Biocompatible lipid-based liquid crystals and emulsions

Due to its potential relevance as a fully biocompatible formulation useful in cosmetic, food, and pharmaceutical applications, the glycerol trioleate/sodium oleate/water ternary system was investigated via optical microscopy and NMR methods. The ternary diagram is dominated by monophasic and biphasic regions where a lamellar phase coexists with different isotropic phases. A broad emulsion region, characterized by small oil droplets dispersed within the lamellar phase, extends from the center toward the water corner of the diagram. Information on the inner structure of these emulsion-like samples is supplied by modeling water and oil NMR self-diffusion data. Sizing of oil droplets was provided at different storage times. A highly polydisperse log-normal distribution was observed. The presence of the liquid crystalline phase is called into play for the negligible differences found in the droplets size distribution upon samples aging. Indeed, samples within this region stored at 25 degrees C did not show phase separation after several months from their preparation.