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Master's Dissertation
DOI
10.11606/D.60.2008.tde-02102008-163152
Document
Author
Full name
Fernanda Frota de Andrade
Institute/School/College
Knowledge Area
Date of Defense
Published
Ribeirão Preto, 2008
Supervisor
Committee
Rocha Filho, Pedro Alves da (President)
Leonardi, Gislaine Ricci
Lopez, Renata Fonseca Vianna
Title in Portuguese
Desenvolvimento e avaliação de cristais líquidos obtidos em emulsões O/A à base de oléo de andiroba e éster fosfórico
Keywords in Portuguese
atividade cosmética
avaliação sensorial
Cristal líquido
emulsão
óleo de andiroba
propriedades físico-químicas.
Abstract in Portuguese
Nesta pesquisa emulsões O/A contendo cristais líquidos (CL) foram desenvolvidas a partir da técnica do diagrama ternário, utilizando óleo de andiroba e uma base auto-emulsionante aniônica constituída de éster fosfórico (Crodafos CES®), como sistema tensoativo. Foram obtidas dispersões com diferentes aspectos, classificadas como instáveis, cerosa e emulsões estáveis. A formulação constituída de 10,0 % óleo de andiroba, 10,0 % Crodafos CES® e 80,0 % de água foi selecionada para dar seqüência a pesquisa, devido a estabilidade e viscosidade aparente adequadas. Devido a aeração, foi adicionado à formulação o silicone PEG- 12 Dimethicone e para analisar a influência desse silicone na formação de cristais líquidos das emulsões, desenvolvemos um diagrama ternário contendo PEG-12 Dimethicone, Crodafos CES® e água onde as emulsões apresentaram melhor fluidez. À formulação com óleo de andiroba selecionada foi adicionada concentrações crescentes de silicone para avaliação da interação deste com o produto obtido. Foram utilizados como parâmetros para a avaliação os testes preliminares de estabilidade, teste de estabilidade acelerada (TEA), comportamento reológico e valores de potencial zeta. Em seguida, estudou-se o comportamento das emulsões durante a evaporação utilizando-se diagrama de fases e testes de evaporação. Três formulações foram submetidas ao estudo de avaliação da atividade cosmética in vivo. Para isto foram empregadas as formulações com CL, e avaliadas a influência sobre os parâmetros de hidratação, oleosidade e pH cutâneos, e também avaliação sensorial. Os resultados sugeriram uma correlação entre ambos os diagramas, onde a taxa de componentes das formulações que apresentaram CL foi similar especialmente associado à concentração de Crodafos CES® sugerindo que o silicone foi efetivo na diminuição da viscosidade das emulsões. Todas as emulsões apresentaram-se estáveis nos testes de estabilidade e foram classificadas como fluido pseudo-plástico e tixotrópicos, características estas relacionadas a formação de CL do tipo lamelar. Durante a evaporação das emulsões houve a manutenção dos CL, porém seu tipo variou em função da diminuição de água no sistema demonstrando a transição de fases dependente da concentração do solvente. Através dos testes in vivo, as emulsões de óleo de andiroba contendo CL promoveram a hidratação da pele independente da adição do silicone, de acordo com o teste de hidratação em curto prazo; não alteraram estatisticamente a oleosidade cutânea, não deixando assim a pele com aspecto gorduroso; alteraram os valores de pH cutâneo devido ao baixo valor encontrado nas emulsões, porém sem provocar nenhum tipo de irritação à pele; e na avaliação sensorial, a formulação sem silicone foi a melhor aceita.
Title in English
Development and evaluation of Liquid Crystals obtained in O/W emulsions based on andiroba oil and phosphoric ester.
Keywords in English
andiroba oil
cosmetic activity
emulsion
Liquid crystal
physical-chemical properties.
sensorial evaluation
Abstract in English
In this researche, O/W emulsions containing liquid crystals were developed using the phase diagram technique, employing andiroba oil and a cripto-anionic selfemulsifying base constituted of phosphoric ester (Crodafos CES®), as surfactant system. Dispersions were obtained with different aspects, being classified as unstable, with wax aspect and stable emulsions. The formulation constituted of 10% andiroba oil, 10% Crodafos CES® and 80% water was selected due stability and appropriated apparent viscosity, to give sequence this research. Trying to improve the macroscopic characteristics, reducing the aeration and viscosity, the silicon PEG- 12 Dimethicone was added to the formulation. To analyze the influence of that silicon in the formation of liquid crystals on emulsions, a ternary phase diagram was developed containing PEG-12 Dimethicone, Crodafos CES® and water. The results were similar with that obtained with the andiroba oil; however the emulsion with silicon presented better fluidity. In selected formulation was an added growing concentrations of silicon in order to evaluate their interaction in the final product. Preliminary and accelerate stability tests, rheological behavior, values of zeta potential were used as evaluation parameters. Afterwards, it was studied the behavior of the emulsions during evaporation, being used phase diagrams and evaporation test. Three formulations were submitted to the study of cosmetic activity in vivo. For this evaluation the formulations with liquid crystal, with or without silicon, parameters, such as hydration, oiliness and cutaneous pH values, and also sensorial evaluation, were used. Results suggested a correlation between both diagrams, where the rate of components of the formulations that presented lamellar liquid crystalline phases was similar, especially associated with Crodafos CES® concentration. It suggests that silicon used in the study was effective in decreasing the viscosity of the emulsions, also maintaining the formation of lamellar phases when compared to formulations of the diagram containing andiroba oil. All the emulsions were stable in the stability tests and they were classified as pseudoplastic fluid and tixotropic, characteristic these related the formation of liquid crystalline phases of the type lamellar. During evaporation of the emulsions, liquid crystals were maintained, however their type varied in function of the decreasing of water rate in system, demonstrating that phase transition is dependent to solvent concentration. Through the in vivo test, emulsions with andiroba oil containing liquid crystal promoted skin hydration independently of the silicon addition, according to hydration test in a short period (kinetic test); the emulsions did not changed cutaneous oiliness, not leaving skin with greasy aspect; they altered cutaneous pH values due low value found in emulsions, however any irritation was showed in the skin; and in the sensorial evaluation, the formulation without addition of the silicon was better accepted by the volunteers.
 
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Publishing Date
2009-01-05
 
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