Application of factorial experimental design for optimization and development of color lipstick containing antioxidant-rich Sacha inchi oil

This study aimed to optimize and develop the color lipstick formulation containing antioxidant-rich Thai Sacha inchi oil using full factorial experimental design. Antioxidant capacity of Sacha inchi oil was elucidated using DPPH and linoleic acid peroxidation assays. The y-tocopherol content of the oil was also determined by high-performance liquid chromatography. Developing the color lipstick, lipstick base was optimized through the variation of %Sacha inchi oil, Ozokerite and Carnauba wax ratio (O:C ratio) and %Fat. Concurrently, the influences of these factors on lipstick physical characteristics were analyzed by means of statistics. Thai Sacha inchi oil exerted a notable antioxidant capacity with the highest y-tocopherol content. The combined effect of all factors influenced on the variations of breaking point and hardness of the lipsticks. Otherwise, only the O: C ratio negatively affected on melting point. The color lipstick containing methyl methacrylate crosspolymer and stearyl dimethicone as texture enhancers, significantly provided a greater color transfer than the plain formulation. In conclusion, Thai Sacha inchi oil could be a promising antioxidant-rich oil for developing into color lipstick. To evolve the desirable lipstick, the optimum proportion of wax, fat and oil played a crucial role in both structural integrity as well as texture and spreadability.