Desenvolvimento farmacotécnico e pesquisa da atividade antimicrobiana de emulsão baseada em poloxâmero 407 contendo associação de óleos essenciais de Origanum vulgare e Thymus vulgaris

• Ano de defesa: 2023
• Autor(a) principal: Guimarães, Nayhara Madeira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Ciências Veterinárias; Centro de Ciências Agrárias e Engenharias; UFES; Programa de Pós-Graduação em Ciências Veterinárias
• Palavras-chave em Português: Mastite; Orégano; Tomilho; Emulsão polimérica; subject.br-rjbn; Ciências Agrárias
• Link de acesso: http://repositorio.ufes.br/handle/10/17192

Bovine mastitis is a multifactorial inflammatory disease that affects the mammary glands of animals, triggered by various factors, including microbial infections. Staphylococcus aureus is the primary microorganism found in clinical isolates of thedisease or in the milk and derivatives of infected animals. The objective of this study was to develop and investigate the preliminary stability of an emulsion based onpoloxamer 407, containing a combination of oregano (OEO) and thyme (OET) essential oils, aiming to obtain antimicrobial activity against microorganisms responsible for bovine mastitis. Initially, the bioactive compounds present in the essential oils were identified using gas chromatography-mass spectrometry. Subsequently, cold emulsions were prepared, containing the essential oils associated in a ratio of 89:11 (OEO:OET) at concentrations of 2.5, 3.5, 5, and 10% w/w. The preliminary stability of the emulsions was studied, as well as the in vitro antimicrobial activity against standard strains of S. aureus and Escherichia coli. Based on the results of the antimicrobial activity, the best concentration for further study was selected. The selected formulation (F4; containing 10% w/w of the essential oils) was prepared usingan aseptic process to obtain a sterile product. Subsequently, the sterility of the formulation was investigated, as well as the in vitro antimicrobial activity against clinical strains of S. aureus, both sensitive and resistant to synthetic antimicrobials, collected from mastitis-infected animals. Samples of the base formulations (FB) and F4, stored under different conditions (room temperature, 25 ± 2°C; incubator, 37 ± 2°C; refrigeration, 6 ± 2°C) for 35 days, were subjected to characterization tests and preliminary stability evaluation. The ability of the formulation to form a film was also investigated. The aseptic process proved to be suitable for preparing the emulsions, which remained sterile. Formulation F4 inhibited the growth of all challenged clinical strains. The emulsions maintained their characteristic appearance, with no changes observed among the different storage conditions and at 0 and 35 days. The type of emulsion formed was determined to be O/W, and the emulsion formation was confirmed by the presence of droplets of one phase dispersed in the other. None of the samples showed changes in physical parameters after preparation and after 35 days when subjected to stress tests. There was a reduction in pH in the formulations kept under different temperature conditions after 35 days. Different storage conditions and time influenced the texture parameters investigated in the samples. Water loss from FB and F4 formulations was approximately 25%. When deposited on a slide, the formulations formed a smooth, glossy, thin, and transparent film that dried completely after 60 minutes. Confocal microscopy images of the films showed the existence of regions with organized crystalline material, typical of poloxamers. Based on the results, it can be inferred that it was possible to produce a sterile emulsion based on poloxamer407 containing oregano and thyme essential oils associated at a concentration of 10% w/w, which demonstrated effectiveness in inhibiting standard and clinical strains of S. aureus isolated from bovine mastitis, both sensitive and resistant to synthetic antimicrobials. The formulation was considered stable, with no need for further pharmaceutic redevelopment.