Application of Pickering Emulsion with Cyclodextrin as an Emulsifier to a Transdermal Drug Delivery Vehicle.

The emulsion prepared with β-cyclodextrin as an emulsifier (βCDE) is considered to be a Pickering emulsion. We examined the characteristics of βCDEs using captopril (CP) as a model drug, and studied the in vitro skin permeation of CP from βCDEs through hairless mouse skin. The stability of βCDE was increased with increasing βCD concentration and conversely decreased with increasing CP concentration. The yield stress value from the rheological measurement results was suggested to be one of the factors determining the stability of the βCDE, and βCDEs with higher yield stress values were more stable. We found that the skin permeability of CP could be improved by using βCDE with isopropyl myristate as the oil phase and that the flux of CP depended on the free CP concentration in the water phase of βCDE.