recombinant proteins. Based on their amino acid sequences, AmyA is proposed to be a lipoprotein with extracellular localization and thus is exposed to the alkaline milieu, while AmyB apparently represents a cytoplasmic enzyme. The amino acid sequences of both enzymes bear high similarity to those of GHF13 proteins. The different cellular localizations of AmyA and AmyB are reflected in their physicochemical properties. The alkaline pH optimum (pH 8), as well as the broad pH range, of AmyA activity (more than 50% activity between pH 6 and pH 9.5) mirrors the conditions that are encountered by an extracellular enzyme exposed to the medium of A. gottschalkii, which grows between pH 6 and pH 10.5. AmyB, on the other hand, has a narrow pH range with a slightly acidic pH optimum at 6 to 6.5, which is presumably close to the pH in the cytoplasm. Also, the intracellular AmyB is less tolerant of high temperatures than the extracellular AmyA. While AmyA has a half-life of 48 h at 70 degrees C, AmyB has a half-life of only about 10 min at that temperature, perhaps due to the lack of stabilizing constituents of the cytoplasm. AmyA and AmyB were very similar with respect to their substrate specificity profiles, clearly preferring amylose over amylopectin, pullulan, and glycogen. Both enzymes also hydrolyzed alpha-, beta-, and gamma-cyclodextrin. Very interestingly, AmyA, but not AmyB, displayed high transglycosylation activity on maltooligosaccharides and also had significant beta-cyclodextrin glycosyltransferase (CGTase) activity. CGTase activity has not been reported for typical alpha-amylases before. The mechanism of cyclodextrin formation by AmyA is unknown.

  13. Effect of 6-O-α-maltosyl-β cyclodextrin and its cholesterol inclusion complex on cellular cholesterol levels and ABCA1 and ABCG1 expression in mouse mastocytoma P-815 cells.

    PubMed

    Okada, Yasuyo; Ueyama, Kiyomi; Nishikawa, Jyun-ichi; Semma, Masanori; Ichikawa, Atsushi

    2012-08-01

    We have previously described 6-O-α-maltosyl-β cyclodextrin (Mal-βCD), which forms soluble inclusion complex with cholesterol. Here we further investigated the effect of Mal-βCD and cholesterol/Mal-βCD inclusion complex (CLM) on cellular cholesterol levels in a mouse mast cell line, mastocytoma P-815 cells (P-815 cells). Mal-βCD removes cellular cholesterol forming inclusion complexes, while Mal-βCD-induced lack of cellular cholesterol was replenished by the addition of CLM without cytotoxicity. Reduction and replenishment of cellular cholesterol in Mal-βCD- and/or CLM-treated P-815 cells, respectively, were demonstrated by LC/MS and fluorescence microscopy with filipin III. CLM rather than free Mal-βCD and free cholesterol was efficiently incorporated into P-815 cells and its incorporation was inhibited by incubation at low temperature, or with sodium azide and cytochalasin D. P-815 cells have been confirmed to express ATP-binding cassette (ABC) transporters, ABCA1, ABCG1, and P-glycoprotein (P-gp), by Western blot and mRNA analysis. Cholesterol reduction by Mal-βCD abolishes the mRNA and protein expression of ABCA1 and ABCG1, but not of P-gp. Cholesterol loading by CLM restores the diminished ABCA1 and ABCG1 mRNA expression in Mal-βCD-treated P-815 cells. However, both Mal-βCD and CLM had no effect on P-gp activity measured by the rhodamine 123 efflux assay. These results indicate that alteration of cholesterol levels with Mal-βCD or CLM led to down- or up-regulation of ABCA1 and ABCG1 expression in P-815 cells.

  14. Spectrofluorometric analytical applications of cyclodextrins.

    PubMed

    Elbashir, Abdalla A; Dsugi, Nuha Fathi Ali; Mohmed, Tamador Omer Mohamoud; Aboul-Enein, Hassan Y

    2014-02-01

    Cyclodextrins (CDs) are a family of cyclic oligosaccharides composed of α-(1,4)-linked glucopyranose subunits. The most important feature of CDs is their ability to form inclusion complexes (host-guest complexes) with a very wide range of solid, liquid and gaseous compounds by a molecular complexation. During the last decade, a considerable number of research papers has been focused on the use of CDs to enhance fluorescence intensity of different analytes and to develop CD-induced spectrofluorimetric method. In this review, the various spectrofluorimetric methods based on host-inclusion complex are presented.

  15. Supramolecular photochirogenesis. 2. Enantiodifferentiating photoisomerization of cyclooctene included and sensitized by 6-O-modified cyclodextrins

    PubMed

    Inoue; Wada; Sugahara; Yamamoto; Kimura; Tong; Gao; Hou; Liu

    2000-11-17

    Supramolecular enantiodifferentiating photoisomerization of (Z)-cyclooctene (1Z) to the chiral (E)-isomer (1E) via inclusion and sensitization by modified alpha-, beta-, and/or gamma-cyclodextrin derivatives, possessing benzoate (2a, 3a, 4a), isomeric phthalates (3b-d), and tethered benzamide (3e) chromophores, has been investigated in aqueous methanol solutions at varying temperatures. The photostationary-state 1E/1Z ratios obtained upon sensitization with 2-4 in 1:1 water-methanol reached 0.4-0.8, which are higher than the value of ca. 0.25 reported for sensitizations by conventional alkyl benzoates in hydrocarbon solvents, although the ratio was reduced to 0.2-0.4 in water or methanol. The sensitizations of 1Z by alpha- and gamma-cyclodextrin benzoates (2a, 4a) with size-mismatched cavities gave 1E of poor enantiomeric excesses (ee's) smaller than 3 and 5%, respectively. In contrast, beta-cyclodextrin derivatives (3a-e) afforded much higher ee's of up to 24%, depending on the solvent composition. Thus, the modification of cyclodextrin with a sensitizing group successfully enhanced the product through the excited-state supramolecular interaction within the cavity. Interestingly, the product ee's obtained with benzoate 3a and methyl phthalate 3b are not a simple function of either temperature or solvent, but are nicely correlated with the host occupancy or the percentage of occupied host. This means that the entropy factor plays an insignificant role in this supramolecular photochirogenesis system, which is in sharp contrast to the decisive role of entropy in the conventional (nonsupramolecular) counterpart performed in homogeneous solutions, where an inversion of product chirality by temperature variation is reported to occur.

  16. The sensitive capillary electrophoretic-LIF method for simultaneous determination of curcuminoids in turmeric by enhancing fluorescence intensities of molecules upon inclusion into (2-hydroxypropyl)-β-cyclodextrin.

    PubMed

    Kalaycıoğlu, Zeynep; Hashemi, Parya; Günaydın, Keriman; Erim, F Bedia

    2015-10-01

    Curcuminoids have received great attention in the past decades due to their health benefit properties. The aim of this study is to develop a very simple, rapid, and sensitive capillary zone electrophoresis technique coupled with a laser induced fluorescence detector (LIF) for the simultaneous determination of three major curcuminoids of turmeric, namely, curcumin, demethoxy curcumin (DMC), and bisdemethoxy curcumin (BDMC). Background electrolyte was selected as borate at pH 9.6 and (2-hydroxypropyl)-β-cyclodextrin (2-HP-β-CD) was added to prevent rapid alkali degradation of curcuminoids in buffer and to increase fluorescence intensities of molecules. With the addition of 2-HP-β-CD to the separation electrolyte, the fluorescence signal intensities of curcuminoids were enhanced considerably by 30, 40, and 54 fold for curcumin, DMC, and BDMC, respectively. The three curcuminoids of turmeric were fully separated and quantified in less than 4.5 min. The repeatability of the peak areas of curcuminoids for intra-day and inter-day experiments was in the satisfactory range of 2.26 and 2.55%, respectively. The LOD and LOQ values for the developed method were equal to or less than 0.081 and 0.270 μg/mL, respectively, for all curcuminoids. The developed method was successfully applied to find curcuminoids amount in turmeric samples and herbal supplements.

  17. Repellent effects of Melaleuca alternifolia (tea tree) oil against cattle tick larvae (Rhipicephalus australis) when formulated as emulsions and in β-cyclodextrin inclusion complexes.

