Nanoscale drug delivery systems(nano-DDSs)have attracted intense interest in tumor chemotherapy in the last decades,to improve antitumor efficacy and minimize toxic and side effects.As a versatile supramolecular build...Nanoscale drug delivery systems(nano-DDSs)have attracted intense interest in tumor chemotherapy in the last decades,to improve antitumor efficacy and minimize toxic and side effects.As a versatile supramolecular building block,cyclodextrins(CDs)have been widely used in the fabrication of the smart nano-DDSs.Besides their multifunctionality,which makes them versatile core in the star(co)polymers for micellar nanomedicines,specific host-vip inclusion complexation via their hydrophobic cavities endows them diversified functions:(i)design of amphiphilic copolymers for micellar nanomedicines,(ii)supramolecular hydrogels and poly(pseudo)rotaxane nano-hydrogels as drug carriers,and(iii)recipient for direct and indirect drug-loading.In the present work,the recent progress of CDs in nano-DDSs for tumor chemotherapy was reviewed,classified by the crucial roles of CD units.Based on the structureperformance relationship,the future perspective was also proposed.展开更多
The effect of β-cyclodextrins(β-CDs) on the enzymatical hydrolysis of chiral dichlorprop methyl ester (DCPPM) was studied. Four kinds of β-cyclodextrins(β-cyclodextrin, Partly methylated-CD(PM-β-CD), hydroxyprop...The effect of β-cyclodextrins(β-CDs) on the enzymatical hydrolysis of chiral dichlorprop methyl ester (DCPPM) was studied. Four kinds of β-cyclodextrins(β-cyclodextrin, Partly methylated-CD(PM-β-CD), hydroxypropyl-cyclodextrin(HP-β-CD) and carboxymethyl-cyclodextrin(CM-β-CD)) were used. Compared with 100% DCPPM in the absence of β-cyclodextrins, the activity of lipase decreased with the increase of β-cyclodextrin and PM-β-cyclodextrin. However, CM-β-cyclodextrin stimulated the lipase activity. The inhibition effect of β-cyclodextrin and PM-β-cyclodextrin on the hydrolysis of DCPPM is affected by many factors other than degree of the methylation blocking the active site of lipase. UV-Vis and Fourier transform infrared(FTIR) spectroscopy studies of the complexation of aqueous DCPPM with β-CDs provide fresh insight into the molecular structure of the complex and explain the effects of β-CDs on enzymatical hydrolysis of chiral DCPPM. Data showed that inclusion complexes had formed by complexation of the CM-β-CD with DCPPM and the solubility of DCPPM was increased in water, which leaded to the increased lipase activity.展开更多
Sildenafil citrate is a potent and selective phosphodiesterase-5inhibitor. It is effectively used in the treatment of erectile dysfunction and pulmonary arterial hypertension. The drug is rapidly absorbed and pharmaco...Sildenafil citrate is a potent and selective phosphodiesterase-5inhibitor. It is effectively used in the treatment of erectile dysfunction and pulmonary arterial hypertension. The drug is rapidly absorbed and pharmacologically acts within30 min to 1 h after oral administration. However, it has a relatively low absolute bioavailability of 41%because its limited solubility in water is the major problem (1)To improve the oral bioavailability of poorly water-soluble drugs.展开更多
To investigate the non-covalent interaction between cyclodextrins （CD） and lithium ion, a stoichiometry of α-CD, β-CD, heptakis（2,6-di-O-methyl）-β-CD （DM-β-CD）, or heptakis（2,3,6-tri-O-methyl）-β-CD （TM-...To investigate the non-covalent interaction between cyclodextrins （CD） and lithium ion, a stoichiometry of α-CD, β-CD, heptakis（2,6-di-O-methyl）-β-CD （DM-β-CD）, or heptakis（2,3,6-tri-O-methyl）-β-CD （TM-β-CD） was mixed with lithium salt, respectively, and then incubated at room temperature for 10 min to reach the equilibrium. In posi- tive mode, the electrospray ionization mass spectrometry （ESI-MS） results demonstrated that lithium ion can conjugate to α-, β-, DM-β- or TM-β-CD and form 1：1 stoichiometric non-covalent complexes. The binding of the complexes was further confirmed by collision- induced dissociation. The dissociation constants Kdl of four complexes （Li＋α-CD, Li＋β- CD, Li＋DM-β-CD, and Li＋TM-β-CD） were determined by mass spectrometric titration. The results showed Kdl were 18.7, 26.7, 33.6, 30.5 μmol/L for the complexes of Li＋ with α-CD, β-CD, DM-β-CD, and TM-β-CD, respectively. Kdl for the Li＋ complexes of/3-CD is smaller than that of DM-β-CD due to its steric effect of the partial substituted -CH3. The Kdl for the Li＋ complexes of DM-β-CD is nearly in agreement with that of TM-β-CD, indicating Li＋ is more likely to locate in the small rim of DM-β-CD＇s hydrophobic cavity. The DFT results showed through electrostatic interaction, one Li＋ can strongly conjugate to four neighboring oxygen atoms. For the （α-CD＋Li）＋ complex, one Li＋ may also situate the small rim of α-CD＇s hydrophobic cavity to form a non-specific host-vip complex.展开更多
