scholarly journals Thermodynamic and Calorimetric Study of Acetylsalicylic Acid (Aspirin) and Ibuprofen

2011 ◽  
Vol 8 (3) ◽  
pp. 1298-1308 ◽  
Author(s):  
Juan Carlos Moreno-Piraján ◽  
Vanessa Silenia García-Cuello ◽  
Liliana Giraldo-Gutierréz
Keyword(s):  
Differential Scanning Calorimetry ◽  
Acetylsalicylic Acid ◽  
Virial Coefficients ◽  
Thermodynamic Characteristics ◽  
Calorimetric Study ◽  
Enthalpies Of Solution ◽  
Acid Salt ◽  
Scanning Calorimetry ◽  
Isoperibolic Calorimeter ◽  
Excess Thermodynamic Functions

Enthalpies of solution and dilution of aqueous solutions of sodium acetylsalicylic acid salt and ibuprofen salt were measured with an isoperibolic calorimeter at 293.15 K, 298.15 K, 303.15 K, 308.15 K and 318.15 K. The concentration of the electrolyte was restricted to the solubility of the salt at various temperatures and did not exceed 0.035–0.057 mol kg-1, depending on the temperature studied. The Virial coefficients were derived from Pitzer's model and the excess thermodynamic functions of both the solution and the components of the solution were calculated. An analysis of the thermodynamic characteristics of the solution in terms of concentration and temperature interval was carried out and discussed. Additionally, an analysis was performed by differential scanning calorimetry (DSC).

Probing of the combined effect of bisquaternary ammonium antimicrobial agents and acetylsalicylic acid on model phospholipid membranes: differential scanning calorimetry and mass spectrometry studies

2014 ◽  
Vol 10 (12) ◽  
pp. 3155-3162 ◽  
Author(s):  
N. A. Kasian ◽  
V. A. Pashynska ◽  
O. V. Vashchenko ◽  
A. O. Krasnikova ◽  
A. Gömöry ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Differential Scanning Calorimetry ◽  
Acetylsalicylic Acid ◽  
Antimicrobial Agents ◽  
Combined Effect ◽  
Phospholipid Membranes ◽  
Scanning Calorimetry ◽  
Combined Use ◽  
The Individual

Qualitatively different membranotropic effects of the individual drugs and complexes formed in their combined use were demonstrated by differential scanning calorimetry.

scholarly journals Calorimetric study on Bi-Cu-Sn alloys

2019 ◽  
Vol 38 (2019) ◽  
pp. 541-546
Author(s):  
Jolanta Romanowska
Keyword(s):  
Differential Scanning Calorimetry ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Temperature Interval ◽  
Energy Dispersive Spectrometer ◽  
Energy Dispersive ◽  
Calorimetric Study ◽  
Calorimetric Investigation ◽  
Scanning Calorimetry ◽  
Scanning Electron

AbstractThe paper presents results of calorimetric investigation of the Bi-Cu-Sn system by means of differential scanning calorimetry (DSC) at the temperature interval 25-1250∘C, Values of liquidus, solidus and invariant reactions temperatures, as well as melting enthalpies of the selected alloys were determined. Microstructure investigation of the alloys were performed by the use of a scanning electron microscope (SEM) equipped with an energy-dispersive spectrometer (EDS).

scholarly journals Thermodynamic study of binary mixture of citric acid and tartaric acid

2012 ◽  
Vol 10 (5) ◽  
pp. 1584-1589 ◽  
Author(s):  
Viorica Meltzer ◽  
Elena Pincu
Keyword(s):  
Phase Diagram ◽  
Differential Scanning Calorimetry ◽  
Citric Acid ◽  
Binary Mixture ◽  
Tartaric Acid ◽  
Heat Of Mixing ◽  
Scanning Calorimetry ◽  
Entropy Of Fusion ◽  
Excess Thermodynamic Functions ◽  
Solid Liquid

AbstractThe solid — liquid phase equilibria for binary mixture of citric acid with tartaric acid were measured using differential scanning calorimetry. The phase diagram showed the existence a simple eutectic behavior. The thermal properties of this system as heat of mixing, entropy of fusion and excess thermodynamic functions were computed using enthalpy of fusion values. The composition of eutectic was determined using a Tammann diagram.

