scholarly journals Inclusion of trans-resveratrol in methylated cyclodextrins: synthesis and solid-state structures

2014 ◽  
Vol 10 ◽  
pp. 3136-3151 ◽  
Author(s):  
Lee Trollope ◽  
Dyanne L Cruickshank ◽  
Terence Noonan ◽  
Susan A Bourne ◽  
Milena Sorrenti ◽  
...  
Keyword(s):  
Solid State ◽  
Inclusion Complexes ◽  
Crystal Packing ◽  
Aqueous Solubility ◽  
Solubility Limit ◽  
Phase Solubility ◽  
Crystalline Inclusion ◽  
Scanning Calorimetry ◽  
Full Structure ◽  
Methylated Cyclodextrins

The phytoalexin trans-resveratrol, 5-[(1E)-2-(4-hydroxyphenyl)ethenyl]-1,3-benzenediol, is a well-known, potent antioxidant having a variety of possible biomedical applications. However, its adverse physicochemical properties (low stability, poor aqueous solubility) limit such applications and its inclusion in cyclodextrins (CDs) has potential for addressing these shortcomings. Here, various methods of the attempted synthesis of inclusion complexes between trans-resveratrol and three methylated cyclodextrins (permethylated α-CD, permethylated β-CD and 2,6-dimethylated β-CD) are described. Isolation of the corresponding crystalline 1:1 inclusion compounds enabled their full structure determination by X-ray analysis for the first time, revealing a variety of guest inclusion modes and unique supramolecular crystal packing motifs. The three crystalline inclusion complexes were also fully characterized by thermal analysis (hot stage microscopy, thermogravimetric analysis and differential scanning calorimetry). To complement the solid-state data, phase-solubility studies were conducted using a series of CDs (native and variously derivatised) to establish their effect on the aqueous solubility of trans-resveratrol and to estimate association constants for complex formation.

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.

scholarly journals Native Cyclodextrins as Complexation Agents for Pterostilbene: Complex Preparation and Characterization in Solution and in the Solid State

Pharmaceutics ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 8
Author(s):  
Laura Catenacci ◽  
Alexios I. Vicatos ◽  
Milena Sorrenti ◽  
Maria Cristina Bonferoni ◽  
Mino R. Caira
Keyword(s):  
Solid State ◽  
Complex Formation ◽  
Aqueous Solubility ◽  
Molar Ratio ◽  
Phase Solubility ◽  
Scanning Calorimetry ◽  
Complex Preparation ◽  
Ft Ir ◽  
Sugar Levels ◽  
Co Precipitation

Pterostilbene (3,5-dimethoxy-4′-hydroxystilbene, PTB) is a natural dietary stilbene, occurring primarily in blueberries and Pterocarpus marsupium heartwood. The interest in this compound is related to its different biological and pharmacological properties, such as its antioxidant, anti-inflammatory, and anticarcinogenic activities and its capacity to reduce and regulate cholesterol and blood sugar levels. Nevertheless, its use in therapy is hindered by its low aqueous solubility; to overcome this limitation we studied the feasibility of the use of cyclodextrins (CDs) as solubility-enhancing agents. CDs are natural macrocyclic oligomers composed of α-d-glucose units linked by α-1,4 glycosidic bonds to form torus-shaped molecules, responsible for inclusion complex formation with organic molecules. In particular, the aim of this study was to evaluate the feasibility of complexation between PTB and native CDs using various preparative methods. The isolated solid products were characterized using differential scanning calorimetry (DSC), simultaneous thermogravimetric/DSC analysis (TGA/DSC), Fourier transform infrared (FT-IR) spectroscopy, and X-ray diffraction (XRD) on powder and single crystals. The results indicated little or no evidence of the affinity of PTB to complex with α-CD using the kneading method. However, with β-CD and γ-CD thermal analysis revealed an interaction which was also corroborated by FT-IR and 1H-NMR spectroscopy. With β-CD, a hydrated complex of PTB was isolated and its characterization by single-crystal XRD revealed, for the first time, the mode of inclusion of the PTB molecule in the cavity of a CD. To complement the solid-state data, liquid-phase studies were carried out to establish the effect of CDs on the aqueous solubility of PTB and to determine the complex stoichiometries and the association constants for complex formation. Phase-solubility studies showed AL-type profiles for α- and β-CD and a BS profile for γ-CD, with K1:1 values of 1144, 4950, and 133 M−1 for α-CD·PTB, β-CD·PTB, and γ-CD·PTB, respectively. The stoichiometry of CD·PTB complexes, determined by Job’s method, revealed for each system a 1:1 molar ratio. The dissolution rate of PTB was approximately doubled just by employing simple physical mixtures, but the best performance was achieved by products obtained via kneading and co-precipitation, which effected the complete dissolution of PTB in 40 and 20 min for β-CD and γ-CD, respectively.

