Synthesis and characterization of a novel amphiphilic copolymer containing β-cyclodextrin

In this article, maleic anhydride was used to attain the modified β-cyclodextrin (MAH-β-CD), and the MAH-β-CD was copolymerized with acrylamide (AM), acrylic acid (AA), and 2-acrylamido-2-methyl propane sulfonic acid (AMPS) via free radical copolymerization. The polymerization conditions were optimized through single-variable method. Subsequently, the copolymer structure was characterized through Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (¹HNMR) spectroscopy, and scanning electron microscopy (SEM). The three-dimensional network structure formed in aqueous solutions was observed via experimental results of SEM. Subsequently, several aspects of the properties of the copolymer, such as temperature tolerance, shear tolerance, salt resistance, and oil displacement ability, were investigated by comparing with hydrolyzed polyacrylamide (HPAM). Results indicate that the copolymer showed better performances than HPAM; thus, it could be concluded that the introduction of β-cyclodextrin in the polymer chain was helpful in enhancing the oil displacement efficiency in high-temperature and high-salinity oil field.     

Synthesis and characterization of a novel amphiphilic biodegradable β-cyclodextrin/poly(γ-benzyl L-glutamate) copolymer

β-Cyclodextrin/poly(γ-benzyl L-glutamate) (β-CD-PBLG) copolymers were synthesized by ring-opening polymerization of N-carboxy-γ-benzyl L-glutamate anhydride (BLG-NCA) in N,N-dimethylformamide (DMF) initiated by mono-amino-β-cyclodex-trin(H2N-β-CD). The structures of the copolymers were confirmed by IR, 1H NMR and GPC. The fluorescence technique was used to determine the critical micelle concentrations (CMC) of copolymer miceU solution, the diameter and the distribution of micelles were characterized by DLS. The results showed that BLG-NCA could be initiated by H2N-β-CD to produce copolymer. The nano-micells were formed by these copolymers in water.     

Synthesis and characterization of biodegradable materials： PDLLA-（MAh-Diol）n-PDLLA copolymer

The novel biodegradable copolymer PDLLA-(MAH-Diol)_n-PDLLAwith unsaturated bond was synthesized by copolymerizing lactide and prepolymer, which was prepared by the polycondensation of maleic anhydride and poly(ethylene glycol), using p- toluene sulphonic acid as catalyst. The new copolymer has improved hydrophilicity and fexibility. The structure and properties of the novel polymers were studied by FTIR, NMR, GPC-MALLS and DSC.     

Synthesis and characterization of praseodymium-2-hydroxypropyl-β-cyclodextrin inclusion complex

Journal of Radioanalytical and Nuclear Chemistry - The inclusion complex of PrCl3-XH2O-2-hidroxypropyl-β-cyclodextrin (Pr-2HPβCD) was prepared to increase the solubility and stability of...     

Synthesis,characterization and redox properties of mono- and bis-β-diketonate ruthenium complexes

Complexes of the type [RuIII(L)Cl2(PPh3)2] and [RuII(L)2(PPh3)2] (HL=benzoylacetone or acetylacetone) have been synthesized by the reaction of [RuCl2(PPh3)3] with HL under various experimental conditions. The [RuIII(L)Cl2(PPh3)2] complexes are one-electron paramagnetic species and, in solution, they show intense LMCT transitions in the visible region together with weak ligand-field transitions at lower energies. The [RuII(L)2(PPh3)2] complexes are diamagnetic and their solutions show sharp 1H n.m.r. signals and also show intense MLCT transitions in the visible region. In MeCN solution, the [RuIII(L)Cl2(PPh3)2] complexes show a reversible RuIII-RuII reduction near –0.3V and an irreversible RuIII- RuIV oxidation near 1.2 V versus s.c.e. A reversible RuII-RuIII oxidation is displayed by the [RuII(L)2(PPh3)2] complexes in MeCN solution near 0.3 V versus s.c.e. followed by another reversible RuIII-RuIV oxidation near 1.1 V versus s.c.e. The [RuII(L)2(PPh3)2] complexes have been oxidized to the corresponding [RuIII(L)2(PPh3)2]+ analogues and isolated as ClO4– salts in the solid state. The oxidized complexes are one-electron paramagnetic. They are 1:1 electrolytes in solution and show intense LMCT transitions in the visible region along with weak ligand-field transitions at lower energies.     

