Oil-in-Oil-Emulsions with Enhanced Substantivity for the Treatment of Chronic Skin Diseases

The therapy of chronic skin diseases often requires several applications of creams or ointments per day. This is inconvenient to the patients and frequently leads to poor acceptance and compliance. We therefore developed oil-in-oil-emulsions that deliver the active pharmaceutical ingredient (API) to the skin over a prolonged period of time. In this study, we compare the permeation of the API from a conventional formulation to its permeation from an oil-in-oil-emulsion under infinite and finite dosing. Furthermore, we evaluate the substantivity of the formulations. Our results show that the permeation from oil-in-oil-emulsions is constant over a prolonged time and that the emulsions show significantly higher substantivity than conventional formulations. Because of that, the treatment intervals can be extended substantially and compliance can be increased. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.