Research on Preparation Technology and Performance of Phillyrin Self-Microemulsion

Phillyrin has many effects, such as reducing blood lipids, anti-inflammatory properties, lowering blood pressure, and decreasing tyrosinase activity. However, the bioavailability of phillyrin with oral administration is very low due to its poor water solubility. In order to overcome the bioavailability problems of phillyrin, a phillyrin self-microemulsion was prepared by changing the dosage form, the preparation process of which was optimized, and its characterizations were investigated. Based on a self-microemulsion administration system, appropriate ingredients were chosen first on the basis of a solubility test, and the range of application of each ingredient was determined by ternary phase diagrams. Second, the formula of the phillyrin self-microemulsion was optimized through the response surface method by using the mass percentage of ethyl oleate and K _m value (the ratio between surfactant and cosurfactant) as independent variables and using the encapsulation efficiency (EE), grain size, and polydispersity index (PDI) as dependent variables. The average grain size, PDI, and encapsulation efficiency of the optimized microemulsion are 42.37 nm, 0.244, and 69.51%, respectively. Finally, the apparent properties, stability, and pharmic content of the prepared phillyrin self-microemulsion were characterized. Moreover, in vitro dissolution was analyzed by using the rotatory-basket method, proving the self-microemulsion could improve the in vitro dissolution of phillyrin. The above-mentioned results indicated that self-microemulsion could be used to improve the solubility and bioavailability of phillyrin, which might be a good alternative solution to improve the oral utilization of phillyrin.