Identifying Cosmetic Forms And Crystalline Phases From Ternary Systems

April 21, 2006 | Contact Author | By: M. Ferrari, College of Pharmacy and Biochemistry, University of Cuiaba; L.C.L. Monteiro, D.J.A. Netz and P.A. Rocha-Filho, College of Pharmaceutical Sciences
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Keywords: ternary systems | formulation techniques | emulsion | gels | crystalline phases | andiroba oil | copaiba oil

Abstract: Diagrams of the oil, surfactant and water at stepped proportions in ternary systems characterize the system’s cosmetic forms (emulsions, gels, dispersions), crystalline phases and stability in this study using two Brazilian oils.

Within the field of cosmetology, studies of ternary systems have been used primarily for two reasons: to achieve different cosmetic forms by using a unique watersurfactant- oil system and to improve our comprehension of several features of physical chemistry.

The diagrams used in these studies allow us to prepare different water-surfactant-oil mixtures proportionally. Once the balance is set up, the diagrams help us determine the nature of the product resulting from each mixture. Finally, the diagrams enable us to display the results as an equilateral triangle in which each side represents one component.

Another aspect of contemporary cosmetology is the potential applications for liquid crystals. Several studies have shown that liquid crystals are useful in prolonging the release period of various actives and in stabilizing both single and multiple emulsions.

Matter can exist as solids (three-dimensional molecular patterns; rigid structure), liquids (no molecular pattern; fluid flow) and something between called liquid crystals that show phases, which are varying degrees of molecular patterning and flow, depending on factors such as temperature. G. Friedel, in 1922, used the term “mesomorphic state” (mesos, intermediate; morphé, form) to describe the intermediate state in the thermal transformation from the solid to the liquid state. Among the liquid crystals, the phases most important and commonly noted are the following:

• Lamellar or “neat phase” liquid crystals usually consist of double layers of surfactant molecule with the polar groups protruding into the intervening layers of aqueous interface;

• Hexagonal or “middle phase” liquid crystals generally consist of cylindrical structures;

• Cubic phase liquid crystals in which the molecules pack in a spherical pattern. In an aqueous environment, the molecules sometimes pack in a cubic pattern;

 • Both watery and non-watery isotropic micellar solutions.