Calorimetric Study of the Energetics and Kinetics of Interdiffusion in Cu/Cu6sn5 Thin Film Diffusion Couples

1995 ◽  
Vol 398 ◽  
Author(s):  
W. K. Neils ◽  
R. R. Chromik ◽  
K. F. Dreyer ◽  
D. Grosman ◽  
E. J. Cotts
Keyword(s):  
Differential Scanning Calorimetry ◽  
Bulk Diffusion ◽  
Heat Of Formation ◽  
Calorimetric Study ◽  
Diffusion Couples ◽  
Scanning Calorimetry ◽  
Metal Diffusion ◽  
Diffusion Limited ◽  
Thin Film Diffusion ◽  
Kinetics Of

ABSTRACTWe find differential scanning calorimetry to be suitable for the characterization of the energetics and kinetics of interdiflusion in solder/metal diffusion couples. Differential scanning calorimetry studies of interdiffusion in Cu/Cu6Sn5 diffusion couples have shown that the driving force for interdiffusion is similar for thin film composites and for bulk diffusion couples. The heat of formation of Cu3Sn from Cu6Sn5 and Cu thin films was found to be ΔHr = −4.3 + 0.3 kJ/mol. Portions of our differential scanning calorimetry scans are identified with diffusion limited growth of Cu3Sn. From these calorimetry data we have estimated D(cm2 / s) = Do exp(−E / kbT), where kb is Boltzmann's constant, D0 = 3.2 × 10–2 cm2/s, and E=0.87 eV/atom.

A Differential Scanning Calorimetric Study of the Mg-Cu-Y System

2012 ◽  
Vol 706-709 ◽  
pp. 1215-1220 ◽  
Author(s):  
Mohammad Mezbahul-Islam ◽  
Elhachmi Essadiqi ◽  
Mamoun Medraj
Keyword(s):  
Differential Scanning Calorimetry ◽  
Metallic Glass ◽  
Thermodynamic Modeling ◽  
Differential Scanning Calorimetric ◽  
Phase Assemblage ◽  
Calorimetric Study ◽  
Solidification Behavior ◽  
Scanning Calorimetry ◽  
Ternary Compounds ◽  
Melting Temperatures

The Mg-Cu-Y system has been experimentally investigated using differential scanning calorimetry (DSC). Vertical sections and phase assemblage diagrams are calculated using thermodynamic modeling. Solidification behavior of the key alloys was discussed in light of the thermodynamic calculation. Melting temperatures of two of the ternary compounds; Mg18CuY and Mg4CuY, are predicted using the modified thermodynamic database of this system. Key words: Mg alloys, Bulk metallic glass, Differential scanning calorimetry, Thermodynamic modeling.

scholarly journals A calorimetric study of human CuZn superoxide dismutase

1987 ◽  
Vol 248 (3) ◽  
pp. 981-984 ◽  
Author(s):  
C G Biliaderis ◽  
R J Weselake ◽  
A Petkau ◽  
A D Friesen
Keyword(s):  
Differential Scanning Calorimetry ◽  
Binding Sites ◽  
Specific Activity ◽  
Calorimetric Study ◽  
Thermal Transitions ◽  
Scanning Calorimetry ◽  
Structural Units ◽  
Conformational Order ◽  
Higher Temperature ◽  
Cuzn Superoxide Dismutase

