The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Massao Ionashiro - One of the best experts on this subject based on the ideXlab platform.
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Synthesis, characterization and thermal behaviour of heavy lanthanide and yttrium pyruvates in the solid state
Journal of Thermal Analysis and Calorimetry, 2009Co-Authors: Adriano Buzutti De Siqueira, Cláudio Teodoro De Carvalho, E. C. Rodrigues, E. Y. Ionashiro, Gilbert Bannach, Massao IonashiroAbstract:Solid-state Ln–L compounds, where Ln stands for heavy trivalent lanthanides or yttrium (III) (Tb–Lu, Y) and where L is pyruvate, have been synthesized. Thermogravimetry and Derivative Thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), X-Ray powder diffractometry, infrared spectroscopy, elemental analysis and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, thermal behaviour, ligand denticity of the isolated complexes.
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synthesis characterization and thermal behaviour on solid pyruvates of some bivalent metal ions
Eclética Química, 2009Co-Authors: Adriano Buzutti De Siqueira, Cláudio Teodoro De Carvalho, E. Y. Ionashiro, Massao IonashiroAbstract:Solid state M-L compounds, were M stands for bivalent Mn, Fe, Co, Ni, Cu, Zn and L is pyruvate, have been synthesized. Thermogravimetry and Derivative Thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), X-Ray powder diffractometry, infrared spectroscopy, elemental analysis, and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, ligand denticity, and thermal decomposition of the isolated compounds.
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thermal decomposition of the magnesium zinc lead and niobium chelates derived from 8 quinolinol
Journal of Thermal Analysis and Calorimetry, 1997Co-Authors: S A Juiz, M I G Leles, A C F Caires, N Boralle, Massao IonashiroAbstract:Solid M-Ox compounds, whereM represents Mg(II), Zn(II), Pb(II) and NbO(III), and Ox is 8-quinolinol, have been prepared. Thermogravimetry, Derivative Thermogravimetry (TG, DTG), differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR) and infrared absorption spectra (IR) have been used to characterize and to study the thermal stability and thermal decomposition of these compounds.
Ali K Attia - One of the best experts on this subject based on the ideXlab platform.
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study of thermal analysis behavior of fenbendazole and rafoxanide
Advanced Pharmaceutical Bulletin, 2017Co-Authors: Ali K Attia, Ahmed S Saad, Manal Sami Alaraki, Ema S ElzanfalyAbstract:Purpose: Thermal analysis techniques have been applied to study the thermal behavior of fenbendazole (Fen) and rafoxanide (Raf). Semi-empirical molecular orbital calculations were used to confirm these results. Methods: Thermogravimetric analysis, Derivative Thermogravimetry, differential thermal analysis and differential scanning calorimetry were used to determine the thermal behavior and purity of the drugs under investigation. Results: Thermal behavior of Fen and Raf were augmented using semi-empirical molecular orbital calculations. The purity values were found to be 99.17% and 99.60% for Fen and Raf, respectively. Conclusion: Thermal analysis techniques gave satisfactory results to obtain quality control parameters such as melting point and degree of purity at low cost, furthermore, its simplicity and sensitivity justifies its application in quality control laboratories.
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thermal analysis study of antihypertensive drugs telmisartan and cilazapril
Advanced Pharmaceutical Bulletin, 2014Co-Authors: Refaat Saber, Ali K Attia, Waheed M SalemAbstract:Purpose: The aim of the present work is to study the thermal analysis of telmisartan and cilazapril. Methods: Thermogravimetry (TGA), Derivative Thermogravimetry (DTG) and differential thermal analysis (DTA) were used through the work to achieve the thermal analysis study of some antihypertensive drugs, telmisartan and cilazapril. Results: The results led to thermal stability data and also to the interpretation concerning the thermal decomposition. Thermogravimetry data allowed determination of the kinetic parameters such as, activation energy and frequency factor. Conclusion: The simplicity, speed and low operational costs of thermal analysis justify its application in the quality control of pharmaceutical compounds for medications.
Jivaldo Do Rosario Matos - One of the best experts on this subject based on the ideXlab platform.
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thermal behavior study and decomposition kinetics of salbutamol under isothermal and non isothermal conditions
Journal of Thermal Analysis and Calorimetry, 2009Co-Authors: Fabiana S Felix, L Cides C Da Silva, Lucio Angnes, Jivaldo Do Rosario MatosAbstract:Abstract The thermal decomposition of salbutamol (β2 — selective adrenoreceptor) was studied using differential scanning calorimetry (DSC) and Thermogravimetry/Derivative Thermogravimetry (TG/DTG). It was observed that the commercial sample showed a different thermal profile than the standard sample caused by the presence of excipients. These compounds increase the thermal stability of the drug. Moreover, higher activation energy was calculated for the pharmaceutical sample, which was estimated by isothermal and non-isothermal methods for the first stage of the thermal decomposition process. For isothermal experiments the average values were E act=130 kJ mol−1 (for standard sample) and E act=252 kJ mol−1 (for pharmaceutical sample) in a dynamic nitrogen atmosphere (50 mL min−1). For non-isothermal method, activation energy was obtained from the plot of log heating rates vs. 1/T in dynamic air atmosphere (50 mL min−1). The calculated values were E act=134 kJ mol−1 (for standard sample) and E act=139 kJ mo...
