Selective incorporation of the polar ingredients on the formulation of clear gels through phase diagrams.

Synopsis This paper attempts to systematize the preparation of cosmetic formulations by means of phase diagrams. The general criteria used to adapt the usually complex cosmetic systems to simple ternary diagrams W/O/S, consists of grouping the different ingredients according to their functional characteristics (hydrophilics, lipophilics and amphiphilics) that are located respectively in the corresponding vertices W, O and S. Thus, the polar ingredients are always incorporated simultaneously as a single phase, over the initial combinations O/S according to the classical titration procedure. Selective incorporation of the polar ingredients by means of the so-called double-titration procedures was studied. Independent consideration of the polar ingredients leads to modelling of the system in a regular tetrahedron in which the components are located at the four vertices. Several possibilities of double-titration procedures are considered in the tetrahedron depending on the different sequences of incorporating the polar ingredients. The results obtained show a critical influence of the double-titration procedures on two main aspects: limits of existence of the transparent gel realms, and rheological behaviour of some selected compositions. The different possibilities compared with the fixed characteristics obtained by the conventional method of preparation constitute an advantage in adapting a final formulation to the specific needs.