Optimization, characterization and in vitro evaluation of curcumin microemulsions.

The purpose of this study was to improve the solubility and the stability and oral uptake of curcumin by developing an o/w microemulsion, using food grade components. Three microemulsions were developed and characterized, stabilized by non ionic surfactants Cremophor EL, Tween 20, Tween 80 or Lecitin and containing a variety of oils, namely olive oil, wheat germ oil, vitamin E. Chemical and physical stabilities of three systems was also evaluated within two months. The oral absorption of curcumin from the best microemulsion was investigated in vitro using parallel artificial membrane permeability assay (PAMPA). The optimal formulation consisted of 3.3 g/100 g of vitamin E, 53.8 g/100 g of Tween 20, 6.6 g/100 g of ethanol and water (36.3 g/100 g), with a maximum solubility of curcumin up to 14.57 mg/ml and a percentage of permeation through the artificial membrane of about 70%.