Biopolymeric films with silver sulfadiazine (AgSD) are proposed as an alternative to the occlusive AgSD-containing creams and gauzes, which are commonly used in the treatment of conventional burns. While the recognized cytotoxicity of AgSD has been reported to compromise its use as an antimicrobial drug in pharmaceuticals, this limitation can be overcome by developing sustained-release formulations. Microporous materials as zeolites can be used as drug delivery systems for sustained release of AgSD. The purpose of this work was the development and characterization of chitosan/zeolite composite films to be used as wound dressings. Zeolite was impregnated with AgSD before the production of the composite films. The physicochemical properties of zeolites and the films were evaluated, as well as the antimicrobial activity of the polymeric films and the cytotoxicity of the films in fibroblasts Balb 3T3/c. Impregnated zeolite exhibited changes in FTIR spectra and XRD diffraction patterns, in comparison to non-impregnated composites, which corroborate the results obtained with EDX-SEM. The pure chitosan film was compact and without noticeable defects and macropores, while the film with zeolite was opaquer, more rigid, and efficient against Candida albicans and some gram-negative bacteria. The safety evaluation showed that although the AgSD films present cytotoxicity, they could be used in a concentration-dependent fashion.

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ResumoZeólitas foram submetidas à troca iônica ou impregnação com prata e posteriormente adicionadas em filmes de quitosana para a confecção de curativos para queimaduras. As zeólitas foram avaliadas por Ressonância magnética nuclear (RMN), Fluorescência de raios X por reflexão total (TXRF), Microscopia eletrônica de varredura (MEV). Os filmes poliméricos foram analisados com relação às suas propriedades mecânicas, permeabilidade ao vapor d'água (PVA) e liberação de prata. Observou-se que o procedimento de troca iônica não alterou a morfologia das zeólitas de partida. Grumos de zeólita foram observados nas micrografias dos filmes e estes influenciaram nas propriedades mecânicas devido à desorganizaçao local no empacotamento das cadeiras poliméricas da quitosana. A metodologia de troca iônica ou impregnação influenciou diretamente na quantidade de prata presente superficialmente na zeólita e consequentemente alterou o perfil de liberação de prata em uma solução simulada de exudato de ferida. Os modelos cinéticos sugeriram que a liberação da prata não foi essencialmente regulada pela lei de difusão de Fick. Palavras-chave: impregnação, troca-iônica, curativos para queimados, zeólita Y. AbstractZeolites were subjected to ion exchange or impregnation with silver and added to chitosan films for producing burns dressings. Zeolites were characterized by nuclear magnetic resonance (NMR), total reflection X-ray fluorescence (TXRF), scanning electron microscopy (SEM). The polymer films were analyzed with respect to their mechanical properties, water vapor permeability (WVP), and release of silver. It was observed that the ion exchange did not modify the morphology of the starting zeolite. Clusters of zeolite were observed in the micrographs of the films and they influenced the mechanical properties due to local disruption in the packing of the polymer chains of chitosan. The methodology of ion exchange or impregnation directly influenced the amount of silver present in the zeolite surface and consequently changed the silver release profile in an of simulated exudate fluid. The kinetic models suggested that the release of the silver was not primarily governed by Fick's law of diffusion.

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