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determinacao dos teores de umidade e cinzas de amostras comerciais de guarana utilizando metodos convencionais e analise termica
Revista Brasileira De Ciencias Farmaceuticas, 2006Co-Authors: Adriano Antunes De Souza Araujo, Silvia Storpirtis, Lucildes Pita Mercuri, Sergio Ricardo Stuckert Seixas, Jivaldo Do Rosario MatosAbstract:Paullinia cupana Kunth a vegetable popularly known as guarana, belongs to the Sapindaceas plant family and is predominant in the Amazon region. The low quality of this product can be attributed to the species and less noble varieties, harvest techniques and/or inadequate processing or, yet due to addition of substances that are not included in its natural composition. The main goal of this work was to evaluate from Thermogravimetry (TG)/Derivative Thermogravimetry (DTG) and differential scanning calorimetry (DSC), the thermal behavior of powdered guarana samples in the Brazilian market in order to evaluate the thermal behavior of guarana powder samples commercialized in Brazil and to establish a comparative study between conventional and TG methods for humidity contents determination and ashes. In general, the samples did not present significant differences in the DSC curves profiles and TG/DTG. The Thermogravimetry showed that it is possible to decrease the time of the analysis using less amount of sample and allowed to determine humidity and ashes contents. In relation to conventional method the errors of analysis inherent of the samples manipulation were decreased. The thermoanalytical techniques have shown potential applications in the determination of technological parameters, such as: quality control, toasting and adequate stock conditions.
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thermal behaviour compatibility study and decomposition kinetics of glimepiride under isothermal and non isothermal conditions
Journal of Thermal Analysis and Calorimetry, 2006Co-Authors: L C S Cides, Adriano Antunes De Souza Araujo, M Santosfilho, Jivaldo Do Rosario MatosAbstract:Abstract In the present work, the thermal decomposition of glimepiride (sulfonylurea hypoglycemic agent) was studied using differential scanning calorimetry (DSC) and Thermogravimetry/Derivative Thermogravimetry (TG/DTG). Isothermal and non-isothermal methods were employed to determine kinetic data of decomposition process. The physical chemical properties and compatibilities of several commonly used pharmaceutical excipients (glycolate starch, microcrystalline cellulose, stearate, lactose and Plasdone) with glimepiride were evaluated using thermoanalytical methods. The 1:1 physical mixtures of these excipients with glimepiride showed physical interaction of the drug with Mg stearate, lactose and Plasdone. On the other hand, IR results did not evidence any chemical modifications. From isothermal experiments, activation energy (Ea) can be obtained from slope of lnt vs. 1/T at a constant conversion level. The average value of this energy was 123 kJ mol–1. For non-isothermal method Ea can be obtained from p...
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thermal analysis of the antiretroviral zidovudine azt and evaluation of the compatibility with excipients used in solid dosage forms
International Journal of Pharmaceutics, 2003Co-Authors: Adriano Antunes De Souza Araujo, Silvia Storpirtis, Lucildes Pita Mercuri, Flavio Machado De Souza Carvalho, Mery Dos Santos Filho, Jivaldo Do Rosario MatosAbstract:Modern thermal analysis techniques are frequently used because of their ability to provide detailed information about both the physical and the energetic properties of a substance. In the present work, the thermal decomposition of zidovudine (AZT) was studied using differential scanning calorimetry (DSC) and Thermogravimetry/Derivative Thermogravimetry (TG/DTG). Thermal analysis was supplemented using elemental analysis (C, H, and N), infrared (IR) spectroscopy, and X-ray powder diffraction to characterize the solid intermediates products. Volatile products of the thermal decomposition of AZT were studied by a system composed of the TG/DTA coupled gas chromatography/mass spectrometry (GC/MS). The physical-chemical properties and compatibilities of several commonly used pharmaceutical excipients with AZT were evaluated using thermal methods. The results showed that the product originated from the first thermal decomposition stage corresponds to the cleavage followed by elimination of the azide group and consequent formation of thymine. The second event corresponds to thermal decomposition of thymine. TG/DTA-GC/MS system identified thymine's decomposition products as furan and 2-furanmethanol like volatile species. Comparison of the thermoanalytical profiles of the mixtures with individual compounds did not give any evidence of interactions.
Ema S Elzanfaly - One of the best experts on this subject based on the ideXlab platform.
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study of thermal analysis behavior of fenbendazole and rafoxanide
Advanced Pharmaceutical Bulletin, 2017Co-Authors: Ali K Attia, Ahmed S Saad, Manal Sami Alaraki, Ema S ElzanfalyAbstract:Purpose: Thermal analysis techniques have been applied to study the thermal behavior of fenbendazole (Fen) and rafoxanide (Raf). Semi-empirical molecular orbital calculations were used to confirm these results. Methods: Thermogravimetric analysis, Derivative Thermogravimetry, differential thermal analysis and differential scanning calorimetry were used to determine the thermal behavior and purity of the drugs under investigation. Results: Thermal behavior of Fen and Raf were augmented using semi-empirical molecular orbital calculations. The purity values were found to be 99.17% and 99.60% for Fen and Raf, respectively. Conclusion: Thermal analysis techniques gave satisfactory results to obtain quality control parameters such as melting point and degree of purity at low cost, furthermore, its simplicity and sensitivity justifies its application in quality control laboratories.
Waheed M Salem - One of the best experts on this subject based on the ideXlab platform.
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thermal analysis study of antihypertensive drugs telmisartan and cilazapril
Advanced Pharmaceutical Bulletin, 2014Co-Authors: Refaat Saber, Ali K Attia, Waheed M SalemAbstract:Purpose: The aim of the present work is to study the thermal analysis of telmisartan and cilazapril. Methods: Thermogravimetry (TGA), Derivative Thermogravimetry (DTG) and differential thermal analysis (DTA) were used through the work to achieve the thermal analysis study of some antihypertensive drugs, telmisartan and cilazapril. Results: The results led to thermal stability data and also to the interpretation concerning the thermal decomposition. Thermogravimetry data allowed determination of the kinetic parameters such as, activation energy and frequency factor. Conclusion: The simplicity, speed and low operational costs of thermal analysis justify its application in the quality control of pharmaceutical compounds for medications.