Application of food-grade magnesium stearate microparticles as stabilizer in preparation of biocompatible Pickering emulsions

Abstract

In this paper, the application of food-grade magnesium stearate microparticles as a stabilizer in the preparation of a novel biocompatible Pickering emulsions was reported. Water-in-oil (W/O) Pickering emulsions were successfully prepared in various solvents such as n-heptane, silicone oil, and food/cooking-grade olive oil, which are all acceptable solvents in the pharmaceutical, cosmetic, and food industries. To the best of our knowledge, there are no available reports on the application of safe and easily available Pickering emulsions prepared using stearate solid particles. It was found that the emulsions could be prepared using mild agitation methods such as shaking by hand, magnetic stirring, and vortex mixing. In contrast, vigorous agitations such as using a homogenizer prevented emulsion formation. It was realized that inorganic salts are a requisite for stable emulsion formations and CaCl2 produced the most stable emulsion. The size of the emulsion was dependent upon the concentration of the microparticle; therefore, its concentration was optimized in this study. The Sauter mean diameter of the emulsions was proportional to agitation speed, which is consistent with those of surfactant-free emulsion systems. We have shown that consistent preparation of emulsions is possible using the novel Pickering emulsion systems in comparison to the conventional surfactant-based emulsion systems. We demonstrated that safe and biocompatible Pickering emulsions can be prepared using easily available food-grade magnesium stearate microparticles without the need for artificial surfactants.