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

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.

Download Full-text

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

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.10.331 ◽

2014 ◽

Vol 10 ◽

pp. 3136-3151 ◽

Cited By ~ 22

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.

Download Full-text

Sustainable Pharmaceutical Preparation Methods and Solid-state analysis Supporting Green Pharmacy

Current Pharmaceutical Analysis ◽

10.2174/1573412916999200711150729 ◽

2020 ◽

Vol 16 ◽

Author(s):

Ilma Nugrahani

Keyword(s):

Solid State ◽

Pharmaceutical Preparation ◽

Three Dimensional ◽

Chemical Properties ◽

Environmental Damage ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Preparation Methods ◽

Physical And Chemical ◽

State Analysis

: Every "entity" or compound has physical and chemical properties as references for the synthesis and determination of the entity's structure. Thermodynamically, solid-state is the most stable matter in the universe and to be the ideal form in structure elucidation of pharmaceutical. The dry treatments become popular, such as mechanochemistry, microwave heating, and the using of deep eutectic agent. These techniques are viewed as the futuristic methods for reducing environmental damage, in line with "green pharmacy" concept. On the other hand, solid-state analysis methods from the simplest to the most sophisticated one have been used in the long decades, but most are for qualitative purposes. Recently many reports have proven that solid-state analysis instruments are reliable and prospective for implementing in the quantitative measurement. Infrared spectroscopy, powder x-ray diffraction, and differential scanning calorimetry have been employed in various kinetics and content determination studies. A revolutionary method developed for structural elucidation is single-crystal diffraction, which is capable of rapidly and accurately determining a three-dimensional chemical structure. Hereby it shown that the accurate, precise, economical, ease, rapid-speed, and reliability of solid-state analysis method are eco-benefits by reducing the reagent, catalyst, and organic solvent.

Download Full-text

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

Pharmaceutics ◽

10.3390/pharmaceutics14010008 ◽

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.

Download Full-text

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

International Journal of Pharmaceutical Sciences and Nanotechnology ◽

10.37285/ijpsn.2009.2.2.5 ◽

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.

Download Full-text

Identification of Amber and the Copal under Heat Pressurized Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.554-556.2112 ◽

2012 ◽

Vol 554-556 ◽

pp. 2112-2115

Author(s):

Hui Li ◽

Xuan Wang ◽

Yong Zhu ◽

Qin Ren

Keyword(s):

Chemical Properties ◽

Peak Position ◽

Exothermic Peak ◽

Endothermic Peak ◽

Scanning Calorimetry ◽

Natural Resin ◽

Before And After ◽

Artificial Heat ◽

Physical And Chemical ◽

And Chemical Properties

Amber and copal belong to the natural resin, which are similar and transitional in the physical and chemical properties. The artificial heat-pressurized treatment is contributed to the polymerization of the natural copal, and turns into green, yellow-green and deep orange-yellow copal. It is very difficult to identify amber from the heat- pressurized treatment copal only based on the gemological parameters.The thermal behavior of amber and the copal before and after heat-pressurized treatment were analyzed by means of differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy(FTIR) and nuclear magnetic resonance(NMR). The results show that amber exists an evident endothermic peak around 123~132°C, and copal reveals an obvious endothermic peak at about 174~178°C, and the heat pressurized treatment copal occurs a clear exothermic peak around 150~152°C. The differences between endothermic or exothermic transition and peak position reveal occurring thermal oxidation or the bond breaking or the melting, which are of great significance in the identification.

Download Full-text

DISSOLUTION ENHANCEMENT OF ATOVAQUONE USING CYCLODEXTRINS AND FORMULATING TO ORODISPERSIBLE TABLETS

INDIAN DRUGS ◽

10.53879/id.53.06.10427 ◽

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.

Download Full-text

A rapid microwave synthesis of green-emissive carbon dots with solid-state fluorescence and pH-sensitive properties

Royal Society Open Science ◽

10.1098/rsos.180245 ◽

2018 ◽

Vol 5 (7) ◽

pp. 180245 ◽

Cited By ~ 16

Author(s):

Tingting Yu ◽

Haijiao Wang ◽

Chongzheng Guo ◽

Yanli Zhai ◽

Jianzhou Yang ◽

...

Keyword(s):

Solid State ◽

Photoelectron Spectroscopy ◽

Phthalic Acid ◽

Chemical Properties ◽

Carbon Quantum Dots ◽

Feed Ratio ◽

Quantum Yields ◽

Ph Sensing ◽

Wavelength Emission ◽

Physical And Chemical

The emerging carbon quantum dots (CQDs) have been attracting significant attention for their prominent fluorescence, excellent stability and outstanding biocompatibility. Here, we report a facile one-step synthesis of highly fluorescent CQDs by using phthalic acid and triethylenediamine hexahydrate as precursors through a simple microwave-assisted method. The reaction time needed is only 60 s, which is less time-consuming than most previous reports. The phthalic acid with a benzene ring can improve the photoluminescence properties of CQDs as it can provide foreign sp 2 conjugating units, and then finally result in long-wavelength emission. The synthesized CQDs were fully characterized by transmission electron microscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Besides, the impacts of different freed ratio on physical and chemical properties of CQDs were investigated in detail. The prepared CQDs exhibited strong green fluorescence with a broad maximum emission wavelength. The quantum yields of the CQDs can reach 16.1% in aqueous solution and they were successfully used in cell imaging with good biocompatibility. Moreover, in solid state, the CQDs with the feed ratio of 1 : 0.5 showed a strong green–yellow fluorescence which may have great potential to fabricate optoelectronic devices. Furthermore, the prepared CQDs also showed high pH sensitivity and can act as a fluorescence nanosensor for pH sensing.

