scholarly journals Cyclodextrin inclusion complexes of the antioxidant α-lipoic acid

2014 ◽  
Vol 70 (a1) ◽  
pp. C992-C992 ◽  
Author(s):  
Mino Caira ◽  
Susan Bourne ◽  
Buntubonke Mzondo
Keyword(s):  
Inclusion Complex ◽  
Inclusion Complexes ◽  
Lipoic Acid ◽  
Aqueous Solubility ◽  
Phase Solubility ◽  
Monoclinic System ◽  
Space Group ◽  
Racemic Form ◽  
Native Host

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.

scholarly journals Physicochemical Profiling of Baicalin Along with the Development and Characterization of Cyclodextrin Inclusion Complexes

2019 ◽  
Vol 20 (8) ◽  
Author(s):  
Géza Jakab ◽  
Dóra Bogdán ◽  
Károly Mazák ◽  
Ruth Deme ◽  
Zoltán Mucsi ◽  
...  
Keyword(s):  
Inclusion Complexes ◽  
Structural Information ◽  
Aqueous Solubility ◽  
Distribution Coefficients ◽  
Scientific Data ◽  
Phase Solubility ◽  
Traditional Chinese Herbal Medicine ◽  
Form Design ◽  
C Nmr

Abstract Baicalin is a flavone glycoside extracted from Scutellaria baicalensis, a traditional Chinese herbal medicine. Numerous pharmacological effects of baicalin were reported (e.g. antioxidant, anxiolytic); nevertheless, the most important physicochemical properties influencing the pharmacokinetic behaviour and the concomitant oral bioavailability have not yet been described in a comprehensive study. The aim of this project was to characterize the acid-base, lipophilicity, biorelevant solubility and permeability properties of the drug substance and providing scientific data to support the dosage form design. Another important objective was the comparative evaluation of six various baicalin-cyclodextrin (CD) inclusion complexes along with the creation of a suitable Drug Delivery System (DDS) for this BCS IV drug. Biorelevant profiling was carried out by NMR-pH titrations, saturation shake-flask and distribution coefficients (logP) measurements, while CD inclusion studies were fulfilled by experimental methods (phase solubility, 1H/13C NMR, 2D ROESY) and computational approaches. Due to low aqueous solubility (67.03 ± 1.60 μg/ml) and low permeability (Papp = 0.037 × 10−6 cm/s), baicalin is classified as BCS IV. The γ-CD complexation significantly increased the solubility of baicalin (~ 5 times). The most promoted chemical shift change occurred in baicalin-γ-CD complex. Computational studies showed disparate binding pattern for baicalin in case of β- and γ-CD; furthermore, the calculated complexation energy was − 162.4 kJ mol−1 for β-CD, while it was significantly stronger for γ-CD (− 181.5 kJ mol−1). The physicochemical and structural information of baicalin and its CD complexes introduced herein can create molecular basis for a promising DDS with enhanced bioavailability containing a bioactive phytopharmacon.

scholarly journals Preparation and in vitro Evaluation of Inclusion Complexes of Nelfinavir with Chemically Modified ?-cyclodextrins

2013 ◽  
Vol 11 (2) ◽  
pp. 107-116 ◽  
Author(s):  
Shivanand Hiremath ◽  
Ganesh Godge
Keyword(s):  
Inclusion Complex ◽  
Inclusion Complexes ◽  
Solubility Diagram ◽  
Aqueous Solubility ◽  
Water Soluble ◽  
Phase Solubility ◽  
Ir Study ◽  
Order Complexes ◽  
Phase Solubility Diagram

Nelfinavir is a poorly water-soluble antiretroviral drug with relatively low bioavailability. In the present study, the practically insoluble drug, nelfinavir (NFV) and its inclusion complexes with hydroxypropyl-?-cyclodextrin (HP-?-CD) were investigated to improve the aqueous solubility and the dissolution rate of the drug, thus enhancing its bioavailability. The phase solubility diagram with HP-?-CD was classified as AL-type at all temperatures investigated, indicating the formation of higher order complexes. The apparent complexation constants (K1:1) calculated from phase solubility diagram were 145.49, 188.45 and 255.54 M-1 at 25, 37 and 45 ± 0.5°C, respectively. Aqueous solubility and dissolution studies indicated that the dissolution rates were remarkably increased; this could be mainly attributed to the improved solubility and dissolution associated with inclusion complex between drug and HP- ? -CD. Absence of endothermic and characteristic diffraction peaks corresponding to NFV was observed for the inclusion complex in DSC and PXRD. FT-IR study indicated that the presence of intermolecular hydrogen bonds between NFV and HP-?-CD in inclusion complex, resulting in the formation of amorphous form. DOI: http://dx.doi.org/10.3329/dujps.v11i2.14558 Dhaka Univ. J. Pharm. Sci. 11(2): 107-116, 2012 (December)

