[Development of preparation process of icaritin-coix seed oil microemulsion based on quality by design concept]

To optimize the formulation and preparation process of icaritin-coix seed oil microemulsion(IC-MEs) based on quality by design(QbD) concept. IC-MEs were prepared by water titration. Firstly, the risk factors that may affect the quality of IC-MEs were evaluated. Then Plackett-Burman design was used to screen out prescription factors and process parameters that had a significant effect on the indicators. Finally, Box-Behnken design was used to optimize the prescription ratio of IC-MEs. Through the risk assessment and Plackett-Burman design, three formulation factors [drug loading efficiency, the ratio of mixed-oil(coix seed oil-Glycerol tributyrate) to mixed-surfactant(HS15-RH40) and water addition] were determined as the key factors affecting IC-MEs. The regression model established by Box-Behnken design had a good predictability. The optimal formula was as following: the drug loading efficiency of 0.92%, the ratio of mixed-oil(coix seed oil-glycerol tributyrate) to mixed-surfactant(HS15-RH40) of 4∶6, and the water addition of 5.7 mL. According to this prescription, IC-MEs were prepared, and its encapsulation efficiency after 1 week was 92.45%±1.00%. Therefore, the stability of IC-MEs could be improved by optimizing prescription and process parameters of IC-MEs based on the QbD concept, which can provide certain reference value for the future development of IC-MEs.