    PubMed

    Yim, Wei Tsun; Bhandari, Bhesh; Jackson, Louise; James, Peter

    2016-07-30

    Rhipicephalus australis (formerly Boophilus microplus) is a one host tick responsible for major economic loss in tropical and subtropical cattle production enterprises. Control is largely dependent on the application of acaricides but resistance has developed to most currently registered chemical groups. Repellent compounds that prevent initial attachment of tick larvae offer a potential alternative to control with chemical toxicants. The repellent effects of Melaleuca alternifolia oil (TTO) emulsions and two β-cyclodextrin complex formulations, a slow release form (SR) and a modified faster release form (FR), were examined in a series of laboratory studies. Emulsions containing 4% and 5% TTO applied to cattle hair in laboratory studies completely repelled ascending tick larvae for 24h whereas 2% and 3% formulations provided 80% protection. At 48h, 5% TTO provided 78% repellency but lower concentrations repelled less than 60% of larvae. In a study conducted over 15 days, 3% TTO emulsion applied to cattle hair provided close to 100% repellency for 2 days, but then protection fell to 23% by day 15. The FR formulation gave significantly greater repellency than the emulsion and the SR formulation from day 3 until the end of the study (P<0.05), providing almost complete repellency at day 3 (99.5%), then decreasing over the period of the study to 49% repellency at day 15. Proof of concept is established for the use of appropriately designed controlled-release formulations to extend the period of repellency provided by TTO against R. australis larvae. PMID:27369582

  18. Immunization with amyloid-beta attenuates inclusion body myositis-like myopathology and motor impairment in a transgenic mouse model

    PubMed Central

    Kitazawa, Masashi; Vasilevko, Vitaly; Cribbs, David H.; LaFerla, Frank M.

    2009-01-01

    Inclusion body myositis (IBM), the most common muscle disease to afflict the elderly, causes slow but progressive degeneration of skeletal muscle and ultimately paralysis. Hallmark pathological features include T-cell mediated inflammatory infiltrates and aberrant accumulations of proteins, including amyloid-beta (Aβ), tau, ubiquitinated-proteins, apolipoprotein E, and α-synuclein in skeletal muscle. A large body of work indicates that aberrant Aβ accumulation contributes to the myodegeneration. Here we investigated whether active immunization to promote clearance of Aβ from affected skeletal muscle fibers mitigates the IBM-like myopathological features as well as motor impairment in a transgenic mouse model. We report that active immunization markedly reduces intracellular Aβ deposits and attenuates the motor impairment compared to untreated mice. Results from our current study indicate that Aβ oligomers contribute to the myopathy process as they were significantly reduced in the affected skeletal muscle from immunized mice. In addition, the anti-Aβ antibodies produced in the immunized mice blocked the toxicity of the Aβ oligomers in vitro, providing a possible key mechanism for the functional recovery. These findings provide support for the hypothesis that Aβ is one of the key pathogenic components in IBM pathology and subsequent skeletal muscle degeneration. PMID:19439591

  19. Cyclodextrin-based drug stabilizing system

    NASA Astrophysics Data System (ADS)

    Roik, N. V.; Belyakova, L. A.

    2011-02-01

    UV spectroscopy study of para-aminosalicylic acid behaviour in the presence of β-cyclodextrin and without it in buffer solutions was realized. Influence of duration of contact, acidity of solution, temperature, and content of reagents in the binary solutions on the complex formation between β-cyclodextrin and para-aminosalicylic acid was examined. The stability constants of the supramolecular complexes formed at pH = 1.00 and pH = 6.86 were calculated by the Ketelar equation at various temperatures. It was found that the inclusion interaction of β-cyclodextrin with protonated type of para-aminosalicylic acid is superior to that for its anionic one. From the temperature dependence of stability constants the thermodynamic parameters involved in the complex formation (ΔG, ΔH, ΔS) were calculated. It was proved that complex formation between β-cyclodextrin and para-aminosalicylic acid is spontaneous process accompanied by the release of heat and decrease of entropy. To characterize the solid product of para-aminosalicylic acid inclusion into the cavity of β-cyclodextrin supramolecular complex with a 1:1 mole ratio of components have been prepared by kneading method and studied by IR spectroscopy and X-ray diffraction.

  20. Study of the inclusion complexes formed between cetirizine and α-, β-, and γ-cyclodextrin and evaluation on their taste-masking properties.

    PubMed

    Stojanov, Mladen; Wimmer, Reinhard; Larsen, Kim L

    2011-08-01

    Complexation properties of cetirizine dihydrochloride (cetirizine) with α-, β-, and γ-cyclodextrin (CD) were investigated by ultra violet (UV) and nuclear magnetic resonance (NMR) spectroscopies and isothermal titration calorimetry (ITC). The use of the continuous variation method, applied on UV and NMR data, demonstrated 1:1 complex stoichiometry for cetirizine-α-CD, cetirizine-β-CD, and cetirizine-γ-CD, respectively. NMR two-dimensional Rotational nuclear Overhauser Effect SpectroscopY experiments revealed that for α- and β-CD, the complexation takes place by including either the phenyl or chlorophenyl ring of the cetirizine into the CD cavity, whereas in the case of γ-CD, both rings can be included simultaneously. Association constants (K(a)) determined by UV spectroscopy demonstrated that cetirizine forms more stable complex with β-CD (K(a) = 5641 ± 358 M(-1)) than α-CD (K(a) = 1434 ± 60 M(-1)). No information could be extracted from the UV spectroscopic analysis of cetirizine-γ-CD solutions. ITC results for association constant determination were in compliance with UV results and confirmed that the highest association constant was found for the cetirizine-β-CD complex (2540 ± 122 M(-1)). The association constants from ITC measurements for cetirizine-γ-CD and cetirizine-α-CD complexes were found to be 1200 ± 50 and 800 ± 22 M(-1) , respectively. Taste-masking studies revealed that β-CD is the only native CD recommendable for oral pharmaceutical formulations. PMID:21394723

  1. Cyclodextrins found in enzyme- and heat-processed starch-containing foods.

    PubMed

    Szente, Lajos; Harangi, Janos; Greiner, Manfred; Mandel, Friedrich

    2006-09-01

    Native and branched-type (glucosylated and maltosylated) cyclodextrins have been isolated and identified in different enzyme- and heat-processed starch-containing food products. Amylolytic enzyme-processed foods such as different beer samples, corn syrup of different dextrose equivalents, and thermally-processed food such as bread, contained minute amounts of different types of cyclodextrins. HPLC/MS Analyses of appropriately preconcentrated and purified food samples indicated the presence of parent beta- and gamma-cyclodextrins and all the three, alpha-, beta-, and gamma-branched cyclodextrins with different degrees of glycosylation. The data presented in this account are thought to be of practical importance in terms of both the analysis methods used for the cyclodextrins and the approval status of different cyclodextrin-containing food, cosmetic, and pharmaceutical products.

  2. Budesonide-hydroxypropyl-β-cyclodextrin inclusion complex in binary poloxamer 407/403 system for ulcerative colitis treatment: A physico-chemical study from micelles to hydrogels.

    PubMed

    Santos Akkari, Alessandra Cristina; Ramos Campos, Estefânia Vangelie; Keppler, Artur Franz; Fraceto, Leonardo Fernandes; de Paula, Eneida; Tófoli, Giovana Radomille; de Araujo, Daniele Ribeiro

    2016-02-01

    Budesonide (BUD) is a glucocorticoid widely used for the treatment of ulcerative colitis. In this work, we propose the study of the system BUD-HP-β-CD inclusion complex incorporated into PL 407 and PL407-PL403 thermoreversible hydrogels, considering physico-chemical and pharmaceutical aspects. Complexation between BUD and HP-β-CD was confirmed by phase solubility studies (1:1 stoichiometry, Kc=8662.8 M(-1)), DSC, FTIR and microscopy analyzes. BUD solubility in simulated upper and lower colon fluids was improved in a dependence of HP-β-CD and PL 407 or PL407-PL403 association. Micellar hydrodynamic diameter studies showed the interaction between HP-β-CD and PL blocks, as well as the reorganization of the micellar system in the presence of BUD and its inclusion complex. Micellization temperature (Tm) was not shifted, but sol-gel phase transition studies showed that in the presence of BUD, HP-β-CD or BUD:HP-β-CD complex, the association PL407-PL403 favored the gel formation close to the physiological temperature. Physico-chemical and in vitro release assays studies revealed no competitive displacement of BUD from the HP-β-CD cavity evoked by PL407 or PL407-PL403 addition. These findings point out the BUD-HP-β-CD in PL-based hydrogels as strategies for future investigations on development of new pharmaceutical formulations for the treatment of ulcerative colitis. PMID:26674842

