Synthesis, Characterization and Solubility Determination of 6-Phenyl-pyridazin-3(2H)-one in Different Pharmaceutical Solvents

The current research work proposed the solubility data and solution thermodynamic properties of the cardiovascular agent 6-phenylpyridazin-3(2H)-one [PPD] in twelve pharmaceutical solvents at “T = 298.2 K to 318.2 K” and “p = 0.1 MPa”. The measured solubilities of PPD were regressed well with “van’t Hoff and Apelblat models”. The solid phases of pure and equilibrated PPD were characterized using differential scanning calorimetry and powder X-ray differactometry, and the results suggested no transformation of PPD into solvates/hydrates/polymorphs after equilibrium. The solubilities of PPD in a mole fraction at “T = 318.2 K” were noted at a maximum in dimethyl sulfoxide (DMSO, 4.73 × 10−1), followed by polyethylene glycol-400 (PEG-400, 4.12 × 10−1), Transcutol® (3.46 × 10−1), ethyl acetate (EA, 81 × 10−2), 2-butanol (2.18 × 10−2), 1-butanol (2.11 × 10−2), propylene glycol (PG, 1.50 × 10−2), isopropyl alcohol (IPA, 1.44 × 10−2), ethylene glycol (EG, 1.27 × 10−2), ethanol (8.22 × 10−3), methanol (5.18 × 10−3) and water (1.26 × 10−5). Similar tendencies were also noted at other studied temperatures. The results of the “apparent thermodynamic analysis” showed an endothermic and entropy-driven dissolution of PPD in all pharmaceutical solvents. The results of the activity coefficients suggested a maximum interaction at the molecular level in PPD-DMSO, PPD-PEG-400 and PPD-Transcutol, compared with other combination of the solute and solvents.

Download Full-text

Development and In-Vitro Evaluation of pH Responsive Polymeric Nano Hydrogel Carrier System for Gastro-Protective Delivery of Naproxen Sodium

Advances in Polymer Technology ◽

10.1155/2019/6090965 ◽

2019 ◽

Vol 2019 ◽

pp. 1-13

Author(s):

Rai Muhammad Sarfraz ◽

Muhammad Rouf Akram ◽

Muhammad Rizwan Ali ◽

Asif Mahmood ◽

Muhammad Usman Khan ◽

...

Keyword(s):

Drug Release ◽

Naproxen Sodium ◽

Research Work ◽

Entrapment Efficiency ◽

Gravimetric Analysis ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Swelling Behaviour ◽

X Ray

Current research work was carried out for gastro-protective delivery of naproxen sodium. Polyethylene glycol-g-poly (methacrylic acid) nanogels was developed through free radical polymerization technique. Formulation was characterized for swelling behaviour, entrapment efficiency, Fourier transform infrared (FTIR) spectroscopy, Differential scanning calorimetry (DSC), and Thermal Gravimetric Analysis (TGA), Powder X-ray diffraction (PXRD), Zeta size distribution, and Zeta potential measurements, and in-vitro drug release. pH dependent swelling was observed with maximum drug release at higher pH. PXRD studies confirmed the conversion of loaded drug from crystalline to amorphous form while Zeta size measurement showed size reduction. On the basis of these results it was concluded that prepared nanogels proved an effective tool for gastro-protective delivery of naproxen sodium.

Download Full-text

Curcumin and Quercetin-Loaded Nanoemulsions: Physicochemical Compatibility Study and Validation of a Simultaneous Quantification Method

Nanomaterials ◽

10.3390/nano10091650 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1650

Author(s):

Gustavo Richter Vaz ◽

Adryana Clementino ◽

Juliana Bidone ◽

Marcos Antonio Villetti ◽

Mariana Falkembach ◽

...

Keyword(s):

