Two-Phase Channel Structures Based on α-Cyclodextrin−Polyethylene Glycol Inclusion Complexes

Topchieva, I. N.; Tonelli, Alan E.; Панова, И. Г.; Matuchina, Elena V.; Kalashnikov, F. A.; Gerasimov, V. I.; Rusa, Cristian C.; Rusa, Mariana; Hunt, Martin A.

doi:10.1021/la048970d

Cited by 143 publications

(150 citation statements)

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“…A discernible break in the conductivity curve occurred at a concentration of about 5.0 mmol L À1 b-CD, suggesting that the stoichiometry of the b-CDbmimPF 6 (1) ionic compound is equimolar. [41] This conclusion is the same as that deduced from the solubility curves above. Palepu et al determined the conductivity of solutions www.chemeurj.org of sodium alkyl carboxylates in water with different alkyl groups and b-CD, [40] and produced conductivity curves similar to that shown in Figure 2.…”

supporting

confidence: 77%

Preparation and Characterization of Inclusion Complexes of β‐Cyclodextrin with Ionic Liquid

Gao

et al. 2005

Chemistry A European J

139

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The solubilities of beta-cyclodextrin (beta-CD), ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6), and their mixture in water were determined, and the conductivity of these aqueous solutions was measured. It was demonstrated that beta-CD and bmimPF6 could enhance the solubility of each other, and the solubility curves of each were linear with gradients of about 1. The conductivity decreased remarkably with increasing beta-CD concentration, and a discernible break in the conductivity curve could be observed when beta-CD and bmimPF6 were equimolar in the solution. The solubility and conductivity results indicated that inclusion complexes (ICs) of 1:1 stoichiometry were formed. The inclusion compounds were further characterized by using powder X-ray diffraction (XRD) analysis, 13C CP/MAS (cross-polarization magic-angle spinning) NMR and 1H NMR spectroscopy, and thermogravimetric analysis (TGA). The results showed that the ICs were a fine crystalline powder. The host-guest system exhibited a channel-type structure and each glucose unit of beta-CD was in a similar environment. The decomposition temperature of the ICs was lower than that of bmimPF6 and beta-CD individually.

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confidence: 77%

Preparation and Characterization of Inclusion Complexes of β‐Cyclodextrin with Ionic Liquid

Gao

et al. 2005

Chemistry A European J

139

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“…[24][25][26][27] Therefore, the diffraction patterns of the a-and g-CyD polypseudorotaxanes with the pegylated insulin were indexed on the basis of the two-dimensional hexagonal and tetragonal unit cells with dimensions aϭbϭ27.44 Å and aϭbϭ24.02 Å, respectively, as shown in Table 2 were used to calculate the unit cell dimensions (Fig. 2).…”

Section: Resultsmentioning

confidence: 99%

Polypseudorotaxane Formation of Randomly-Pegylated Insulin with Cyclodextrins: Slow Release and Resistance to Enzymatic Degradation