  3. THE BINDING OF COCAINE TO CYCLODEXTRINS. (R826653)

    EPA Science Inventory

    Abstract

    Cocaine binds into beta.gif" alt="small beta, Greek" border=0>-cyclodextrin, but not detectably into small alpha, Greek

  4. Applications of cyclodextrins in medical textiles - review.

    PubMed

    Radu, Cezar-Doru; Parteni, Oana; Ochiuz, Lacramioara

    2016-02-28

    This paper presents data on the general properties and complexing ability of cyclodextrins and assessment methods (phase solubility, DSC tests and X-ray diffraction, FTIR spectra, analytical method). It focuses on the formation of drug deposits on the surface of a textile underlayer, using a cyclodextrin compound favoring the inclusion of a drug/active principle and its release onto the dermis of patients suffering from skin disorders, or for protection against insects. Moreover, it presents the kinetics, duration, diffusion flow and release media of the cyclodextrin drug for in vitro studies, as well as the release modeling of the active principle. The information focuses on therapies: antibacterial, anti-allergic, antifungal, chronic venous insufficiency, psoriasis and protection against insects. The pharmacodynamic agents/active ingredients used on cotton, woolen and synthetic textile fabrics are presented. PMID:26796039

  5. Regioselective self-acylating cyclodextrins in organic solvent

    PubMed Central

    Cho, Eunae; Yun, Deokgyu; Jeong, Daham; Im, Jieun; Kim, Hyunki; Dindulkar, Someshwar D.; Choi, Youngjin; Jung, Seunho

    2016-01-01

    Amphiphilic cyclodextrins have been synthesized with self-acylating reaction using vinyl esters in dimethylformamide. In the present study no base, catalyst, or enzyme was used, and the structural analyses using thin layer chromatography, nuclear magnetic resonance spectroscopy and mass spectrometry show that the cyclodextrin is substituted preferentially by one acyl moiety at the C2 position of the glucose unit, suggesting that cyclodextrin functions as a regioselective catalytic carbohydrate in organic solvent. In the self-acylation, the most acidic OH group at the 2-position and the inclusion complexing ability of cyclodextrin were considered to be significant. The substrate preference was also observed in favor of the long-chain acyl group, which could be attributed to the inclusion ability of cyclodextrin cavity. Furthermore, using the model amphiphilic building block, 2-O-mono-lauryl β-cyclodextrin, the self-organized supramolecular architecture with nano-vesicular morphology in water was investigated by fluorescence spectroscopy, dynamic light scattering and transmission electron microscopy. The cavity-type nano-assembled vesicle and the novel synthetic methods for the preparation of mono-acylated cyclodextrin should be of great interest with regard to drug/gene delivery systems, functional surfactants, and carbohydrate derivatization methods. PMID:27020946

  6. Regioselective self-acylating cyclodextrins in organic solvent

    NASA Astrophysics Data System (ADS)

    Cho, Eunae; Yun, Deokgyu; Jeong, Daham; Im, Jieun; Kim, Hyunki; Dindulkar, Someshwar D.; Choi, Youngjin; Jung, Seunho

    2016-03-01

    Amphiphilic cyclodextrins have been synthesized with self-acylating reaction using vinyl esters in dimethylformamide. In the present study no base, catalyst, or enzyme was used, and the structural analyses using thin layer chromatography, nuclear magnetic resonance spectroscopy and mass spectrometry show that the cyclodextrin is substituted preferentially by one acyl moiety at the C2 position of the glucose unit, suggesting that cyclodextrin functions as a regioselective catalytic carbohydrate in organic solvent. In the self-acylation, the most acidic OH group at the 2-position and the inclusion complexing ability of cyclodextrin were considered to be significant. The substrate preference was also observed in favor of the long-chain acyl group, which could be attributed to the inclusion ability of cyclodextrin cavity. Furthermore, using the model amphiphilic building block, 2-O-mono-lauryl β-cyclodextrin, the self-organized supramolecular architecture with nano-vesicular morphology in water was investigated by fluorescence spectroscopy, dynamic light scattering and transmission electron microscopy. The cavity-type nano-assembled vesicle and the novel synthetic methods for the preparation of mono-acylated cyclodextrin should be of great interest with regard to drug/gene delivery systems, functional surfactants, and carbohydrate derivatization methods.

  7. Regioselective self-acylating cyclodextrins in organic solvent.

    PubMed

    Cho, Eunae; Yun, Deokgyu; Jeong, Daham; Im, Jieun; Kim, Hyunki; Dindulkar, Someshwar D; Choi, Youngjin; Jung, Seunho

    2016-01-01

    Amphiphilic cyclodextrins have been synthesized with self-acylating reaction using vinyl esters in dimethylformamide. In the present study no base, catalyst, or enzyme was used, and the structural analyses using thin layer chromatography, nuclear magnetic resonance spectroscopy and mass spectrometry show that the cyclodextrin is substituted preferentially by one acyl moiety at the C2 position of the glucose unit, suggesting that cyclodextrin functions as a regioselective catalytic carbohydrate in organic solvent. In the self-acylation, the most acidic OH group at the 2-position and the inclusion complexing ability of cyclodextrin were considered to be significant. The substrate preference was also observed in favor of the long-chain acyl group, which could be attributed to the inclusion ability of cyclodextrin cavity. Furthermore, using the model amphiphilic building block, 2-O-mono-lauryl β-cyclodextrin, the self-organized supramolecular architecture with nano-vesicular morphology in water was investigated by fluorescence spectroscopy, dynamic light scattering and transmission electron microscopy. The cavity-type nano-assembled vesicle and the novel synthetic methods for the preparation of mono-acylated cyclodextrin should be of great interest with regard to drug/gene delivery systems, functional surfactants, and carbohydrate derivatization methods. PMID:27020946

  8. The role of normal versus twisted intramolecular charge transfer fluorescence in predicting the forms of inclusion complexes of ethyl-4-dialkylaminobenzoate with α-cyclodextrin in aqueous solution.

    PubMed

    Al-Hassan, Khader A

    2013-11-01

    An evidence is introduced through the b- and the twisted intramolecular charge transfer (TICT) fluorescence of ethyl-4-(N,N-dimethylamino)benzoate (EDMAB) and ethyl-4-(N,N-diethylamino)benzoate (EDEAB), confirming the role of donor size on the formation and emission of various inclusion complexes formed between these probes and α-CD in aqueous solution. A large variation in the b-fluorescence band of EDEAB as compared to that of EDMAB and a large variation in the TICT-fluorescence band of EDMAB as compared to that EDEAB, as the concentration of α-CD is increased in their aqueous solutions are observed. These variations are supported by time resolved fluorescence (TRF) spectra, fluorescence decay lifetimes and red edge effect (REE) results.

  9. Complex formation of fenchone with α-cyclodextrin: NMR titrations.

    PubMed

    Nowakowski, Michał; Ejchart, Andrzej

    2014-01-01

    (13)C NMR titration studies of inclusion complexes of bicyclic terpenoid, fenchone enantiomers with α-cyclodextrin revealed their 1:2 guest-host stoichiometry. Sequential binding constants were determined indicating a strong binding cooperativity of two α-cyclodextrin to fenchone. The overall association constants were used to calculate the Gibbs free energies of diastereomeric complex formation, which might be used as a measure of chiral recognition of fenchone by α-cyclodextrin. These results were compared with corresponding data derived for camphor, which is an isomeric bicyclic terpenoid.

  10. Synthesis of uniform cyclodextrin thioethers to transport hydrophobic drugs

    PubMed Central

    Becker, Lisa F; Schwarz, Dennis H

    2014-01-01

    Summary Methyl and ethyl thioether groups were introduced at all primary positions of α-, β-, and γ-cyclodextrin by nucleophilic displacement reactions starting from the corresponding per-(6-deoxy-6-bromo)cyclodextrins. Further modification of all 2-OH positions by etherification with iodo terminated triethylene glycol monomethyl ether (and tetraethylene glycol monomethyl ether, respectively) furnished water-soluble hosts. Especially the β-cyclodextrin derivatives exhibit very high binding potentials towards the anaesthetic drugs sevoflurane and halothane. Since the resulting inclusion compounds are highly soluble in water at temperatures ≤37 °C they are good candidates for new aqueous dosage forms which would avoid inhalation anaesthesia. PMID:25550759

  11. Selective nanomolar detection of dopamine using a boron-doped diamond electrode modified with an electropolymerized sulfobutylether-beta-cyclodextrin-doped poly(N-acetyltyramine) and polypyrrole composite film.

