Sintese de hidrogeis de phema para liberação controlada de drogas e meios acido e neutro e estudo da difusão

AUTOR(ES)
DATA DE PUBLICAÇÃO

1997

RESUMO

In this work, hydrogels of poly (2 hydroxyethyl methacrylate) PHEMA were prepared by chemical crosslinks using N, N-methylene - bis - acrylamide as the crosslinking agent. Hydrogels with different crosslinking degrees were obtained by varying the crosslinker concentration from 0.12% up to 3.0% (w/w). the films of PHEMA obtained were characterized by differential scanning calorimetry - DSC, scanning electron microscopy -MEV and mechanical properties. The mechanical tensile test was the method of characterization that showed more properties variation of the hydrogels obtained. The swelling was estimated by the variation in the samples weight when they reached the equilibrium, after have been immersed into distilled water and buffer solution at room temperature. It was observed that there is influence of the pH in the hydrogel swelling. The diffusion studies were carried out using Rhodamine B as the diffusive model specimen. The diffusion analysis were conducted at 37 GRAUS C, in buffer solution at pH=1 and distilled water at pH~7. The Fick s Second Law has been used to calculate the solute diffusion coefficient (D). The experimental data obtained and the mathematical model elaborated permited the evaluation of diffusion coefficient using iterative numerical methods. The results obtained have shown that there is physical crosslinking in the PHEMA hydrogel formation, so its utilization without crosslinker was permited. A significative variation of the diffusion coefficient was observed when the crosslinking agent was added.

ASSUNTO(S)

modelos matematicos biopolimeros tecnologia da liberação controlada difusão

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