Synthesis,characterization, and photoluminescence properties of difluoroboron complexes with bis-β-diketone ligands

Some novel difluoroboron bis-β-diketonates containing a pyridyl moiety were synthesized from diethyl 2,6-pyridinedicarboxylate via Claisen condensation with the corresponding aryl methyl ketones and followed by complexation with boron trifluoride etherate. Their spectroscopic behaviors were studied by FTIR, ¹H NMR, UV–Vis, and fluorescence spectroscopic techniques. The results indicated that difluoroboron bis-β-diketonates exhibited violet or blue fluorescence emission at 428–454 nm under UV illumination in DMSO and possessed high extinction coefficients. It was found that the nature of the substituents at benzene ring in bis-β-diketone ligands had a significant impact on the photoluminescence behaviors of difluoroboron complexes. The complex 5b exhibited the strongest photoluminescence intensity and highest quantum yield (Φ _u = 0.93), due to two strong electron-donating methoxyl moieties in molecule and the compound 4b displayed the lowest photoluminescence intensity and quantum yield, assigned to the heavy atom effect of the chlorine atom in its molecule. The photoluminescence intensity and quantum yield of these difluoroboron complexes decreased in the sequence, 5b > 2b > 1b > 3b > 4b.     

Synthesis and characterization of diblock copolymer of butadiene and 2-ethyl-2-oxazoline

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Responsive core–shell microgels: Synthesis,characterization, and possible applications

Core–shell microgels are of increasing interest as smart carriers of catalysts, as sensors, or as building blocks for colloidal superstructures. In the context of colloidal assemblies, photonic applications are probably the most promising ones. This progress report presents and discusses the most recent results in this area focusing on the last 2–3 years, and also gives some background information. In addition, potential perspectives of this area will be outlined. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1073–1083     

Synthesis and characterization of biodegradable aliphatic polyesters using dibutylmagnesium as initiator

Aliphatic polyesters were synthesized via the ring opening polymerization of the corresponding lactones initiated with dibutylmagnesium both in bulk and in solution. The resulting polymers were characterized by 1H, 13C NMR, GPC and XRD. The results indicated that dibutylmagnesium is an effective initiator for the ring opening polymerization of lactones.     

Inclusion complexes of γ-cyclodextrin and carboxyl-modified γ-cyclodextrin with C60: synthesis, characterization and controlled release application via microgels

Carboxyl modified γ-cyclodextrin (CDSA) with a substitution degree of about 9.5 was prepared by the esterification of γ-cyclodextrin (CD) with succinic anhydride in pyridine at 90 °C. The chemical composition and the structure of CDSA were characterized by FT-IR, MALDI-TOF, X-ray diffraction pattern, potentiometric titration and TGA. Modified and native γ-cyclodextrin associate with fullerene (C₆₀) in DMF-toluene mixture resulting 1:1 CDSA:C₆₀ and CD:C₆₀ inclusion complexes. Aqueous solutions of native cyclodextrin, carboxyl-modified cyclodextrin and their inclusion complexes with C₆₀ were used as microgel solvent (or swelling agent) for controlled release application. The release of solutions was induced by shear stress and demonstrated using rheo-optical set-up.     

