Trissoralen um medicamento de baixa dosagem: estudos termoanalíticos da compatibilidade do fármaco-excipientes e determinação de parâmetros de qualidade para cápsulas magistrais

The trioxsalen (Tri) is a low-dose drug used in the treatment of psoriasis and other skin diseases. The aim of the study was applying the thermal analysis and complementary techniques for characterization, evaluation of the trioxsalen stability and components of manipulated pharmaceutical formulations. The thermal behavior of the Tri by TG/DTG-DTA in dynamic atmosphere of synthetic air and nitrogen showed the same profile with a melting peak followed by a volatilization-related event. From the curves TG / DTG is observed a single stage of mass loss. By heating the drug in the stove at temperatures of 80, 240 and 260 °C, it had no change in chemical structure through the techniques of XRD, HPLC, MIR, OM and SEM. From the non-isothermal and isothermal TG kinetic studies was possible to calculate the activation energy and reaction order for the Tri. The drug showed good thermal stability. Studies on drug-excipient compatibility showed interaction of trissoralen with sodium lauryl sulfate 1:1. There was no interaction with aerosol, pregelatinized starch, sodium starch glycolate, cellulose, croscarmellose sodium, magnesium stearate, lactose and mannitol.The characterization of three trioxsalen formulations at concentrations of 2.5, 5, 7.5, 10, 12.5 and 15 mg was performed by DSC, TG / DTG, XRD, NIR and MIR. The PCA classification method based on spectral data from the NIR and MIR of trissoralen formulations allows successful differentiation into three groups. The formulation 3 was the one that best showed analytical profile with the following composition of aerosil excipients, pre-gelatinized starch and cellulose. The activation energy of the volatilization process of the drug was determined in binary mixtures and formulation 3 through fitting and isoconversional methods. The binary mixture with sodium starch glycolate and lactose showed differences in kinetic parameters compared to the drug isolated. The thermoanalytical techniques (DSC and TG / DTG) were shown to be promising methodologies for quantifying trioxsalen obtained by the linearity, selectivity, no use solvents, without sample preparation, speed and practicality.

Avaliação da Capacidade Antioxidante e da Estabilidade Após Embalamento a Vácuo de Hambúrgueres de Pata-roxa (Scyliorhinus canicula).

Toneladas de pescado são desperdiçadas diariamente aquando do processamento do peixe e o hambúrguer de pata-roxa foi desenvolvido para reaproveitar esse pescado subvalorizado e para ser uma fonte nutricional rica em antioxidantes. No presente trabalho, pretendeu-se comprovar o potencial antioxidante antes e após o tratamento térmico do hambúrguer de pata-roxa, e o potencial citotóxico e antiproliferativo sobre um modelo celular do cancro da mama (MCF-7). Foi também observada a estabilidade do hambúrguer de pata-roxa embalado a vácuo e refrigerado. A extração dos compostos fitoquímicos foi realizada com solventes de polaridade distinta (água, metanol e diclorometano) e com diferentes durações do processo (12h e 24h). O tratamento térmico aplicado foi vinte minutos a 180ºC. O potencial antioxidante foi avaliado pela capacidade de redução do radical livre 1,1-difenil-2-picrilhidrazil (DPPH) e pela capacidade de redução de radicais de oxigénio (ORAC), e através da quantificação total de polifenóis (QTP) pelo método de Folin-Ciocalteu (FC). O potencial citotóxico e antiproliferativo foi avaliado na linha celular MCF-7, cujos resultados foram revelados por ensaios espectrofotométricos (método do brometo de 3- (4,5-dimetiltiazol-2-il)-2,5-difenil tetrazólio (MTT)) e fluorimétricos (método de acetoxi-metil éster de calceína (calceína-AM)). A estabilidade do hambúrguer de pataroxa em vácuo e refrigerado foi avaliada através do estudo microbiológico com metodologias de referência (contagens de “totais” e produtores de sulfureto de hidrogénio (H2S) aeróbios e anaeróbios, esporos de Clostridium sulfitos-redutores, enterobactérias, Escherichia coli e pesquisa de Salmonella spp.), da determinação do índice de ácido tiobarbitúrico (TBA) e da avaliação da cor do hambúrguer pelo sistema CIE-L*a*b*. Os ensaios de DPPH e ORAC comprovaram a atividade antioxidante do extrato de hambúrguer de pata-roxa (metanol, 12h) com 79,5% de redução do DPPH e 8603,01μmol ET/100g para amostras sem tratamento térmico, e 87,4% de redução do DPPH e 2567,27μmol ET/100g para amostras com tratamento térmico. Quanto ao conteúdo fenólico, os extratos (metanol, 12h) revelaram 17,13mg EAG/100g do hambúrguer cru e 31,81mg EAG/100g do hambúrguer cozinhado. A extração de 24 horas não aumentou a quantidade de compostos fitoquímicos presentes no extrato. O hambúrguer apenas revelou ainda um potencial citotóxico in vitro relevante na linha celular MCF-7 (1mg/mL, 24h).Apesar do abuso observado na temperatura de armazenamento em refrigeração (temperatura média de 10,3ºC), o hambúrguer de pata-roxa cru, quando submetido ao embalamento a vácuo, apresentou um aumento no período de vida útil de prateleira de 4 dias relativamente à pata-roxa. Foi detetada a presença de esporos de Clostridium sulfito-redutores e 1,0x101ufc E. coli por 1g de hambúrguer de pata-roxa. Não foi detetada a presença de Salmonella spp. O índice de TBA manteve-se estável, mas o hambúrguer de pata-roxa sofreu uma perda na vivacidade (Cab) e na tonalidade (hab) da cor ao fim de 6 dias em refrigeração. É necessário continuar o estudo para melhorar o novo produto alimentar funcional, mas o presente trabalho permitiu concluir que o hambúrguer de pata-roxa reúne as condições para ter um elevado potencial antioxidante, apresentar maior estabilidade em armazenamento e, em simultâneo, constituir uma solução para o desperdício de pescado.