Studies on the Preparation, Characterization and Solubility of -Cyclodextrin-Roxythromycin Inclusion Complexes

2009 ◽  
Vol 2 (2) ◽  
pp. 523-530
Author(s):  
D. Nagasamy Venkatesh ◽  
S. Karthick ◽  
M. Umesh ◽  
G. Vivek ◽  
R.M. Valliappan ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Inclusion Complexes ◽  
Phase Solubility ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ir Studies ◽  
Poorly Soluble ◽  
Poorly Soluble Drug

Roxythromycin/ β-cyclodextrin (Roxy/ β-CD) dispersions were prepared with a view to study the influence of β-CD on the solubility and dissolution rate of this poorly soluble drug. Phase-solubility profile indicated that the solubility of roxythromycin was significantly increased in the presence of β-cyclodextrin and was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. Physical characterization of the prepared systems was carried out by differential scanning calorimetry (DSC), X-ray diffraction studies (XRD) and IR studies. Solid state characterization of the drug β-CD binary system using XRD, FTIR and DSC revealed distinct loss of drug crystallinity in the formulation, ostensibly accounting for enhancement of dissolution rate.

Evaluation of the phase solubility of inclusion complexes of diisopropylphenol (INN) with hydroxypropyl-β-cyclodextrin

2021 ◽  
pp. 27-32
Author(s):  
Olga Mikhailovna Balakhonova ◽  
Viktoriya Sergeevna Tyukova ◽  
Stanislav Anatolievich Kedik
Keyword(s):  
Aqueous Solution ◽  
Inclusion Complex ◽  
Inclusion Complexes ◽  
Tween 80 ◽  
Phase Solubility ◽  
Cyclodextrin Inclusion ◽  
Solubility Method ◽  
Cyclodextrin Inclusion Complex ◽  
The Stability ◽  
Solubility Profiles

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.

scholarly journals CHARACTERIZATION AND INTRINSIC DISSOLUTION RATE STUDY OF MICROWAVE ASSISTED CYCLODEXTRIN INCLUSION COMPLEXES OF GEMFIBROZIL

2016 ◽  
Vol 8 (10) ◽  
pp. 160
Author(s):  
S. Ain ◽  
R. Singh ◽  
Q. Ain
Keyword(s):  
Inclusion Complex ◽  
Dissolution Rate ◽  
Inclusion Complexes ◽  
Microwave Drying ◽  
Phase Solubility ◽  
Intrinsic Dissolution ◽  
Intrinsic Dissolution Rate ◽  
Solubility Study ◽  
Microwave Assisted ◽  
Rate Study

<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>

scholarly journals Inter-molecular physiochemical characterization for etodolac-hydroxypropyl-β-cyclodextrin polymeric systems in solid and liquid state

2010 ◽  
Vol 8 (4) ◽  
pp. 953-962 ◽  
Author(s):  
Vivek Sinha ◽  
Renu Chadha ◽  
Honey Goel ◽  
Keyword(s):  
Solid State ◽  
Inclusion Complexes ◽  
Liquid State ◽  
Chemical Properties ◽  
Aqueous Solubility ◽  
Phase Solubility ◽  
Scanning Calorimetry ◽  
Polymeric Systems ◽  
Hydrophobic Molecule ◽  
Physical And Chemical

AbstractThe purpose of this study was to explore the utility of hydroxypropyl-β-cyclodextrin (HP-β-CD) systems in forming inclusion complexes with the anti-rheumatic or anti-arthritic drug, etodolac (EDC), in order to overcome the limitation of its poor aqueous solubility. This inclusion system achieved high solubility for the hydrophobic molecule. The physical and chemical properties of each inclusion compound were investigated. Complexes of EDC with HP-β-CD were obtained using the kneading and co-evaporation techniques. Solid state characterization of the products was carried out using Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), powder X-ray diffraction (XRD) and Scanning electron microscopy (SEM). Studies in the solution state were performed using UV-Vis spectrophotometry and 1H-NMR spectroscopy. Phase solubility profiles with HP-β-CD employed was found to be AL type. Stability constants (Kc) from the phase solubility diagrams were calculated indicating the formation of 1:1 inclusion complex. Stability studies in the solid state and in liquid state were performed; the possible degradation by RP-HPLC was monitored. The dissolution studies revealed that EDC dissolution rate was improved by the formation of inclusion complexes.

