Solubilization of ?-tocopherol and curcumin by polyoxyethylene alkyl ether surfactants: Effect of alkyl chain structure

The effects of the structural characteristics of the alkyl chains of polyoxyethylene alkyl ether-type surfactants (Brij) on the solubilization of alpha-tocopherol and curcumin by surfactant micelles were investigated: Brij L23 (lauryl; C12:0); S20 (stearyl; C18:0); and Brij O20 (oleyl; C18:1). When alpha-tocopherol or curcumin were solubilized in Brij micelle solutions below their maximum solubilization concentrations (Cmax), the Brij L23 micelles exhibited the largest increase in dimensions due to the presence of the guest molecules. Above Cmax, excess alpha-tocopherol existed as microemulsion droplets whereas excess curcumin existed as insoluble crystals. Our results suggest that the guest molecules were preferentially located within the palisade layers of micelles, which can be attributed to the fact that they contained bother polar and non-polar moieties. These results may be important for the formulation of colloidal delivery systems to encapsulate and deliver oil-soluble vitamins and nutraceuticals.

Automated summary

The effects of alkyl chains on the solubilization of alpha-tocopherol and curcumin in Brij micelles were investigated. Brij L23 micelles showed the largest increase in dimensions due to the presence of the guest molecules. The guest molecules were preferentially located within the palisade layers of micelles, suggesting the potential importance of these findings for the formulation of colloidal delivery systems.