Higashi

Hirayama

Misumi

et al. 2009

CHEMICAL & PHARMACEUTICAL BULLETIN

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NotesPegylation technology is one of the useful methods for sustained release systems, because when poly(ethylene glycol) (PEG) is covalently attached to a protein, it transfers many of the polymer's favorable characteristics to the resulting conjugate, i.e. a number of benefits such as increased circulating half-life, enhanced proteolytic resistance, reduced antigenicity and immunogenicity, reduced aggregation, and improved bioavailability, etc. There are many examples of protein conjugates that are mono-or randomly-substituted with PEG, such as adenosine deamidase, insulin, interferona2, b-lactoglobulin, a-chymotrypsin, lipase, bovine liver catalase, asparaginase, and superoxide dismutase, etc. of which the first three conjugates are on the market.1-3) Most of commercially available pegylated drugs are randomly-substituted derivatives, because of synthetic difficulty of the mono-pegylation.Supramolecular assemblies have attracted a great amount of attention, due to its intriguing topologies and its application in various fields such as nanodevices, sensors, molecular switches, and drug delivery systems, etc. Cyclodextrins (CyDs) are cyclic oligosaccharides composed of 6 (a-CyD), 7 (b-CyD), and 8 (g-CyD) glucopyranose units and can form inclusion complexes with various organic and inorganic compounds.4) Harada et al. first reported the supramolecular assemblies of PEG and a-CyD, in which a number of the cyclic molecule are spontaneously threaded onto the polymer chain.5,6) These complexes are called polypseudorotaxanes, because the CyD can be dethreaded from the polymer chain when dissolved in water. Recently, many studies on CyD polypseudorotaxanes with various polymers were reported, e.g. blanched PEG, poly(ethylene imine) and poly(lactic acid), etc. [7][8][9] In addition, a number of applications of polypseudorotaxanes as a biomaterial were reported, e.g. gene delivery carrier, 10-13) biodegradable hydrogel 11,[14][15][16][17] and galectin binding material. 18) In previous studies, 19,20) we found that the mono-substituted pegylated insulin forms polypseudorotaxanes with a-and g-CyDs in a similar manner as PEG does. However, there are no evidences if randomly-or multiply-pegylated proteins form polypseudorotaxanes with CyDs. In this study, therefore, we prepared randomly-substituted pegylated insulin and its CyD polypseudorotaxanes and evaluated it as a sustained release system. Further, proteolytic behavior of insulin in the polypseudorotaxane was investigated. ExperimentalMaterials Bovine Zn-insulin (27.5 IU/mg, approximately 0.5% Zn) was obtained from Sigma Chemicals (St. Louis, MO, U.S.A.). a-Succinimidyloxysuccinyl-w-methoxy-polyoxyethylene (MW about 2300) was obtained from NOF Co. (Tokyo, Japan). CyDs were donated by Nihon Shokuhin Kako (Tokyo, Japan). All other materials were of reagent grade, and deionized double distilled water was used.Preparation of Randomly-Pegylated Insulin Randomly-pegylated insulin was synthesized according to the modified method of Hinds et al. 3,21) Briefly, insulin (MW 5734...

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“…13 C CP/MAS NMR and X ray spectra of these complexes suggest that cyclodextrines are threaded along the polymer chain creating a ''channel type'' structure which was described by Mc Mullan et al [26]. Other authors (Wenz [27,28], Topchieva and Tonelli [29,30]) have also studied this kind of complexes as well as poly(rotaxan)s formed by direct complexation of CD's with block copolymers [31,32]. We have studied the stoichiometry and rigidity of some of these compounds by Molecular Dynamics [14,15]; their high aspect ratio, their low conformational flexibility along with plenty of functional groups over which a rich chemistry can be done to couple them to polymer matrices make them good candidates as nanoreinforcements.…”

Section: Introductionmentioning

confidence: 76%

Synthesis of novel nanoreinforcements for polymer matrices by ATRP: Triblock poly(rotaxan)s based in polyethyleneglycol end-caped with poly(methyl methacrylate)

Miguel

González

Pozuelo

et al. 2009

Polymer

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Poly(rotaxan)s of poly(ethylene glycol) and a cyclodextrines (CD) block copolymers end capped with poly(methyl methacrylate) chains were synthesized by atom transfer radical polymerization. The synthesized copolymers were characterized by 1 H NMR, 2D NOESY NMR, X ray and Thermogravimetric analysis. Assuming a maximum relation of 2 CDs per ethyleneglycol unit, a coverage degree of 18% and 15% was achieved. X ray analysis showed a characteristic signal around 20q for all copolymers with an amorphous halo mainly due to inter crystal poly(ethylene glycol) and poly(methyl methacrylate) chains. Full Molecular Dynamics of 20 ns was used to simulate the crystal structure of these copolymers. A pair correlation function was used to determine the coupling between hydrogen atoms of PEG, PMMA and cyclodextrine obtained by 2D NOESY NMR.

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Two-Phase Channel Structures Based on α-Cyclodextrin−Polyethylene Glycol Inclusion Complexes

Cited by 143 publications

References 13 publications

Preparation and Characterization of Inclusion Complexes of β‐Cyclodextrin with Ionic Liquid

Preparation and Characterization of Inclusion Complexes of β‐Cyclodextrin with Ionic Liquid

Polypseudorotaxane Formation of Randomly-Pegylated Insulin with Cyclodextrins: Slow Release and Resistance to Enzymatic Degradation

Synthesis of novel nanoreinforcements for polymer matrices by ATRP: Triblock poly(rotaxan)s based in polyethyleneglycol end-caped with poly(methyl methacrylate)

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