Structural Study of Inclusion Complex of Andrographolide with β-Cyclodextrin Prepared under Microwave Irradiation

Andrographolide (Andro) (Figure 1) is a diterpene lactone isolated from Andrographis paniculate Nees1. It has showed several biological activities including analgesic, antipyretic and anti-inflammatory effects2. However, its poor water solubility and unstability towards oxygen restrained its application. In pharmaceutics, b-CD is used to increase solubility and stability3. We have prepared the inclusion compound of Andro/b-CD (Figure 2) under microwave irradiation4. It has been found…     

Inclusion Complexation of β-CD with Phenothiazine and N-Alkylphenothiazine Derivatives

Phenothiazinederivatives(PTZ)havebeenstudiedfOrdecadesbecauseoftheirwideapplicationsintranquilizingdrugs,dyestuffsandsolarenergyconversionmaterialsI.Recently,westudiedtheelectrontransferreactionsofNsubstilutedphenothiazinewithelectronacceptorsinAcyclodextrin(ffCD)aqueous,olution2'3.TheelectrontransferprocesswassignificantlyinfluencedbythepresenceofffCD.IthasbeennotedthatthePTZwereincludedbyACDtoforminclusioncomplexes.Inthisletter,wereportthestudyofinclusioncomplexationofffCDwithphenoth…     

Study on the Structure of Supramolecular Inclusion Complex of β-Cyclodextrin with Retinoic Acid

The importance of Vitamin A for human health has been stressed in resent studies1, meanwhile its derivative so-called retinoic acid (RA) has been widely used as pharmaceutical to treat several types of skin disease and cancer2,3. However the application of retinoic acid is restrained for its poor water solubility, unstability and side effect on the human body.Cyclodextrins (CDs) are macrocyclic oligosaccharides built up from 6, 7, or 8 glucopyranose units called (, (, and (-CD, respectively…     

Study of the Podophyllotoxin β-Cyclodextrin Inclusion Complex

The structure of the podophyllotoxin (P)/-cyclodextrin(-CD) inclusion complexhas been studied by infrared spectroscopy, UVspectroscopy, NMR spectroscopy and X-raydiffractometry. The association constant is 128 M^-1in water, calculated from thestraight portion of the phase-solubility diagram.     

Study on the Synthesis and Characterization of Novel Immobilized β-Cyclodextrin Polymer (Ⅰ)

A series of novel β-cyclodextrin polymers was synthesized by immobilization of β-cyclodextrin on the chloromethylated crosslinked polystyrene carriers. The synthetic conditions such as reaction time, temperature, molar feeding ratio of reactants, the degree of crosslinking of polystyrene and the catalysts used were studied in detail and the chemical and physical structures of the formed β-CDpolymers were characterized. Results show that the preparation method is simple and the amount of β-CD immobilized is high. As biomedical adsorbents, they were tested for removal of various endogenous and exogenous toxins such as phenols, aromatic amins, barbitals and unconjugated bilirubin. Results indicate that the adsorptión capacity for those toxins can be enhanced by the inclusion interaction among the β-CD, the substrate molecules and the β-CD polymers.     

NMR Study of the Inclusion Complexes of Carboxy-Phenoxathiin Derivatives with β-Cyclodextrin

The inclusion complexes of the carboxylate forms of 3-carboxy-(I) and 2-carboxy-phenoxathiin (II) with -cyclodextrin were studied by bothone- and two-dimensional NMR spectroscopy. The analysis of the induced chemical shifts of theguests in the presence of different amounts of the host indicates the formation of complexes with 1:1stoichiometry and association averaged pK values of 3.75 (I) and 4.4 (II). Thequalitative analysis of cross peaks in the ROESY spectra support the inclusion of the guests in the cavitywith the substituted phenyl ring, the COO^- group being in the proximity of the primary rim.     