    PubMed

    Shang, Fengjun; Zhou, Lin; Mahmoud, Khaled A; Hrapovic, Sabahudin; Liu, Yali; Moynihan, Humphrey A; Glennon, Jeremy D; Luong, John H T

    2009-05-15

    N-acetyltyramine was synthesized and electropolymerized together with a negatively charged sulfobutylether-beta-cyclodextrin on a boron-doped diamond (BDD) electrode followed by the electropolymerization of pyrrole to form a stable and permselective film for selective dopamine detection. The selectivity and sensitivity of the formed layer-by-layer film was governed by the sequence of deposition and the applied potential. Raman results showed a decrease in the peak intensity at 1329 cm(-1) (sp(3)), the main feature of BDD, upon each electrodeposition step. Such a decrease was correlated well with the change of the charge-transfer resistance derived from impedance data, i.e., reflecting the formation of the layer-by-layer film. The polycrystalline BDD surface became more even with lower surface roughness as revealed by scanning electron and atomic force microscopy. The modified BDD electrode exhibited rapid response to dopamine within 1.5-2 s and a low detection limit of 4-5 nM with excellent reproducibility. Electroactive interferences caused by 4-dihydroxyphenylalanine, 3,4-dihydroxyphenylacetic acid, ascorbic acid, and uric acid were completely eliminated, whereas the signal response of epinephrine and norepinephrine was significantly suppressed by the permselective film.

  12. Selective detection of uric acid in the presence of ascorbic acid at physiological pH by using a beta-cyclodextrin modified copolymer of sulfanilic acid and N-acetylaniline.

    PubMed

    Wu, Shouguo; Wang, Taoling; Gao, Zongyong; Xu, Haihong; Zhou, Baineng; Wang, Chuanqin

    2008-07-15

    A beta-cyclodextrin (CD) modified copolymer membrane of sulfanilic acid (p-ASA) and N-acetylaniline (SPNAANI) on glassy carbon electrode (GCE) was prepared and used to determine uric acid (UA) in the presence of a large excess of ascorbic acid (AA) by differential pulse voltammetry (DPV). The properties of the copolymer were characterized by X-ray photoelectron spectra (XPS) and Raman spectroscopy. The oxidation peaks of AA and UA were well separated at the composite membrane modified electrode in phosphate buffer solution (PBS, pH 7.4). A linear relationship between the peak current and the concentration of UA was obtained in the range from 1.0 x 10(-5) to 3.5 x 10(-4)mol L(-1), and the detection limit was 2.7 x 10(-6)mol L(-1) at a signal-to-noise ratio of 3. Two hundred and fifty-fold excess of AA did not interfere with the determination of UA. The application of the prepared electrode was demonstrated by measuring UA in human serum samples without any pretreatment, and the results were comparatively in agreement with the spectrometric clinical assay method.

  13. Cyclodextrin-based Polymeric Nanoparticles as Efficient Carriers for Anticancer Drugs.

    PubMed

    Duchene, Dominique; Cavalli, Roberta; Gref, Ruxandra

    2016-01-01

    Among the difficulties encountered in the treatment of cancer are the physico-chemical properties of the chemotherapeutic agents; in particular low water solubility and low stability, resulting in poor efficacy. Due to their capability to form molecular inclusions with apolar molecules (or part of them) cyclodextrins constitute a powerful tool to prepare more efficient chemotherapeutic delivery systems such as nanoparticles. This review focuses on polymeric nanoparticles for cancer therapy prepared from either cyclodextrin molecules, or polymer and cyclodextrins. PMID:26517333

  14. γ-Cyclodextrin capped silver nanoparticles for molecular recognition and enhancement of antibacterial activity of chloramphenicol.

    PubMed

    Gannimani, Ramesh; Ramesh, Muthusamy; Mtambo, Sphamandla; Pillay, Karen; Soliman, Mahmoud E; Govender, Patrick

    2016-04-01

    Computational studies were conducted to identify the favourable formation of the inclusion complex of chloramphenicol with cyclodextrins. The results of molecular docking and molecular dynamics predicted the strongest interaction of chloramphenicol with γ-cyclodextrin. Further, the inclusion complex of chloramphenicol with γ-cyclodextrin was experimentally prepared and a phenomenon of inclusion was verified by using different characterization techniques such as thermogravimetric analysis, differential scanning calorimetry, (1)H nuclear magnetic resonance (NMR) and two dimensional nuclear overhauser effect spectroscopy (NOESY) experiments. From these results it was concluded that γ-cyclodextrins could be an appropriate cyclodextrin polymer which can be used to functionalize chloramphenicol on the surface of silver nanoparticles. In addition, γ-cyclodextrin capped silver nanoparticles were synthesized and characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR) and zeta potential analysis. Molecular recognition of chloramphenicol by these cyclodextrin capped silver nanoparticles was confirmed by surface enhanced raman spectroscopy (SERS) experiments. Synergistic antibacterial effect of chloramphenicol with γ-cyclodextrin capped silver nanoparticles was evaluated against Pseudomonas aeruginosa (ATCC 27853), Enterococcus faecalis (ATCC 5129), Klebsiella pneumoniae (ATCC 700603) and Staphylococcus aureus (ATCC 43300). The results from the antibacterial experiment were favourable thus allowing us to conclude that the approach of modifying organic drug molecules with cyclodextrin capped inorganic silver nanoparticles could help to enhance the antibacterial activity of them.

  15. Molecular entrapment of volatile organic compounds (VOCs) by electrospun cyclodextrin nanofibers.

    PubMed

    Celebioglu, Asli; Sen, Huseyin Sener; Durgun, Engin; Uyar, Tamer

    2016-02-01

    In this paper, we reported the molecular entrapment performance of hydroxypropyl-beta-cyclodextrin (HPβCD) and hydroxypropyl-gamma-cyclodextrin (HPγCD) electrospun nanofibers (NF) for two common volatile organic compounds (VOCs); aniline and benzene. The encapsulation efficiency of CD samples were investigated depending on the various factors such as; CD form (NF and powder), electrospinning solvent (DMF and water), CD (HPβCD and HPγCD) and VOCs (aniline and benzene) types. BET analysis indicated that, electrospun CD NF have higher surface area compared to their powder form. In addition DMA measurement provided information about the mechanical properties of CD NF. The encapsulation capability of CD NF and CD powder was investigated by (1)H-NMR and HPLC techniques. The observed results suggested that, CD NF can entrap higher amount of VOCs from surroundings compared to their powder forms. Besides, molecular entrapment efficiency of CD NF also depends on CD, solvent and VOCs types. The inclusion complexation between CD and VOCs was determined by using TGA technique, from the higher decomposition temperature of VOCs. Finally, our results were fortified by the modeling studies which indicated the complexation efficiency variations between CD and VOC types. Here, the inclusion complexation ability of CD molecules was combined with very high surface area and versatile features of CD NF. So these findings revealed that, electrospun CD NF can serve as useful filtering material for air filtration purposes due to their molecular entrapment capability of VOCs. PMID:26408981

