scholarly journals Study of possibility physical interactions antimalarial combination drugs

2020 ◽  
Author(s):  
Timbul Partogi H. Simorangkir
Keyword(s):  
Phase Diagram ◽  
Solid State ◽  
Melting Point ◽  
Crystal Habit ◽  
Supersaturated Solution ◽  
Physical Interaction ◽  
Contact Method ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

Identification of solid state to investigate the possibility of physical interaction between Antimalarial Artemisinin Combination Treatment base Artesunate (AS) and Amodiaquine (AQ) by hot contact method Kofler, cold contact method (crystallization reaction) and binary phase diagram confirmation had been carried out. The results of hot contact method Kofler shown the formation a new crystalline habit as a long and thin needle on the contact zone (mixing zone) between AS and AQ. A different melting point was seen in its single component. Cold contact methods between two of supersaturated solution of component AS and AQ in methanol solvent also indicated the growth of crystal habit as similar as hot contact method Kofler. Confirmation by biner phase diagram shown the specific diagram for cocrystalline phase. Solid state interaction between AS and AQ was analysed by powder X-ray diffraction, FTIR (Fourier Transformed Infra Red) spectrophotometric, microscopic SEM (Scanning Electron Microscopic) and thermal DTA (Differential Thermal Analysis), TG-DSC (Thermal Gravimetry- Differential Scanning Calorimetry). Microscopic analysis by SEM showed significantly the change of habit and morphology of crystal to long and thin needle shaped. The difference of powder X-ray diffraction (PXRD) interferences peaks were observed in addition to PXRD interference peaks of each component and its physical mixtures that proved formation of cocrystalline phase. DSC Thermogram indicated a new endothermic peak corresponding to melting point of a new cocrystalline phase at temperature 160,4°C.

PHASE TRANSFORMATIONS DURING HEATING OF AMORPHOUS/NANOCRYSTALLINE Ni–Ti POWDERS

2010 ◽  
Vol 24 (09) ◽  
pp. 1137-1140 ◽  
Author(s):  
M. M. VERDIAN ◽  
M. SALEHI ◽  
K. RAEISSI
Keyword(s):  
Differential Scanning Calorimetry ◽  
Solid State ◽  
Phase Transformations ◽  
Low Energy ◽  
Heating Process ◽  
Study Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Niti Phase

Amorphous/nanocrystalline 50 Ni –50 Ti powders were synthesized from elemental Ti and Ni powders by solid state synthesis utilizing low energy mechanical alloying with times up to 100 h. The produced powders were investigated by X-ray diffraction and differential scanning calorimetry to study phase transformations that occurred during heating in the calorimeter. It was found that at the first stage of the heating process, a disordered NiTi phase was formed at temperature of about 400°C. Further investigations indicated that this phase transformed into the Ni 3 Ti and Ti 2 Ni intermetallic compounds after heating at a temperature of about 800°C.

Tautomeric polymorphism of the neuroactive inhibitor kynurenic acid

2019 ◽  
Vol 75 (6) ◽  
pp. 793-805
Author(s):  
Dorota Pogoda ◽  
Jan Janczak ◽  
Sylwia Pawlak ◽  
Michael Zaworotko ◽  
Veneta Videnova-Adrabinska
Keyword(s):  
Solid State ◽  
Kynurenic Acid ◽  
Variable Temperature ◽  
Neurological Diseases ◽  
Crystal Form ◽  
Phase Behaviour ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

Kynurenic acid (KYN; systematic name: 4-hydroxyquinoline-2-carboxylic acid, C10H7NO3) displays a therapeutic effect in the treatment of some neurological diseases and is used as a broad-spectrum neuroprotective agent. However, it is understudied with respect to its solid-state chemistry and only one crystal form (α-KYN·H2O) has been reported up to now. Therefore, an attempt to synthesize alternative solid-state forms of KYN was undertaken and six new species were obtained: five solvates and one salt. One of them is a new polymorph, β-KYN·H2O, of the already known KYN monohydrate. All crystal species were further studied by single-crystal and powder X-ray diffraction, thermal and spectroscopic methods. In addition to the above methods, differential scanning calorimetry (DSC), in-situ variable-temperature powder X-ray diffraction and Raman microscopy were applied to characterize the phase behaviour of the new forms. All the compounds display a zwitterionic form of KYN and two different enol–keto tautomers are observed depending on the crystallization solvent used.

Physicochemistry of the Tomb of Nefertari, Egypt.

