Netsu Sokutei
Online ISSN : 1884-1899
Print ISSN : 0386-2615
ISSN-L : 0386-2615
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Volume 38, Issue 4
Displaying 1-5 of 5 articles from this issue
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  • Thermoanalysis-based Rapid Stability Predicting for Drug Candidates
    Akinori Goto, Hirotoshi Mori
    2011 Volume 38 Issue 4 Pages 112-115
    Published: August 31, 2011
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.38.4_112
    JOURNAL FREE ACCESS
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    For thermoanalysis-based stability prediction of a drug candidate, the highest temperature applicable so far to humidity-controlling of gas flow into a heat furnace has been limited to about 80℃. We solved this limitation by placing a water-containing bottle between gas-flow tubing segments and then flowing a humidity-saturated nitrogen gas at room temperature into the heat furnace to decompose a sample. This allowed furnace-heating at 150℃. In this study, the predicted decomposition rate was compatible with the actual decomposition rate, but it would be necessary to validate this method in future.
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Review
  • Cleaning Technology in Electronic Industries and Its Improvement Based on Thermodynamics
    Takashi Minamihonoki
    2011 Volume 38 Issue 4 Pages 116-124
    Published: August 31, 2011
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.38.4_116
    JOURNAL FREE ACCESS
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    Solvents used in industrial cleaning processes have been required to be replaced with safer ones from ecological view point. For example CFC (Chlorofluorocarbon) was replaced with HFE (Hydrofluoroether) or HFC (Hydorofluorocarbon) to avoid ozone depletion and SPM (Sulfuric acid / Hydrogen peroxide water mixture) was replaced with ozonated water or supercritical fluid. Replacement of these well-known compounds to new materials requires improvement of rinse and drying processes as well because the new solvents have notably different properties from the conventional ones. In this report outline of the advanced cleaning technologies in electronic industries are described and improvement of cleaning process using HFE solvent is explained based on thermodynamics.
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  • Evaluation of Crystallization of Amorphous Drugs by Thermal Analysis
    Tamaki Miyazaki, Yukio Aso
    2011 Volume 38 Issue 4 Pages 125-131
    Published: August 31, 2011
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.38.4_125
    JOURNAL FREE ACCESS
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    About half of candidates for active pharmaceutical ingredients are poorly water soluble compounds. Amorphization of poorly water soluble drugs has attracted much attention due to improved dissolution characteristics and bioavailability of amorphous drugs. On the other hand, crystallization during storage is of concern for amorphous drugs. Therefore, evaluation of crystallization of amorphous drug is important for developing stable pharmaceuticals using amorphous drugs. In this article, feasibility of thermal method such as differential scanning calorimeter and isothermal microcalorimeter for evaluating crystallization of amorphous drugs and research topics on the crystallization of amorphous drug are described.
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  • Thermodynamic and Kinetic Stability of p-type Transparent Conducting Oxide
    Takuya Hashimoto
    2011 Volume 38 Issue 4 Pages 132-139
    Published: August 31, 2011
    Released on J-STAGE: November 20, 2022
    DOIhttps://doi.org/10.11311/jscta.38.4_132
    JOURNAL FREE ACCESS
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    Stability of p-type transparent conducting oxides, CuAlO2, CuGaO2 and SrCu2O2, at high temperature has been studied by thermogravimetry, X-ray diffraction and thermodynamic calculation. It has been revealed that they decompose at high temperature in air according to the following chemical reaction formula; 4CuMO2＋O2 → 2CuO ＋2CuM2O4 (M = Al, Ga) and 28SrCu2O2＋17O2 → 2Sr14Cu24O41＋8CuO. Assuming the first order reaction, kinetics of the chemical reactions and their activation energies have been evaluated from weight variation by time at the constant temperature measured by thermogravimetry. It was concluded that the order of the kinetic stability was CuAlO2, CuGaO2 and SrCu2O2. Ellingham diagram of the chemical reactions prepared in this study showed that thermodynamic stability of CuAlO2 was higher than that of CuGaO2 and SrCu2O2. It was also revealed that CuAlO2, CuGaO2 and SrCu2O2 are not thermodynamically stable in air below 800 ℃, 1200 ℃ and 1140 ℃, respectively, showing agreement with the weight increase due to the chemical reactions at constant temperatures in air. It can be expected that the p-type transparent conducting oxides would be kinetically stable with decreasing oxygen partial pressure, since temperatures where CuAlO2, CuGaO2 and SrCu2O2 decomposed decreased in the Ellingham diagram. However, decomposition of SrCu2O2 was observed even at 400 ℃ under oxygen partial pressure of 10 －3 atm, which could be attributed to fast kinetics of the reaction even at 400 ℃ under such a low oxygen partial pressure.
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