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| Alves,Ricardo; Reis,Thaís Vitória da Silva; Silva,Luis Carlos Cides da; Storpírtis,Silvia; Mercuri,Lucildes Pita; Matos,Jivaldo do Rosário. |
| The thermal behavior of two polymorphic forms of rifampicin was studied by DSC and TG/DTG. The thermoanalytical results clearly showed the differences between the two crystalline forms. Polymorph I was the most thermally stable form, the DSC curve showed no fusion for this species and the thermal decomposition process occurred around 245 ºC. The DSC curve of polymorph II showed two consecutive events, an endothermic event (Tpeak = 193.9 ºC) and one exothermic event (Tpeak = 209.4 ºC), due to a melting process followed by recrystallization, which was attributed to the conversion of form II to form I. Isothermal and non-isothermal thermogravimetric methods were used to determine the kinetic parameters of the thermal decomposition process. For non-isothermal... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Rifampicin; Tuberculosis; Thermal analysis; Thermal decomposition; Kinetic analysis. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-82502010000200022 |
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| Almeida,Mariana Mandelli de; Lima,Cibele Rosana Ribeiro de Castro; Quenca-Guillen,Joyce Santos; Moscardini Filho,Elder; Mercuri,Lucildes Pita; Santoro,Maria Inês Rocha Miritello; Kedor-Hackmann,Erika Rosa Maria. |
| In view of the increase in the number of cosmetic preparations containing antioxidant vitamins, chiefly, due to their action in preventing the process of skin aging, there is a need to develop pre-formulation studies and to validate analytical methods in order to obtain high quality products. Thus, the objective of this research was to evaluate and compare the thermal behavior of tocopheryl acetate and ascorbyl tetraisopalmitate as raw materials, and incorporated into a base cream. Thermogravimetry (TG / DTG) and differential scanning calorimetry (DSC) were used for this purpose. Both vitamins were found to be stable up to 250ºC. The base cream (placebo) and the sample (base cream containing the vitamins) presented different weight loss. Thermal analysis... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Thermal analysis; Cosmetic emulsion/qualitative analysis; Cosmetics/quality control; Tocopheryl acetate/antioxidant action; Ascorbyl tetraisopalmitate/antioxidant action; Vitamins/use in cosmetics. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-82502010000100015 |
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