Within the scope of a published study  in collaboration with Lonza Ltd. (Basel, Switzerland) and Azelis (Azelis Deutschland Kosmetik GmbH, Moers, Germany), the surfactant polyglyceryl-10 monooleate was tested for its suitability as a skin-compatible emulsifier for low-viscosity sprays and lotions and as a builder for liposomal structures. The aspect of skin compatibility in particular makes it necessary to achieve the desired stabilization of the emulsion with the smallest possible amount of active ingredient. In particular, the number of free surfactant monomers not bound in micelles or liposomes should be as low as possible. Against this background, the determination of the critical micelle concentration (CMC) and the surfactant concentration necessary for the maximum reduction of the interfacial tension between hydrophilic and hydrophobic phase played an important role in the evaluation of the emulsifier.
Here we present the results of our interfacial analytical measurements, which form a section of the broader publication. The complete study includes additional polariation microscopic investigations of the liposomal structure as well as particle size determinations and rheological measurement of complex formulations with polyglyceryl-10 monooleate as emulsifier to evaluate the suitability for finest droplet, low viscosity emulsions.