Limit Of Detection ◽

Biological Fluids ◽

Thermal Analyses ◽

Entrapment Efficiency ◽

Compatibility Study ◽

Scanning Calorimetry ◽

Limit Of Quantification ◽

X Ray ◽

Simultaneous Quantification

Biphasic oil/water nanoemulsions have been proposed as delivery systems for the intranasal administration of curcumin (CUR) and quercetin (QU), due to their high drug entrapment efficiency, the possibility of simultaneous drug administration and protection of the encapsulated compounds from degradation. To better understand the physicochemical and biological performance of the selected formulation simultaneously co-encapsulating CUR and QU, a stability test of the compound mixture was firstly carried out using X-ray powder diffraction and thermal analyses, such as differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA). The determination and quantification of the encapsulated active compounds were then carried out being an essential parameter for the development of innovative nanomedicines. Thus, a new HPLC–UV/Vis method for the simultaneous determination of CUR and QU in the nanoemulsions was developed and validated. The X-ray diffraction analyses demonstrated that no interaction between the mixture of active ingredients, if any, is strong enough to take place in the solid state. Moreover, the thermal analysis demonstrated that the CUR and QU are stable in the nanoemulsion production temperature range. The proposed analytical method for the simultaneous quantification of the two actives was selective and linear for both compounds in the range of 0.5–12.5 µg/mL (R2 > 0.9997), precise (RSD below 3%), robust and accurate (recovery 100 ± 5 %). The method was validated in accordance with ICH Q2 R1 “Validation of Analytical Procedures” and CDER-FDA “Validation of chromatographic methods” guideline. Furthermore, the low limit of detection (LOD 0.005 µg/mL for CUR and 0.14 µg/mL for QU) and the low limit of quantification (LOQ 0.017 µg/mL for CUR and 0.48 µg/mL for QU) of the method were suitable for the application to drug release and permeation studies planned for the development of the nanoemulsions. The method was then applied for the determination of nanoemulsions CUR and QU encapsulation efficiencies (> 99%), as well as for the stability studies of the two compounds in simulated biological fluids over time. The proposed method represents, to our knowledge, the only method for the simultaneous quantification of CUR and QU in nanoemulsions.

Download Full-text

Study of an Energetic-oxidant Co-crystal: Preparation, Characterisation, and Crystallisation Mechanism

Defence Science Journal ◽

10.14429/dsj.67.10188 ◽

2017 ◽

Vol 67 (5) ◽

pp. 510 ◽

Cited By ~ 1

Author(s):

Han Gao ◽

Wei Jiang ◽

Jie Liu ◽

Gazi Hao ◽

Lei Xiao ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Differential Scanning Calorimetry ◽

Diffraction Spectrum ◽

Solvent Evaporation Method ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Scanning Electron

<p>An energetic co-crystal consisting of the most promising military explosive 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and the most well-known oxidant applied in propellants ammonium perchlorate has been prepared with a simple solvent evaporation method. Scanning electron microscopy revealed that the morphology of co-crystal differs greatly from each component. The X-ray diffraction spectrum, FTIR, Raman spectra, and differential scanning calorimetry characterisation further prove the formation of the co-crystal. The result of determination of hygroscopic rate indicated the hygroscopicity was effectively reduced. At last, the crystallisation mechanism has been discussed.</p>

Download Full-text

Phase Transitions and Thermal Expansion of 10mol%Sc2O3-1mol% CeO2-ZrO2 Ceramics

Volume 3: Design and Manufacturing ◽

10.1115/imece2007-43109 ◽

2007 ◽

Author(s):

Sergey Yarmolenko ◽

Devendra Ray ◽

Devdas Pai ◽

Jag Sankar

Keyword(s):

Thermal Expansion ◽

Phase Transitions ◽

Grain Structure ◽

Slow Phase ◽

Cubic Phase ◽

Scanning Calorimetry ◽

X Ray ◽

Operational Conditions ◽

Β Phase

Phase transitions and CTE of 10mol%Sc2O3-1mol%CeO2-ZrO2 ceramics sintered from two commercial powders produced by Praxair Surface Technologies, USA and DKKK, Japan are studied. Morphology of powders and grain structure of ceramics were studied by SEM and AFM. Ceramics produced from Praxair powder exist in cubic phase while DKKK-based ceramics exhibit slow phase transformation from cubic to rhombohedral (β) phase at temperatures 350–400°C. c-β Phase transition temperature is 440°C obtained by high temperature x-ray diffractometry (HTXRD) and differential scanning calorimetry. Coefficients of thermal expansion of cubic and β-phases were calculated from temperature dependence of lattice parameters obtained by HTXRD in the temperature range of 25–800°C. These results can be further used for the optimal design of SOFC layered structures as well as for determination of their reliability and durability under operational conditions.

Download Full-text

GLOBAL PROPERTIES OF BIOMIMETIC MEMBRANES: PERSPECTIVES ON MOLECULAR FEATURES

Biophysical Reviews and Letters ◽

10.1142/s1793048006000069 ◽

2006 ◽

Vol 01 (01) ◽

pp. 57-84 ◽

Cited By ~ 71

Author(s):

GEORG PABST

Keyword(s):

Molecular Level ◽

Local Perturbation ◽

Scanning Calorimetry ◽

X Ray ◽

Analysis Techniques ◽

Biomimetic Membranes ◽

Molecular Features ◽

Global Properties ◽

Complementary Techniques ◽

Dynamic Scattering

Global properties of biological model membranes such as, e.g., structure or elasticity, are known to be closely related to their local features. If a membrane active compound interacts with the membrane assembly, the membrane will primarily be affected on the local, molecular level. The local perturbation may than, through some coupling, translate into a global adjustment of the membrane. In order to address this coupling x-ray and neutron diffraction data analysis techniques have been developed that allow accurate monitoring of changes in global properties. This offers new perspectives on molecular membrane features that in combination with complementary techniques, such as differential scanning calorimetry, spectroscopy or dynamic scattering lead to a better understanding of biomimetic membranes. The present article reviews these aspects giving application examples for single- and multicomponent membranes, respectively.