Structural alterations, as manifested by thermal transitions, caused by removal or binding of metal ions to human and bovine CuZn superoxide dismutases (SODs) were investigated by differential scanning calorimetry. Although holo forms of the two mammalian enzymes exhibited irreversible thermal transitions (delta Hcal. = 27.7 J/g and Td = 104 degrees C for bovine SOD; delta Hcal. = 23.6 J/g and Td = 101 degrees C for human SOD), only the bovine apoenzyme showed the presence of a less thermostable form (delta Hcal. = 10.7 J/g and Td = 63 degrees C). These observations suggested that human apo-SOD had considerably less conformational order than bovine apo-SOD. Reconstitution of human and bovine apoenzymes with Cu2+ and Zn2+ resulted in recovery of thermodynamic parameters and specific activity. Binding of Zn2+ alone to human apo-SOD resulted in the formation of two distinct structural units, detectable by differential scanning calorimetry, which underwent conformational disorder at 82 and 101 degrees C respectively. Saturation of binding sites with both Zn2+ and Cu2+ appeared to stabilize the enzyme structure further as shown by elimination of the low-temperature transition and the appearance of another thermal transition at a higher temperature.

scholarly journals Effect of tartaric acid on conformation and stability of human prostatic phosphatase: an infrared spectroscopic and calorimetric study.

2001 ◽  
Vol 48 (3) ◽  
pp. 755-762 ◽  
Author(s):  
S Bem ◽  
W S Ostrowski
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Tartaric Acid ◽  
Solution Structure ◽  
Prostatic Acid Phosphatase ◽  
Thermal Unfolding ◽  
Calorimetric Study ◽  
Scanning Calorimetry ◽  
Thermal Stability Of

The solution structure and thermal stability of human prostatic acid phosphatase (hPAP) in the absence and in the presence of tartaric acid were studied by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The temperature dependence of the infrared spectrum and DSC scans indicate that hPAP undergoes thermal unfolding at a temperature between 49.5 and 52.5 degrees C. Binding of tartaric acid does not lead to major changes in the secondary structure of hPAP, however, hPAP with bound tartaric acid shows a significantly increased thermal stability. These results helped to better understand the mechanism of hPAP unfolding at the elevated temperature.

scholarly journals Thermal Behavior of the Nimesulide-Salicylic Acid Eutectic Mixtures Prepared by Mechanosynthesis and Recrystallization

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7715
Author(s):  
Mona Georgescu ◽  
Viorica Meltzer ◽  
Ioana Stănculescu ◽  
Elena Pincu
Keyword(s):  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Salicylic Acid ◽  
Infrared Spectroscopy ◽  
Binary Systems ◽  
Molar Fraction ◽  
Scanning Calorimetry ◽  
Eutectic Mixtures ◽  
Excess Thermodynamic Functions ◽  
Viable Approach

Nimesulide, salicylic acid and their binary mixtures were studied by differential scanning calorimetry (DSC) and Fourier Transform Infrared spectroscopy (FTIR). The study of such systems is a promising and viable approach for solving the problem of poor solubility of materials in general and drug systems in particular. All areas of human activity are inextricably linked to materials, and thus, the study presented in the paper and not reported in the literature is very important and provides useful data for those working in various fields. The eutectic mixtures were obtained by mechanosynthesis and by recrystallization from ethanol over the entire 0–1 range of molar fractions. For both situations at the molar fraction of nimesulide 0.5, the mixture has a eutectic that suggests an increase in solubility at this composition. The interactions that take place between the components were determined with the help of the excess thermodynamic functions (GE, SE, µE), which highlight the deviation from the ideality of the considered binary systems.

A calorimetric study of the thermal transitions of Halobacterium cutirubrum

1982 ◽  
Vol 60 (4) ◽  
pp. 419-421 ◽  
Author(s):  
K. C. Cho ◽  
K. C. Chow ◽  
K. K. Mark
Keyword(s):  
Differential Scanning Calorimetry ◽  
Envelope Glycoprotein ◽  
Hydrophobic Interactions ◽  
Major Protein ◽  
Calorimetric Study ◽  
Thermal Transitions ◽  
Scanning Calorimetry ◽  
Previous Proposal ◽  
Protein Components

The thermal transitions of Halobacterium cutirubrum have been examined by differential scanning calorimetry. Two distinct peaks corresponding to the denaturation of two major protein components were observed in the heating curves. One of the peaks has been assigned to the denaturation of the envelope glycoprotein. The variations of the denaturation temperatures with the addition of glucose, glycerol, NaNO3, and NaSCN are consistent with the previous proposal that hydrophobic interactions are essential in stabilizing the glycoprotein.

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