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Authors
Abstract(s)
A utilização de extratos naturais como ingredientes ativos em cosméticos é cada vez
mais exigida pelos consumidores, principalmente apoiada por princípios de
sustentabilidade e tendências de “rótulo limpo” (clean label). Para obter produtos
eficazes, um passo essencial é o desenvolvimento de transportadores adequados para
carregar e fornecer os princípios ativos visados. Neste contexto, o presente trabalho
centra-se no desenvolvimento de uma emulsão sólido-em-óleo-em-água (S/O/A) que visa
a produção de produtos à base de extratos de casca de bolota. Com esta estratégia, é
possível incorporar um extrato sólido como parte de uma emulsão óleo-em-água (O/A),
tirando partido da eficácia destes sistemas para aplicações tópicas. A conceção do
processo incluiu, numa primeira fase, o desenvolvimento de um sistema O/A estável.
Posteriormente, no processo final completo, o extrato sólido é finamente disperso na fase
óleo, seguido da dispersão desta fase em água. Os melhores resultados foram obtidos
utilizando uma relação O/A de 30/70 (v/v) com 30% de goma Arábica (m/v, base água)
e 2% de Tween 80 (m/v, base óleo) adicionados à fase aquosa. Para atingir a emulsão
S/O/A final, 5% de PGPR (Poliglicerol polirricinoleato) (m/v, base óleo), foi adicionado
à fase óleo para dispersar o extrato (1%, m/v, base óleo). Como esta emulsão revelou
vestígios de contaminação microbiana procurou-se substituir este polímero por outras
opções, tais como várias hidroxipropilmetilcelulose (HPMC), nomeadamente o Tylopur,
a Metolose e o quitosano, visando minorar este aspeto. Estes foram testados em diferentes
concentrações, tendo-se verificado que o quitosano a 4% (m/v; base emulsão total)
conduziu ao produto com a melhor estabilidade, embora apresentasse, após 15 dias, uma
viscosidade muito elevada e um comportamento viscoelástico. Os dois sistemas que
conduziram a melhores resultados foram caracterizados quanto à estabilidade, análise da
cor, viscosidade e capacidade antioxidante, verificando-se que a emulsão produzida com
30% de goma Arábica, no global, continuou a ser a mais promissora. Esta possuiu uma
viscosidade de 8907 mPa/s, tom acastanhado e atividade antioxidante de 2,19 mg/mL. A
eficiência de encapsulação do extrato foi de 99,13%. Quanto aos ensaios de permeação
na pele (células de Franz) não foi possível quantificar a libertação do extrato devido a
dificuldades experimentais, nomeadamente dificuldade na sua extração a partir da
emulsão, exigindo estudos complementares.
Using natural extracts as active ingredients in cosmetics is increasingly demanded by consumers, primarily supported by sustainable principles and clean-label trends. To reach effective products, an essential step is the development of suitable carriers to load and deliver the target active principles. In this context, the present work is focused on the development of a solid-in-oil-in-water (S/O/W) emulsion targeting the production of acorn shell extracts-based cosmetic products. With this strategy, it is possible to incorporate a solid extract as a part of an O/W emulsion, taking advantage of the effectiveness of these systems for topical applications. The process design comprised, in the first stage, the development of a stable O/W system. Thereafter, in the final complete process, the solid extract was finely dispersed in the oil phase, followed by the dispersion of this phase in water. The best results were obtained using an O/W ratio of 30/70 (v/v) with 30% of Arabic gum (w/v, water-basis) and 2% of Tween 80 (w/v, oil-basis) added to the aqueous phase. To achieve the final S/O/W, 5% of PGPR (Polyglycerol polyricinoleate) (w/v, oil-basis) was added to the oil phase to disperse the extract (1%, w/v, oil-basis). As the emulsion prepared with Arabic gum developed signs of microbial contamination, this polymer was replaced by several alternatives, such as some hydroxypropylmethylcellulose (HPMC), namely Tylopur, Metolose, and chitosan, in order to circumvent this constraint. These polymers were tested at different concentrations, where it was found that chitosan at 4% (w/v; total emulsion basis) was the one giving rise to the best stability, although it presented after 15 days a very high viscosity and a viscoelastic behavior. The two systems leading to the best results were characterized in terms of stability, color, viscosity, and antioxidant capacity, being verified that the emulsion produced with 30% of gum Arabic, overall, continued to be the most promising one. It was characterized by a viscosity of 8907 mPa/s, brownish tone, and antioxidant activity of 2.19 mg/mL. The encapsulation efficiency of the extract was 99.13%. For skin permeation tests (Franz cells), it was not possible to quantify the release of the extract due to experimental difficulties, namely in what concerns extracting it from the emulsion, which requires further studies.
Using natural extracts as active ingredients in cosmetics is increasingly demanded by consumers, primarily supported by sustainable principles and clean-label trends. To reach effective products, an essential step is the development of suitable carriers to load and deliver the target active principles. In this context, the present work is focused on the development of a solid-in-oil-in-water (S/O/W) emulsion targeting the production of acorn shell extracts-based cosmetic products. With this strategy, it is possible to incorporate a solid extract as a part of an O/W emulsion, taking advantage of the effectiveness of these systems for topical applications. The process design comprised, in the first stage, the development of a stable O/W system. Thereafter, in the final complete process, the solid extract was finely dispersed in the oil phase, followed by the dispersion of this phase in water. The best results were obtained using an O/W ratio of 30/70 (v/v) with 30% of Arabic gum (w/v, water-basis) and 2% of Tween 80 (w/v, oil-basis) added to the aqueous phase. To achieve the final S/O/W, 5% of PGPR (Polyglycerol polyricinoleate) (w/v, oil-basis) was added to the oil phase to disperse the extract (1%, w/v, oil-basis). As the emulsion prepared with Arabic gum developed signs of microbial contamination, this polymer was replaced by several alternatives, such as some hydroxypropylmethylcellulose (HPMC), namely Tylopur, Metolose, and chitosan, in order to circumvent this constraint. These polymers were tested at different concentrations, where it was found that chitosan at 4% (w/v; total emulsion basis) was the one giving rise to the best stability, although it presented after 15 days a very high viscosity and a viscoelastic behavior. The two systems leading to the best results were characterized in terms of stability, color, viscosity, and antioxidant capacity, being verified that the emulsion produced with 30% of gum Arabic, overall, continued to be the most promising one. It was characterized by a viscosity of 8907 mPa/s, brownish tone, and antioxidant activity of 2.19 mg/mL. The encapsulation efficiency of the extract was 99.13%. For skin permeation tests (Franz cells), it was not possible to quantify the release of the extract due to experimental difficulties, namely in what concerns extracting it from the emulsion, which requires further studies.
Description
Mestrado em parceria com a Escola Superior de Saúde do Instituto Politécnico da Guarda
Keywords
Extrato de casca de bolota Emulsão sólido-em-óleo-em-água (S/O/A) Goma arábica Quitosano Aplicações tópicas