COVER STORY: Phospholipids - nature’s skin care all-rounders

They number among the body’s own building blocks and are essential constituents of the human cell membrane. These compounds are therefore highly biocompatible and benign, and hence predestined for use in superior high-end skin care products. Owing to their amphiphilic nature and their ability to interact with human skin, phospholipids can serve as active ingredients for skin protection and skin rejuvenation, as carrier systems for cosmetic active ingredients, and as skin friendly emulsifier systems.

Phospholipids support more efficient and better controlled transport of active ingredients

One of the best-known applications of unsaturated phospholipids is the encapsulation of cosmetic active ingredients, ensuring more effi cient and better controlled transport into the skin. Such encapsulation is accomplished by vesicles (so-called liposomes) whose outer membrane consists of a phospholipid double layer. The liposomes conventionally used for this purpose in cosmetic formulations have a particle size of 150–300 nm. The relatively large total surface area of the vesicles then comes into intimate contact with the surface of the skin, permitting mass transfer. The phase-transition temperature of unsaturated phospholipids lies below 0°C and the liposomes therefore exist in a liquid-crystalline state at skin temperature. These conditions permit optimum interaction of phospholipids with the stratum corneum and facilitate penetration of cosmetic actives into the skin, even into the dermis. This eff ect could be confi rmed in an in vivo study. An enrichment of niacinamide up to a skin depth of 20 µm could be established by a double-blind Raman spectroscopy study. An unsaturated phospholipid-based formulation successfully increased the niacinamide concentration in the deeper skin layers by up to 50 % compared to a placebo formulation (Figure 1).