Download Full-text

Synthesis and thermal properties of some phenolic resins

Innovaciencia Facultad de Ciencias Exactas Físicas y Naturales ◽

10.15649/2346075x.508 ◽

2019 ◽

Vol 7 (1) ◽

pp. 1-15

Author(s):

Alshawi F M ◽

Abdul Razzq K ◽

Hanoosh W S

Keyword(s):

Phenol Formaldehyde ◽

Chemical Properties ◽

Decomposition Temperature ◽

Industrial Applications ◽

Stability Study ◽

Curing Temperature ◽

Molar Ratio ◽

Scanning Calorimetry ◽

Phenolic Resins ◽

Physical And Chemical

Introduction: Phenolic resins have been in use since the early twentieth century and are considered the first class of synthetic polymers to achieve commercial success, moreover phenolic resins continue to succeed and attract special interest in a large range of industrial applications such as adhesives, paints, and composites; because of their unique physical and chemical properties. Materials and Methods: Prepolymers resol resins (RR, RH, RP, and RC) were synthesized by the reaction of phenolic compounds (resorcinol, hydroquinone, phloroglucinol, and catechol) respectively, with formaldehyde at molar ratio phenol/ formaldehyde 1/1.5, using sodium hydroxide as a catalyst. These resins were characterized by FTIR. The curing reaction of these resins was evaluated using differential scanning calorimetry (DSC), while the thermal stability study was evaluated using thermogravimetric analysis (TGA). Results and Discussion:From the results showing that these prepolymers have different curing temperatures and curing energy, while the TGA study showed that the cured resins have decomposition temperature more than 300 ºC, and char residue at 650 ºC more than 60%. Conclusions: These resol resins have different gel times (8-55) min, and viscosities (435-350) mpa.s. The curing temperature of these resin obtained from DSC curves was (120, 129, 105 and 127 °C), while the thermal behavior of the cured resins obtained from TGA curves showed that these cured resin have two decomposition temperatures and the rate of decomposition in the order of RC < RR< .

Download Full-text

Solid-State Characterization and Compatibility Studies of Penciclovir, Lysine Hydrochloride, and Pharmaceutical Excipients

Materials ◽

10.3390/ma12193154 ◽

2019 ◽

Vol 12 (19) ◽

pp. 3154 ◽

Cited By ~ 3

Author(s):

Rafaela Z. C. Meira ◽

Isabela F. B. Biscaia ◽

Camila Nogueira ◽

Fabio S. Murakami ◽

Larissa S. Bernardi ◽

...

Keyword(s):

Solid State ◽

Ethylenediaminetetraacetic Acid ◽

Therapeutic Potential ◽

Chemical Characterization ◽

Compatibility Studies ◽

Ambient Conditions ◽

Scanning Calorimetry ◽

Crystalline Materials ◽

Physical And Chemical ◽

Solid State Characterization

The physical and chemical characterization of the solid-state properties of drugs and excipients is fundamental for planning new formulations and developing new strategies for the treatment of diseases. Techniques such as differential scanning calorimetry, thermogravimetry, X-ray powder diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy are among the most commonly used techniques for these purposes. Penciclovir and lysine are individually used to treat the herpes virus. As such, the development of a formulation containing both drugs may have therapeutic potential. Solid-state characterization showed that both penciclovir and lysine were crystalline materials with melting points at 278.27 °C and 260.91 °C, respectively. Compatibility studies of penciclovir and lysine indicated a possible interaction between these substances, as evidenced by a single melting point at 253.10 °C. The compatibility of several excipients, including ethylenediaminetetraacetic acid, cetostearyl alcohol, sodium lauryl sulphate, di-tert-butyl methyl phenol, liquid petrolatum, methylparaben, nonionic wax, paraffin, propylene glycol, and propylparaben, was evaluated in ternary (penciclovir-lysine-excipient) mixtures (1:1:1, w/w/w) to determine the optimal formulation. The developed formulation was stable under accelerated and ambient conditions, which demonstrated that the interaction between penciclovir and lysine was suitable for the development of a formulation containing both drugs.

Download Full-text

Impact of solid-state photochemical [2+2] cycloaddition on coordination polymers for diverse applications

Dalton Transactions ◽

10.1039/d0dt01534b ◽

2020 ◽

Vol 49 (28) ◽

pp. 9556-9563 ◽

Cited By ~ 4

Author(s):

Samim Khan ◽

Basudeb Dutta ◽

Mohammad Hedayetullah Mir

Keyword(s):

Solid State ◽

Coordination Polymers ◽

Chemical Properties ◽

Physical And Chemical Properties ◽

Physical And Chemical ◽

Fine Tune ◽

And Chemical Properties

This Frontier article highlights the advancement of [2+2] photocycloaddition reactions within coordination polymers to fine tune their diverse physical and chemical properties.

Download Full-text