Optimization of dermal pickering emulsion formulations and evaluation of in vitro performances

Emulsions are colloidal carriers widely used in dermal formulations for pharmaceutical and cosmetic applications. The surfactants are often used as emulsifiers to reduce the free surface energy of the emulsions, which allow mixing of two phases. However, they have the potential to cause skin irritation. Pickering emulsions are prepared with solid particles having emulsifier features. It is advantageous to use solid particles with high biocompatibility which do not have negative effects on the skin instead of surface active agents. Thus, incompatibility, instability and irritation effect on the skin observed in conventional emulsions are reduced or eliminated. The aims of this master thesis is optimization of skin-compatible and stable Pickering emulsions that provide superiority over conventional emulsions consisting surfactants and, to evaluate the penetration of tacrolimus selected as a model drug from Pickering emulsions through skin in vitro. For this purpose; Pickering emulsions were prepared by cyclodextrins as solid particle. The cyclodextrin/oil/water ratios were optimized with triangular phase diagrams. The physical stability and rheological properties were evaluated. pH and the conductivity and, morphological properties of the selected formulations were determined. Subsequently, the localization of tacrolimus in the skin layers from Pickering emulsions was examined by tape-stripping method following in vitro skin penetration studies. When the findings were evaluated; Pickering emulsions prepared using a simple production technology have exhibited suitable properties. For the first time, tacrolimus loaded Pickering emulsions optimized with cyclodextrins showed drug penetration in the layers of skin comparable to that of commercial ointment. As a result, the potential of tacrolimus loaded Pickering emulsions is shown to be an alternative carrier system for dermal application.