Six peralkylated β- cyclodec\xtrins used as capillary gas chromatographic stationary phases were prepared and characterized by differential by differential scannning calorimetry(DSC) and pyrolysis gas chromatograp...Six peralkylated β- cyclodec\xtrins used as capillary gas chromatographic stationary phases were prepared and characterized by differential by differential scannning calorimetry(DSC) and pyrolysis gas chromatography (PyGC). The DSC profiles illustrated that the peralkylated β-cyclodextrins synthesized possess the supercoooled state and the glass state below their melting point The PYGC results showed that the long-chain alkylated β-cyclodextrins are more thermostable than the short-chain. one All ofthese peralkylated β-cyclodextrins are suitable for use as capillary column gas chromatographic stationary phases,which can easily be coatal on the fused silica capilary columns and have nice chromatographic retention behaviour. For example, the capillary colunns coated with these materials can excellently separate three methylphenol isomers and six dimehylphenol isomers.展开更多
In the current study, we prepared a ground mixture(GM) of caffeic acid(CA) with α-cyclodextrin(αCD) and with β-cyclodextrin(βCD), and then comparatively assessed the physicochemical properties and antioxidant capa...In the current study, we prepared a ground mixture(GM) of caffeic acid(CA) with α-cyclodextrin(αCD) and with β-cyclodextrin(βCD), and then comparatively assessed the physicochemical properties and antioxidant capacities of these GMs. Phase solubility diagrams indicated that both CA/αCD and CA/βCD formed a complex at a molar ratio of 1/1. In addition, stability constants suggested that CA was more stable inside the cavity of αCD than inside the cavity of βCD. Results of powder X-ray diffraction(PXRD) indicated that the characteristic diffraction peaks of CA and CD disappeared and a halo pattern was produced by the GMs of CA/αCD and CA/βCD(molar ratios = 1/1). Dissolution testing revealed that both GMs had a higher rate of dissolution than CA alone did. Based on the1 H-1 H NOESY NMR spectra for the GM of CA/αCD, the vinylene group of the CA molecule appeared to be included from the wider to the narrower rim of the αCD ring. Based on spectra for the GM of CA/βCD, the aromatic ring of the CA molecule appeared to be included from the wider to the narrower rim of the βCD ring. This suggests that the structures of the CA inclusion complexes differed between those involving αCD rings and those involving βCD rings. Results of a DPPH radical-scavenging activity test indicated that the GM of CA/αCD had a higher antioxidant capacity than that of the GM of CA/βCD. The differences in the antioxidant capacities of the GMs of CA/αCD and CA/βCD are presumably due to differences in stability constants and structures of the inclusion complexes.展开更多
The methylated β-cyclodextrins derived optically active polymers are firs synthesized through asymmetric polymerization of N-diphenylmethyl maleimide with lithium salt of heptakis(2,6-O-dimethyl) β-cyclodextrin (DM-...The methylated β-cyclodextrins derived optically active polymers are firs synthesized through asymmetric polymerization of N-diphenylmethyl maleimide with lithium salt of heptakis(2,6-O-dimethyl) β-cyclodextrin (DM-β-CD) as an initiator. The resulting polymers show negative specific rotation which is opposite in sign to that of DM-β-CD. The asymmetric induction is further confirmed by circular dichroism. The structure is characterized by IR and NMR spectroscopies展开更多
Phenothiazine and i^+s derivatives were oxidized by l_2 and 2,2,6,6-tetrametbyl-4- acetyloxypiperidine oxoammonium hexachloroantimonate to the corresponding radical cations in the cavity of β-cyclodextrins in aqueous...Phenothiazine and i^+s derivatives were oxidized by l_2 and 2,2,6,6-tetrametbyl-4- acetyloxypiperidine oxoammonium hexachloroantimonate to the corresponding radical cations in the cavity of β-cyclodextrins in aqueous solution.The mechanism of electron transfer between substrates and oxidants is discussed in terms of association of β-CDs.展开更多
GM1-gangliosidosis is a rare lysosomal storage disorder characterized clinically by a wide range of variable neurovisceral,ophthalmological and dysmorphic features. Without enough functionalβ-galactosidase, GM1-gangl...GM1-gangliosidosis is a rare lysosomal storage disorder characterized clinically by a wide range of variable neurovisceral,ophthalmological and dysmorphic features. Without enough functionalβ-galactosidase, GM1-gangliosides cannot be degraded in lysosomes, and accumulate to toxic levels in many tissues and organs, particularly in the brain. In spite of several approaches for the treatment of GM1-gangliosidosis.展开更多