Download Full-text

DETERMINATION OF LEAD FROM GOLD ORE USING PROTON INDUCED X-RAY EMISSION TECHNIQUE

FUDMA Journal of Sciences ◽

10.33003/fjs-2021-0501-594 ◽

2021 ◽

Vol 5 (1) ◽

pp. 490-494

Author(s):

A. Bello

Keyword(s):

Research Work ◽

World Health ◽

Elemental Content ◽

Northern Nigeria ◽

X Ray ◽

Mining Sites ◽

The World ◽

Health Organization ◽

Pb Concentration

The impetus for this research work arose from alleged signs of Lead (Pb) poisoning from Medicines Sans Frontiers (Doctors without Borders).These poisonings were narrowed down to areas of solid minerals mining and extraction in Northern Nigeria. The aim of this research work is to identify mining Sites with ores having high Pb concentration. Fifteen samples were collected from areas located at approximately latitudes 𝟶𝟶70𝟶8.69𝟶ˈE and longitudes 𝟶90 34ˈ224ˈˈN and interrogated using Proton induced X-ray emission (PIXE) technique for their elemental content. PIXE was chosen because of its sample nondestructive and it does not contaminate the environment. The result obtained varied between 24.3 – 632303.3 ppm. The world Health Organization recommends that sites with Pb concentration above 400 ppm are inimical to human health and ordered that children be evacuated from such areas. Exposure to Pb poisoning may cause anemia, weakness, and Kidney and brain damage; particularly in children.

Download Full-text

Assessment of the X-ray diffraction–absorption method for quantitative analysis of largely amorphous pharmaceutical composites

Journal of Applied Crystallography ◽

10.1107/s002188980201926x ◽

2003 ◽

Vol 36 (1) ◽

pp. 74-79 ◽

Cited By ~ 9

Author(s):

P. Bergese ◽

I. Colombo ◽

D. Gervasoni ◽

Laura E. Depero

Keyword(s):

Weight Fraction ◽

Toxic Waste ◽

X Ray Diffraction ◽

Amorphous Halo ◽

Scanning Calorimetry ◽

X Ray ◽

The Matrix ◽

Diffraction Patterns ◽

Challenging Question

Determination of the residual weight fraction of a crystalline drug in a largely amorphous pharmaceutical composite is still a challenging question. None of the quantitative X-ray diffraction (QXRD) methods found in the literature is suitable for these inclusion systems. The composite's diffraction patterns present a structured amorphous halo (arising from the amorphous matrix and drug molecular clusters) in which the crystalline drug peaks rise up. Moreover, the matrix traps a non-negligible quantity of water (which cannot be directly detected by X-ray diffraction) and the crystal structure of the drug may be unknown. In this work, a development of the QXRD analysis based on the diffraction–absorption technique is presented. The method is standardless, avoids the interpretation of the amorphous halo and the knowledge of the crystal structures of the phases, and takes into account the absorbed water. Results are in excellent agreement with those obtained by differential scanning calorimetry (DSC). The general features of the technique open its application to other classes of largely amorphous composite materials, like glass systems generated in the stabilization/solidification of toxic waste.

Download Full-text

Solubility and Solution Thermodynamics of Baricitinib in Six Different Pharmaceutically Used Solvents at Different Temperatures

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2018-1323 ◽

2019 ◽

Vol 233 (8) ◽

pp. 1129-1144 ◽

Cited By ~ 3

Author(s):

Abdullah S. Alshetaili

Keyword(s):

