Thermal Characterization of Gelatin-Chitosan Free Films Crosslinked with Genipin

Hidrocolóides têm sido amplamente estudados no desenvolvimento de novos materiais voltados a aplicação em sistemas para liberação modificada de fármacos, especialmente em função das características de biodegradabilidade e ampla variedade de estruturas e propriedades. Todavia muitos desses materiais apresentam elevada hidrossolubilidade, podendo quando aplicados na condição de carreadores de fármaco, promover liberação prematura do conteúdo. Esta limitação encontra na reticulação química alternativa promissora tanto em nível terapêutico quanto industrial. Neste trabalho foram estudadas as propriedades térmicas de filmes isolados de gelatina, quitosana e suas associações, reticulados com genipina, através das técnicas de termogravimetria (TG) e calorimetria exploratória diferencial (DSC). Os resultados demonstraram que a reticulação com genipina em todas as composições avaliadas, promoveu maior resistência à perda de massa tanto por evaporação de água, quanto por degradação térmica. Filmes com maior concentração de quitosana apresentaram maior hidrofilicidade, cuja característica foi mantida após a reticulação dos filmes com genipina.The use of hydrocolloids had been widely studied for development of new materials for modified drug delivery system, due to their characteristics, like biodegradability and availability in a variety of structure with varied properties, although due to their high water solubility can lead to early drug delivery and the chemical modification can be an alternative for this inconvenience. Gelatin-Chitosan free films crosslinked with genipin were studied in terms of thermal properties by thermogravimetry (TG) and differential scanning calorimetry (DSC). The results demonstrated that films crosslinked with genipin in all the evaluated compositions promoted higher resistance to the mass change due to the water evaporation and thermal degradation. Films with higher concentration of chitosan presented higher hydrophilicity and this characteristic was kept even after to promote the crosslink with genipin.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Modulation of T Cell Function by Combination of Epitope Specific and Low Dose Anticytokine Therapy Controls Autoimmune Arthritis

Innate and adaptive immunity contribute to the pathogenesis of autoimmune arthritis by generating and maintaining inflammation, which leads to tissue damage. Current biological therapies target innate immunity, eminently by interfering with single pro-inflammatory cytokine pathways. This approach has shown excellent efficacy in a good proportion of patients with Rheumatoid Arthritis (RA), but is limited by cost and side effects. Adaptive immunity, particularly T cells with a regulatory function, plays a fundamental role in controlling inflammation in physiologic conditions. A growing body of evidence suggests that modulation of T cell function is impaired in autoimmunity. Restoration of such function could be of significant therapeutic value. We have recently demonstrated that epitope-specific therapy can restore modulation of T cell function in RA patients. Here, we tested the hypothesis that a combination of anti-cytokine and epitope-specific immunotherapy may facilitate the control of autoimmune inflammation by generating active T cell regulation. This novel combination of mucosal tolerization to a pathogenic T cell epitope and single low dose anti-TNFα was as therapeutically effective as full dose anti-TNFα treatment. Analysis of the underlying immunological mechanisms showed induction of T cell immune deviation

Efeito do polietilenoglicol e da albumina na imobilização de lipase microbiana e na catálise em meio orgânico Effect of poly (ethylene) glycol and albumin on the immobilization of microbial lipase and catalysis and catalysis in organic media

<abstract language="eng">Poly (ethylene) glycol (PEG) and bovine serum albumin (BSA), as additive agents, were used to enhance the activity of immobilized microbial lipase in organic solvent. Controlled pore silica (CPS) was selected as matrix and different immobilization procedures were evaluated: directly lipase binding on CPS and simultaneous addition of lipase and additive agent on the same support. The highest coupling yield (59.6%) was attained when the immobilization procedure was performed at lipase loading of 150 U/g support in the presence of PEG-1.500. This immobilized system was used in esterification reactions under repeated batch cycles and the biocatalyst half-life was found to increase 2.7 times when compared with the control