CONICET | Buscador de Institutos y Recursos Humanos

The goal of this work was to characterize films for the treatment of burn wounds. Films containing hyaluronan, sodium alginate, glycerin, lidocaine and ciprofloxacin (CL-films) were obtained by solvent casting method. The average thickness was 181 ± 5 µm and the swelling index was 2. Powder X-ray diffraction patterns showed changes in the microstructure of CL-films, assigned to intermolecular interactions between the components, which were confirmed by FTIR spectroscopy. Thermogravimetric analysis indicated a water content of 20 % which was unaffected by the presence of glycerin. Glycerin improved stretch-ability and smoothness of the films, showing elongation at break (59±7 %), tensile strength (23.7±0.5 mPa) and Young´s module (37±3 mPa) values that are appropriate for topical administration. The morphology and mechanical properties were examined by SEM/EDS and optical and polarized light microscopy. The CL-films exhibited a porous but homogeneous surface, with uniform drug distribution. The absence of drug birefringent crystals was confirmed. They also showed good physical barrier properties as observed in microbial penetration tests. Drug release in Franz cells towards water and saline solutions showed that the release of ciprofloxacin and lidocaine occurs thorough an ionic interchange mechanism. Ciprofloxacin release rate was slower than that of lidocaine suggesting a higher affinity constant with polyelectrolyte´s acidic groups. Antimicrobial activity was assayed by agar diffusion methods against Staphylococcus aureus and Pseudomonas aeruginosa, including ciprofloxacin-resistant strains. CL-films exhibited similar antimicrobial efficacy than ciprofloxacin solutions at the same concentration, suggesting that the modulated release does not interfere with efficacy, even against the multi-resistant strains.