Novel Chiral Recognition in Host−Guest Inclusion Complexes Depends on Their Molar Ratios:  Efficient Resolution of 2,2‘-Dihydroxy-1,1‘-biphenyl Derivatives and CD Spectral Study of Inclusion Complex Crystals

1997 ◽  
Vol 62 (5) ◽  
pp. 1192-1193 ◽  
Author(s):  
Koichi Tanaka ◽  
Ayao Moriyama ◽  
Fumio Toda
RSC Advances ◽  
2021 ◽  
Vol 11 (22) ◽  
pp. 13091-13096
Author(s):  
Lu Chen ◽  
Yanbin Huang

Guest polymers have significant influence on the dissolution of drug–polymer inclusion complex crystals.


2018 ◽  
Vol 69 (7) ◽  
pp. 1838-1841
Author(s):  
Hajnal Kelemen ◽  
Angella Csillag ◽  
Bela Noszal ◽  
Gabor Orgovan

Ezetimibe, the antihyperlipidemic drug of poor bioavailability was complexed with native and derivatized cyclodextrins.The complexes were characterized in terms stability, stoichiometry and structure using various 1D and 2D solution NMR spectroscopic techniques. The complexes were found to be of moderate stability (logK[3). The least stable inclusion complex is formed with b-cyclodextrin, while the ezetimibe-methylated-b--cyclodextrin has a 7-fold higher stability. The results can be useful to improve the poor water-solubility and the concomitant bioavailability of ezetimibe.


2017 ◽  
Vol 5 (2) ◽  
pp. 195
Author(s):  
Mayara Coêlho ◽  
Herlane Da Silva ◽  
Muhammad Islam ◽  
Vicente Viana ◽  
Ana Amélia Melo-Cavalcante

Nerol is an acyclic type monoterpene with important biological activities. However, the low solubility in aqueous media is a limiting factor for its user. Cyclodextrins have been widely used in order to improve the solubility, stability and bioavailability of nonpolar molecules through the formation of inclusion complexes. Thus, the present study consists in the development of nerol inclusion complex in combination with the β-cyclodextrin (β-CD) followed by characterizing by thermal analysis and spectrophotometric absorption in the infrared (FTIR). The results suggest a complexation of nerol with β-CD having detours and changed the intensity of various bands. The thermo gravimetric curve of CI found to indicate an output of solvating water molecules from the complex cavity formed for replacement of drug molecules probably included. Thus, it is concluded a possibility to obtain inclusion complexes of nerol monoterpene with β-CD, which will increase its solubility and facilitate delivery process.


2021 ◽  
pp. 27-32
Author(s):  
Olga Mikhailovna Balakhonova ◽  
Viktoriya Sergeevna Tyukova ◽  
Stanislav Anatolievich Kedik

The paper presents the results of a study of the stability of aqueous solutions of inclusion complexes of hydroxypropyl-β-cyclodextrin with diisopropylphenol in various systems by the Higuchi-Connors phase solubility method. The phase solubility profiles for each system corresponding to the AN type are determined graphically, and the stability constants of the resulting inclusion complexes are calculated. An aqueous solution containing 0.2 % Tween 80 and 0.2 % mannitol was selected as the optimal condition for obtaining the hydroxypropyl-β-cyclodextrin inclusion complex with diisopropylphenol.


Author(s):  
S. Ain ◽  
R. Singh ◽  
Q. Ain

<p><strong>Objective: </strong>The aim of the present study was to carry out characterization and intrinsic dissolution rate study of microwave assisted inclusion complex of poorly water soluble, lipid lowering agent gemfibrozil [5-(2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid]<strong> </strong>with naturally occurring β-cyclodextrins (CDs) or cycloheptaamylase.</p><p><strong>Methods: </strong>In this work, the phase solubility study was performed to find the ratio of drug and cyclodextrin complexes. Inclusion complexes were prepared by kneading and the prepared complex was subjected to microwave drying and conventional drying techniques. The prepared complexes were evaluated by intrinsic dissolution rate studies and equilibrium solubility study. Further characterization was done by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and X-ray powder diffractometry (DSC).</p><p><strong>Results: </strong>The phase solubility studies showed a linear A<sub>L</sub>-type diagram indicating the formation of inclusion complexes in 1:1 molar ratio β-CD-gemfibrozil complex with maximum stability constant of 148.88 M<sup>-1</sup>was selected for preparation of inclusion complex. The microwave dried product was identified as the inclusion complex with maximum IDR when compared to the conventional dried product.</p><p><strong>Conclusion: </strong>This study was concluded that the microwave drying is the most suitable of the previously occurring drying techniques. Since it showed the highest solubility and IDR value.</p>


Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4487 ◽  
Author(s):  
Wenhui Li ◽  
Lidan Ran ◽  
Fei Liu ◽  
Ran Hou ◽  
Wei Zhao ◽  
...  

