Formulation and evaluation of a α-linolenic acid and vitamin E succinate microemulsion with low surfactant content and free of co-surfactant for use as a nutritional supplement.

Herein, we have designed an alcohol-free and low-surfactant microemulsion to safely and effectively supply α-linolenic acid (ALA) and vitamin E (VE). Ternary phase diagrams show that the use of medium- or short-chain alcohols as the co-surfactant (CoS) was unfavorable for the formation of the ALA microemulsion due to the competitive hydrogen bonding effect and vitamin E succinate (VES) significantly increased the ALA microemulsion region by improving the hydrophilicity of the oil phase. The optimal microemulsion formulation (M) was 6.86% ALA, 1.14% VES, 12% surfactant and 80% water, with uniformly dispersed spherical particles with diameters of ~ 25.41 nm and viscosity of 35.17 mPa·s. The M was stable to high temperature, ionic strength and pH, and exhibited good physical and anti-oxidation stability. The M facilitated the release and hydrolysis of VES, indicating that the CoS-free microemulsion with low surfactant content is promising for the safe and effective supply of ALA and VE.