Abstract:

The unique properties of jojoba oil make it an essential raw material in the manuf. of cosmetics. New, totally dilutable U-type microemulsions of water, jojoba oil, alcs., and the nonionic surfactant polyoxyethylene-10EO-oleyl alc. (Brij 96V) were formulated recently. Here, these microemulsions are shown to be capable of solubilizing lycopene, a nutraceutical insol. in water and/or oil, much more effectively than the solvent (or a solvent and surfactant blend) can dissolve them. In water-in-oil (W/O) and oil-in-water (O/W) microemulsions with 10 and 90 wt% water, resp., the normalized maximal solubilization efficiency $\alpha$ is ca. 20-fold larger than its soly. The solubilization capacity of the system is mainly surfactant-concn. dependent. The lycopene resides at the interfaces of the W/O and O/W microemulsions and engenders significant structural changes in the organization of the microemulsion droplets. In the absence of lycopene, the droplets are spherical; when lycopene is added, compaction of the droplets and formation of threadlike droplets are obsd. On further addn. of lycopene, the bridging effect wanes and the droplets revert to a spherical shape. The enhanced solubilization demonstrated for lycopene opens up new options for formulators interested in making liq. and transparent products for cosmetic or pharmaceutical uses. [on SciFinder(R)]