Cyclodextrins have gained wide attentions for their unique physicochemicai properties. In recent years, conducting polymers with special micro-structure and properties are synthesized in the presence of cyclodextrins....Cyclodextrins have gained wide attentions for their unique physicochemicai properties. In recent years, conducting polymers with special micro-structure and properties are synthesized in the presence of cyclodextrins. In this article, the application of cyclodextrins in the synthesis process of conducting polymer metarials is discussed. And authors＇ study results are summarized.展开更多
Cyclodextrins are naturally oligosaccharides which had cyclic glucopyranoside units even if six units to form <em>α</em>-cyclodextrin (<em>α</em>-CD), seven units <em>β</em>-cycl...Cyclodextrins are naturally oligosaccharides which had cyclic glucopyranoside units even if six units to form <em>α</em>-cyclodextrin (<em>α</em>-CD), seven units <em>β</em>-cyclodextrin (<em>β</em>-CD) or eight units <em>γ</em>-cyclodextrin (<em>γ</em>-CD) and some other derivatives. It has a truncated cone shape with a hydrophobic cavity and a hydrophilic from the external surface of cyclodextrins. Gold nanoparticles incorporated with cyclodextrins enhanced optical and electrical properties of the resulting conjugates, due to the gold nanoparticles’ unique physical and chemical properties because of their surface plasmon resonance. Here is a review of gold nanoparticles/cyclodextrin’s different applications including sensing, antimicrobial effect, and their variable medical/pharmaceutical applications. Generally, gold nanoparticles and cyclodextrin conjugates showed developed and pronounced advantages due to their biocompatibility and enhanced physical and electric properties.展开更多
Two highly water-soluble amino acids, which derived from β-CDs, i.e., glutamic acid-β-cyclodextrin （GluCD） and ethylene-diamine- β-cyclodextrin （EDCD）, were synthesized and were examined for their effect on sol...Two highly water-soluble amino acids, which derived from β-CDs, i.e., glutamic acid-β-cyclodextrin （GluCD） and ethylene-diamine- β-cyclodextrin （EDCD）, were synthesized and were examined for their effect on solubilization of anthracene （ANT）, complexation of cadmium （Cd^2＋）, and elution removal of ANT and Cd^2＋ in soil. The results showed that GluCD and EDCD were powerful complexant for ANT and Cd^2＋. In the presence of 10 g/L GIuCD and EDCD, the solubilization of ANT increased by 47.04 and 23.85 times compared to the control, respectively. GluCD resulted in approximately 90% complexation of Cd^2＋ while 70% complexation was observed for EDCD. Simultaneously, GluCD and EDCD could greatly enhance the elution removal of ANT and Cd^2＋ from soil. GluCD resulted in the highest elution efficiency of ANT and Cd^2＋. With the addition of 10 g/L GluCD, 53.5% of ANT and 85.6% of Cd^2＋ were eluted, respectively. The ANT had a negligible effect on the Cd^2＋ removal due to different complexing sites of ANT and Cd^2＋, while Cd^2＋ enhanced the ANT removal under the addition of GluCD because Cd^2＋ neutralized the -COOH group of GIuCD. Adversely, the removal of ANT was decreased with Cd^2＋ under the addition of EDCD, this was due to the fact that Cd^2＋ enhanced the polarity of EDCD molecule and inhibited the complexation between ANT and EDCD. The study suggested that GluCD could be preferred and be successfully applied to remediation of heavy metals or organic compounds in contaminated soil.展开更多
Aim To study the chromatographis beheviors of three new cinnamyl cyclodextrin derivative stationary phases. Mehtods Three new cinnamyl β-cyclodextrins, heptakis-(2, 6-di-O-cinnamyl-3-O-methyl)-β-CD, heptakis-(2, 6-...Aim To study the chromatographis beheviors of three new cinnamyl cyclodextrin derivative stationary phases. Mehtods Three new cinnamyl β-cyclodextrins, heptakis-(2, 6-di-O-cinnamyl-3-O-methyl)-β-CD, heptakis-(2, 6-di-O-cinnamyl-3-O-acetyl-)-β-CD and heptakis-2, 6-di-O-cirinamyl-3-O-trifluoroacetyl)-β-CD were synthesized and coatal on fused-silica capillary columns . Results The new stationary phases have better thermal stability, good column efficiency and excellent mpaxation power for some sutstituted benzene positional isomers. It was found that the introduction of cinnamyl groups has a significant effect on these stationary phases. Conclusion There new subetituted β-CD compounds are very suitable to be ed as gas chromatographic stationary phases.展开更多
Aim To study the chromatographic behaviors of two dipentyl cyclodextrin derivative stationary phases. Methods Two new β-cyclodextrin derivatives, heptakis-[2, 6-di-O-pentyl-3-O-(4-nitrobenzyl)] -β-CD and heptakis-[...Aim To study the chromatographic behaviors of two dipentyl cyclodextrin derivative stationary phases. Methods Two new β-cyclodextrin derivatives, heptakis-[2, 6-di-O-pentyl-3-O-(4-nitrobenzyl)] -β-CD and heptakis-[2, 6-di-O-pentyl-3 -O-(5 -hexenyl)]-β-CD, were synthesized and coatal on fed-silica capillary columns. The chromatographic behaviors of the columns were characterized . Results It was found that the she, polarity, and aromatic property of the substituted group at the 3-position of heptakis-(2, 6 - di - O - pentyl) - β - cyclodextrins greatly influenced their chromatographic properties and separation ability. The introduction of aromatic group or a group containing a double-bond may bring π-π interactions between the host and vip molecules, and therefore increases the separation ability of the β-CDs for substituted benzene isomers. Conclusion The new substituted β-CD compounds are very suitable for being used as gas chromatogaphic stationary phases.展开更多