Activity Coefficients ◽

Physical State ◽

Solution Thermodynamics ◽

Scanning Calorimetry ◽

Polyethylene Glycol 400 ◽

Saturation State ◽

Peg 400 ◽

Different Temperatures ◽

Solid Phases

Abstract The preset study was undertaken to determine solubility and solution thermodynamics of a novel anticancer drug baricitinib in some pharmaceutically used mono/pure solvents including “water, ethanol, polyethylene glycol-400 (PEG-400), ethyl acetate (EA), dichloromethane (DCM) and dimethyl sulfoxide (DMSO)” at “T = 298.2 K to 323.2 K” and “p = 0.1 MPa”. The solubility of baricitinib after equilibrium (saturation state) was analyzed spectrophotometrically by applying an isothermal technique. Characterization of solid phases of initial and equilibrated baricitinib was confirmed with the help of differential scanning calorimetry (DSC). Measured solubilities of baricitinib were regressed using “van’t Hoff and Apelblat models”. DSC spectra of baricitinib showed no change in physical state of baricitinib after equilibrium. Solubilities of baricitinib (as mole fraction) were estimated highest in DMSO (1.65 × 10−1) followed by PEG-400 (1.42 × 10−1), DCM (1.29 × 10−3), ethanol (7.41 × 10−4), EA (4.74 × 10−4) and water (1.76 × 10−4) at “T = 323.2 K” and same tendencies were also noted at other temperatures studied. With the help of theoretical solubilities of baricitinib, activity coefficients were estimated. The estimated data of activity coefficients indicated higher molecular interactions in baricitinib-DMSO and baricitinib-PEG-400 as compared with baricitinib-water, baricitinib-EA, baricitinib-DCM and baricitinib-ethanol. Thermodynamic treatment of solubility values of baricitinib showed “endothermic and entropy-driven dissolution” of baricitinib in all pharmaceutically used solvents evaluated.

Download Full-text

Membrane protein crystallography in the era of modern structural biology

Biochemical Society Transactions ◽

10.1042/bst20200066 ◽

2020 ◽

Vol 48 (6) ◽

pp. 2505-2524

Author(s):

Tristan O. C. Kwan ◽

Danny Axford ◽

Isabel Moraes

Keyword(s):

Structural Biology ◽

Molecular Level ◽

Protein Structures ◽

Three Dimensional ◽

Biological Macromolecules ◽

X Ray ◽

X Ray Crystallography ◽

Cellular Processes ◽

Biochemical Level

The aim of structural biology has been always the study of biological macromolecules structures and their mechanistic behaviour at molecular level. To achieve its goal, multiple biophysical methods and approaches have become part of the structural biology toolbox. Considered as one of the pillars of structural biology, X-ray crystallography has been the most successful method for solving three-dimensional protein structures at atomic level to date. It is however limited by the success in obtaining well-ordered protein crystals that diffract at high resolution. This is especially true for challenging targets such as membrane proteins (MPs). Understanding structure-function relationships of MPs at the biochemical level is vital for medicine and drug discovery as they play critical roles in many cellular processes. Though difficult, structure determination of MPs by X-ray crystallography has significantly improved in the last two decades, mainly due to many relevant technological and methodological developments. Today, numerous MP crystal structures have been solved, revealing many of their mechanisms of action. Yet the field of structural biology has also been through significant technological breakthroughs in recent years, particularly in the fields of single particle electron microscopy (cryo-EM) and X-ray free electron lasers (XFELs). Here we summarise the most important advancements in the field of MP crystallography and the significance of these developments in the present era of modern structural biology.

Download Full-text

Tellurium doped zinc imidazole framework (Te@ZIF-8) for quantitative determination of hydrogen peroxide from serum of pancreatic cancer patients

Scientific Reports ◽

10.1038/s41598-020-78115-6 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Batool Fatima ◽

Dilshad Hussain ◽

Adeela Saeed ◽

Muhammad Salman Sajid ◽

Saadat Majeed ◽

...

Keyword(s):

Pancreatic Cancer ◽

Hydrogen Peroxide ◽

Quantitative Determination ◽

Cancer Patients ◽

Modified Electrode ◽

Electrochemical Sensing ◽

Serum Samples ◽

Scanning Calorimetry ◽

X Ray

AbstractThe tellurium doped zinc imidazole framework (Te@ZIF-8) is prepared by a two-step hydrothermal strategy for the electrochemical sensing of hydrogen peroxide. Material is characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The electrochemical characterization of the MOF modified electrode is done by a three-electrode system. Electrochemical sensing of hydrogen peroxide is made by cyclic voltammetry, amperometry, and impedance measurements. Results demonstrate that Te@ZIF-8 shows a detection limit of 60 µM with linearity up to 0.98855. Material is stable to 1000 cycles with no significant change in electrochemical response. Amperometry depicts the recovery of hydrogen peroxide from human serum up to 101%. Impedance curve reveals the surface of Te@ZIF-8-GCE (glassy carbon electrode) as porous and rough and an interface is developed between analyte ions and the sensing material. Finally, the modified electrode is used for the quantitative determination of hydrogen peroxide from serum samples of pancreatic cancer patients, diagnosed with CA 19-9.

Download Full-text