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The physical and chemical characterization of the solid-state properties of drugs and excipients is fundamental for planning new formulations and developing new strategies for the treatment of diseases. Techniques such as differential scanning calorimetry, thermogravimetry, X-ray powder diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy are among the most commonly used techniques for these purposes. Penciclovir and lysine are individually used to treat the herpes virus. As such, the development of a formulation containing both drugs may have therapeutic potential. Solid-state characterization showed that both penciclovir and lysine were crystalline materials with melting points at 278.27 °C and 260.91 °C, respectively. Compatibility studies of penciclovir and lysine indicated a possible interaction between these substances, as evidenced by a single melting point at 253.10 °C. The compatibility of several excipients, including ethylenediaminetetraacetic acid, cetostearyl alcohol, sodium lauryl sulphate, di-tert-butyl methyl phenol, liquid petrolatum, methylparaben, nonionic wax, paraffin, propylene glycol, and propylparaben, was evaluated in ternary (penciclovir-lysine-excipient) mixtures (1:1:1, w/w/w) to determine the optimal formulation. The developed formulation was stable under accelerated and ambient conditions, which demonstrated that the interaction between penciclovir and lysine was suitable for the development of a formulation containing both drugs.

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This study evaluated the effect of ultrasound processing as a pre-treatment of amyloglucosidase on the enzymatic activity and stability. The activity was evaluated under optimal (65°C/ pH = 4.5) and non-optimal conditions of temperature and pH and its stability was evaluated during storage at 8°C. The enzyme solution was processed at 9.5 W L-1, 40 kHz, 23°C and at pH 3.5, 4.5, and 5.5, for up to 120 min. The activity was measured at 35, 65 and 80°C. The US process was able to increase, reduce or not alter the enzymatic activity, depending on the conditions applied. These modifications depended on the pH of the enzyme solution, the ultrasound processing time and the activity temperature. In different ultrasound conditions, mainly at 35 and 65°C, the enzyme activity did not change, demonstrating that this technology can be used for other purposes, such as microbial inactivation, without affecting the enzyme. The activity increase (up to 15%) occurred under non-optimal pH and temperature conditions (pH 3.5 or 5.5/ 80°C), suggesting that ultrasound promoted stabilization and enzymatic protection. This result is interesting in the starch saccharification, which requires the enzymatic reaction at high temperatures. Therefore, such results can increase the application range of this enzyme in different industrial applications.

Introdução: A Espectroscopia Fotoacústica (PAS) é uma técnica que permite a obtenção de espectros de absorção óptica de sólidos, líquidos e gases. A medição in vitro do Fator de Proteção Solar (FPS) via PAS apresenta-se como promissora, pois permite a obtenção do espectro de absorção UV do protetor solar, independente da natureza do filtro, orgânico ou inorgânico. Objetivo: Correlacionar o FPS de protetores solares com seus respectivos espectros fotoacústicos, visando a aplicação da PAS para a análise in vitro de FPS. Metodologia: O espectro fotoacústico foi medido na região do UV (280-400nm) para protetores solares de três marcas diferentes. Resultados e Discussão: A marca A obteve o melhor desempenho para o FPS 60, diminuindo no 50 e mantendo a sua curva linear no FPS 15 e 30; a marca B teve sua curva linear até o FPS 50 diminuindo em 60, e para a marca C o FPS com a maior área integrada foi o de FPS 30, diminuindo sua intensidade em 50. Conclusão: Não observou-se um um comportamento linear em relação ao espectro de PAS e os protetores solares analisados, fato que pode estar relacionado com a fotoestabilidade dos filtros e a interação dos mesmos com a pele.