The free radical polymerization of styrene in water in the presence of β-cyclodextrin (β-CD) is described. It is found that β-CD could greatly accelerate the polymerization, enhance the final conversion of monomer....The free radical polymerization of styrene in water in the presence of β-cyclodextrin (β-CD) is described. It is found that β-CD could greatly accelerate the polymerization, enhance the final conversion of monomer. The particle-size distribution of the final polymer is also improved than that without β-CD in the system.展开更多
Six new kinds of amino acid derived β-cyclodextrins were synthesized to improve their water solubility and chiral separation properties. They are heptakis{2,6-di-O-[3-L-(1-isopropyl carboxyl methyl amino)-2-(hydroxy)...Six new kinds of amino acid derived β-cyclodextrins were synthesized to improve their water solubility and chiral separation properties. They are heptakis{2,6-di-O-[3-L-(1-isopropyl carboxyl methyl amino)-2-(hydroxy) propyl]}-β-cyclodextrin (i.e. L-Val-β-CD), heptakis{2,6-di-O-[3-L-(1-benzyl carboxyl methyl amino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Phe-β-CD), heptakis{2,6-di-O-[3-(D, L-1-benzyl carboxyl methyl amino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. D,L-Phe-β-CD), heptakis{2,6-di-O-[3-(L-1-hydroxymethyl carboxyl methyl amino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Ser-β-CD), heptakis{2,6-di-O-[3-(L-1-carboxylmethyl carboxyl methyl amino)- 2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Asp-β-CD), heptakis{2,6-di-O-[3-(L-2-carboxyl tetramethylene amino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Pro-β-CD). Their chemical structures were certified using FTIR and ()~1H NMR. Except for L-Phe-β-CD and D,L-Phe-β-CD, that are in soluble in water, the other amino acid derived β-CDs all have good water solubility. D,L-tyrosine and promethazine were baselinely separated by L-Val-β-CD in capillary electrophoresis.展开更多
Cyclodextrins （CDs）, with hydrophobic interior cavity and hydrophilic external surface, are capable of accelerating or inhibiting chemical degradation of organophosphorus pesticides through forming inclusion complex...Cyclodextrins （CDs）, with hydrophobic interior cavity and hydrophilic external surface, are capable of accelerating or inhibiting chemical degradation of organophosphorus pesticides through forming inclusion complexes between CDs and pesticides. This work evaluated the effects of CDs on hydrolysis of malathion in an attempt to assess their potential application in environmental approach. β-CD and its two derivatives, randomly methylated β-CD （RAMEB） and hydroxypropyl β-CD （HP-β-CD）, were tested. It was found that RAMEB could inhibit the hydrolysis of malathion, and this was the function of pH and temperature, the inhibitory effects increase with increasing concentration of RAMEB and elevating temperature between 15 and 35℃. On the other hand, β-CD and HP-β-CD have little or no stabilizing effects on malathion at all pH and temperature studied, except that the large concentration of β-CD and HP- β-CD can mildly reduce hydrolysis of malathion. Both 2 mol/L and 5 mol/L urea increase the inhibitory effects of RAMEB on hydrolysis of malathion at 25℃, oH 9.0.展开更多
The inclusion behaviors of three native or modified CDs including p-CD,2-hydroxypropyl-β-CD（2-Hp-β-CD） and 2,6-dimethyl-β-CD（Me-β-CD） toward 5-amino-6-methyl-2-benzimidazolone（AMBI） were comparatively invest...The inclusion behaviors of three native or modified CDs including p-CD,2-hydroxypropyl-β-CD（2-Hp-β-CD） and 2,6-dimethyl-β-CD（Me-β-CD） toward 5-amino-6-methyl-2-benzimidazolone（AMBI） were comparatively investigated by NMR and fluorescence titration in combination with IR spectra,X-ray diffractometry and scanning electron microphotographs.The experimental results jointly demonstrated that the phenyl ring of AMBI entered into the cavity of the CDs and located close to the narrow rims accompanied by the formation of the 1：1 inclusion complex with large stability constant in aqueous solution.The introduction of the hydroxypropyl unit to the host improved the solubility,ultimately effecting an obvious promoting in the fluorescence intensity and the stability constant展开更多
Eight pairs of enantiomers of cyclopropane derivatives were resolved on capillary gas chromatographic columns using three new 2, 6-di-O-allyl-3-O-acylated-β-cyclodextrins as chiral stationary phases. It was found th...Eight pairs of enantiomers of cyclopropane derivatives were resolved on capillary gas chromatographic columns using three new 2, 6-di-O-allyl-3-O-acylated-β-cyclodextrins as chiral stationary phases. It was found that the three β-CDs can separate some of the racemic cyclopropane derivatives well.展开更多
