Preparation of a supersaturatable self-microemulsion as drug delivery system for ellagic acid and evaluation of its antioxidant activities

The objective of this study was to improve the solubility of ellagic acid using supersaturatable self-microemulsifying drug delivery system (S-SMEDDS). Ternary phase diagrams and central composite design were constructed to optimize the formulation of ellagic acid-loaded supersaturatable self-microemulsion. It was found that the optimal formulation was comprised of 10% ethyl oleate, 67.5% Tween 80, 22.5% polyethylene glycol 400, 0.5% polyvinylpyrrolidone K30 and 4 mg g−1 ellagic acid. The morphologies and particle size studies indicated that ellagic acid-loaded S-SMEDDS were spherical particles with a droplet size of about 40 nm. And the in vitro dissolution study showed that ellagic acid could dissolute from the S-SMEDDS within a short time and exhibited more rapid release from S-SMEDDS than from SMEDDS. What's more, the in vitro and in vivo antioxidant ability of ellagic acid-loaded S-SMEDDS were significantly higher than those of pure ellagic acid at the same concentration. In conclusion, supersaturatable self-microemulsion is a potential carrier for the ellagic acid.