1988 ◽  
Vol 123 ◽  
Author(s):  
J. E. Smeaton ◽  
George Burns
Keyword(s):  
Differential Scanning Calorimetry ◽  
Sodium Chloride ◽  
Solid State ◽  
Kinetic Study ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Physicochemical Processes ◽  
Gypsum Dehydration

AbstractThe Tomb of Nefertari, no. 66, Valley of the Queens, is an internationally known monument of historic and artistic importance; it is considere d one of the most beautiful of the Royal Egyptian tombs. The fragility of its plaster along with its ubiquitous sodium chloride crystals and microcrystals have complicated its conservation and restoration. In order to determine the optimum pathway for its conservation, the physicochemical processes which occur now in this Tomb must be well understood. To improve this understanding, samples of plaster taken from the Tomb have been analyzed using Differential Scanning Calorimetry and X-ray Diffraction and have been shown to be fully dehydrated; previous findings suggest that this is not the case in all contemporary Royal tombs. Although we are not aware of any kinetic study of gypsum dehydration in the solid state, the presence of anhydrite in the Tomb of Nefertari suggests that the CaSO4 ·2H2O → CaSO4 + 2H2O reaction is catalyzed. It is reasoned that finely-dispersed sodium chloride crystals act as effective catalysts in this reaction.

scholarly journals The Usefulness of X-ray Diffraction and Thermal Analysis to Study Dietary Supplements Containing Iron

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 197
Author(s):  
Izabela Jendrzejewska ◽  
Robert Musioł ◽  
Tomasz Goryczka ◽  
Ewa Pietrasik ◽  
Joanna Klimontko ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Melting Point ◽  
Dietary Supplements ◽  
Polymorphic Form ◽  
Food Supplements ◽  
X Ray Diffraction ◽  
Iron Compounds ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Amorphous Compounds

X-ray powder diffraction (XRPD) and thermal analysis (differential scanning calorimetry/derivative of thermogravimetry (DSC/DTG)) are solid-state techniques that can be successfully used to identify and quantify various chemical compounds in polycrystalline mixtures, such as dietary supplements or drugs. In this work, 31 dietary supplements available on the Polish market that contain iron compounds, namely iron gluconate, fumarate, bisglycinate, citrate and pyrophosphate, were evaluated. The aim of the work was to identify iron compounds declared by the manufacturer as food supplements and to try to verify compliance with the manufacturer’s claims. Studies performed by X-ray and thermal analysis confirmed that crystalline iron compounds (iron (II) gluconate, iron (II) fumarate), declared by the manufacturers, were present in the investigated dietary supplements. Iron (II) bisglycinate proved to be semi-crystalline. However, depending on the composition of the formulation, it was possible to identify this compound in the tested supplements. For amorphous iron compounds (iron (III) citrate and iron (III) pyrophosphate), the diffraction pattern does not have characteristic diffraction lines. Food supplements containing crystalline iron compounds have a melting point close to the melting point of pure iron compounds. The presence of excipients was found to affect the shapes and positions of the endothermic peaks significantly. Widening of endothermic peaks and changes in their position were observed, as well as exothermic peaks indicating crystallization of amorphous compounds. Weight loss was determined for all dietary supplements tested. Analysis of the DTG curves showed that the thermal decomposition of most food supplements takes place in several steps. The results obtained by a combination of both simple, relatively fast and reliable XRPD and DSC/DTG methods are helpful in determining phase composition, pharmaceutical abnormalities or by detecting the presence of the correct polymorphic form.

scholarly journals Preparation and thermal decomposition of solid state cinnamates of alkali earth metals, except beryllium and radium

1998 ◽  
Vol 23 (0) ◽  
pp. 91-98 ◽  
Author(s):  
Ana Glauce ZAINA CHIARETTO ◽  
Marco Aurélio da Silva CARVALHO FILHO ◽  
Nedja Suely FERNANDES ◽  
Massao IONASHIRO
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermal Decomposition ◽  
Solid State ◽  
General Formula ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Preparation And Thermal Decomposition ◽  
Derivative Thermogravimetry

Solid state compounds of general formula ML2.nH2O [where M is Mg, Ca, Sr or Ba; L is cinnamate (C6H5 -CH=CH-COO-) and n = 2, 4, 0.8, 3 respectively], have been synthetized. Thermogravimetry (TG), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC) and X-ray diffraction powder patterns have been used to characterize and to study the thermal stability and thermal decomposition of these compounds.

scholarly journals Evaluation of Thermal-Induced Polymorphic Transformation on Desloratadine and Desloratadine-Benzoic Acid Salt

2020 ◽  
Vol 26 (4) ◽  
pp. 399-405
Author(s):  
Ahmad Ainurofiq ◽  
Rachmat Mauludin ◽  
Diky Mudhakir ◽  
Sundani Nurono Soewandhi
Keyword(s):  
Melting Point ◽  
Benzoic Acid ◽  
Polymorphic Transformation ◽  
Heating Process ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Pharmaceutical Ingredients ◽  
Physicochemical Changes ◽  
Transformation Methods

