Desenvolvimento de sistemas de liberação controlada de fármacos: quitosana/insulina.

Abstract

The use of biomaterials was induced to help people borned with problems in organs / tissue or people that acquired them by traumas. This demand was increased by the human beings prolonged life expectance. Recently in the area of biomaterials, many studies have been published, such as researches on drug delivery systems, biosensors and biomedical devices. One of the high incidences of chronic diseases in contemporary society is Diabetes mellitus type 1, which treatment consists of daily subcutaneous administration of insulin. The aim of this study was to develop biofilms composed of chitosan and insulin, towards an alternative to the injectable drug administration, using drug delivery systems to increase adherence to the treatment. Biofilms were developed from chitosan from two different suppliers and NPH insulin was used in two different concentrations. The films were characterized by the techniques of Wettability, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), Scanning Electron Microscopy (SEM), Enzymatic Biodegradation, Assessment of Viability and Determination of Macrophage Nitric Oxide Production. We found small differences in hydrophilicity of the samples observing wettability analysis. The results of FTIR and XRD confimed the formation of biofilms chitosan / insulin. The biofilms morphology didn’t change substantially, regardless the presence of insulin concentrations and the type of chitosan used, presenting a nature fibrous polymer characteristic morphology, typical for chitosan. Tests conducted by XRD showed a variation of crystallinity in the samples. The highest crystallinity was found for the chitosan (1%), Sigma Aldrich ®, 75% GD (B2.1) preparation and lowest for the chitosan (1.5%), Sigma Aldrich ®, GD 85%, plus 50 IU of insulin, (B1.4) preparation. The DSC observed three thermal events showing that insulin presence in preparations of low molecular weight was equivalent to the effects of that in preparations of high molecular weight. The TG showed a higher weight loss for preparations of chitosan without insulin. The biodegradation tests were applied to chitosan from Sigma Aldrich® 1% biofilms, and showed the highest degradation for the composition of 1% / 50 IU of insulin (B1.3) and the lowest for the composition of chitosan 1% without insulin ( B1.1). The toxicity tests showed the feasibility to use this system as a viable alternative for the treatment of Diabetes mellitus.