2-acetoxy-benzencarboxylic acid is one of the most famous salicylate drugs today, a pharmaceutically active compound known as aspirin. It is poorly soluble in water which results in decreased bioavailability of the dr...2-acetoxy-benzencarboxylic acid is one of the most famous salicylate drugs today, a pharmaceutically active compound known as aspirin. It is poorly soluble in water which results in decreased bioavailability of the drug in the organism. The increase in water solubility of insoluble or poorly soluble drugs is therefore of great importance, which is the aim of this study. Inclusion of the drug in the molecule with a higher water solubility significantly increases its solubility and biological availability. Natural and hydrophilic derivatives of natural cyclodextrins are in the spotlight for their role as solubilizing excipients. Studies indicate that the use of β-cyclodextrin inclusion complexes with acetylsalicylic acid formed, increases the solubility of the drug in water. Many advantages of drug-complexation with cyclodextrins have been reported in scientific literature which includes increased solubility, enhanced bioavailability, improved stability, masking of bad test or odour, reduced side effect. Orally administered aspirin requires high and frequent dosing because it undergoes extensive pre systematic metabolism. Also chronic oral aspirin use is associated with serious gastrointestinal side-effects. Complexation with CD alleviates the side effects to some extent. The bioavailability and solubility of aspirin has to be increased to overcome the side-effects of aspirin related to stomach and gastro intestinal tract. The phase solubility study was performed according to the method of Higuchi and Connors by adding the 2-acetoxi-benzencarboxylic acid in excess to different concentrations of different beta cyclodextrins solutions. Phase solubility study records shown that the stability constant and complex stoichiometry of 2-acetoxi-benzencarboxylic acid-CD complexes gives linearly improve with the concentration of CD. Complexes were analyzed by UV-VIS spectroscopy and were characterized by infrared spectroscopy.展开更多
文摘Nanoscale drug delivery systems(nano-DDSs)have attracted intense interest in tumor chemotherapy in the last decades,to improve antitumor efficacy and minimize toxic and side effects.As a versatile supramolecular building block,cyclodextrins(CDs)have been widely used in the fabrication of the smart nano-DDSs.Besides their multifunctionality,which makes them versatile core in the star(co)polymers for micellar nanomedicines,specific host-vip inclusion complexation via their hydrophobic cavities endows them diversified functions:(i)design of amphiphilic copolymers for micellar nanomedicines,(ii)supramolecular hydrogels and poly(pseudo)rotaxane nano-hydrogels as drug carriers,and(iii)recipient for direct and indirect drug-loading.In the present work,the recent progress of CDs in nano-DDSs for tumor chemotherapy was reviewed,classified by the crucial roles of CD units.Based on the structureperformance relationship,the future perspective was also proposed.
文摘The effect of β-cyclodextrins(β-CDs) on the enzymatical hydrolysis of chiral dichlorprop methyl ester (DCPPM) was studied. Four kinds of β-cyclodextrins(β-cyclodextrin, Partly methylated-CD(PM-β-CD), hydroxypropyl-cyclodextrin(HP-β-CD) and carboxymethyl-cyclodextrin(CM-β-CD)) were used. Compared with 100% DCPPM in the absence of β-cyclodextrins, the activity of lipase decreased with the increase of β-cyclodextrin and PM-β-cyclodextrin. However, CM-β-cyclodextrin stimulated the lipase activity. The inhibition effect of β-cyclodextrin and PM-β-cyclodextrin on the hydrolysis of DCPPM is affected by many factors other than degree of the methylation blocking the active site of lipase. UV-Vis and Fourier transform infrared(FTIR) spectroscopy studies of the complexation of aqueous DCPPM with β-CDs provide fresh insight into the molecular structure of the complex and explain the effects of β-CDs on enzymatical hydrolysis of chiral DCPPM. Data showed that inclusion complexes had formed by complexation of the CM-β-CD with DCPPM and the solubility of DCPPM was increased in water, which leaded to the increased lipase activity.
文摘Sildenafil citrate is a potent and selective phosphodiesterase-5inhibitor. It is effectively used in the treatment of erectile dysfunction and pulmonary arterial hypertension. The drug is rapidly absorbed and pharmacologically acts within30 min to 1 h after oral administration. However, it has a relatively low absolute bioavailability of 41%because its limited solubility in water is the major problem (1)To improve the oral bioavailability of poorly water-soluble drugs.