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.

DISSOLUTION ENHANCEMENT OF ATOVAQUONE USING CYCLODEXTRINS AND FORMULATING TO ORODISPERSIBLE TABLETS

INDIAN DRUGS ◽  
2016 ◽  
Vol 53 (06) ◽  
pp. 32-39
Author(s):  
A. K Mahapatra ◽  
◽  
P. N. Murthy
Keyword(s):  
Inclusion Complexes ◽  
Dissolution Enhancement ◽  
Phase Solubility ◽  
Scanning Calorimetry ◽  
Compression Technique ◽  
Sodium Starch Glycolate ◽  
Orodispersible Tablets ◽  
Kneading Method ◽  
Gibb’S Free Energy ◽  
Better Than

The aim of the study was to enhance the dissolution rate of atovaquone by preparing inclusion complexes with cyclodextrins (β-CD/ HP β-CD) and formulating their orodispersible tablets. Phase solubility studies were conducted by adding 0.5, 1, 2 and 4% of cyclodextrins in water. The values of Gibb’s free energy were found increased. Inclusion complexes of atovaquone were prepared using β -CD/ HP β -CD by kneading method. Tablets were formulated using superdisintegrants i.e., sodium starch glycolate, crospovidone and Ac-Di sol at concentrations of 4, 8 and 12% of tablet weight by direct compression technique. The interaction studies were made by Fourier transform infrared spectroscopy and differential scanning calorimetry, and no significant interaction was observed. Inclusion complexes showed better dissolution than pure atovaquone and HP-β-CD established better than β-CD. Inclusion complexes of atovaquone at 1:0.25 w/w (drug: HP β -CD) in the tablets with 12% of crospovidone showed satisfactory results.

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 Physical properties and biological activities of hesperetin and naringenin in complex with methylated β-cyclodextrin

2015 ◽  
Vol 11 ◽  
pp. 2763-2773 ◽  
Author(s):  
Waratchada Sangpheak ◽  
Jintawee Kicuntod ◽  
Roswitha Schuster ◽  
Thanyada Rungrotmongkol ◽  
Peter Wolschann ◽  
...  
Keyword(s):  
Physical Properties ◽  
Inclusion Complexes ◽  
Biological Activities ◽  
Solubility Diagram ◽  
Dynamics Simulation ◽  
Phase Solubility ◽  
Free Energies ◽  
Scanning Calorimetry ◽  
Host Interaction ◽  
Vdw Force

The aim of this work is to improve physical properties and biological activities of the two flavanones hesperetin and naringenin by complexation with β-cyclodextrin (β-CD) and its methylated derivatives (2,6-di-O-methyl-β-cyclodextrin, DM-β-CD and randomly methylated-β-CD, RAMEB). The free energies of inclusion complexes between hesperetin with cyclodextrins (β-CD and DM-β-CD) were theoretically investigated by molecular dynamics simulation. The free energy values obtained suggested a more stable inclusion complex with DM-β-CD. The vdW force is the main guest–host interaction when hesperetin binds with CDs. The phase solubility diagram showed the formation of a soluble complex of AL type, with higher increase in solubility and stability when hesperetin and naringenin were complexed with RAMEB. Solid complexes were prepared by freeze-drying, and the data from differential scanning calorimetry (DSC) confirmed the formation of inclusion complexes. The data obtained by the dissolution method showed that complexation with RAMEB resulted in a better release of both flavanones to aqueous solution. The flavanones-β-CD/DM-β-CD complexes demonstrated a similar or a slight increase in anti-inflammatory activity and cytotoxicity towards three different cancer cell lines. The overall results suggested that solubilities and bioactivities of both flavanones were increased by complexation with methylated β-CDs.

