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  • Author or Editor: Ana Gomes x
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Abstract  

The objective of this work was to develop and validate a fast and reproducible method which is able to determine the concentration of ketoconazole in raw materials and tablets. The samples were analyzed by dynamic thermogravimetry at heating rates of 10, 20, 40, 60 and 80°C min−1 in nitrogen and nitrogen-synthetic air mixture. The concentrations of ketoconazole in the raw material and in the tablets were obtained from the vapor pressure curves. The data showed that there is no significant difference between the vapor pressure profiles of ketoconazole itself and in its tablet in both studied environmental conditions confirming that the process is really vaporization. The concentration of ketoconazole was determined in the raw material and tablets of the drug.

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Abstract  

The objective of this work was to develop and validate a fast and reproducible method able to determine the concentration of mebendazole in raw materials and tablets. The samples were analyzed by dynamic thermogravimetry, in the heating rates of 10, 20, 40, 60 and 80C min–1, in the atmospheres of nitrogen and nitrogen with synthetic air. Obtained data were used in the equations of Antoine and Langmuir, with the purpose to get the pressure curves of those. Vapor pressure curves of drug and tablet of mebendazole were evaluated using the mathematical indexes of difference factor, f 1, and similarity factor, f 2, to compare its profiles. The data showed that there is no significant difference between the vapor pressure profiles of drug and tablet of mebendazole in both environmental conditions studied, what confirms that the process is really vaporization. The concentration of mebendazole was determined in the raw material and tablets with the drug.

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Abstract  

The objective of this work was to develop and validate a fast and reproducible method to determine the concentration of metronidazole in drug substance and tablets. The samples were analyzed by dynamic thermogravimetry, using 10, 20, 40, 60 and 80C min–1 heating rates in nitrogen and in nitrogen with synthetic air. Obtained data were used in the Antoine and Langmuir equations in order to have the pressure curves. Vapor pressure curves of drug and tablet of metronidazole were evaluated using the mathematical indexes of difference factor, f 1, and similarity factor, f 2, to compare their profiles. The data showed that there is no significant difference between the vapor pressure profiles of drug and tablet of metronidazole in both environmental conditions, which confirms that the process is really vaporization. The concentration of metronidazole was determined in the raw material and tablets of the drug.

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Abstract

Warifteine and methylwarifteine are bisbenzylisoquinoline alkaloids from Cissampelos sympodialis Eichl., produces a reversible, nonspecific, and noncompetitive antagonism of histamine, anti-allergic therapy, and used in the folk medicine for the treatment of airway respiratory diseases. Thermal techniques are used for several purposes, e.g., for thermal characterization, and measurement of the vapor pressure with objective of the quantitative determination. The objective of this study was to evaluate of the vapor pressure of the curves of warifteine and methylwarifteine by thermogravimetry analysis, how a fast and sensible method for quantitative determination. This method is based on the ratio of the Arrhenius, Langmuir, and Antoine equations for a reference material and the sample under investigation. The results showed these alkaloids follow zero-order kinetics with respect to volatilization. The vapor pressure curves of warifteine and methylwarifteine were plotted for the rates of 10, 15, and 20 °C min−1. The proposed method also possesses the potential.

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