Chitosan-Paracetamol Nanostructure Self-Assembling Matrices as Drug Delivery Systems

The amphiphilic polymers can form associated structures in aqueous solution by mutual interaction and/or interaction with other components such as surfactants and active colloidal molecules. In this paper, results regarding nanolevel associative behaviour of chitosan based systems with surfactant and paracetamol are presented. The viscosity measurements of the solutions prepared were made with a view to take into consideration viscosity as an associative parameter. The thin films topography obtained by spin-coating was analyzed by Atomic Force Microscopy (AFM). The nanostructured matt-ices were investigated by Scanning Electronic Microscopy (SEM), X-Ray Diffraction (XRD) and by Fourier Transform InfraRed (FTIR) Spectroscopy. From FTIR and X-Ray investigations it can be concluded that, at nano - level, in the chitosan matrix, crystalline surfactant and paracetamol domains like nanocapsules are localized. By visual analysis of the AFM and SEM images it can be observed that the nanocapsules are orderly structured in horizontal layers and present a vertical gradient, the paracetamol nanocapsules formed having dimensions in the range of 21 - 170 nm. The chitosan-paracetamol nanostructured matrices obtained by the phase inversion method stand as a remarkable candidate to be used to control release of this drug.