Currently, treatment of Chagas disease is restricted to the use of benznidazole and nifurtimox; however, nifurtimox was temporarily suspended in some countries. Based on the limitations in pharmacological treatments, it is essential to guarantee the quality of benznidazole. Therefore, this work aimed to identify the degradation products of benznidazole and to validate a stability indicating method. The stability test was performed through a forced degradation study, exposing benznidazole under a range of conditions. Benznidazole proved to be unstable under acidic and alkaline conditions, and three products were identified by liquid chromatography coupled to a hybrid quadrupole time-of-flight mass spectrometer (UPLC-QTOF-MS). Furthermore, a stability indicating method by high performance liquid chromatography with a diode array detector (HPLC-DAD) for benznidazole was developed and validated according to ICH (International Conference on Harmonisation) and ANVISA (Agência Nacional de Vigilância Sanitária) guidelines. The method was linear (180-420 µg mL-1 range), selective in the presence of degradation products, precise (relative standard deviation (RSD) < 0.6%), accurate (recovery > 99.2%), robust, and free of matrix effects. The method was successfully able to quantify the benznidazole in pharmaceutical formulations.

Kojic acid (KA) is an organic acid widely used in pharmaceutical industry, mainly as a skin lightening agent. Based on the ability of KA to form complexes with ions, we found the most possible kind of complex formed with cation aluminum. KA-Al3+ complex structures were studied using potentiometric and spectrophotometric (UV) titrations, FTIR and 13C NMR. The electronic spectroscopy showed that the KA-Al3+ complexes absorb at higher wavelengths (λmax= 305 nm) than do the non-complexed KA (λmax= 269 nm), confirming complexation. The IR spectra of KA complexed and not complexed allowed us to correlate the changes in the absorption of enol and carbonyl groups in absence and presence of Al3+ in aqueous solutions. The complexation suggested by the potentiometric titration and FTIR spectroscopy are in accordance with the data obtained from NMR results. Calculations based on quantum mechanics were utilized to understand the differences found in the noncomplexed and complexed KAH electronic spectra

Agaro- and carra-oligosaccharides were produced by partial acid hydrolysis of commercial agarose and kappa-carrageenan. Di- and tetrasaccharides were purified by gel filtration chromatography and characterized by NMR (1D and 2D) spectroscopy and ESIMS. The following oligosaccharides were obtained: agarobiose, agarotetraose, kappa-carrabiose and kappa-carratetraose. Agarobiose and agarotetraose were used as standards to develop a high performance size exclusion chromatography (HPSEC) method which was utilized to study the hydrolysis rate of agarose and oligosaccharide production. Six hours of hydrolysis (0.1 M TFA, 65 ºC) produced mainly di- and tetrasaccharides. The methodology for oligosaccharide production and evaluation developed in the present work shows good potential for the production of bioactive oligosaccharides.