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Oil incorporation in foamable mixtures of phospholipids and surfactants
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O presente trabalho tem por base o estudo de espumas potencialmente medicamentosas, obtidas a partir de emulsões que incorporem na sua constituiçãoóleos, fosfolípidos e os tensioativos adequados para obter uma espuma estável e com uma estrutura satisfatória do ponto de vista técnico.
As formulações estudadas neste trabalho, não contêm substância ativa. O objetivo édesenvolver uma espuma formada a partir de uma emulsão contendo um óleo compolaridade variável que seja adequada para veicular uma substância ativa com ação a nível cutâneo. Por exemplo, corticosteroides para o tratamento da psoríase.
As espumas têm interesse a nível farmacêutico devido à comodidade da sua utilização. Permitem uma administração eficaz em zonas de difícil acesso, como a raiz capilar, e, portanto, ajudam à promoção da adesão à terapêutica.
Neste estudo foram desenvolvidas 72 formulações. Todas elas têm por base emulsões em que a fase oleosa inclui um dos seguintes óleos: triglicéridos de cadeia média, parafina líquida ou óleo de rícino, em concentrações de 10 ou 20%. O óleo é disperso em misturas aquosas de fosfolípidos e tensioativos que possuem capacidade de formar espuma. Capacidade previamente comprovada através de um método utilizado, também neste trabalho, para avaliar a formação e a estabilidade das espumas denominado “screening method”, em que três colunas graduadas são dispostas lado a lado. A emulsão que dá origem à espuma é introduzida dentro das colunas e o ar é impulsionado a partir da base das colunas através de um filtro em forma de disco, dispersando-se assim na emulsão.
As espumas foram avaliadas e classificadas segundo: a sua capacidade de serem ou não produzidas; a sua estrutura inicial e ao longo de todo o tempo da experiência; e segundo a sua altura em relação ao líquido. As emulsões que dão origem às espumas foram também avaliadas em relação à sua estabilidade. As que mesmo sendo capazes de produzir uma espuma com uma boa estrutura, se não apresentassem estabilidade, não eram consideradas formulações adequadas.
Com os resultados foi possível concluir que o óleo de rícino não é adequado nestas formulações e que os demais componentes são determinantes no seu comportamento.
The present work is based on the study of potentially medicated foams, obtained from emulsions that are constituted of oils, phospholipids and the appropriate surfactants in order to produce stable foams, with a technically satisfactory structure. The studied formulations do not contain an active substance. The objective of the investigation is to develop a foam obtained from an emulsion in which the oil phase can have variable polarity depending on the oil used. This emulsion must be adequate to vehiculate an active substance that acts on the skin. For example, corticosteroids for the treatment of psoriasis. Foams are of pharmaceutical interest because of the commodity of their utilization. They allow the efficient administration in areas of difficult access, such as the scalp, and therefore they promote patient adhesion to therapy. In this study, 72 formulations were developed. Each one of them is based on an emulsion in which the oil phase includes one of the following oils: medium chain triglycerides, liquid paraffin or castor oil, in concentrations of either 10 or 20%. The oil is dispersed in aqueous mixtures of phospholipid and surfactants which are known to be capable of producing a foam, this was previously demonstrated using a method also applied in this work to evaluate the foamability and the foam structure called "screening method" in which three graduated columns are arranged side by side. The emulsion that gives rise to the foam is introduced into the columns and the air is driven from the base of the columns through a disc-shaped filter, thus dispersing into the emulsion. The foams were evaluated and classified according to: their ability to be produced; their initial structure and over the time of the experiment; and their height in relation to the liquid. The emulsions that give rise to the foams were also evaluated according to their stability. Those that, even though they were able to produce a foam with a good structure, if they were not stable, they were not considered adequate formulations. With the results it was possible to conclude that castor oil is not suitable in these formulations and that the other components are determinant in their behavior.
The present work is based on the study of potentially medicated foams, obtained from emulsions that are constituted of oils, phospholipids and the appropriate surfactants in order to produce stable foams, with a technically satisfactory structure. The studied formulations do not contain an active substance. The objective of the investigation is to develop a foam obtained from an emulsion in which the oil phase can have variable polarity depending on the oil used. This emulsion must be adequate to vehiculate an active substance that acts on the skin. For example, corticosteroids for the treatment of psoriasis. Foams are of pharmaceutical interest because of the commodity of their utilization. They allow the efficient administration in areas of difficult access, such as the scalp, and therefore they promote patient adhesion to therapy. In this study, 72 formulations were developed. Each one of them is based on an emulsion in which the oil phase includes one of the following oils: medium chain triglycerides, liquid paraffin or castor oil, in concentrations of either 10 or 20%. The oil is dispersed in aqueous mixtures of phospholipid and surfactants which are known to be capable of producing a foam, this was previously demonstrated using a method also applied in this work to evaluate the foamability and the foam structure called "screening method" in which three graduated columns are arranged side by side. The emulsion that gives rise to the foam is introduced into the columns and the air is driven from the base of the columns through a disc-shaped filter, thus dispersing into the emulsion. The foams were evaluated and classified according to: their ability to be produced; their initial structure and over the time of the experiment; and their height in relation to the liquid. The emulsions that give rise to the foams were also evaluated according to their stability. Those that, even though they were able to produce a foam with a good structure, if they were not stable, they were not considered adequate formulations. With the results it was possible to conclude that castor oil is not suitable in these formulations and that the other components are determinant in their behavior.
Descrição
Trabalho Final de Mestrado Integrado, Ciências Farmacêuticas, 2021, Universidade de Lisboa, Faculdade de Farmácia.
Palavras-chave
Foam Emulsion Oil Phospholipid Surfactant Mestrado integrado - 2021