Dermal targeting using colloidal carrier systems with linoleic acid

In the basic therapy of chronic skin diseases characterized by xerosis, the local treatment is an essential strategy to reach ideal therapeutic effects. Suitable active ingredients for this aim are fatty acids, in particular linoleic acid, which is an essential component for the organization and perpetuation of the skin barrier. In the present work, the development of a well-tolerated colloidal carrier system (microemulsion) containing linoleic acid as active ingredient is described. A comprehensive physiochemical characterization of the novel microemulsion system was performed using different techniques. The potential of the developed microemulsion system compared to a cream as suitable carrier for the dermal delivery of linoleic acid was determined. Penetration studies showed higher linoleic acids concentrations after administration of the colloidal carrier system in all skin layers independent of the time of incubation. Up to 23% of applied dose reached the skin from the colloidal carrier system whereas at most 8% of the active ingredient could be detected after applying the cream. Particularly, the percentage of the linoleic acids penetrated through the microemulsion in the stratum corneum and the viable epidermis differed significantly (p < 0.01) when compared to that through a standard cream. Furthermore, linoleic acids accumulated in the epidermis at longer incubation times. Using the microemulsion, the penetration of linoleic acids was enhanced significantly (p < 0.01). Hence, the microemulsion might be an innovative vehicle for the delivery of linoleic acids to the epidermis improving its use as their barrier regeneration and providing possible anti-inflammatory effects.