Preparation and characterisation of polymeric films containing propolis

Propolis is a natural resinous substance, with a high polyphenol content, produced by honeybees and characterized by antimicrobial, anti-inflammatory and antioxidant properties, which make it useful for different therapeutic applications, especially in the stomatological field in the treatment of mild buccal diseases. The aim of this study was to prepare some polymeric film formulations for local delivery of propolis into the oral cavity. For this purpose, a commercial propolis fluid extract and three extracts (dry, ethanolic, glyceric) obtained from raw propolis were previously characterized with regard to their polyphenolic fraction composition and their antimicrobial properties against Candida albicans, Escherichia coli and Staphylococcus aureus strains. Commercial fluid extract, judged the most suitable in terms of polyphenol content and antimicrobial activity, was then incorporated into alginate, alginate-chitosan and agar films, prepared using a casting-solvent evaporation technique, which were finally evaluated in terms of thickness, total polyphenol content, in vitro polyphenol release profiles, swelling behaviour and antimicrobial properties. Our results demonstrate that polymeric films can be proposed as new propolis vehicles in the treatment of dental and buccal diseases.