Non-aqueous olive oil-in-glycerin (o/o) Pickering emulsions: Preparation, characterization and in vitro aspirin release

ABSTRACT

Non-aqueous olive oil-in-glycerin Pickering emulsions are successfully prepared and stabilized solely by hydrophobic silica nanoparticles possessing 50% silanol groups. Various aspects related to the preparation and physicochemical stability of such promising emulsions are investigated. The resulted emulsions exhibited excellent stability against coalescence for above one year. The apparent viscosity of the olive oil-in-glycerin emulsions is explored as a function of silica nanoparticle concentration and drop volume fraction for the first time. The flow behavior of these emulsions followed the non-Newtonian shear-thinning trend. Both simple o/o and multiple o/o/o emulsion types can be stabilized by one and the same silica nanoparticles during the catastrophic phase inversion, occurred at drop volume fraction between 0.4–0.5. Our findings are correlated with the widely accepted surfactant or solid-stabilized systems. The potential use of such unique emulsions as drug delivery vehicles is studied.

GRAPHICAL ABSTRACT

KEYWORDS:

• Drug release
• non-aqueous Pickering emulsions
• silica nanoparticles
• stability
• viscosity

Acknowledgments

The authors would like to thank Minia University for affording the homogenizer and Wacker-Chemie for kindly providing the silica nanoparticles.