Topical formulations come primarily as ointments, creams or gels. Creams in particular are often heterogeneous emulsion-based systems consisting of several phases separated by interfaces. They undergo significant changes during application where new interfaces are created and it is thus crucial to understand interfacial phenomena for predicting behavior of formulations at surfaces. Pickering emulsions are dispersions of one liquid in another stabilized by solid particles adsorbed at the liquid-liquid interface. They ought to offer added value to topical formulations as they are surfactant free and possess high long term stability towards coalescence and Ostwald ripening. Emphasizing the advantages of Pickering emulsions it should be stated that their industrial potentials are still not discovered and further fundamental studies are needed.

The main objectives for the current project are i) to establish methods that allow measurements of time dependent transformations of different formulations under well controlled ambient conditions, ii) to gain increased understanding on how ambient conditions, specifically temperature and humidity, affect reformulation upon application, film formation and subsequent molecular mobility in the “dry” film at the surface, and iii) to investigate how the polarity and volatility of the continuous phase influences the stability and behavior of Pickering emulsions when applied on a surface.

From a commercial perspective a major objective of the current project is to gain further understanding on optimization of personal hygiene products production, their interaction with skin and their safe efficacy in their areas of use. For one of the industry partners, Sterisol AB, this can be beneficial for improved product formulation and production within the company’s packaging concept as well as for minimization of effects on skin integrity and function without loss of microcidal and cleansing efficacy. For the other partner, Speximo AB, the project may, by creating surfactant free alternatives, provide a new “leg” in their current technology. The project may also provide the basis for a joint business opportunity for Sterisol and Speximo.

At Malmö University, research activities related to topical formulations and phenomena related to perturbation of, and transport over biological membranes (such as skin) have grown within the frame of Biofilms – Research Center for Biointerfaces. The current project provides an attractive bridge between previous activities where we have looked at effects of formulations on skin barrier function at constant boundary conditions (e.g. KKs 2009/0274) and more recent activities (e.g. KKs 2014/0211) where the goal is to see if the use of specific excipients may help retain the drug in viable skin once it has passed the main barrier, stratum corneum. It would fit perfect into our project portfolio and with the strategy to further develop the Mah-LU “Topical science Cluster” initiative from 2012.

Participating organizations: Speximo AB, Sterisol AB.