Background: Active pharmaceutical ingredients face a challenge in manufacturing due to adverse physicomechanical properties. Desloratadine (DES) form I exhibits poor mechanical behavior through the formation of capping during the tableting process. Salt formation from DES and benzoic acid (BA) has been observed to resolve poor mechanical properties. However, the ability to withstand heat from the manufacturing process should be implemented in DES and DES-BA salt. The aim of this study was to determine the differences between thermal treatment results on DES and DES-BA salt and whether it causes them to undergo polymorphic transformation. Methods: Salt was crystallized between DES and BA using the solvent evaporation method. DES and DES-BA salt were heated at 110°C, 159°C (melting point of DES), 181°C (melting point of DES-BA), and 190°C. Following this, characterization was performed using differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and solubility testing. Results: Polymorphic transformation caused by heat occurred in DES, but not in DES-BA salt. The transformation of DES was induced by the effect of heating, which changed polymorph I to a mixture of polymorph I and III at 110°C, to polymorph II at 159°C, and to a mixture of polymorph I, II, and III at 190°C. Under 190oC, DES-BA is still stable and did not undergo a polymorphic transformation. However, at 190oC, decomposition started to occur, which implied decreased solubility, which did not occur in DES. Conclusion: The heating process did not cause DES-BA salt to undergo a polymorphic transformation. However, it caused decomposition at 190oC. DES underwent a polymorphic transformation when exposed to the same condition without decomposition. This provided information to always pay attention to temperature during manufacturing processes that include DES or DES-BA salt to avoid physicochemical changes.

High-temperature powder x-ray diffraction of yttria to melting point

1999 ◽  
Vol 14 (2) ◽  
pp. 456-459 ◽  
Author(s):  
V. Swamy ◽  
N. A. Dubrovinskaya ◽  
L. S. Dubrovinsky
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Melting Point ◽  
Unit Cell Parameter ◽  
Cell Parameter ◽  
Unit Cell ◽  
Diffraction Spectrum ◽  
X Ray Diffraction ◽  
Thermal Expansion Data ◽  
X Ray

Powder x-ray diffraction data of yttria (Y2O3) were obtained from room temperature to melting point with the thin wire resistance heating technique. A solid-state phase transition was observed at 2512 ± 25 K and melting of the high-uemperature phase at 2705 ± 25 K. Thermal expansion data for α–Y2O3 (C-type) are given for the range 298–2540 K. The unit cell parameter increases nonlinearly, especially just before the solid-state transition. The x-ray diffraction spectrum of the high-temperature phase is consistent with the fluorite-type structure (space group Fm3) with a refined unit cell parameter a = 5.3903(6) Å at 2530 K. The sample recrystallized rapidly above 2540 K, and above 2730 K, all the diffraction lines and spots disappeared from the x-ray diffraction spectrum that suggests complete melting.

Solid State Reactions in Mechanically Deformed Composites in the Ni-Zr and the Ni-Ti Systems

1989 ◽  
Vol 170 ◽  
Author(s):  
B. E. White ◽  
M. E. Patt ◽  
E. J. Cotts
Keyword(s):  
Solid State ◽  
Amorphous Material ◽  
Nucleation And Growth ◽  
Solid State Reactions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Disordered Phase ◽  
Multilayered Composites ◽  
High Degree

AbstractDifferential scanning calorimetry and x-ray diffraction analysis were utilized to monitor solid state reactions in mechanically deformed Ni/Ti multilayered composites. Solid state reactions at temperatures less than = 650 K result in the formation of a highly disordered phase which is apparently amorphous.The subsequent nucleation and growth at higher temperatures of intermetallic compounds from the amorphous phase is examined. The relatively small thickness of amorphous material (less than 100 Å) which can be grown by solid state reaction in our Ni/Ti samples, combined with the indication that a disordered interface such as that produced by mechanical deformation facilitates these reactions in the Ni-Ti system, may provide some explanation for the relatively high degree of success experienced in the production of amorphous Ni- Ti by means of ball milling. Comparisons are made to results obtained in the Ni-Zr system.

Kinetics and Thermodynamics of the Formation of Thin Film Titanium Diselicide

1995 ◽  
Vol 398 ◽  
Author(s):  
R.J. Kasica ◽  
E.J. Cotts ◽  
R.G. Ahrens
Keyword(s):  
Thin Film ◽  
Differential Scanning Calorimetry ◽  
Solid State ◽  
Isothermal Calorimetry ◽  
Sputter Deposition ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Average Composition ◽  
Kinetics And Thermodynamics ◽  
X Ray

ABSTRACTMultilayered difiiision couples consisting of alternating layers of titanium (Ti) and amorphous silicon (a-Si) have been fabricated using sputter deposition with a range of modulation lengths corresponding to an average composition of Ti33 Si67. We have used differential scanning calorimetry to measure the enthalpy evolved during the solid state reaction a-Si + Ti → C49-TiSi2 and have characterized the phases formed using x-ray diffraction analysis. An average measured enthalpy of formation, ΔΗ was found to be ΔΗ = -58 + 9 kJ/g atom for thin film samples. Using scanning and isothermal calorimetry measurements, we have also characterized the kinetics involved during the initial intermixing stage.

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