文摘To investigate the non-covalent interaction between cyclodextrins （CD） and lithium ion, a stoichiometry of α-CD, β-CD, heptakis（2,6-di-O-methyl）-β-CD （DM-β-CD）, or heptakis（2,3,6-tri-O-methyl）-β-CD （TM-β-CD） was mixed with lithium salt, respectively, and then incubated at room temperature for 10 min to reach the equilibrium. In posi- tive mode, the electrospray ionization mass spectrometry （ESI-MS） results demonstrated that lithium ion can conjugate to α-, β-, DM-β- or TM-β-CD and form 1：1 stoichiometric non-covalent complexes. The binding of the complexes was further confirmed by collision- induced dissociation. The dissociation constants Kdl of four complexes （Li＋α-CD, Li＋β- CD, Li＋DM-β-CD, and Li＋TM-β-CD） were determined by mass spectrometric titration. The results showed Kdl were 18.7, 26.7, 33.6, 30.5 μmol/L for the complexes of Li＋ with α-CD, β-CD, DM-β-CD, and TM-β-CD, respectively. Kdl for the Li＋ complexes of/3-CD is smaller than that of DM-β-CD due to its steric effect of the partial substituted -CH3. The Kdl for the Li＋ complexes of DM-β-CD is nearly in agreement with that of TM-β-CD, indicating Li＋ is more likely to locate in the small rim of DM-β-CD＇s hydrophobic cavity. The DFT results showed through electrostatic interaction, one Li＋ can strongly conjugate to four neighboring oxygen atoms. For the （α-CD＋Li）＋ complex, one Li＋ may also situate the small rim of α-CD＇s hydrophobic cavity to form a non-specific host-vip complex.
文摘Six peralkylated β- cyclodec\xtrins used as capillary gas chromatographic stationary phases were prepared and characterized by differential by differential scannning calorimetry(DSC) and pyrolysis gas chromatography (PyGC). The DSC profiles illustrated that the peralkylated β-cyclodextrins synthesized possess the supercoooled state and the glass state below their melting point The PYGC results showed that the long-chain alkylated β-cyclodextrins are more thermostable than the short-chain. one All ofthese peralkylated β-cyclodextrins are suitable for use as capillary column gas chromatographic stationary phases,which can easily be coatal on the fused silica capilary columns and have nice chromatographic retention behaviour. For example, the capillary colunns coated with these materials can excellently separate three methylphenol isomers and six dimehylphenol isomers.
文摘In the current study, we prepared a ground mixture(GM) of caffeic acid(CA) with α-cyclodextrin(αCD) and with β-cyclodextrin(βCD), and then comparatively assessed the physicochemical properties and antioxidant capacities of these GMs. Phase solubility diagrams indicated that both CA/αCD and CA/βCD formed a complex at a molar ratio of 1/1. In addition, stability constants suggested that CA was more stable inside the cavity of αCD than inside the cavity of βCD. Results of powder X-ray diffraction(PXRD) indicated that the characteristic diffraction peaks of CA and CD disappeared and a halo pattern was produced by the GMs of CA/αCD and CA/βCD(molar ratios = 1/1). Dissolution testing revealed that both GMs had a higher rate of dissolution than CA alone did. Based on the1 H-1 H NOESY NMR spectra for the GM of CA/αCD, the vinylene group of the CA molecule appeared to be included from the wider to the narrower rim of the αCD ring. Based on spectra for the GM of CA/βCD, the aromatic ring of the CA molecule appeared to be included from the wider to the narrower rim of the βCD ring. This suggests that the structures of the CA inclusion complexes differed between those involving αCD rings and those involving βCD rings. Results of a DPPH radical-scavenging activity test indicated that the GM of CA/αCD had a higher antioxidant capacity than that of the GM of CA/βCD. The differences in the antioxidant capacities of the GMs of CA/αCD and CA/βCD are presumably due to differences in stability constants and structures of the inclusion complexes.
文摘The methylated β-cyclodextrins derived optically active polymers are firs synthesized through asymmetric polymerization of N-diphenylmethyl maleimide with lithium salt of heptakis(2,6-O-dimethyl) β-cyclodextrin (DM-β-CD) as an initiator. The resulting polymers show negative specific rotation which is opposite in sign to that of DM-β-CD. The asymmetric induction is further confirmed by circular dichroism. The structure is characterized by IR and NMR spectroscopies
文摘Phenothiazine and i^+s derivatives were oxidized by l_2 and 2,2,6,6-tetrametbyl-4- acetyloxypiperidine oxoammonium hexachloroantimonate to the corresponding radical cations in the cavity of β-cyclodextrins in aqueous solution.The mechanism of electron transfer between substrates and oxidants is discussed in terms of association of β-CDs.
文摘GM1-gangliosidosis is a rare lysosomal storage disorder characterized clinically by a wide range of variable neurovisceral,ophthalmological and dysmorphic features. Without enough functionalβ-galactosidase, GM1-gangliosides cannot be degraded in lysosomes, and accumulate to toxic levels in many tissues and organs, particularly in the brain. In spite of several approaches for the treatment of GM1-gangliosidosis.
文摘Cyclodextrins have gained wide attentions for their unique physicochemicai properties. In recent years, conducting polymers with special micro-structure and properties are synthesized in the presence of cyclodextrins. In this article, the application of cyclodextrins in the synthesis process of conducting polymer metarials is discussed. And authors＇ study results are summarized.
