Physicochemical study of solid-state benznidazole–cyclodextrin complexes

Although not being the ideal drug due to its low solubility and high toxicity, the benznidazole is the drug currently chosen for Chagas disease treatment. The deep knowledge about the characteristics of the drug in addition to the knowledge of more effective vectorization techniques of drugs in pharmaceutical forms allows a faster and cheaper development of a new therapeutic alternative in comparison to the introduction of a new molecule in the treatment. The aim of this study is the characterization of inclusion complexes Benznidazole and cyclodextrins in solid state. The interactions between Benznidazole (BNZ) and β-cyclodextrins (β-CD) modified: randomly methylated β-CD (RMβCD) and sulfobutylether β-CD (SBβCD) were studied by differential scanning calorimetry (DSC), fourier transform-infrared spectroscopy, RAMAN, and scanning electron microscopy. The preparation of solid-state binary systems by different techniques, namely, kneading, evaporated, and freeze-drying. The results suggest the formation of inclusion complexes of the drug with both CDs types in solid state by the techniques which were used, based on physicochemical data of interaction compared to the drug or the CDs/drug physical mixture. Thus, the preparation technique played an important role in the BNZ and modified CDs.     

Absolute configuration of diterpenoids from Jatropha dioica by vibrational circular dichroism

The absolute configuration of jatropholone A 1 and B 2, including the possibility to observe the vibrational circular dichroism (VCD) capacity to differentiate between two epimeric compounds in the presence of an inherently dissymmetric chromophore, which normally dominates VCD and electronic circular dichroism (ECD) spectra, followed after comparison of their experimental and DFT calculated VCD spectra, allowed us to conclude that although non-local (M/P) chirality generated by atropisomerism dominates over local chirality generated by an (R/S) change, the stereogenic center can confidently be assigned by VCD after DFT calculations. In addition, the absolute configurations of jatrophatrione 3 and citlalitrione 4, a compound proposed as a taxonomic marker for the genus Jatropha, were assigned by contrasting their respective calculated and experimental IR and VCD spectra. The evaluation of Flack and Hooft parameters obtained from the single-crystal X-ray diffraction data of jatropholone B acetate 6, and of 4 independently confirmed the absolute configurations of these molecules.     

Heat flow,heat capacity and thermal resistance of localized surfaces of the human body using a new calorimetric sensor

Journal of Thermal Analysis and Calorimetry - A non-invasive sensor equipped with a programmable thermostat has been developed to assess in vivo the heat flow transmitted by conduction from human...