Influence of processing parameters on morphology of polymethoxyflavone in emulsions

Polymethoxyflavones (PMFs) are groups of compounds isolated from citrus peels that have been documented with wide arrays of health-promoting bioactivities. Because of their hydrophobic structure and high melting point, crystallized PMFs usually have poor systemic bioavailability when consumed orally. To improve the oral efficiency of PMFs, a viscoelastic emulsion system was formulated. Because of the crystalline nature, the inclusion of PMFs into the emulsion system faces great challenges in having sufficient loading capacity and stabilities. In this study, the process of optimizing the quality of emulsion-based formulation intended for PMF oral delivery was systematically studied. With alteration of the PMF loading concentration, processing temperature, and pressure, the emulsion with the desired droplet and crystal size can be effectively fabricated. Moreover, storage temperatures significantly influenced the stability of the crystal-containing emulsion system. The results from this study are a good illustration of system optimization and serve as a great reference for future formulation design of other hydrophobic crystalline compounds.