Pirólise térmica e catalítica de resíduos de vácuo gerados no refino de petróleo

In this study, was used a very promising technique called of pyrolysis, which can be used for obtaining products with higher added value. From oils and residues, since the contribution of heavier oils and residues has intensified to the world refining industry, due to the growing demand for fuel, for example, liquid hydrocarbons in the range of gasoline and diesel. The catalytic pyrolysis of vacuum residues was performed with the use of a mesoporous material belonging the M41S family, which was discovered in the early 90s by researchers Mobil Oil Corporation, allowing new perspectives in the field of catalysis. One of the most important members of this family is the MCM-41, which has a hexagonal arrangement of mesopores with pore diameters between 2 and 10 nm and a high specific surface area, making it very promising for use as a catalyst in petroleum refining for catalytic cracking, and their mesopores facilitate the access of large hydrocarbon molecules. The addition of aluminum in the structure of MCM-41 increases the acidity of the material, making it more positive for application in the petrochemical industry. The mesoporous material of the type Al-MCM41 (ratio Si / Al = 50) was synthesized by hydrothermal method starting from the silica gel, NaOH and distilled water added to the gel pseudobohemita synthesis. Driver was used as structural CTMABr. Removal of organic driver (CTMABr) was observed by TG / DTG and FTIR, but this material was characterized by XRD, which was observed the formation of the main peaks characteristic of mesoporous materials. The analysis of adsorption / desorption of nitrogen this material textural parameters were determined. The vacuum residues (VR's) that are products of the bottom of the vacuum distillation tower used in this study are different from oil fields (regions of Ceará and Rio de Janeiro). Previously characterized by various techniques such as FTIR, viscosity, density, SARA, elemental analysis and thermogravimetry, which was performed by thermal and catalytic degradation of vacuum residues. The effect of AlMCM-41 was satisfactory, since promoted a decrease in certain ranges of temperature required in the process of conversion of hydrocarbons, but also promoted a decrease in energy required in the process. Thus enabling lower costs related to energy expenditure from degradation during processing of the waste

“Silêncio no Vácuo”

“Silêncio no Vácuo” - Experiência (vídeo de 2 min 21 s, Graça Carraça, Departamento de Física, Escola de Ciências e Tecnologia- Universidade de Évora). O trabalho experimental registado neste vídeo faz parte de um conjunto de trabalhos de divulgação, seleccionados de entre os vários que podem ser explorados nas nossas aulas experimentais de Física. Este trabalho foi recentemente apresentado como demonstração experimental a jovens do Campo de Férias SASUE - 2016, sob o tema “Explorando o som”. Apesar de neste caso estarmos perante um público muito jovem, crianças dos 7 aos 12 anos, suscitou a curiosidade e o interesse sobre a explicação dos fenómenos em causa. Com este registo em vídeo pretende-se sobretudo facilitar o trabalho dos alunos e professores que queiram realizar a experiência e fazer pensar na possibilidade de explorar este sistema para além da demostração aqui apresentada.

