Stabilization of Water Droplets in Oil with PGPR for Use in Oral and Dermal Applications

To stabilize microstructured fluids, like emulsions, strong surfactants are needed. For oral or dermal applications, these surfactants need to comply with strict legal requirements. Polyglycerin-polyricinoleat (PGPR) is described as one of the most potent oil-soluble surfactant in stabilizing water-in-oil (W/O) emulsions. Ways were determined to process W/O emulsions with PGPR meeting legal restrictions. The impact of process and recipe parameters on the formation of W/O emulsions was investigated. It was found that it is possible to stabilize W/O emulsions with very small amounts of PGPR (0.3% in the finished product). Emulsions stabilized with PGPR alone allowed for droplet sizes below 10 mu m, but with mostly multimodal droplet size distributions. PGPR showed a strongly increased performance when combined with NaCl in the aqueous phase. This combination allowed for a stabilization of defined, mono-modal droplet sizes well below 1 mu m. Thus, PGPR is under certain conditions an interesting surfactant for stabilization of W/O emulsions, meeting the legal restrictions for the use in oral and dermal applications. PRACTICAL APPLICATIONS Microstructured fluids, like emulsions, play an important role within food, cosmetic and pharmaceutical products. They allow for e.g., encapsulation of active agents. To stabilize emulsions for oral and dermal applications, the stabilizing surfactants need to meet legal restrictions. For W/O-type emulsion, the available surfactants (e.g., PGPR) need to be concentrated too high to work or are very sensitive to environmental impacts (e.g., phospholipids). Thus, results of the study have a potential application in the formulation of W/O emulsions for foods, cosmetics or pharmaceuticals to meet legal requirements.