Reactions in Molten Alkalimetal Polychalcogenides: What Happens in the Melt? A Study of the Reactions in the System K—Nb—S Using Differential Scanning Calorimetry, Infrared Spectroscopy, and X-Ray Powder Diffraction.

ChemInform ◽  
2003 ◽  
Vol 34 (14) ◽  
Author(s):  
Peter Duerichen ◽  
Wolfgang Bensch
Keyword(s):  
Differential Scanning Calorimetry ◽  
Infrared Spectroscopy ◽  
Powder Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

Metoprolol: solid forms of a top selling antihypertensive

CrystEngComm ◽  
2019 ◽  
Vol 21 (29) ◽  
pp. 4319-4328 ◽  
Author(s):  
Mariani A. Ciciliati ◽  
M. Ermelinda S. Eusébio ◽  
Manuela Ramos Silva ◽  
Éder T. G. Cavalheiro ◽  
Ricardo A. E. Castro
Keyword(s):  
Differential Scanning Calorimetry ◽  
Infrared Spectroscopy ◽  
Nicotinic Acid ◽  
Powder Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Base Form

A new polymorph of metoprolol base, form II, was identified and characterized by differential scanning calorimetry, X-ray powder diffraction and infrared spectroscopy. A new salt of metoprolol and nicotinic acid was also obtained and characterized.

Reactions in Molten Alkalimetal Polychalcogenides: What Happens in the Melt? A Study of the Reactions in the System K-Nb-S Using Differential Scanning Calorimetry, Infrared Spectroscopy, and X-Ray Powder Diffraction

2002 ◽  
Vol 57 (12) ◽  
pp. 1382-1386 ◽  
Author(s):  
Peter Dürichen ◽  
Wolfgang Bensch
Keyword(s):  
Crystal Structure ◽  
Differential Scanning Calorimetry ◽  
Infrared Spectroscopy ◽  
Powder Diffraction ◽  
Analytical Techniques ◽  
Product Formation ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ft Ir ◽  
Short Time

The reactions of potassium polysulfides with elemental Nb were investigated with different analytical techniques. The amount of the polysulfide applied has no influence onto product formation, i. e. the ratio K2Sx: Nb is not important. The length of the polsysulfide chain, i. e. the value of x in K2Sx determines what product is formed. In sulfur-poor melts, K3NbS4 is observed. Increasing x to 5 - 6, K4Nb2S11 is formed with a structure containing S22− anions. Finally, applying a melt with x > 6, K6Nb4S25 is found as the product with a crystal structure containing the S52− polysulfide anion. When K2Sx (x < 5) is heated with sulfur in the first step the pentasulfide K2S5 is formed. Immediately after melting of K2S5 a reaction with elemental Nb occurs. The results of FT-IR and X-ray investigations have demonstrated that after oxidation the anion [Nb2S11]4− is formed relatively fast, and after a short time crystalline K4Nb2S11 can be detected. After 24 h the reaction is complete.

PREPARATION AND CHARACTERIZATION OF AMORPHOUS CEFUROXIME AXETIL

INDIAN DRUGS ◽  
2013 ◽  
Vol 50 (10) ◽  
pp. 53-61
Author(s):  
B. V. Dhokchawle ◽  
◽  
A. B. Bhandari
Keyword(s):  
Differential Scanning Calorimetry ◽  
Infrared Spectroscopy ◽  
Powder Diffraction ◽  
Cefuroxime Axetil ◽  
Scanning Calorimetry ◽  
Amorphous Form ◽  
X Ray ◽  
Saturation Solubility ◽  
Fourier Transformed Infrared Spectroscopy

In the present study, amorphous form of cefuroxime axetil was prepared and characterized by various methods. The result showed that the amorphous form of cefuroxime axetil with hydrophilic carriers was successfully obtained by freeze drying. The amorphous form showed a substantially higher dissolution rate and saturation solubility than cefuroxime axetil and physical mixture. The molecular behaviour of the drug in all samples were characterized by X-ray powder diffraction, Fourier transformed infrared spectroscopy, scanning electron microscopy and differential scanning calorimetry. The dissolution and saturation solubility studies of the samples were performed. The X-ray powder diffraction, Fourier transformed infrared spectroscopy and differential scanning calorimetry provided useful information to support the amorphousness of the samples.

Evidence for room temperature mesomorphism in a mixed-valent diruthenium(II,III) quintapalmitoleate polymer

1998 ◽  
Vol 76 (11) ◽  
pp. 1520-1523
Author(s):  
Jennifer F Caplan ◽  
Christopher A Murphy ◽  
Susan Swansburg ◽  
Robert P Lemieux ◽  
T Stanley Cameron ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Powder Diffraction ◽  
Strong Evidence ◽  
Room Temperature ◽  
Variable Temperature ◽  
Mixed Valence ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Crystal Transition

The synthesis of Ru2(μ-O2CR)4(μ´-O2CR) (1), R = -CH2(CH2)6CH=CH(CH2)5CH3, has been achieved and characterization using elemental analysis and FTIR and UV-Vis spectroscopies undertaken. Strong evidence for a hexagonal discotic mesophase has been found using differential scanning calorimetry, variable-temperature polarizing optical microscopy, and X-ray powder diffraction. A solid to liquid crystal transition was found upon heating at 128°C and the mesophase is found to persist to room temperature upon cooling from 150°C. This is the first report of room temperature mesomorphism in a mixed-valent metallomesogen. Key words: ruthenium carboxylate, liquid crystal, metallomesogen, mixed valence, polymer.