Grape seed extract (GSE) displays strong antioxidant activity, but its instability creates barriers to its applications. Herein, three HP-β-CD/GSE inclusion complexes with host–guest ratios of 1:0.5, 1:1, and 1:2 were successfully prepared by co-precipitation method to improve stability. Successful embedding of GSE in the HP-β-CD cavity was confirmed by fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) analyses. The Autodock Tools 1.5.6 was used to simulate the three-dimensional supramolecular structure of the inclusion complex of 2-hydroxypropyl-β-cyclodextrin and grape seed extract (HP-β-CD/GSE) by molecular docking. The MALDI-TOF-MS technology and chemical database Pubchem, and structural database PDB were combined to reconstitute the three-dimensional structure of target protein. The binding mode of the HP-β-CD/GSE inclusion complex to target protein was studied at the molecular level, and the antioxidant ability of the resulting HP-β-CD/GSE inclusion complexes was investigated by measuring 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging. The effects of HP-β-CD/GSE on myofibrillar protein from lamb tripe were also investigated under oxidative conditions. The positions and interactions of the binding sites of HP-β-CD/GSE inclusion complexes and target protein receptors were simulated by molecular docking. The results showed that HP-β-CD/GSE inclusion complexes were successfully prepared, optimally at a molar ratio of 1:2. At low (5 μmol/g) to medium (105 μmol/g) concentrations, HP-β-CD/GSE inclusion complexes decreased the carbonyl content, hydrophobicity, and protein aggregation of myofibrillar protein from lamb tripe, and increased the sulphydryl content. Furthermore, high concentration (155 μmol/g) of HP-β-CD/GSE inclusion complexes promoted protein oxidation.


1989 ◽  
Vol 67 (10) ◽  
pp. 1550-1553 ◽  
Author(s):  
Ramamurthy Palepu ◽  
Vincent C. Reinsborough

Pre-micellar and micellar sodium perfluorooctanoate solutions (SPFO) were examined conductometrically with added α-cyclodextrin(α-CD), β-cyclodextrin (β-CD), and γ-cyclodextrin (γ-CD). The order of stability of the 1:1 inclusion complex was (β-CD > γ-CD > α-CD determined largely by the goodness of fit of the fluorocarbon chain in the CD cavity. Sodium ion electrode studies revealed that some Na+ ion is associated with the (β-CD/SPFO complex. As shown by fluorine-19 nmr, (β-CD girds the SPFO molecule snugly amidship with the terminal CF3 group still in solution. On the other hand, SPFO manages only a weak penetration of the fluorocarbon chain into the smaller α-CD cavity. Keywords: perflurooctanoate, cyclodextrin complexes, fluorocarbon surfactant, 19F nmr.


2014 ◽  
Vol 70 (a1) ◽  
pp. C992-C992 ◽  
Author(s):  
Mino Caira ◽  
Susan Bourne ◽  
Buntubonke Mzondo

Owing to its potent antioxidant activity,α-lipoic acid (1,2-dithiolane-3-pentanoic acid) is widely used as a supplement and is recommended for treating a number of conditions including chronic liver disease and diabetes. The poor aqueous solubility of the acid (~0.003 M at 250C) has prompted studies of its interaction with cyclodextrins (CDs) as a possible route to improving its solubility. However, relatively few studies have focused on the isolation of solid CD inclusion complexes of the antioxidant, and in most cases the racemic form of the acid was employed. In the comprehensive study reported here, the bioactive (R)-(+)-enantiomeric form of the molecule was used exclusively, resulting in the isolation and structural characterization of its inclusion complexes with each of the native host CDs (α-, β- and γ-CD) as well as permethylated α-CD (TRIMEA), permethylated β-CD (TRIMEB) and 2,6-dimethylated-β-CD (DIMEB). The α-CD complex crystallizes in the trigonal system, space group R32, with three independent CD molecules in the asymmetric unit and is not isostructural with any known CD complex while the β-CD complex crystallizes in the monoclinic system (C2). With the host γ-CD, an orthorhombic (pseudo-tetragonal) inclusion complex was identified, an unusual result as γ-CD complexes generally crystallize in the tetragonal space group P4212. The complexes with TRIMEA and TRIMEB crystallize in the orthorhombic system (P212121), the modes of inclusion of the (R)-(+)-α-lipoic acid molecule in the respective hosts being reversed: the guest molecule is fully encapsulated by the former host with the dithiolane ring located at the secondary rim, while in the latter host, the dithiolane ring rests on the concave surface of the host cavity at the primary side. A significant level of guest disorder was detected in the inclusion complex with DIMEB (P21). Thermal and phase-solubility analyses complemented the X-ray structural studies.


Sign in / Sign up

Export Citation Format

Share Document