Detection and Characterization of Non-covalent Complex between Lappaconitine and β-Cyclodextrin by Electrospray ionization Tandem Mass Spectrometry

Lappaconitine(LA), exhibits antiarrhythm1 and analgesic actions2-5, and has been used to release pain for cancer patients. However, its application is limited due to poor water solubility. But its non-covalent complexes with CDs can solve this problem, th…     

Theoretical Study on the Inclusion Complex of β-Cyclodextrin and Nitrobenzene

Quantum chemical calculations were carried out to investigate the structures and properties for the inclusion complexes of nitrobenzene (NB) into β-cyclodextrin. Two low-energy conformations of β-cyclodextrin (A and B) in the gas phase were initially investigated by the PM3 and B3LYP/6-31+G(d,p) calculations, respectively. Three different orientations were considered in the inclusion process of A and B with NB to form 1:1 complexes. Potential energy scan by PM3 calculations indicated that the phenyl orientation Ab for conformation A and the equator orientation Bc for conformation B are more favorable in energy, respectively. We also considered the 2:1 inclusion complexes of host A or B with guest NB in the gas phase. PM3 calculation indicated that the host-guest interaction energies to form 1:1 complexes are more negative than those to form 2:1 NB/B complexes. Finally, we studied the solvent effect of NB/CD complex, and PM3 results show that the influence of water molecules on the inclusion process is very important. The driving forces for the inclusion process and the geometries of complexes were discussed in detail.     

DSC and NMR Study on the Inclusion Complex of Lappaconitine with β—Cyclodextrin

The inclusion complex of lappaconitine(Lap) with β-cyclodextrin (β-CD) has been studied by the differential scanning calorimetry (DSC) and ^1H-NMR,2D-NMR spectroscopy. The structure of the complex has been deduced.     

Study of the Supramolecular Inclusion of β-Cyclodextrin with Andrographolide

An inclusion complex of -cyclodextrin with andrographolide (Andro) was prepared by using a convenient new method of microwave irradiation. The structure of the inclusion complex was determined by UV and IR analyses as well as ¹H NMR, ¹³C NMR and two dimensional NOE spectroscopic measurements. The results indicated that the possible stoichiometry of complex formation is 1:1 (guest:host ratio) and the two isomeric 1:1 inclusion complexes are present simultaneously in solution. Thermal studies proved the thermal stability of the inclusion complex.     

Stability of Ibuprofen in its Inclusion Complex with β-Cyclodextrin

The ibuprofen--cyclodextrin inclusion complex was prepared by theco-precipitation method. The identity of the obtained product was verified by X-ray and thermogravimetric techniques. The effect of -cyclodextrin on the stability of ibuprofen was analysed.     

Study on the Supramolecular Inclusion Complex of β-Cyclodextrin/Lappaconitine

Lappaconitine (Lap) is a diterpenoid akaliamide, naturally occurring in roots and rhizomes of Aconitum and delphinium. Lap reveals bradycardic, hypotensive, antinocieptive activity. However, its application is restrained owing to its poor water solubility, toxicity and side effects on humans. In a number of pharmaceutical studies,CDs have been reported to interact with many drug molecules to form inclusion complexes. These inclusion complexes have been extensively used to improve water solubility of poorly soluble drugs, to reduce their toxicity, and to increase the dissolution rate [1]. In the present work, the β-CD/Lap complex was prepared by kneading method. The products have been characterized by the solubility measurement as well as UV, FTIR, NMR spectroscopy and X-ray powder diffractometry.     

DSC and NMR Study on the Inclusion Complex of Lappaconitine with b-Cyclodextrin

Lappaconitine (Figure 1) is a diterpenoid alkaloid, naturally occurring in roots and rhizomes of Aconitum and delphinium1. Lap reveals bradycardic and hypotensive activity2. But its application is restrained owing to its poor water solubility, toxicity and side effects on humans. In a number of pharmaceutical studies, b-CD has been reported to interact with many drug molecules to form inclusion complexes for improving the water solubility of drugs, and reducing their toxicity3. We have p…     

Synthesis of a Novel Aromatic Diamino-bridged Bis（β-cyclodextrin） and its Inclusion Complexation with Dyes Molecules

Bridged bis(β-cyclodextrin)s (CDs), as a very important family of CD derivatives, have been known that they can significantly alter the molecular binding ability and selectivity toward a variety of guests in comparison with parent cyclodextrin. Their two…     

The Inclusion Complex of Ferrocene with a Dithiolene Functionalized β-Cyclodextrin

A new cyclodextrin derivative with the anion side-arm, mono[6-deoxy-6-(2-sodium thio-1,2-dicyane ethylenylthio)]-cyclodextrin (6-mnt-CD), and its inclusion complex with ferrocene (6-mnt-CD/Fc), have been prepared and characterized by elemental analysis, IR spectroscopy, UV spectroscopy, mass spectrometry, ¹³C-NMR spectroscopy, thermogravimetry, and cyclic voltammetry (CV). Thermogravimetry analysis of the compound shows that the thermal stabilities of both the host and the guest in the inclusion complex have been greatly improved due to an additional interaction between the side-arm of the host and the guest. The interplay between the guest and the host with side-arm in the complex resulted in smaller positive potential shifts in CV compared to that in the inclusion complex CD/Fc.     

