Microemulsions based on a sunflower lecithin-Tween 20 blend have high capacity for dissolving peppermint oil and stabilizing coenzyme Q10.

The objectives of the present study were to improve the capability of microemulsions to dissolve peppermint oil by blending sunflower lecithin with Tween 20 and to study the possibility of codelivering lipophilic bioactive compounds. The oil loading in microemulsions with 20% (w/w) Tween 20 increased from 3% (w/w) to 20% (w/w) upon gradual supplementation of 6% (w/w) lecithin. All microemulsions had particles of <12 nm that did not change over 70 d of storage at 21 °C. They had relatively low Newtonian viscosities and were physically and chemically stable after 50-200-fold dilution in water, resulting from similar hydrophile-lipophile-balance values of the surfactant mixture and peppermint oil. Furthermore, the microemulsions were capable of dissolving coenzyme Q10 and preventing its degradation at UV 302 nm, more significant for the microemulsion with lecithin. Therefore, natural surfactant lecithin can reduce the use of synthetic Tween 20 to dissolve peppermint oil and protect the degradation of dissolved lipophilic bioactive components in transparent products.