scholarly journals Preparation and characterization of artemether inclusion complexes with hydroxypropyl-β-cyclodextrin

2017 ◽  
Vol 16 (10) ◽  
pp. 2359-2364
Author(s):  
Zwanden Sule Yahaya ◽  
Kenneth C. Ofokansi ◽  
Suzane T. Allagh ◽  
Pat G. Bhatia
Keyword(s):  
Complex Formation ◽  
Inclusion Complex ◽  
Dissolution Rate ◽  
Inclusion Complexes ◽  
In Vitro Dissolution ◽  
Phase Solubility ◽  
Inclusion Complex Formation ◽  
Scanning Calorimetry ◽  
Ft Ir

Purpose: To investigate experimentally the inclusion of artemether into the cavity of  hydroxypropyl-β-cyclodextrin and examine its effect on the solubility and dissolution rate of the drug.Methods: Inclusion complexes of artemether with hydroxypropyl-β-cyclodextrin of molar ratios 1:1, 1:2 and 1:3 were prepared using the kneading method. Phase solubility analysis and in vitro dissolution studies were utilized in evaluating the influence of inclusion complex formation on the solubility and dissolution rate of the drug. The complexes were characterized using differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). The inclusion complex containing equimolar concentrations of artemether and hydroxypropyl-β-cyclodextrin was then formulated into tablets via direct compression and  evaluated for various pharmaceutical characteristics including hardness, friability, absolute drug content and comparative in vitro dissolution profiles with some  commercially available brands of artemether.Results: The phase solubility diagram for the formed complexes in water at 37 oC indicated a linear curve soluble complex system (referred to as the AL system), and a stability constant (KC) value of 143 M-1. Evidence consistent with inclusion complex formation was obtained using FT-IR and DSC. The formulated inclusion complex tablets exhibited a higher rate of dissolution than the pure drug and commercial brands, showing 3.9-, 1.8- and 1.6-fold increases, respectively, over a period of 15 min.Conclusion: Inclusion complexation of artemether with hydroxypropyl-β-cyclodextrin is a promising approach to enhance the solubility and dissolution rate of the drug.Keywords: Artemether, 2-Hydroxypropyl-β-cyclodextrin, Dissolution, Solubility enhancement, Inclusion complex

Preparation and physicochemical characterization of inclusion complexes derived from phytosterols and β-cyclodextrin

2019 ◽  
Vol 16 (2) ◽  
pp. 145-159 ◽  
Author(s):  
Ana Lía Rossi ◽  
Eduardo Miguel Rustoy ◽  
Gabriel Cases ◽  
Adriana Mabel Rosso
Keyword(s):  
Inclusion Complexes ◽  
High Resolution Mass Spectrometry ◽  
Nuclear Overhauser Effect ◽  
Structural Characteristics ◽  
Physicochemical Characterization ◽  
Aqueous Solubility ◽  
Scanning Calorimetry ◽  
Guest Molecules ◽  
Overhauser Effect ◽  
Nuclear Overhauser

Phytosterols (PS), that is vegetable sterols, are compounds widely recognized for lowering the absorption of cholesterol and decreasing cancer risk, with βsitosterol, stigmasterol and campesterol being the most abundant. As PS is poorly soluble in aqueous solutions, many approaches have been proposed to increase their solubility and bioavailability. β-cyclodextrin (β-CD) could be used to increase PS aqueous solubility because of its capacity to entrap a variety of hydrophobic guest molecules in its cavity. In this work, the formation of β-CD/PS inclusion complexes was confirmed by Differential Scanning Calorimetry (DSC), Electrospray Ionization-High Resolution Mass Spectrometry (ESIHRMS) and Fourier Transform Infrared Spectroscopy (FT-IR), while structural characteristics were determined by one- and two-dimensional Nuclear Magnetic Resonance (NMR) techniques. Results confirmed 1:1 binding stoichiometry, which suggests the total inclusion of rings and chains of the different PS. The hypothesis of folding of the lateral chains into the cavity may be supported by the multiple correlations observed in the Nuclear Overhauser Effect Spectroscopy (NOESY) and rotatingframe Nuclear Overhauser Effect Spectroscopy (ROESY) spectra.