文摘Cyclodextrins are naturally oligosaccharides which had cyclic glucopyranoside units even if six units to form <em>α</em>-cyclodextrin (<em>α</em>-CD), seven units <em>β</em>-cyclodextrin (<em>β</em>-CD) or eight units <em>γ</em>-cyclodextrin (<em>γ</em>-CD) and some other derivatives. It has a truncated cone shape with a hydrophobic cavity and a hydrophilic from the external surface of cyclodextrins. Gold nanoparticles incorporated with cyclodextrins enhanced optical and electrical properties of the resulting conjugates, due to the gold nanoparticles’ unique physical and chemical properties because of their surface plasmon resonance. Here is a review of gold nanoparticles/cyclodextrin’s different applications including sensing, antimicrobial effect, and their variable medical/pharmaceutical applications. Generally, gold nanoparticles and cyclodextrin conjugates showed developed and pronounced advantages due to their biocompatibility and enhanced physical and electric properties.
基金supported by the Public Foundation of National Environmental Protection Department(No.201009047)Xi’an Science and Technology Plan Projects(No. CXY09025(3))
文摘Two highly water-soluble amino acids, which derived from β-CDs, i.e., glutamic acid-β-cyclodextrin （GluCD） and ethylene-diamine- β-cyclodextrin （EDCD）, were synthesized and were examined for their effect on solubilization of anthracene （ANT）, complexation of cadmium （Cd^2＋）, and elution removal of ANT and Cd^2＋ in soil. The results showed that GluCD and EDCD were powerful complexant for ANT and Cd^2＋. In the presence of 10 g/L GIuCD and EDCD, the solubilization of ANT increased by 47.04 and 23.85 times compared to the control, respectively. GluCD resulted in approximately 90% complexation of Cd^2＋ while 70% complexation was observed for EDCD. Simultaneously, GluCD and EDCD could greatly enhance the elution removal of ANT and Cd^2＋ from soil. GluCD resulted in the highest elution efficiency of ANT and Cd^2＋. With the addition of 10 g/L GluCD, 53.5% of ANT and 85.6% of Cd^2＋ were eluted, respectively. The ANT had a negligible effect on the Cd^2＋ removal due to different complexing sites of ANT and Cd^2＋, while Cd^2＋ enhanced the ANT removal under the addition of GluCD because Cd^2＋ neutralized the -COOH group of GIuCD. Adversely, the removal of ANT was decreased with Cd^2＋ under the addition of EDCD, this was due to the fact that Cd^2＋ enhanced the polarity of EDCD molecule and inhibited the complexation between ANT and EDCD. The study suggested that GluCD could be preferred and be successfully applied to remediation of heavy metals or organic compounds in contaminated soil.
文摘Aim To study the chromatographis beheviors of three new cinnamyl cyclodextrin derivative stationary phases. Mehtods Three new cinnamyl β-cyclodextrins, heptakis-(2, 6-di-O-cinnamyl-3-O-methyl)-β-CD, heptakis-(2, 6-di-O-cinnamyl-3-O-acetyl-)-β-CD and heptakis-2, 6-di-O-cirinamyl-3-O-trifluoroacetyl)-β-CD were synthesized and coatal on fused-silica capillary columns . Results The new stationary phases have better thermal stability, good column efficiency and excellent mpaxation power for some sutstituted benzene positional isomers. It was found that the introduction of cinnamyl groups has a significant effect on these stationary phases. Conclusion There new subetituted β-CD compounds are very suitable to be ed as gas chromatographic stationary phases.
文摘Aim To study the chromatographic behaviors of two dipentyl cyclodextrin derivative stationary phases. Methods Two new β-cyclodextrin derivatives, heptakis-[2, 6-di-O-pentyl-3-O-(4-nitrobenzyl)] -β-CD and heptakis-[2, 6-di-O-pentyl-3 -O-(5 -hexenyl)]-β-CD, were synthesized and coatal on fed-silica capillary columns. The chromatographic behaviors of the columns were characterized . Results It was found that the she, polarity, and aromatic property of the substituted group at the 3-position of heptakis-(2, 6 - di - O - pentyl) - β - cyclodextrins greatly influenced their chromatographic properties and separation ability. The introduction of aromatic group or a group containing a double-bond may bring π-π interactions between the host and vip molecules, and therefore increases the separation ability of the β-CDs for substituted benzene isomers. Conclusion The new substituted β-CD compounds are very suitable for being used as gas chromatogaphic stationary phases.
文摘The free radical polymerization of styrene in water in the presence of β-cyclodextrin (β-CD) is described. It is found that β-CD could greatly accelerate the polymerization, enhance the final conversion of monomer. The particle-size distribution of the final polymer is also improved than that without β-CD in the system.
