Caracterização físico-química e atividade antimicrobiana de formulação de filmes poliméricos à base de quitosana com óleo-resina de alecrim para o manejo de queimaduras

Abstract

Burns constitute a global public health problem, representing one of the main causes of morbidity, generating low quality of life for those affected, disfigurement and even disability. It is the fourth most common problem caused by trauma in the world, accounting for up to 180,000 deaths per year. It is classified in degrees, with the higher the degree, the greater the associated severity. A very common problem associated with burns is secondary infections. These still represent around 61% of the causes of death in burns, even after therapeutic improvements over the years. Secondary infections present some key microorganisms in the infectious process, such as Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii. However, much still needs to be done to improve the treatment of burns, as burn victims present immunosuppression, low capacity for absorption of antimicrobials in the tissue, in addition to being able to present multi-resistant microorganisms as colonizers of the lesions, resulting in treatment failure. Chitosan is an interesting biopolymer in relation to its properties, presenting good adhesion, absence of cytotoxicity, antimicrobial and healing activity. At the same time, rosemary oleoresin (ORA) also has interesting antimicrobial, anti-inflammatory and antioxidant activities. Therefore, the objective of the present work was to formulate a polymeric film based on chitosan with ORA in different concentrations aiming to control secondary infections in burn injuries. First, the antibacterial activity of ORA was evaluated against screening, using Minimum Inhibitory Concentration (MIC) and Minimum Microbicidal Concentration (MMC), which showed good performance and bacteriostatic activity for all species tested. Subsequently, death kinetic tests were carried out for two strains of S. aureus, in which it was possible to verify that ORA delays the log phase of S. aureus for at least 6 hours. However, after 24 hours the bacteria grew again, which confirms the bacteriostatic action observed in MMC. Regarding the formulated films, homogeneous films were obtained in relation to the mixture of their constituents, but with the presence of irregularities on their surfaces, varying according to the concentration of ORA and the drying temperature used. The films were also evaluated in relation to quality parameters: average weight, thickness, humidity, swelling and solubility, presenting suitable characteristics for a future healing film. Raman and FT-IR spectroscopy analysis allowed the evaluation of molecular interactions between the constituents of the formulation, in addition to the identification of their functional groups, such as regions corresponding to C-O bonds present in alcohols and phenols, as well as O-H regions referring to C-O bonds. hydrogen. Finally, the antibacterial activity of the films using the disk diffusion technique demonstrated activity for the species tested, although on a smaller scale than the polyvidone iodine (10%) activity control. Thus, it is concluded that it was possible to obtain a film formulation based on chitosan and ORA, presenting promising potential in the management of burns considering the control of secondary infections and the need for constant research to develop bioactive topical formulations that are more effective for the patient.