Phospholipids in Cosmetic Carriers

Abstract

Phospholipids are attractive components in cosmetic products because of their natural origin and multifunctional properties. They are used, technically as surface-active compounds, but also as cosmetic actives and modulator of skin penetration. Three classes of phospholipids are being used in cosmetics: saturated and unsaturated phospholipids and monoacylphospholipids (lyso-phospholipids). Whereas the use of monoacylphospholipids is limited to technical use as emulsifiers, the cosmetic use of saturated and unsaturated phospholipids is much broader. The latter are used as actives; additionally saturated phospholipids are used as surface-active compounds, whereas unsaturated phospholipids are suitable to enhance skin penetration. The relation of phospholipids to nanotechnology is apparent when they are, e.g., used as an emulsifier in “nano-emulsions” and as component of “nano-liposomes”, having particle sizes in the nano-range. Regulatory authorities discriminate, however, between nanoparticles comprising solid inorganic non-biodegradable particles, with potential (systemic) toxicity, and flexible lipid biodegradable carriers, respectively, comprising, e.g., phospholipids which are non-toxic [1] and fall apart in the skin. Since basically the particle characteristics in the formulation and the component of the particles are believed to cause the desired beneficial cosmetic skin effects, in this chapter the use and degree of skin interaction of especially natural phospholipids as cosmetics ingredient in traditional and nano-cosmetic carriers are described and demonstrated by means of illustrative products.