On the complexation of Trolox with methyl-β-cyclodextrin: characterization, molecular modelling and photostabilizing properties

Exposure to UV radiations could reduce the efficiency of some antioxidants like Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), a water-soluble vitamin E analogue largely employed in cosmetic products. Accordingly, in this paper we examined the possibility of increasing the stability of Trolox towards UVB irradiation by its complexation with methyl-β-cyclodextrin. Formation of the inclusion complex was confirmed by solubility diagrams, differential scanning calorimetry (DSC), and diffusion study through hydrophilic membrane. The stability constants and docking results suggested that the complexation phenomenon was related to the pH of the medium. The photodegradation studies were carried out in different topical formulations (gel, O/W emulsion, and W/O/W emulsion) containing Trolox free or complexed with methyl-β-cyclodextrin. Results showed that in all the cases Trolox degraded following pseudo-zero order kinetics. Moreover, the host molecule increased Trolox photostability also in the presence of TiO₂, a physical sunscreen well-known as photocatalyzer.     

Synthesis and characterization of water-swellableα,β-polyasparthydrazide derivatives

The synthesis of a new crosslinked polymer by reaction of , -polyasparthydrazide and glutaraldehyde is reported. Different crosslinking degrees were obtained by varying the ratio between the aldehyde and the starting polymer. The crosslinked polymer was characterized by water swelling tests and thermal analysis. In particular, the crosslinking density and its effects on the glass transition temperature of the material were studied. Finally, the microstructure of the obtained polymer was observed using scanning electron microscopy.     

Synthesis and characterization of water-swellableα,β-polyasparthydrazide derivatives

, -polyasparthydrazide (PAHy) was crosslinked by glutaraldehyde to form water-swellable materials possessing a three-dimensional molecular network. Different crosslinking degrees were prepared varying glutaraldehyde/PAHy ratio and samples containing 5-fluorouracil were obtained by incorporating the drug into the polymer networks during the crosslinking reaction. All samples were characterized by swelling tests, thermal, x-ray and SEM analysis. Their microstructure was observed through scanning electron microscopy. Furthermore, for samples containing the anticancer drug,in vitro release studies were performed in pH 7.4 buffer solution.     

Synthesis and characterization of a novel hydroxypropyl chitosan-graft-β-Cyclodextrin copolymer as potential drug carrier

Abstract

One of the most attractive fields in drug delivery is the design of nanoparticles that could be used to transport drugs into the target place at appropriate time. This paper describes the preparation of a novel hydroxypropyl chitosan-graft-β-cyclodextrin (HPCS-g-β-CD) copolymer using the 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) promoted condensation reaction. Structural characterization was finished with FTIR and ¹H NMR spectra, which confirmed the grafting of β-cyclodextrin (β-CD) onto hydroxypropyl chitosan (HPCS). The thermal properties were studied based on DSC and TGA analyses, which revealed the fact that grafting of β-CD onto HPCS resulted in obvious enhancement of the decomposition temperature of the copolymer. Aqueous solution of HPCS-g-β-CD copolymer was stable at pH 7-8 based on the Zeta potential test. The morphological characteristics were investigated by SEM, TEM and AFM analysis, and the results indicated that this copolymer had three-dimensional structure which was suitable for loading drugs.     

Synthesis, characterization and antibacterial properties of multifunctional hindered amine light stabilizers

A series of novel hindered amine light stabilizers containing an N-halamine moiety were designed and synthesized. Their structures were characterized by FT-IR, 1H NMR, and MS. The compounds were tested for antibacterial activity against Candida albicans, Staphylococcus aureus, and Escherichia coll. At a concentration of 0.5 mmol/L, these compounds all exhibited satisfactory antibacterial activity against all the three types of bacteria.     

Synthesis of modified β-cyclodextrin polymers and characterization of their fuchsin adsorption

Three water insoluble β-cyclodextrin polymers HP-β-CDP, CM-β-CDP and AE-β-CDP were synthesized by cross-linking epoxychloropropane with corresponding β-CD derivatives and utilized to adsorb water-soluble dye fuchsin from aqueous solution. FT-IR spectra confirmed the existence of hydroxypropyl, carboxyl group and amidogen in polymers. The influences of several parameters (contact time, pH and temperature) and the degree of substitution (DS) of CM-β-CDP in range of 1.5–4.5 on the adsorption capacity (Q _e) were evaluated. The results showed that all maximum Q _e of polymers appeared at pH 5.2–5.3. CM-β-CDP with carboxyl group was the most effective extractant, and the Q _e of CM-β-CDP with DS 1.5–2.5 kept nearly constant but decreased sharply over 2.5. However, AE-β-CDP with amidogen had displayed a quite low Q _e to fuchsin, even lower than that of unmodified β-CD polymer. The preliminary studies on the morphology of both CM-β-CDP and AE-β-CDP by AFM disclosed the differences in topography of their surfaces.     