Synthesis and Characterization of a Dumbbell-Shaped Polyrotaxane Based on Polytetrahydrofuran bis(3-aminopropyl) Terminated and α-Cyclodextrins Using Polyamidoamine (PAMAM) Dentrimers as Bulky Stoppers

2015 ◽  
Vol 1094 ◽  
pp. 41-48
Author(s):  
Ri Min Cong ◽  
Huai Qing Yu ◽  
Yan Gong Yang ◽  
Si Yi Yang ◽  
Jiao Li ◽  
...  
Keyword(s):  
Thermogravimetric Analysis ◽  
Inclusion Complex ◽  
Inclusion Complexes ◽  
Synthesis And Characterization ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Channel Type

A dumbbell-shaped polyrotaxane based on polytetrahydrofuran bis (3-aminopropyl) terminated and α-cyclodextrins using polyamidoamine (PAMAM) dentrimers as bulky stoppers was successfully prepared. The1H NMR results show that the peaks of α-CDs in these polyrotaxanes are broadened compared with pure α-CDs. Wide-angle X-ray diffraction (XRD) measurements of the resulting polyrotaxanes suggest to produce a channel-type crystalline structure of inclusion complex. Thermogravimetric analysis (TGA) of the resultant polyrotaxanes show that α-CDs are significantly stabilized by the formation of the inclusion complexes.

scholarly journals Development of Starch-Based Antifungal Coatings by Incorporation of Natamycin/Methyl-β-Cyclodextrin Inclusion Complex for Postharvest Treatments on Cherry Tomato against Botrytis cinerea

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3962 ◽  
Author(s):  
Yuexi Yang ◽  
Chen Huan ◽  
Xianrui Liang ◽  
Sheng Fang ◽  
Jian Wang ◽  
...  
Keyword(s):  
Inclusion Complex ◽  
Botrytis Cinerea ◽  
Corn Starch ◽  
Tomato Fruit ◽  
Aqueous Solubility ◽  
Phase Solubility ◽  
Waxy Corn Starch ◽  
Reduce Weight Loss ◽  
Postharvest Treatments

The application of natamycin as a natural fungicide in edible coatings is challenging because of its low aqueous solubility. In this study, the natamycin/methyl-β-cyclodextrin (N/ME-β-CD) inclusion complex was fabricated and incorporated into waxy corn starch-based coatings for postharvest treatments. The phase solubility of natamycin in the presence of ME-β-CD at 293.2 K, 303.2 K, and 313.2 K is determined and used to calculate the process thermodynamic parameters. The N/ME-β-CD inclusion complex was confirmed and characterized by FTIR and 1H NMR spectroscopy. The results indicated that the inclusion complex was formed and the hydrophobic part (C16-C26) of natamycin might be partially inserted into the cavity of ME-β-CD form the wide rim. The effects of N/ME-β-CD incorporated starch-based coatings (N/ME-β-CD S coatings) on postharvest treatments of cherry tomatoes were evaluated in vivo. The N/ME-β-CD S coatings could reduce weight loss, delay fruit ripening, and inhibit fruit decay caused by Botrytis cinerea in tomato fruit during storage.

Synthesis and X-ray characterization of Li(1−2x)NixTiO(PO4) (0≤x≤0.50)

2003 ◽  
Vol 18 (4) ◽  
pp. 301-305 ◽  
Author(s):  
B. Manoun ◽  
A. El Jazouli ◽  
P. Gravereau ◽  
J. P. Chaminade
Keyword(s):  
Dilute Solutions ◽  
Final Temperature ◽  
Monoclinic System ◽  
Orthorhombic System ◽  
Space Group ◽  
X Ray

Li(1−2x)NixTiO(PO4) oxyphosphate powders were prepared from dilute solutions of NiCl2⋅6H2O, Li2CO3, (NH4)2HPO4, and TiCl4 in ethanol. The final temperature was 850 °C. Li(1−2x)NixTiO(PO4) oxyphosphates with 0≤x≤0.10 crystallize in the orthorhombic system with space group Pnma, while those with 0.10<x≤0.25 crystallize in the monoclinic system with space group P21/c.

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