  16. Functionalized β-cyclodextrin based potentiometric sensor for naproxen determination.

    PubMed

    Lenik, Joanna; Łyszczek, Renata

    2016-04-01

    Potentiometric sensors based on neutral β-cyclodextrins: (2-hydroxypropyl)-β-cyclodextrin, heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin, heptakis(2,3,6-tri-O-benzoyl)-β-cyclodextrin and anionic β-cyclodextrin: (2-hydroxy-3-N,N,N-trimethylamino)propyl-β-cyclodextrin chloride for naproxen are described. Inclusion complexes of naproxen with the above-mentioned cyclodextrins were studied using IR spectroscopy. The electrode surface was made from PVC membranes doped with the appropriate β-cyclodextrin as ionophores and quaternary ammonium chlorides as positive charge additives that were dispersed in plasticizers. The optimum membrane contains heptakis(2,3,6-tri-O-benzoyl)-β-cyclodextrin, o-nitrophenyloctyl ether and tetraoctyl ammonium chloride as a lipophilic salt. The electrode is characterized by a Nernstian response slope of -59.0 ± 0.5 mV decade(-1) over the linear range of 5.0 × 10(-5)-1.0 × 10(-2) mol L(-1) and the detection limit 1.0 × 10(-5) mol L(-1), as well as the response time 10s. It can be used in the pH range 6.2-8.5 for 10 months without any considerable deterioration. Incorporation of β-cyclodextrins improved the electrode selectivity towards naproxen ions from several inorganic and organic interferents and some common drug excipients due to concovalent interactions (host molecule-guest molecule). The notable advantages of the naproxen-selective electrode include its high sensitivity, high selectivity, cost-effectiveness as well as accurate and comfortable application in drug analysis and milk samples. PMID:26838835

  17. Phase solubility, 1H NMR and molecular modelling studies of bupivacaine hydrochloride complexation with different cyclodextrin derivates

    NASA Astrophysics Data System (ADS)

    Jug, Mario; Mennini, Natascia; Melani, Fabrizio; Maestrelli, Francesca; Mura, Paola

    2010-11-01

    A novel method, which simultaneously exploits experimental (NMR) and theoretically calculated data obtained by a molecular modelling technique, was proposed, to obtain deeper insight into inclusion geometry and possible stereoselective binding of bupivacaine hydrochloride with selected cyclodextrin derivatives. Sulphobuthylether-β-cyclodextrin and water soluble polymeric β-cyclodextrin demonstrated to be the best complexing agents for the drug, resulting in formation of the most stable inclusion complexes with the highest increase in aqueous drug solubility. The drug-carrier binding modes with these cyclodextrins and phenomena which may be directly related to the higher stability and better aqueous solubility of complexes formed were discussed in details.

  18. β-Cyclodextrin as the suitable molecular container for isopulegol enantiomers.

    PubMed

    Ceborska, Magdalena; Szwed, Kamila; Suwinska, Kinga

    2013-09-12

    Isopulegol, an insoluble in water and highly volatile compound, due to its neuroactive properties is a potentially important agent for medical applications. Formation of "host-guest" molecular complexes with cyclodextrins would lead to the increase of its water solubility and bioavailability. Interactions between native cyclodextrins (α, β and γ) and isopulegol enantiomers were studied in solution proving the formation of inclusion complexes for β- and γ-cyclodextrins. For the more stable complexes with β-cyclodextrin crystal structures were obtained showing the formation of molecular capsules forming molecular container able to accommodate two guest molecules. PMID:23911483

  19. Study on the spectral and inclusion properties of a sensitive dye, 3-naphthyl-1-phenyl-5-(5-fluoro-2-nitrophenyl)-2-pyrazoline, in solvents and β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Varghese, Beena; Al-Busafi, Saleh N.; Suliman, FakhrEldin O.; Al-Kindy, Salma M. Z.

    2015-02-01

    3-Naphthyl-1-phenyl-5-(5-fluoro-2-nitrophenyl)-2-pyrazoline (NPFP), a fluorogenic probe and its derivative NPFP-Phenylephrine were synthesized and their absorption and fluorescence properties were recorded in solvents of varying polarity. Spectroscopic studies reveal that, the solvatochromic behavior of the compounds depend not only on the polarity but also on the hydrogen-bonding properties of the solvents. The effects of β-cyclodextrin on the fluorescence properties of both compounds were studied. It was found that there is an enhancement in the fluorescence intensity of labeled drug (NPFP-Phenylephrine) in the presence of β-cyclodextrin. In the present study, the molecular motions of NPFP-Phenylephrine embedded in a β-cyclodextrin cavity have been investigated by fluorescence techniques in steady-state and time resolved modes.

  20. [Study on quantitative mechanism and the interference of the UV spectrum of HABS reduced by β-Cyclodextrin].

    PubMed

    Shi, Dong-Po; Yin, Xian-Qing; Zheng, Yan-Cheng; Chen, Wu; Fu, Jia-Xin; Ren, Zhao-Hua

    2014-09-01

    A novel ultraviolet absorption spectrometry method was developed for the quantitative determination of HABS by adding β-cyclodextrin with the molar ratio of 1:1 in strong interference aqueous solution. The results indicated that the effect of several common interfering flooding agents (SAS, OP-10, HPAM) on the determination of HABS could be greatly reduced in β- cyclodextrin aqueous solution. Thus, the determination errors of the determined HABS were less than 2.0% under strong inter- ference, and the detection limit (S/N==3) of the method could be also as high was 8.3-9.1 x 10(-4) mg · L(-1). Various characterization results including 1H-NMR, TG-DSC and FTIR showed the interaction between β-cyclodextrin and HABS. The results of H-NMR analysis showed that HABS molecule could enter into the interior of the cavity of β-cyclodextrin molecule. TG-DSC analysis exhibited that the stable inclusion of β-cyclodextrin and HABS could be automatically formed. The interactions between the functional groups of β-cyclodextrin and HABS were showed by FTIR analysis, which also exhibited that the stable inclusion could be formed by HABS entering from the narrow or the broad mouth of the β-cyclodextrin. The interference of the UV spectrum of HABS could be reduced by β-cyclodextrin since the interaction between β-cyclodextrin due to the interaction between β-cyclodextrin and HABS in the inclusion complex.

  1. Rimmed vacuoles with beta-amyloid and ubiquitinated filamentous deposits in the muscles of patients with long-standing denervation (postpoliomyelitis muscular atrophy): similarities with inclusion body myositis.

    PubMed

    Semino-Mora, C; Dalakas, M C

    1998-10-01

    In the chronically denervated muscles of patients with prior paralytic poliomyelitis, there are secondary myopathic features, including endomysial inflammation and rare vacuolated fibers. To assess the frequency and characteristics of the vacuoles and their similarities with those seen in inclusion body myositis (IBM), we examined 58 muscle biopsy specimens from patients with prior paralytic poliomyelitis for (1) the presence of rimmed vacuoles; (2) acid-phosphatase reactivity; (3) Congo-red-positive amyloid deposits; (4) electron microscopy, searching for tubulofilaments; and (5) immunoelectron microscopy, using antibodies against beta-amyloid and ubiquitin. We found vacuolated muscle fibers in 18 of 58 (31%) biopsies, with a mean frequency of 2.06 +/- 0.42 fibers per specimen. The vacuoles contained acid phosphatase-positive material in 6 of the 18 (33.30%) specimens and stained positive for Congo red in five (27.80%). By immunoelectron microscopy, the vacuoles contained 5.17 +/- 0.13 nm fibrils and 14.9 +/- 0.31 nm filaments that immunoreacted with antibodies to beta-amyloid and ubiquitin in a pattern identical to the one seen in IBM. We conclude that vacuolated muscle fibers containing filamentous inclusions positive for amyloid and ubiquitin are not unique to IBM and the other vacuolar myopathies but can also occur in a chronic neurogenic condition, such as postpoliomyelitis. The chronicity of the underlying disease, rather than the cause, may lead to vacuolar formation, amyloid deposition, and accumulation of ubiquitinated filaments.

  2. Synthesis and Evaluation of Cyclodextrin-based Polymers for Patulin Extraction from Aqueous Solutions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Patulin is a mycotoxin produced by fungi that contaminate fruits, juices, and other agricultural commodities. Sorption properties of polyurethane-beta-cyclodextrin polymers were evaluated for the ability to remove patulin from solutions, including apple juice. Freundlich isotherm analysis determin...

  3. Cyclodextrins, blood-brain barrier, and treatment of neurological diseases.

    PubMed

    Vecsernyés, Miklós; Fenyvesi, Ferenc; Bácskay, Ildikó; Deli, Mária A; Szente, Lajos; Fenyvesi, Éva

    2014-11-01

    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.

  4. Enhanced Fenton degradation of hydrophobic organics by simultaneous iron and pollutant complexation with cyclodextrins.