Physicochemical characterization of sanguinarine-hydroxypropyl-β-cyclodextrin binary and ternary systems

Complexation of sanguinarine with hydroxy-propyl-β-cyclodextrin (HPβCD) in the presence and absence of hydrophilic polymer—polyvinylpyrrolidone K30 was studied. Respective binary and ternary systems were prepared using two techniques, physical mixture and lyophilization, and characterized by FT-infrared spectrometry, differential scanning calorimetry and X-ray diffractometry. The Fourier Transform Infrared spectra of the lyophilized binary and ternary systems showed significant shifts in the regions of 1240–1300 cm^?1, 1450–1525 cm^?1 and 1600–1650 cm^?1, where absorptions of –C–O–C– asymmetrical stretching of sanguinarine rings A and F and ν_C=C ring vibrations of sanguinarine benzo[c]phenanthridine system can be observed respectively. Moreover, in the case of ternary products ν_C=O amide band absorption of polyvinylpyrrolidone (1600–1750 cm^?1) shifted to the lower wavenumbers in both the physical mixture and the lyophilized product. These changes in the spectra of the studied systems proved the involvement of the respective molecular groups in complexation process. Differential scanning calorimetry and X-ray diffractometry indicated different states of drug amorphization and entrapment in HPβCD in the presence and without polyvinylpyrrolidone. The obtained results let us conclude that obtained binary and ternary systems represent sanguinarine-HPβCD molecular complexes, with different rate of inclusion in the presence and without polyvinylpyrrolidone.     

Preparation and characterization of inclusion complexes of carvedilol with methyl-β-cyclodextrin

Aim of the present work was to investigate the effect of methyl-β-cyclodextrin (MβCD) on the solubility and dissolution rate of carvedilol (CAR), a drug used orally for the treatment of hypertension. Phase solubility studies showed an A_L-type diagram indicating the formation of inclusion complex in 1:1 molar ratio. Solid binary systems of the drug with MβCD were prepared by various methods. Physicochemical characterizations were performed using Fourier Transformation Infrared Spectroscopy, Differential Scanning Calorimetry and powder X-Ray Diffractometry. It could be concluded that CAR can form inclusion complex with MβCD. The dissolution profiles of inclusion complexes were determined and compared with those of CAR alone and the physical mixture. The dissolution rate of CAR was increased by MβCD inclusion complexation remarkably.     

Synthesis and characterization of a functionalized amphiphilic diblock copolymer: MePEG-b-poly(DL-lactide-co-RS-β-malic acid)

A class of novel amphiphilic diblock copolymer of MePEG-b-poly(DL-lactide-co-RS-β-malic acid) has been synthesized via the hydrogenation over palladium on charcoal of MePEG-b-poly(DL-lactide-co-RS-β-benzyl malolactonate), which was prepared by ring-opening copolymerization of DL-lactide and RS-β-benzyl malolactonate (MABz) using methyl-polyethylene glycol (MePEG) as the initiator and stannous octoate as the catalyst. The influence of copolymerization temperature, reaction time, macro-initiator (MePEG-5000) proportion and monomer ratio was studied. Gel permeation chromatography measurements revealed that the molecular weight decreased with increasing MABz feeding dose. The configurational structures of the protected and de-protected copolymers were determined by ¹³C nuclear magnetic resonance (NMR), ¹H NMR and Fourier transform infrared. A water-swollen core of the nanospheres formed from the de-protected copolymer was discovered by transmission electron microscopy measurement. Additionally, the degradation experiments indicated that more hydrophilic malic acid content led to higher degradation rate.