Inclusion Behavior of Dimer β-CyclodextrinBridged with Aspartic Acid Derivative

The capped cyclodextrins (CDs) are very useful macromolecular hosts in supramolecular chemistry. Previously, we demonstrated that the dimer cyclodextrin bridged with 1,2-diaminoethane causes significant enhancement of affinity to a small organic guest molecule1. A variety of interesting peptides have been developed as artificial enzymes. Here our designed peptide, Adm-Trp-Arg-Arg-NH2, named ATA was synthesized by the usual solid-phase Fmoc strategy2 with trityl resin in Shimadzu-PSSM8 p…     

Synthesis and Structure of Dimeric β-Diketiminato Co(Ⅱ) Chloride Complex

Introduction Recently, late-transition-metal complexes have been extensively used as both inorganic and organometallic catalysts[1]. Some complexes have been developed as the novel olefin polymerization catalysts[2-4] and copolymerization catalysts for ethylene and polar comonomers[5] due to their lower oxophilicity and presumed greater functional tolerance. Moreover, compounds with imine ligands have received more attention and have been reported for the synthesis method, structure, mechanism and application[6-9]. In this contribution, we report the synthesis of the dimericβ-diketiminato Co(Ⅱ)chloride complex:     

Solubility Study of Nimodipine Inclusion Complexation with α- and β-Cyclodextrin and some Substituted Cyclodextrins

The solubility of nimodipine was measured in aqueous solutions of the following cyclodextrins: -cyclodextrin (-CD), hydroxypropyl--CD (HP--CD), -cyclodextrin (-CD), random substituted methyl--CD (M--CD), three hydroxypropyl--CDs (HP--CD) with mutually different average degree of substitution, and hydroxypropyl--cyclodextrin (HP--CD). From the determined linear solubility diagrams the values of the binding constant K₁₁ of the inclusion complexes of nimodipine with the respective CDs were evaluated. The -CDs efficiently solubilized sparingly soluble nimodipine, the highest value of K₁₁ was found for M--CD (1680 M^-1), followed by -CD (550 M^-1) and HP--CDs, where the higher degree of substitution lowered K₁₁. Only slight solubilization of nimodipine was observed in the solutions of the -CDs and HP--CD.     

A Spectrophotometric Study on the Host-Guest Complexation of β-Cyclodextrin with 3-Indolyl Acetate in Dilute Aqueous Solution by Determining Solubility of Guest Substance

Interestincyclodextrinshasincreasedsteadily,becausetheirinclusioncompoundshaveprovedmoreandmoreusefulinbothresearcllandindustry'.Furthermore,theyareofgreatilllportanceforsupramolecularchemistry,sincetheyaremembersofahomologousseriesofW'ater-solubleandchiralhostmoleculeswhichcanbeusedasmodelsforstudyingweakinteractionsl-'.Ontheotherhand.indolylgroupexistsinsomeimportantbiogentcsubstancessuchastryptophan.Soinvestigationontheinteractionsbetweenindolylderivativesandsuchbiologicmodelsubstancesascyc…     

Study of the Inclusion Complexes of β-Cyclodextrin with the Sodium Salt of Trisulfonated Triphenylphosphine

The formation of inclusion complexesbetween the sodium salt of trisulfonatedtriphenylphosphine and -cyclodextrin has beeninvestigated at two temperatures by high field nuclearmagnetic resonance, electrospray mass and UV-visspectroscopies. At 268 K, titration experiments andJob's method suggest that the major species insolution is a 1 : 1 inclusion complex. The moleculargeometry of this inclusion complex was studied usingthe ROESY NMR technique complemented by molecularmodelling. All these methods converged towards thestructure attained by inserting one aromatic ring intothe hydrophobic cavity of the host from the side ofthe secondary hydroxyls. At 298 K, a higher proportionof 2 : 1 and 3 : 1 complexes induces strong alterations ofthe NMR signals, preventing an easy and reliabledetermination of association constants. Nevertheless,an apparent association constant can be determinedfrom UV-vis data by assuming a 1 : 1 equilibrium. Thegeometry of the 2 : 1 and 3 : 1 complexes is also brieflydiscussed from ROESY NMR experiments.