    PubMed

    Lindsey, Michele E; Xu, Guoxiang; Lu, Jia; Tarr, Matthew A

    2003-05-20

    The effectiveness and selectivity of Fenton degradation of hydrophobic organic compounds (HOCs) can be improved by simultaneous complexation of Fe(2+) and the organic compound with a cyclodextrin or derivatized cyclodextrin. Such selective complexation of a target substrate and a catalytic metal is a crude mimic of enzyme systems. Both beta-cyclodextrin and carboxymethyl-beta-cyclodextrin (CMCD) were able to simultaneously complex Fe(2+) and an aromatic hydrocarbon, such as phenol, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls (PCBs). Degradation of compounds included in cyclodextrins was unaffected by hydroxyl radical scavengers, indicating that the radical was formed at the ternary complex (HOC-cyclodextrin-iron) and in close proximity to the included molecule. Without cyclodextrins, humic acid (HA) decreased degradation efficiency. However, in the presence of CMCD, HA did not inhibit degradation of the target compound. CMCD is capable of removing HOCs from HA binding sites while at the same time complexing Fe(2+). PCBs sorbed to glass were resistant to Fenton degradation, but were significantly degraded using a cyclodextrin modified Fenton system. In all of these systems, the ternary HOC-cyclodextrin-iron complexes effectively direct hydroxyl radical reaction toward the HOC, increasing the efficiency of Fenton degradation. One potential application of such targeted degradation systems is the in situ remediation of hydrophobic organic pollutants in contaminated soil and groundwater or in industrial waste streams.

  5. Simultaneous determination of 9-ethylphenanthrene, pyrene and 1-hydroxypyrene in an aqueous solution by synchronous fluorimetry using the double scans method and hydroxyl-propyl beta-cyclodextrin as a sensitizer.

    PubMed

    Zhang, Zhen-Xuan; Zhu, Ya-Xian; Zhang, Yong

    2015-11-01

    A novel method for the simultaneous determination of 9-ethylphenanthrene (9-EP), pyrene (Pyr) and 1-hydroxypyrene (1-OH-Pyr) in an aqueous solution using hydroxyl-propyl β-cyclodextrin (HPCD) as a sensitizer has been established. The overlap of the conventional fluorescence spectra of these molecules is resolved using synchronous fluorescence spectrometry with the double scans method. The simultaneous quantitative determination of three compounds was carried out with Δλ=36 nm and Δλ=55 nm. The signals detected at these three wavelengths (i.e., 298 nm, 337 nm and 351 nm) vary linearly when the concentrations of 9-EP, Pyr and 1-OH-Pyr were in the range of 5.00×10(-8)-1.60×10(-6) mol L(-1), 2.00×10(-8)-1.80×10(-6) mol L(-1), and 2.00×10(-8)-1.20×10(-5) mol L(-1), respectively. The limits of detection (LOD) for 9-EP, Pyr and 1-OH-Pyr were 3.97×10(-9) mol L(-1), 5.25×10(-)(9) mol L(-1), 4.20×10(-9) mol L(-1), respectively, with relative standard deviations (R.S.D.) of 1.62%, 2.45% and 1.73% (n=9), respectively. The inclusion behaviors between HPCD and the guest molecules were observed by synchronous fluorimetry and the association constants for the 1:1 complexes with HPCD were determined. The binding and complexation energies for different orientations are discussed. The proposed method was successfully applied to the analysis of 9-EP, Pyr and 1-OH-Pyr in tap and lake water with good recoveries in the range of 92.9-110.0%.

  6. Preparation and characterization of amorphous solid dispersions of nimesulide in cyclodextrin copolymers.

    PubMed

    Skiba, M; Skiba, M; Milon, N; Bounoure, F; Fessi, H

    2014-04-01

    A study to enhance the dissolution rate of nimesulide (NIM), a poorly water-soluble, non-steroidal anti-inflammatory drug, was carried out through developing new amorphous solid dispersions (ASD) based on soluble or insoluble water cyclodextrin copolymers (alpha-cyclodextrin, beta-cyclodextrin and y-cyclodextrin polymers) synthesized by direct melt polycondensation. Amorphous solid dispersions of NIM in cyclodextrin copolymers, obtained by solvent evaporation, were characterized by thermogravimetric analyzer (TGA), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and fourier transform-infrared spectroscopy (FT-IR). These analyses provided the existence of interactions between amorphous drug and its carrier. A burst release of more than 80% NIM within approximately 70 minutes was seen with soluble alpha-cyclodextrin polymers (poly-alpha-sol) and insoluble gamma-cyclodextrin polymers (poly-gamma-insol) where no significant differences were observed with the other copolymers. Mathematical kinetic models such as zero order, Higuchi and Korsmeyer-Peppas were used to evaluate the kinetic and mechanism of release of NIM from the different ASD compared to lactose reference matrix. The kinetic of release of NIM from different ASD followed a Higuchi model and the mechanism of release was explained by Korsmeyer-Peppas model in which a fickian diffusion for lactose and soluble beta-cyclodextrin polymers (poly-beta-sol) was observed. However, an anomalous non-Fickian transport was found for the other copolymers. PMID:24734689

  7. Comparison of host-guest Langmuir-Blodgett multilayer formation by two different amphiphilic cyclodextrins

    SciTech Connect

    Parazak, D.P.; Khan, A.R.; D`Souza, V.T.; Stine, K.J.

    1996-08-07

    We report here our results for Langmuir monolayers of the derivatives of cyclodextrin shown: hexakis(6-deoxy-6-dodecylamino)-{alpha}-cyclodextrin (1a), heptakis(6-deoxy-6-dodecylamino)-{beta}-cyclodextrin (1b), and heptakis(6-deoxy-6-dodecylthio)-{beta}-cyclodextrin (2b ), which was found to be partially substituted. Langmuir films of these derivatives were examined using {Pi}-A isotherm measurements and Brewster angle microscopy. Langmuir-Blodgett (LB) multilayer films of these derivatives were deposited from subphases containing p-nitrophenol to determine the extent of incorporation of the guest molecule in the LB film. The transfer ratios of the film exhibited a noteworthy evolution with the transfer pressure. The variation in the extent of guest molecule incorporation is discussed and compared with the binding behavior in solution of unmodified cyclodextrins. 29 refs., 4 figs.

  8. Endocytosis of fluorescent cyclodextrins by intestinal Caco-2 cells and its role in paclitaxel drug delivery.

    PubMed

    Réti-Nagy, Katalin; Malanga, Milo; Fenyvesi, Éva; Szente, Lajos; Vámosi, György; Váradi, Judit; Bácskay, Ildikó; Fehér, Pálma; Ujhelyi, Zoltán; Róka, Eszter; Vecsernyés, Miklós; Balogh, György; Vasvári, Gábor; Fenyvesi, Ferenc

    2015-12-30

    Cyclodextrins are widely used excipients in pharmaceutical formulations. They are mainly utilized as solubilizers and absorption enhancers, but recent results revealed their effects on cell membranes and pharmacological barriers. In addition to the growing knowledge on their interaction with plasma membranes, it was confirmed that cyclodextrins are able to enter cells by endocytosis. The number of the tested cyclodextrins was limited, and the role of this mechanism in drug absorption and delivery is not known. Our aim was to examine the endocytosis of fluorescently labeled hydroxypropyl-β-cyclodextrin, random methyl-β-cyclodextrin and soluble β-cyclodextrin polymer, and the cellular uptake of the fluorescent paclitaxel derivative-random methyl-β-cyclodextrin complex. The studied cyclodextrin derivatives were able to enter Caco-2 intestinal cells and localized in vesicles in the cytoplasm, while their permeability was very limited through Caco-2 monolayers. We demonstrated for the first time that the fluorescent paclitaxel derivative and rhodamine-labeled random methyl-β-cyclodextrin were detected in the same intracellular vesicles after treating cells with their inclusion complex. These results indicate that the endocytosis of cyclodextrin complexes can contribute to drug absorption processes.

