Study of the electrochemical reduction of amoebicide Teclozan and its amperometric determination in pharmaceutical formulations

Neste trabalho, a redução eletroquímica do amebicida Teclozan (TEC) foi estudada sobre um eletrodo de carbono vítreo em meio de acetonitrila. Eletrólises com potencial controlado foram realizadas visando, tanto a determinação do número de elétrons envolvidos na redução do fármaco, quanto a identificação dos produtos eletrogerados, os quais foram isolados por extração líquido-líquido e caracterizados por 1H RMN. Foi verificado que o TEC apresenta dois picos voltamétricos, cada um associado à quebra redutiva de duas ligações C-Cl. Em presença de um doador de prótons, foi observado que o primeiro pico voltamétrico em −1,8 V corresponde principalmente à redução dos grupamentos -CHCl2 a -CH2Cl; enquanto o segundo pico em −2,2 V é responsável pela redução dos grupos -CH2Cl a CH3, fornecendo como único produto o derivado totalmente desalogenado do TEC, com rendimentos entre 82 e 97%. Este trabalho descreve também o desenvolvimento de um método eletroanalítico baseado na detecção amperométrica do TEC em condições hidrodinâmicas, o qual forneceu um limite de detecção de 8,9 × 10-6 mol L-1.The electrochemical reduction of amoebicide Teclozan (TEC) was studied on a glassy carbon electrode in acetonitrile. Controlled-potential electrolyses were performed for coulometric and preparative purposes. The electrogenerated products were isolated by liquid-liquid extraction and characterized by 1H NMR. It was observed that TEC presents two voltammetric peaks, each one associated with the cleavage of two C-Cl bonds. In presence of a proton donor it was observed that the first peak at −1.8 V promotes mainly the reduction of the groups CHCl2 to CH2Cl and the second one at −2.2 V promotes the reduction of the groups CH2Cl to CH3 giving as the sole product the completely dechlorinated TEC derivative with yields between 82 and 97%. In addition, a comparative study between the analytical performance of voltammetric techniques and amperometric detection of TEC in hydrodynamic conditions was performed. The amperometric detection was more sensitive than all evaluated voltammetric techniques, providing a detection limit of 8.9 × 10-6 mol L-1.FAPESP; CAPES; FC

El rendimiento académico de dos poblaciones de alumnos, una con asistencia presencial a clase, otra bajo la modalidad virtual

Este es un tiempo de cambios, el ámbito de la enseñanza aprendizaje, no puede quedar ajeno a los mismos. Para adaptarse a las necesidades de la sociedad actual, las Universidades deben flexibilizarse y desarrollar vías de integración de las tecnologías de la información y la comunicación (TIC) en los procesos de formación. Las TIC experimentan un desarrollo constante y rápido. Ya en 1958, aparece el primer programa para la enseñanza dedicado a la aritmética binaria, desarrollado por Raht y Anderson, con un ordenador IBM 650, han pasado más de 50 años desde este acontecimiento y en nuestras universidades todavía hay docentes que no saben utilizar las TIC. El rendimiento académico es una preocupación continua de los docentes, el aprendizaje ha traspasado los muros del salón de clases convencional, los alumnos y profesores se pueden comunicar obviando las barreras geográficas. Para adaptarnos debemos incorporar cambios en el rol del profesor, en el del alumno, cambios metodológicos y en estas transformaciones quedan implicadas directamente las instituciones

OCT Analysis of Retinal Pigment Epithelium in Myopic Choroidal Neovascularization: Correlation Analysis with Different Treatments

Objective: The objective of this study was to analyze the status of the retinal pigment epithelium (RPE) by means of the spectral domain optical coherence tomography (SD-OCT) overlying the myopic neovascular lesions in the involutive phase, looking for any correlations between the status of the RPE and the size of the lesions and the type and duration of the treatment. Methods: SD-OCT examinations of 83 consecutive patients with myopic choroidal neovascularization (CNV) were reviewed and divided into two groups: group A, patients with CNV characterized by uniformity of the overlying RPE, and group B, patients with CNV characterized by non-uniformity of the overlying RPE. Results: The median lesion area, major diameter, and minimum diameter were, respectively, 0.42 mm2 (0.30–1.01 mm2), 0.76 mm2 (0.54–1.28 mm2), and 0.47 mm2 (0.63–0.77 mm2) in group A, and 1.60 mm2 (0.72–2.67 mm2), 1.76 mm2 (1.13–2.23 mm2), and 0.98 mm2 (0.65–1.33 mm2) in group B. These values were lower in group A than in group B (p < 0.001). The number of treatments with a period free of disease recurrence for at least 6 months was greater (p < 0.010) in group B (6.54 ± 2.82) than in group A (3.67 ± 2.08), and treatments include intravitreal anti-vascular endothelial growth factor injection, photodynamic therapy, or both. Conclusions: Our results showed that the size of myopic neovascular lesion influences the development of a uniform RPE above the lesion and therefore the disease prognosis. The presence of uniform RPE was found to be extremely important in the follow-up of patients with myopic CNV, as it influences the duration of the disease and the number of treatments required

Electrochemical and theoretical evaluation of the interaction between dna and amodiaquine: evidence of the guanine adduct formation

The electrochemical behavior of the interaction of amodiaquine with DNA on a carbon paste electrode was studied using voltametric techniques. In an acid medium, an electroactive adduct is formed when amodiaquine interacts with DNA. The anodic peak is dependent on pH, scan rate and the concentration of the pharmaceutical. Adduct formation is irreversible in nature, and preferentially occurs by interaction of the amodiaquine with the guanine group. Theoretical calculations for optimization of geometry, and DFT analyses and on the electrostatic potential map (EPM), were used in the investigation of adduct formation between amodiaquine and DNA