Relação dose-dependente do uso crônico de fenitoína e atrofia cerebelar em pacientes com epilepsia

The chronic treatment with phenytoin or the acute intoxication by this drug may cause permanent cerebellar injury with atrophy of cerebellum vermis and hemispheres, which can be detected by neuroimaging studies. The aim of the present study was to investigate the correlation between the dosage and duration of treatment with phenytoin and the occurrence of cerebellar atrophy. Sixty-six patients were studied and had their tomographies analyzed for cerebellar atrophy. Of the 66 patients studied, 18 had moderate/severe atrophy, 15 had mild atrophy and 33 were considered to be normal. The patients with moderate/severe atrophy were those with higher exposure to phenytoin (longer duration of treatment and higher total dosage) showing statistically significant difference when compared to patients with mild atrophy or without atrophy (p=0.02). Further, the patients with moderate/severe atrophy had serum levels of phenytoin statistically higher than those of patients with mild atrophy or without atrophy (p = 0.008). There was no association between other antiepileptic drugs dosage or duration of treatment and degree of cerebellar atrophy. We also found that older patients had cerebellar atrophy more frequently, indicating that age or duration of the seizure disorder may also be important in the determination of cerebellar degeneration in these patients. We conclude that although there is a possibility that repeated seizures contribute to cerebellar damage, long term exposure to phenytoin, particularly in high doses and toxic serum levels, cause cerebellar atrophy.

Características físicas e mecânicas de misturas de solo, cimento e casca de arroz

The main objective of this work is the study of the effect of rice husk addition on the physical and mechanical properties of soil-cement, in order to obtain an alternative construction material. The rice husk preparation consisted of grinding, sieving, and the pre-treatment with lime solution. The physical characteristics of the soil and of the rice husk were determined. Different amounts of soil, cement and rice husk were tested by compaction and unconfined compression. The specimens molded according to the treatments applied to the mixtures were subsequently submitted to compression testing and to tensile splitting cylinder testing at 7 and 28 days of age and to water absorption testing. After determining its physical and mechanical characteristics, the best results were obtained for the soil + 12% (cement + rice husk) mixture. The results showed a promising use as an alternative construction material.

Desenvolvimento e avaliação de uma servoválvula de baixo custo para a aplicação de insumos líquidos

The present work aimed the development of a low cost servo-valve that answers to an electronic control signal, for variable rates liquid inputs application. A literature research to define which valve type should be used was made. A mechanically activated proportional valve with an electronically controlled servo-engine was designed and evaluated. Since developed the servo-valve, the system was submited to a number of tests .The evaluation of its behavior was obtained in terms of repeatability, hystheresis and linearity. The test was accomplished in a bench, specially developed for this aim. As a result, were obtained three curves of opening percentage as function of flow rate, describing three opening and closing increments in two different work pressures. The servo-valve presented a good repeatability, reasonable hysteresis and a typically quadratic curve. This one maintained the low cost target. These results were very satisfied because the non-linearity and the hysteresis could be easily corrected by software.

Folhas verdes, folhas secas, fibra do colmo e a clarificação do caldo de cana-de-açúcar

The presence of vegetal impurities in sugarcane delivered to sugarmills as green and dry leaves is a problem not only because they are non-value materials to be processed along with sugarcane stalks, but also because they can rise the color of the clarified juice and, consequently, the color of the sugar produced, with a reduction of its quality for the market. Another problem is the mud volume sedimented in the clarifiers, which also can result in a larger recirculation and greater volume of filtrate juice, with higher losses of sucrose and utilization of the vacuum rotary filters. The objective of this work was to observe the effect of the presence of green and dry leaves on sugarcane juice clarification, related to a control treatment with the addition of fiber extracted from the stalks. The experiments were planned based on the addition of quantities of fibrous sources in order to formulate samples with absolute increase of 0.25 , 0.50 and 0.75 percentual points over the fiber content of the sugarcane stalks (control treatment). The juice clarification was conducted with a laboratory clarifier. The clarified juice color and the mud volume were evaluated. The presence of green leaves caused higher color and mud volume due to the extraction of non-sucrose components of the leaves. Soluble compounds of dry leaves were also extracted, though not detected by juice analysis. The addition of the fiber extracted from the stalks did not induce alterations in the clarification process.