  9. Analytical techniques for characterization of cyclodextrin complexes in the solid state: A review.

    PubMed

    Mura, Paola

    2015-09-10

    Cyclodextrins are cyclic oligosaccharides able to form inclusion complexes with a variety of hydrophobic guest molecules, positively modifying their physicochemical properties. A thorough analytical characterization of cyclodextrin complexes is of fundamental importance to provide an adequate support in selection of the most suitable cyclodextrin for each guest molecule, and also in view of possible future patenting and marketing of drug-cyclodextrin formulations. The demonstration of the actual formation of a drug-cyclodextrin inclusion complex in solution does not guarantee its existence also in the solid state. Moreover, the technique used to prepare the solid complex can strongly influence the properties of the final product. Therefore, an appropriate characterization of the drug-cyclodextrin solid systems obtained has also a key role in driving in the choice of the most effective preparation method, able to maximize host-guest interactions. The analytical characterization of drug-cyclodextrin solid systems and the assessment of the actual inclusion complex formation is not a simple task and involves the combined use of several analytical techniques, whose results have to be evaluated together. The objective of the present review is to present a general prospect of the principal analytical techniques which can be employed for a suitable characterization of drug-cyclodextrin systems in the solid state, evidencing their respective potential advantages and limits. The applications of each examined technique are described and discussed by pertinent examples from literature.

  10. Dual chiral recognition system involving cyclodextrin derivatives in capillary electrophoresis II. Enhancement of enantioselectivity.

    PubMed

    Jakubetz, H; Juza, M; Schurig, V

    1998-05-01

    The enantiomer separation of hexobarbital was investigated by open tubular electrochromatography (OTEC) using the chiral stationary phase (CSP) CHIRASIL-DEX (a permethylated beta-cyclodextrin covalently linked to a dimethylpolysiloxane) and by cyclodextrin-electrokinetic chromatogaphy (CD-EKC) using anionic beta-cyclodextrin-sulfo-n-propyl ether (SPE-beta-CD) and cationic beta-cyclodextrin-2-hydroxy-3-trimethylammoniumpropyl ether chloride (HTAP-beta-CD) added to the running buffer. By employing two chiral selectors, the enantiomer separation of hexobarbital was then studied simultaneously by OTEC with CHIRASIL-DEX and by CD-EKC with either SPE-beta-CD or HTAP-beta-CD in the dual chiral recognition mode. In conjunction with CHIRASIL-DEX, anionic SPE-beta-CD decreased the chiral separation factor alpha due to compensation of enantioselectivity whereas the cationic additive HTAP-beta-CD increased the chiral separation factor alpha due to enhancement of enantioselectivity. It is concluded that CHIRASIL-DEX imparts an opposite enantioselectivity to the enantiomers of hexobarbital as compared to the charged CDs SPE-beta-CD and HTAP-beta-CD. Unusual peak broadening phenomena are observed in the dual chiral recognition system comprised of CHIRASIL-DEX and HTAP-beta-CD. The possible consequences of accidental dual chiral recognition systems caused by wall stacking effects of the mobile phase additives onto the inner surface of the capillary column are discussed. PMID:9629908

  11. Electrokinetic remediation and microbial community shift of β-cyclodextrin-dissolved petroleum hydrocarbon-contaminated soil.

    PubMed

    Wan, Chunli; Du, Maoan; Lee, Duu-Jong; Yang, Xue; Ma, Wencheng; Zheng, Lina

    2011-03-01

    Electrokinetic (EK) migration of β-cyclodextrin (β-CD), which is inclusive of total petroleum hydrocarbon (TPH), is an economically beneficial and environmentally friendly remediation process for oil-contaminated soils. Remediation studies of oil-contaminated soils generally prepared samples using particular TPHs. This study investigates the removal of TPHs from, and electromigration of microbial cells in field samples via EK remediation. Both TPH content and soil respiration declined after the EK remediation process. The strains in the original soil sample included Bacillus sp., Sporosarcina sp., Beta proteobacterium, Streptomyces sp., Pontibacter sp., Azorhizobium sp., Taxeobacter sp., and Williamsia sp. Electromigration of microbial cells reduced the biodiversity of the microbial community in soil following EK remediation. At 200 V m(-1) for 10 days, 36% TPH was removed, with a small population of microbial cells flushed out, demonstrating that EK remediation is effective for the present oil-contaminated soils collected in field.

  12. Electrokinetic remediation and microbial community shift of β-cyclodextrin-dissolved petroleum hydrocarbon-contaminated soil.

    PubMed

    Wan, Chunli; Du, Maoan; Lee, Duu-Jong; Yang, Xue; Ma, Wencheng; Zheng, Lina

    2011-03-01

    Electrokinetic (EK) migration of β-cyclodextrin (β-CD), which is inclusive of total petroleum hydrocarbon (TPH), is an economically beneficial and environmentally friendly remediation process for oil-contaminated soils. Remediation studies of oil-contaminated soils generally prepared samples using particular TPHs. This study investigates the removal of TPHs from, and electromigration of microbial cells in field samples via EK remediation. Both TPH content and soil respiration declined after the EK remediation process. The strains in the original soil sample included Bacillus sp., Sporosarcina sp., Beta proteobacterium, Streptomyces sp., Pontibacter sp., Azorhizobium sp., Taxeobacter sp., and Williamsia sp. Electromigration of microbial cells reduced the biodiversity of the microbial community in soil following EK remediation. At 200 V m(-1) for 10 days, 36% TPH was removed, with a small population of microbial cells flushed out, demonstrating that EK remediation is effective for the present oil-contaminated soils collected in field. PMID:21052991

  13. Cyclodextrins and antioxidants.

    PubMed

    López-Nicolás, José Manuel; Rodríguez-Bonilla, Pilar; García-Carmona, Francisco

    2014-01-01

    In recent years, the growth of the functional foods industry has increased research into new compounds with high added value for use in the fortification of traditional products. One of the most promising functional food groups is those enriched in antioxidant compounds of a lipophilic nature. In spite of the numerous advantages reported for such antioxidant molecules, they may also have disadvantages that impede their use in functional foods, although these problems may well avoided by the use of encapsulant agents such as cyclodextrins. This explains the recent increase in the number of research papers dealing with the complexation of different guest molecules possesing important antioxidant properties using natural and modified cyclodextrins. This paper presents a review of the most recent studies on the complexes formed between several important types of antioxidant compounds and cyclodextrins, focusing on the contradictory data reported in the literature concerning to the antioxidant activity of the host/guest molecule complexes, the different complexation constants reported for identical complexes, the bioavailability of the antioxidant compound in the presence of cyclodextrins and recommendation concerning the use of natural or modified cyclodextrins. Moreover, the use of cyclodextrins as antibrowning agents to prevent enzymatic browning in different foods is revised. Finally, we look at studies which suggest that cyclodextrins act as ''secondary antioxidants," enhancing the ability of traditional antioxidants to prevent enzymatic browning.

  14. Cyclodextrins and antioxidants.

    PubMed

    López-Nicolás, José Manuel; Rodríguez-Bonilla, Pilar; García-Carmona, Francisco

    2014-01-01

    In recent years, the growth of the functional foods industry has increased research into new compounds with high added value for use in the fortification of traditional products. One of the most promising functional food groups is those enriched in antioxidant compounds of a lipophilic nature. In spite of the numerous advantages reported for such antioxidant molecules, they may also have disadvantages that impede their use in functional foods, although these problems may well avoided by the use of encapsulant agents such as cyclodextrins. This explains the recent increase in the number of research papers dealing with the complexation of different guest molecules possesing important antioxidant properties using natural and modified cyclodextrins. This paper presents a review of the most recent studies on the complexes formed between several important types of antioxidant compounds and cyclodextrins, focusing on the contradictory data reported in the literature concerning to the antioxidant activity of the host/guest molecule complexes, the different complexation constants reported for identical complexes, the bioavailability of the antioxidant compound in the presence of cyclodextrins and recommendation concerning the use of natural or modified cyclodextrins. Moreover, the use of cyclodextrins as antibrowning agents to prevent enzymatic browning in different foods is revised. Finally, we look at studies which suggest that cyclodextrins act as ''secondary antioxidants," enhancing the ability of traditional antioxidants to prevent enzymatic browning. PMID:24188271

  15. Host-guest interaction between pinocembrin and cyclodextrins: Characterization, solubilization and stability

    NASA Astrophysics Data System (ADS)

    Zhou, Shu-Ya; Ma, Shui-Xian; Cheng, Hui-Lin; Yang, Li-Juan; Chen, Wen; Yin, Yan-Qing; Shi, Yi-Min; Yang, Xiao-Dong

    2014-01-01

    The inclusion complexation behavior, characterization and binding ability of pinocembrin with β-cyclodextrin (β-CD) and its derivative 2-hydroxypropyl-β-cyclodextrin (HPβCD) were investigated in both solution and the solid state by means of XRD, DSC, 1H and 2D NMR and UV-vis spectroscopy. The results showed that the water solubility and thermal stability of pinocembrin were obviously increased in the inclusion complex with cyclodextrins. This satisfactory water solubility and high stability of the pinocembrin/CD complexes will be potentially useful for their application as herbal medicines or healthcare products.

