ABSTRACT
Objective: To investigate the feasibility of Pickering emulsion stabilized by puerarin nanocrystalline. Methods: The new puerarin nanocrystalline self-stabilized Pickering emulsion (Pu-NSSPE) has been developed using the high pressure homogenization method. The influences of drug addition sequence, property, and construction of oil phase, drug concentration, oil/water ratio, homogenization pressure, and pH value of water phase on the formation and stability of Pu-NSSPE were investigated to optimize the preparation technology of Pu-NSSPE. Results: The stability and structure of optimized Pu-NSSPE were studied. It was difficult to form stable Pu-NSSPE if puerarin was first added into water during preparation. The three-phase contact angle and pH value of water phase were key factors for the formation and stability of Pu-NSSPE. Pickering emulsion could be stabilized by puerarin nanocrystalline only when three-phase contact angle of puerarin approaches 90° and water phase was alkaline. When the drug concentration was between 1.0-5.0 mg/mL, stable Pu-NSSPE could be formed. The higher oil/water ratio was, the more oil creamed from Pu-NSSPE was. Low homogenization pressure (below 80 MPa) could not form stable Pu-NSSPE. The size of emulsion droplet of optimized Pu-NSSPE was (10.66 ± 4.81) μm, and drug content was 4.28 mg/mL. The appearance, morphology, and size of emulsion droplets, Zeta potential and drug content were not changed significantly after storage for six months at room temperature. The adsorption of puerarin at the surface of oil droplets was observed by fluorescence microscope. Conclusion: Nanocrystalline of puerarin could stabilize Pickering emulsions, which will provide a promising drug delivery system for puerarin.