Polymers for drug delivery systems formulations

The different carrier systems have shown therapeutic potential for a wide variety of drugs, satisfying multiple requirements, such as prevention of rapid elimination, reducing toxicity, promoting stabilization, optimization of metabolism, drug delivery and defense mechanisms. However, it has been recognized several other challenges associated with the specific release of actives in drug delivery. Therefore, to overcome chemical and biological obstacles, the selection of the polymer used to prepare the transport system is crucial. This paper presents a report on the main natural and synthetic polymers used in the preparation of drug carrier systems in vivo.Os diferentes sistemas de transporte têm evidenciado potencial terapêutico para uma grande variedade de princípios ativos, satisfazendo vários requisitos, como a prevenção da sua eliminação rápida do organismo, a redução da sua toxicidade sistêmica, a estabilização e a otimização do seu metabolismo, e o direcionamento específico ao local alvo e os mecanismos de defesa. No entanto, têm sido reconhecidos vários outros desafios associados à liberação específica do princípio ativo ao local alvo, pelo que, para ultrapassar os obstáculos químicos e biológicos, a seleção do polímero utilizado para a preparação do sistema de transporte é de importância crucial. O presente trabalho apresenta um relato sobre os principais polímeros naturais e sintéticos utilizados para a preparação de sistemas de transporte de princípios ativos in vivo.361368Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Synthesis of polyHEMA hydrogels for using as biomaterials. Bulk and solution radical-initiated polymerization techniques

Dense and porous polyHEMA hydrogels were synthesized by bulk and solution radical-initiated polymerization techniques. The morphologic analysis (SEM) of obtained hydrogels showed an amorphous dense structure for the samples obtained by bulk polymerization and a porous structure with non connected porous as a result of bulk polymerization in the presence of water soluble crystals (sucrose/NaCl). The use of solution polymerization technique using different amounts of water as diluent resulted in the formation of a sponge-like structure with connected microporous in case of using water amount equal or higher than 57.5%. The saline solution uptake and dynamic mechanical behavior of dense hydrogels were influenced by the amount of crosslinking between the polymer chains

Polímeros usados como sistemas de transporte de princípios ativos Polymers for drug delivery systems formulations

Os diferentes sistemas de transporte têm evidenciado potencial terapêutico para uma grande variedade de princípios ativos, satisfazendo vários requisitos, como a prevenção da sua eliminação rápida do organismo, a redução da sua toxicidade sistêmica, a estabilização e a otimização do seu metabolismo, e o direcionamento específico ao local alvo e os mecanismos de defesa. No entanto, têm sido reconhecidos vários outros desafios associados à liberação específica do princípio ativo ao local alvo, pelo que, para ultrapassar os obstáculos químicos e biológicos, a seleção do polímero utilizado para a preparação do sistema de transporte é de importância crucial. O presente trabalho apresenta um relato sobre os principais polímeros naturais e sintéticos utilizados para a preparação de sistemas de transporte de princípios ativos in vivo.The different carrier systems have shown therapeutic potential for a wide variety of drugs, satisfying multiple requirements, such as prevention of rapid elimination, reducing toxicity, promoting stabilization, optimization of metabolism, drug delivery and defense mechanisms. However, it has been recognized several other challenges associated with the specific release of actives in drug delivery. Therefore, to overcome chemical and biological obstacles, the selection of the polymer used to prepare the transport system is crucial. This paper presents a report on the main natural and synthetic polymers used in the preparation of drug carrier systems in vivo

Effects Of Chitosan Solution Concentration And Incorporation Of Chitin And Glycerol On Dense Chitosan Membrane Properties.

The aim of this work was to perform a systematic study about the effects induced by chitosan solution concentration and by chitin or glycerol incorporation on dense chitosan membranes with potential use as burn dressings. The membrane properties analyzed were total raw material cost, thickness, morphology, swelling ratio, tensile strength, percentage of strain at break, crystallinity, in vitro enzymatic degradation with lysozyme, and in vitro Vero cells adhesion. While the use of the most concentrated chitosan solution (2.5% w/w) increased membrane cost, it also improved the biomaterial mechanical resistance and ductility, as well as reduced membrane degradation when exposed for 2 months to lysozyme. The remaining evaluated properties were not affected by initial chitosan solution concentration. Chitin incorporation, on the other hand, reduced the membranes cost, swelling ratio, mechanical properties, and crystallinity, resulting in thicker biomaterials with irregular surface more easily degradable when exposed to lysozyme. Glycerol incorporation also reduced the membranes cost and crystallinity and increased membranes degradability after exposure to lysozyme. Strong Vero cells adhesion was not observed in any of the tested membrane formulations. The overall results indicate that the majority of the prepared membranes meet the performance requirements of temporary nonbiodegradable burn dressings (e.g. adequate values of mechanical resistance and ductility, low values of in vitro cellular adhesion on their surfaces, low extent of degradation when exposed to lysozyme solution, and high stability in aqueous solutions).80394-40