scholarly journals The solid-state structure of the β-blocker metoprolol: a combined experimental and in silico investigation

2019 ◽  
Vol 75 (2) ◽  
pp. 87-96 ◽  
Author(s):  
Patrizia Rossi ◽  
Paola Paoli ◽  
Laura Chelazzi ◽  
Luca Conti ◽  
Andrea Bencini
Keyword(s):  
Solid State ◽  
Surface Analysis ◽  
Crystal Packing ◽  
Variable Temperature ◽  
Blocking Agent ◽  
Hirshfeld Surface ◽  
Hirshfeld Surface Analysis ◽  
Scanning Calorimetry ◽  
Β Blocker ◽  
Β Blockers

Metoprolol {systematic name: (RS)-1-isopropylamino-3-[4-(2-methoxyethyl)phenoxy]propan-2-ol}, C15H25NO3, is a cardioselective β1-adrenergic blocking agent that shares part of its molecular skeleton with a large number of other β-blockers. Results from its solid-state characterization by single-crystal and variable-temperature powder X-ray diffraction and differential scanning calorimetry are presented. Its molecular and crystal arrangements have been further investigated by molecular modelling, by a Cambridge Structural Database (CSD) survey and by Hirshfeld surface analysis. In the crystal, the side arm bearing the isopropyl group, which is common to other β-blockers, adopts an all-trans conformation, which is the most stable arrangement from modelling data. The crystal packing of metoprolol is dominated by an O—H...N/N...H—O pair of hydrogen bonds (as also confirmed by a Hirshfeld surface analysis), which gives rise to chains containing alternating R and S metoprolol molecules extending along the b axis, supplemented by a weaker O...H—N/N—H...O pair of interactions. In addition, within the same stack of molecules, a C—H...O contact, partially oriented along the b and c axes, links homochiral molecules. Amongst the solid-state structures of molecules structurally related to metoprolol deposited in the CSD, the β-blocker drug betaxolol shows the closest analogy in terms of three-dimensional arrangement and interactions. Notwithstanding their close similarity, the crystal lattices of the two drugs respond differently on increasing temperature: metoprolol expands anisotropically, while for betaxolol, an isotropic thermal expansion is observed.

Enhancement of aqueous solubility of itraconazole by complexation with cyclodextrins using supercritical carbon dioxide

2005 ◽  
Vol 83 (10) ◽  
pp. 1833-1838 ◽  
Author(s):  
Ibrahim Shehatta ◽  
Ali Hassan Al-Marzouqi ◽  
Baboucarr Jobe ◽  
Ali Dowaidar
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Stability Constant ◽  
Inclusion Complexes ◽  
Driving Forces ◽  
Aqueous Solubility ◽  
Phase Solubility ◽  
Static Mode ◽  
The Stability ◽  
Supercritical Carbon

The formation of inclusion complexes between itraconazole, a highly hydrophobic drug, and α-, β-, γ-, and hydroxylpropyl-β-cyclodextrin (HP-β-CD) were assessed using phase-solubility techniques. The solubility of itraconazole increased as a function of cyclodextrin concentration showing an AL phase diagram indicating the formation of soluble complexes with 1:1 stoichiometry. The Gibbs free energies of transfer of the drug from aqueous solution to the cavity of cyclodextrin are negative and increase in magnitude with increasing cyclodextrin concentration. The solubility of itraconazole, as well as the stability constant of its complex with HP-β-CD, are found to be affected by the pH of the medium. The HP-β-CD cavity was found to have a greater affinity for the unionized itraconazole than the protonated one. It was found that the interaction between the drug and the cyclodextrin is weakened as the medium becomes more apolar by the addition of methanol. Also, the size of the cavity of the cyclodextrins plays an important role in the association process. Furthermore, the thermodynamic parameters of the complexation process were calculated, by monitoring the isothermic solubility diagrams of itraconazole–HP-β-CD and itraconazole–β-CD at various temperatures, to gain information on the driving forces for the formation of inclusion complexes. Drug formulations of itraconazole were prepared by complexation of the drug into different cyclodextrins using supercritical carbon dioxide in a static mode. The effects of cyclodextrins on the prepared inclusion complexes were studied and characterized by differential scanning calorimetry.Key words: cyclodextrin, itraconazole, inclusion complex, solubility, stability constant.

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