  16. Study on the interaction of methylene blue with cyclodextrin derivatives by absorption and fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Guomei; Shuang, Shaomin; Dong, Chuan; Pan, Jinghao

    2003-11-01

    The ability of β-cyclodextrin (β-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD), and carboxymethyl-β-cyclodextrin (CM-β-CD) to break the aggregate of the methylene blue (MB) and to form 1:1 inclusion complexes has been studied by absorption and fluorescence spectroscopy. Experimental conditions including concentrations of various cyclodextrins (β-CD, HP-β-CD and CM-β-CD) and media acidity were investigated for the inclusion formation in detail. The formation constants are calculated by using steady-state fluorimetry, from which the inclusion capacity of different cyclodextrins (CDs) is compared. The results suggest that the charged β-cyclodextrin (CM-β-CD) is more suitable for inclusion of the cationic dye MB than the neutral β-cyclodextrins (β-CD, HP-β-CD) at pH>5. A mechanism is proposed which is consistent with the stronger binding of MB with CM-β-CD compared with the other CDs at pH>5.

  17. Efficacy and Tolerability of Conventional Nimesulide Versus Beta-Cyclodextrin Nimesulide in Patients with Pain After Surgical Dental Extraction: A Multicenter, Prospective, Randomized, Double-Blind, Double-Dummy Study☆

    PubMed Central

    Bocanegra, Mildred; Seijas, Alberto; Yibirín, Maria González

    2003-01-01

    Background: Pain following extraction of an impacted third molar is widely used to assess analgesic efficacy, especially that of a single dose of a drug. The analgesic activity of conventional nimesulide (CN) has been documented in a variety of types of acute and chronic pain. Beta-cyclodextrin nimesulide (BN) is a new formulation in which nimesulide is included in a cyclodextrin molecule, which increases its solubility in water and its dilution rate, allowing extended, rapid absorption of the drug. Objective: The aim of this study was to assess the efficacy and tolerability of a single dose of BN compared with CN in patients with pain following extraction of an impacted third molar. Methods: This was a prospective, randomized, double-blind, double-dummy study conducted at 3 dentistry centers in Venezuela. The patients were randomized to 1 of 2 groups. One group received a single dose of BN (400-mg tablet, equivalent to 100 mg of nimesulide); the other group received a single dose of CN (100-mg tablet). Both groups also received a placebo. The efficacy variables were (1) pain intensity (PI), assessed on a visual analog scale (VAS) at the following times: 0, 5, 10, 15, 30, and 45 minutes and 1, 2, 4, 6, 8, 10, and 12 hours after drug administration; (2) time to first measurable difference in PI from baseline (PID) (PID ≥1 cm on the VAS; ie, the beginning of analgesic action); (3) maximum PID (max PID); (4) sum of PIDs in the 12-hour observation period; (5) pain relief (PR), as rated on a 5-point scale; (6) maximum PR; and (7) sum of the PR scores in the 12-hour observation period (ie, total PR). For the tolerability analysis, all adverse events (AEs) were to be recorded, and the investigators were to assess whether each AE was drug related. Results: Seventy-two patients were enrolled in the study. Of these, 62 patients (40 women, 22 men; mean [SD] age, 20.1 [5.9] years) were assessed; 35 were treated with BN and 27 with CN. PI reduction was more rapid and greater

  18. New asymmetrical per-substituted cyclodextrins (2-O-methyl-3-O-ethyl- and 2-O-ethyl-3-O-methyl-6-O-t-butyldimethylsilyl-beta-derivatives) as chiral selectors for enantioselective gas chromatography in the flavour and fragrance field.

    PubMed

    Bicchi, Carlo; Cagliero, Cecilia; Liberto, Erica; Sgorbini, Barbara; Martina, Katia; Cravotto, Giancarlo; Rubiolo, Patrizia

    2010-02-12

    Asymmetrically substituted 6(I-VII)-O-t-butyldimethylsilyl(TBDMS)-3(I-VII)-O-ethyl-2(I-VII)-O-methyl-beta-cyclodextrin (MeEt-CD) and 6(I-VII)-O-TBDMS-2(I-VII)-O-ethyl-3(I-VII)-O-methyl-beta-cyclodextrin (EtMe-CD) were synthesised to evaluate the role of the substitution pattern in positions 2 and 3 on the enantioselectivity, in particular in view of their application to routine analysis in fast enantioselective gas chromatography (Es-GC). The chromatographic properties and enantioselectivities of the new derivatives were tested by separating the enantiomers of a series of medium-to-high volatility racemates in the flavour and fragrance field, and compared to those of the corresponding symmetrically substituted 6(I-VII)-O-TBDMS-2(I-VII),3(I-VII)-O-methyl-beta-CD (MeMe-CD) and 6(I-VII)-O-TBDMS-2(I-VII),3(I-VII)-O-ethyl-beta-CD (EtEt-CD), and were then applied to analysis of real-world essential oil (e.o.) samples. A new synthetic process including the sonochemical approach to obtain synthetic reproducibility and significant yields of the per-substituted derivatives with acceptable reaction times was developed. The results show that asymmetrically substituted methyl/ethyl CDs compared to the methyl or ethyl symmetrical derivatives in general provide better enantioselectivity in terms of both enantiomer resolution and number of separated chiral compounds, and show how the substitution pattern in positions 2 and 3 of the CD ring can influence the separation. Moreover, these new CD derivatives with better enantioselectivity are also shown to be very useful in routine analysis for the exhaustive control of samples containing several chiral characterizing markers in a single run.

  19. Triethanolamine Stabilization of Methotrexate-β-Cyclodextrin Interactions in Ternary Complexes

    PubMed Central

    Barbosa, Jahamunna A. A.; Zoppi, Ariana; Quevedo, Mario A.; de Melo, Polyanne N.; de Medeiros, Arthur S. A.; Streck, Letícia; de Oliveira, Alice R.; Fernandes-Pedrosa, Matheus F.; Longhi, Marcela R.; da Silva-Júnior, Arnóbio A.

    2014-01-01

    The interaction of methotrexate (MTX) with beta-cyclodextrin (β-CD) in the presence of triethanolamine (TEA) was investigated with the aim to elucidate the mechanism whereby self-assembly cyclodextrin systems work in association with this third component. Solubility diagram studies showed synergic increment of the MTX solubility to be about thirty-fold. Experiments using 2D ROESY and molecular modeling studies revealed the inclusion of aromatic ring III of the drug into β-CD cavity, in which TEA contributes by intensifying MTX interaction with β-CD and stabilizes MTX:β-CD:TEA ternary complex by electrostatic interaction. The maintenance of these interactions in solid phase was also studied in ternary MTX:β-CD:TEA and comparisons were made with freeze dried binary MTX:β-CD and physical mixtures. FTIR studies evidenced that MTX–β-CD interaction remained in solid ternary complexes, which was also supported by thermal (differential scanning calorimetry (DSC), thermogravimetric analysis (TG)/first derivative of TG analysis (DTG) and C,N,H elementary analysis) and structural (X-ray diffraction analysis, (XRD)) studies, mainly regarding the increment of drug stability. The efficient in vitro drug dissolution studies successfully demonstrated the contribution of ternary complexes, which highlights the importance of this possible new raw material for further applications in drug delivery systems. PMID:25257529

  20. Space filling of β-cyclodextrin and β-cyclodextrin derivatives by volatile hydrophobic guests

    PubMed Central

    Fourmentin, Sophie; Ciobanu, Anca; Landy, David

    2013-01-01

    Summary The inclusion of volatile derivatives of benzene and cyclohexane in β-cyclodextrin (β-CD), hydroxypropyl-β-CD, and hydrophilic β-CD-thioethers was investigated by static headspace gas chromatography (HS-GC) and molecular modelling. The obtained binding constants strongly increase with the amount of space filling of the CD cavity and the salt concentration. β-CD thioethers show a 3–10 times higher binding potential than native β-CD. PMID:23843912