文摘Six new kinds of amino acid derived β-cyclodextrins were synthesized to improve their water solubility and chiral separation properties. They are heptakis{2,6-di-O-[3-L-(1-isopropyl carboxyl methyl amino)-2-(hydroxy) propyl]}-β-cyclodextrin (i.e. L-Val-β-CD), heptakis{2,6-di-O-[3-L-(1-benzyl carboxyl methyl amino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Phe-β-CD), heptakis{2,6-di-O-[3-(D, L-1-benzyl carboxyl methyl amino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. D,L-Phe-β-CD), heptakis{2,6-di-O-[3-(L-1-hydroxymethyl carboxyl methyl amino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Ser-β-CD), heptakis{2,6-di-O-[3-(L-1-carboxylmethyl carboxyl methyl amino)- 2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Asp-β-CD), heptakis{2,6-di-O-[3-(L-2-carboxyl tetramethylene amino)-2-hydroxy propyl]}-β-cyclodextrin (i.e. L-Pro-β-CD). Their chemical structures were certified using FTIR and ()~1H NMR. Except for L-Phe-β-CD and D,L-Phe-β-CD, that are in soluble in water, the other amino acid derived β-CDs all have good water solubility. D,L-tyrosine and promethazine were baselinely separated by L-Val-β-CD in capillary electrophoresis.
基金The National Basic Research Program of China (No. 2002CB410800), the National Natural Science Foundation of China (No.30270767) and the National Natural Science Foundation of China for Distinguished Young Scholars Program (No. 20225721)
文摘Cyclodextrins （CDs）, with hydrophobic interior cavity and hydrophilic external surface, are capable of accelerating or inhibiting chemical degradation of organophosphorus pesticides through forming inclusion complexes between CDs and pesticides. This work evaluated the effects of CDs on hydrolysis of malathion in an attempt to assess their potential application in environmental approach. β-CD and its two derivatives, randomly methylated β-CD （RAMEB） and hydroxypropyl β-CD （HP-β-CD）, were tested. It was found that RAMEB could inhibit the hydrolysis of malathion, and this was the function of pH and temperature, the inhibitory effects increase with increasing concentration of RAMEB and elevating temperature between 15 and 35℃. On the other hand, β-CD and HP-β-CD have little or no stabilizing effects on malathion at all pH and temperature studied, except that the large concentration of β-CD and HP- β-CD can mildly reduce hydrolysis of malathion. Both 2 mol/L and 5 mol/L urea increase the inhibitory effects of RAMEB on hydrolysis of malathion at 25℃, oH 9.0.
基金the National Natural Science Foundation of China (Nos. 21572177, 21272184, 21103137 and J1210057)the Shaanxi Provincial Natural Science Fund Project (No. 2015JZ003)+2 种基金the Xi’an City Science and Technology Project (No. CXY1511(3))the Northwest University Science Foundation for Postgraduate Students (No. YZZ14052)the Chinese National Innovation Experiment Program for University Students (No. 201510697004)
文摘The inclusion behaviors of three native or modified CDs including p-CD,2-hydroxypropyl-β-CD（2-Hp-β-CD） and 2,6-dimethyl-β-CD（Me-β-CD） toward 5-amino-6-methyl-2-benzimidazolone（AMBI） were comparatively investigated by NMR and fluorescence titration in combination with IR spectra,X-ray diffractometry and scanning electron microphotographs.The experimental results jointly demonstrated that the phenyl ring of AMBI entered into the cavity of the CDs and located close to the narrow rims accompanied by the formation of the 1：1 inclusion complex with large stability constant in aqueous solution.The introduction of the hydroxypropyl unit to the host improved the solubility,ultimately effecting an obvious promoting in the fluorescence intensity and the stability constant
文摘Eight pairs of enantiomers of cyclopropane derivatives were resolved on capillary gas chromatographic columns using three new 2, 6-di-O-allyl-3-O-acylated-β-cyclodextrins as chiral stationary phases. It was found that the three β-CDs can separate some of the racemic cyclopropane derivatives well.
文摘2-acetoxy-benzencarboxylic acid is one of the most famous salicylate drugs today, a pharmaceutically active compound known as aspirin. It is poorly soluble in water which results in decreased bioavailability of the drug in the organism. The increase in water solubility of insoluble or poorly soluble drugs is therefore of great importance, which is the aim of this study. Inclusion of the drug in the molecule with a higher water solubility significantly increases its solubility and biological availability. Natural and hydrophilic derivatives of natural cyclodextrins are in the spotlight for their role as solubilizing excipients. Studies indicate that the use of β-cyclodextrin inclusion complexes with acetylsalicylic acid formed, increases the solubility of the drug in water. Many advantages of drug-complexation with cyclodextrins have been reported in scientific literature which includes increased solubility, enhanced bioavailability, improved stability, masking of bad test or odour, reduced side effect. Orally administered aspirin requires high and frequent dosing because it undergoes extensive pre systematic metabolism. Also chronic oral aspirin use is associated with serious gastrointestinal side-effects. Complexation with CD alleviates the side effects to some extent. The bioavailability and solubility of aspirin has to be increased to overcome the side-effects of aspirin related to stomach and gastro intestinal tract. The phase solubility study was performed according to the method of Higuchi and Connors by adding the 2-acetoxi-benzencarboxylic acid in excess to different concentrations of different beta cyclodextrins solutions. Phase solubility study records shown that the stability constant and complex stoichiometry of 2-acetoxi-benzencarboxylic acid-CD complexes gives linearly improve with the concentration of CD. Complexes were analyzed by UV-VIS spectroscopy and were characterized by infrared spectroscopy.