scholarly journals Organic Salts of Pharmaceutical Impurity p-Aminophenol

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1910
Author(s):  
U. B. Rao Khandavilli ◽  
Leila Keshavarz ◽  
Eliška Skořepová ◽  
René R. E. Steendam ◽  
Patrick J. Frawley
Keyword(s):  
Differential Scanning Calorimetry ◽  
Salicylic Acid ◽  
Infrared Spectroscopy ◽  
Efficacy And Safety ◽  
Salt Formation ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Organic Salts ◽  
X Ray ◽  
Dark Color

The presence of impurities can drastically affect the efficacy and safety of pharmaceutical entities. p-Aminophenol (PAP) is one of the main impurities of paracetamol (PA) that can potentially show toxic effects such as maternal toxicity and nephrotoxicity. The removal of PAP from PA is challenging and difficult to achieve through regular crystallization approaches. In this regard, we report four new salts of PAP with salicylic acid (SA), oxalic acid (OX), l-tartaric acid (TA), and (1S)-(+)-10-camphorsulfonic acid (CSA). All the PAP salts were analyzed using single-crystal X-ray diffraction, powder X-ray diffraction, infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The presence of minute amounts of PAP in paracetamol solids gives a dark color to the product that was difficult to remove through crystallization. In our study, we found that the addition of small quantities of the aforementioned acids helps to remove PAP from PA during the filtration and washings. This shows that salt formation could be used to efficiently remove challenging impurities.

scholarly journals Polymorphism of 1,3-X-adamantanes (X = Br, OH, CH3) and the crystal plastic phase formation ability

CrystEngComm ◽  
2020 ◽  
Vol 22 (7) ◽  
pp. 1230-1238 ◽  
Author(s):  
Philippe Negrier ◽  
Bacem Ben Hassine ◽  
Maria Barrio ◽  
Michela Romanini ◽  
Denise Mondieig ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
High Pressure ◽  
Phase Formation ◽  
Powder Diffraction ◽  
Scanning Calorimetry ◽  
Density Measurements ◽  
X Ray ◽  
Plastic Phase

The polymorphism of 1,3-dimethyladamantane (13DMA), 1,3-adamantanediol (13DOHA) and 1,3-dibromoadamantane (13DBrA) has been studied by X-ray powder diffraction, density measurements and differential scanning calorimetry at normal and high-pressure.

scholarly journals PREPARATION AND EVALUATION OF ORALLY DISINTEGRATING TABLETS OF DROTAVERINE HYDROCHLORIDE USING SUBLIMATION TECHNIQUE

2018 ◽  
Vol 10 (5) ◽  
pp. 85
Author(s):  
Kuralla Hari ◽  
Saripilli Rajeswari ◽  
Kolapalli Venkata Ramanamurthy
Keyword(s):  
Differential Scanning Calorimetry ◽  
Infrared Spectroscopy ◽  
Fourier Transformation ◽  
Taste Masking ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Orally Disintegrating Tablets ◽  
Fourier Transformation Infrared Spectroscopy ◽  
Drotaverine Hydrochloride ◽  
Sublimation Technique

Objective: To formulate orally disintegrating taste masked tablets of drotaverine hydrochloride (HCl) by sublimation technique.Methods: Initially superdisintegrant was selected and its concentration was optimized by pre-compression and post-compression parametric evaluation. Camphor and menthol were used as sublimating agents alone and in combination to mask the taste of drotaverine hydrochloride. Prepared tablets were evaluated for physicochemical evaluation, in vitro dissolution studies and fourier transformation-infrared spectroscopy, differential scanning calorimetry and X-ray diffractometry studies.Results: The optimised formulation DCM2 prepared with a mixture of camphor and menthol was characterised by fourier transformation-infrared spectroscopy, differential scanning calorimetry and X-ray diffractometry studies and found no incompatibility and no major shifts were noticed.Conclusion: The results demonstrated that the prepared drotaverine HCl orally disintegrating tablets showed better taste masking. The present sublimation technique can be effectively used for taste masking and also for orally disintegrating tablets.

Thermal annealing of natural, radiation-damaged pyrochlore

2017 ◽  
Vol 232 (1-3) ◽  
Author(s):  
Peter Zietlow ◽  
Tobias Beirau ◽  
Boriana Mihailova ◽  
Lee A. Groat ◽  
Thomas Chudy ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Raman Scattering ◽  
Radiation Damage ◽  
Thermal Annealing ◽  
Powder Diffraction ◽  
Scanning Calorimetry ◽  
Natural Radiation ◽  
Α Decay ◽  
X Ray ◽  
Decay Products

AbstractRadiation damage in minerals is caused by the α-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400–1000 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia [6.4 wt% Th, 23.1·10

Crystallisation of caesium borosilicate glasses with approximate boroleucite composition

2002 ◽  
Vol 217 (6) ◽  
Author(s):  
R. Hübner ◽  
A. Belger ◽  
D. C. Meyer ◽  
P. Paufler ◽  
I. G. Polyakova
Keyword(s):  
Differential Scanning Calorimetry ◽  
Powder Diffraction ◽  
Borosilicate Glass ◽  
Orthorhombic Phase ◽  
Borosilicate Glasses ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Annealing Behaviour ◽  
Profile Fitting

AbstractCrystallisation and annealing behaviour of two caesium borosilicate glass samples with approximate boroleucite composition were characterised by means of differential scanning calorimetry measurements as well as X-ray powder diffraction investigations with subsequent profile fitting of the observed patterns according to the Rietveld and/or Pawley method. While one sample crystallised primarily in an orthorhombic phase (

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