W/O Lecithin Microemulsions With Vegetable Oils and Turmeric Essential Oil for Medical and Cosmetic Use

ABSTRACT Reverse microemulsions of lecithin with oleic acid and oils of natural origin are proposed for use in medicine and cosmetics. For the microemulsions with gac, soybean and olive oils, the maximum water content is achieved at a ratio of molar concentrations of water and lecithin of 0.4–0.6; for the microemulsions with coconut and sunflower oils, it is practically independent of this ratio. For the microemulsions with a ratio of molar concentrations of water and lecithin of 0.6 and a mass ratio of vaseline and vegetable oils equal to 1:1, the maximum water content is observed for the oils (wt.%): gac—13, soybean—11, olive—9, coconut—5, sunflower—4. The presence of both hydrated and bulk water in the droplets was established. The microemulsions are stable up to 65°C. The size of water droplets in the microemulsions is in the range of 6–20 nm (depending on the water content); the viscosity is 0.08–0.13 Pa s at 25°C. Microemulsions have a low rate of release of water‐soluble substances: after 7 h of dialysis, 3.0%–3.5% of the Rhodamine C dye was released into the physiological solution.