Caracterização térmica e espectroscópica de chocolate medicamentoso contendo captopril para terapêutica cardiovascular na pediatria

Abstract

High blood pressure is a chronic disease that, in addition to affecting adults, can begin in childhood. There is a shortage of commercial medications suitable for the treatment of pediatric hypertension. To solve the problem of organoleptic characteristics (flavor, aroma and texture) of many medicines, chocolate is an interesting alternative to incorporate into a pharmaceutical preparation to mask unpleasant flavors. However, aiming for better applicability, the characterization of physicochemical properties is important in preliminary pre-formulation studies. Therefore, this work aimed to characterize, through thermal and spectroscopic techniques, medicated chocolate containing captopril for cardiovascular therapy in pediatrics. The five chocolate samples in flavors: milk ct., milk h., blend, white and semi-sweet were purchased from local stores and captopril was made available by the university. The evaluation of the thermal profile of isolated chocolates, captopril and medicinal chocolate was carried out using thermoanalytical techniques (TG and DTA), in addition to determining the activation energy (Ea) by the kinetic model of thermal degradation using the Flynn- Wall-Ozawa methods. (FWO) and Kissinger-Akahira-Sunose (KAS). To verify the presence of characteristic functional groups in the study samples, Fourier Transform Infrared Spectroscopy (FTIR) was used. In the thermogravimetric analysis, milk, blend and semi-sweet chocolates presented similar events. The first thermal event is characteristic of a probable decomposition of sugars such as lactose, the second may be associated with a possible degradation of beta lactose, in the third event a rapid loss of mass as a function of time which is characteristic of the thermal degradation of cocoa butter , the fourth event that occurred saw continuous loss of mass, due to the great degradation of more complex sugars such as polysaccharides. In white chocolate, it was possible to observe that the second thermal event occurred at a higher temperature when compared to other chocolates. In the kinetic models used in the study, the white chocolate base and the binary mixture with milk chocolate ct. showed lower activation energy in both methods used. The Fourier transform infrared (FTIR) spectrum was observed in all chocolates, three characteristic bands 2923 and 2853 cm-1 were attributed to the ‒CH stretching in aldehyde and 1744 cm-1 was attributed to the ‒ (C=O) stretching of lipids. In white and milk chocolates h. two similar characteristic bands 3200 to 3400 cm-1 were assigned to ‒OH carboxylic acid. In binary mixtures (chocolates and captopril), the presence of characteristic captopril bands was observed in all mixtures with chocolate. The results obtained offer additional contributions to the scientific literature, thermal characterization of chocolates and binary mixtures. These results can serve as a basis for future studies aimed at applying these substances in pharmaceutical formulations.