Microemulsions and Lyotropic Liquid Crystals of Lecithin as Systems for Transdermal Drug Delivery

Abstract

Reverse microemulsions in the lecithin–oleic acid–paraffin oil–avocado oil–tea tree essential oil–water system and lamellar liquid crystals in the lecithin–avocado oil–tea tree essential oil–water system were studied as systems for transdermal drug delivery. Oil- and water-soluble substances, as well as substances that are poorly soluble in water and oil in the form of solid-phase particles, can be introduced into liquid crystals in concentrations of a few percent. Oil-soluble substances can be introduced into reverse microemulsions in concentrations of a few percent and water-soluble substances can be introduced in concentrations of tenths of a percent. The dialysis method showed that the rate of release of water-soluble substances from the reverse microemulsion containing 4.8 wt % water is approximately 2.5 times higher than that from the lamellar liquid crystal containing 15 wt % water. This is explained by the fact that the viscosity of liquid crystals is more than 100 times higher than the viscosity of microemulsions.