Formation and stability of Vitamin E nano-emulsion based delivery systems by spontaneous emulsification method: Glycerol as a co-solvent

There is considerable interest in using nano-emulsions (NEs) as delivery systems for lipophilic
bioactive ingredients. In this study, the influence of G on the properties of vitamin E (VE) enriched NEs
prepared using spontaneous emulsification (SE) method, were investigated. The particle size and optical clarity
of the NEs depended strongly on the co-solvent presence, absence, and concentration. The smallest droplets
(mean diameter less than 23.5 and 236.771 nm) and highest transparency (lowest turbidity, 0.0069 and 0.0161 cm-1) were observed in the absence of G (A formulation) and the presence of 30 wt.% G (D formulation), respectively. However, these NEs were highly unstable for droplet growth during storage, especially at high temperatures, which was attributed to coalescence and Ostwald ripening (OR). Dilution of the NEs (100× with water) before of storage considerably were improved their storage stability especially at higher storage temperatures. Undiluted NEs exhibited a sharp and irreversible increase in turbidity upon heating: ≈75 °C and 70 °C for A formulation and D formulation, respectively. Diluted NEs had much better thermal stability, with a sharp increase in turbidity occurring at ≈75 °C for these systems. This study provides useful information for use in pharmaceutical, personal care, and food products.