Desenvolvimento de filme polimérico oral contendo extrato aquoso de Psidium guajava L. para tratamento da doença periodontal em cães

Abstract

Periodontal disease is the most common oral disease affecting both humans and animals, predominantly affecting dogs over three years of age. It is the result of progressive inflammatory response due to the accumulation of bacterial plaque, and signs and symptoms include halitosis, pain, increased dental calculus and gingival pockets, severe inflammation and infection, destruction of the gums, teeth and bones, and bacteremia with evolution to septicemia. Plant extracts have antimicrobial activity and the potential for use in the prevention and treatment of oral diseases, such as Psidium guajava L., popularly known as guava in Brazil and used worldwide in traditional medicine and food. The objective of this study was the development and quality control of an oral polymeric film of modified release mucoadhesive containing the aqueous extract of the guava leaf, this evaluated its antimicrobial and antioxidant activity, for the treatment and prophylaxis of periodontal disease in dogs. Methods were used for the development of the film, such as solvent casting, and for quality control, weight uniformity, pH, swelling index, disintegration time, infrared and sterility. In addition, microbiological methods such as disk diffusion and broth microdilution, chemical methods such as thin layer chromatography, antioxidant analysis (DPPH) and total phenolics were used. The oral film formulation presented homogeneity and malleability, with pH compatible with the oral cavity (6.35 ± 0.07 to 6.45 ± 0.18), swelling index from 27.0 % ± 62 to 369.8 % ± 28 and disintegration time approximately 4 minutes. The infrared test showed that there were no interactions between the constituents and the formulation developed. In the preparation of the aqueous extract a yield of 1.2 % was obtained, the presence of flavonoids was found in the thin layer chromatography, besides antioxidant capacity (EC50) of 140 µg.mL-1 and total phenolics of 17.02 mg ± 6.87 gallic acid equivalent per g of dry extract. In the evaluation of microbial susceptibility, maximum halos of inhibition were obtained for Staphylococcus aureus, Staphylococcus pseudintermedius and beta-hemolytic Streptococcus, with means between 16 and 21 mm, being the inhibition mean at a concentration of 3.6 mg/cm². In the microdilution broth test, the minimum inhibitory concentration (MIC) for all strains was 8.8 mg.mL-1 and the minimum bactericidal concentration (MBC) for S. pseudintermedius was 8.8 mg.mL-1; while for the other strains it was higher than 11.4 mg.mL-1. The results showed that it was possible to develop an oral dissolving polymeric film formulation possessing antioxidant and antimicrobial capacity.