Preparationof Multiple Emulsion In Loading Synephrine And Its Stability

The W/O/W multiple emulsion prepared by two-step emulsification method withbeewax, monoglyceride and sodium dodecyl sulfate(SDS) as raw material. The stabilityof W/O/W multiple emulsions was investigated by determining the relatively volumeratio, viscosity andparticlesize.Firstly, the effects of viscosity on the stability of W/O/W multiple emulsion wasstudied. When the viscosity of multiple emulsion is over210mPa·s, the multipleemulsion are very stable. The results indicate multiple emulsion with the higherviscosity have the higher stability. What’s more, the viscosity of oil phase has less effecton the viscosity of multiple emulsions than the viscosity of external water phase.Meanwhile, according to the classical viscosity model, the viscosity model was derivedwhich is the most suitable for the W/O/W multiple emulsion with paraffin oil.Secondly, the effect of interfacial properties is studied. The lower interfacialtension of the oil and water will decrease the particlesizeof the W/O/W multipleemulsions and boost the stability of the W/O/W multiple emulsions.The results showthat the interfacial tension between the oil phase and external water phase has greaterinfluence on the W/O/W multiple emulsions’ stability.Thirdly, the water transport of the W/O/W multiple emulsions is researched, andthree measures were taken to control the water transfer.(i)The higher osmotic pressureof theexternal water phase can control the water transport,and the studies show that theoptimum NaCl concentration was0.5～0.7mol/L.(ii) With improvingthe viscosity oftheexternal water phase, the rate of the water transport will reduce, and the researchshows that when the molecular weight of thickeners is over250000, the water transportrate was so low that have hardly effect on the stability of the W/O/W multiple emulsions.(iii) The water transport could be prevented by the cross linking of emulsifier. Thestudies indicate that reinforcing the interfacial strength between the internal water andoil has a significant influence on the control of the water transferon the basis of thesame dosage of emulsifier.Finally, the preparation conditions and the formula of multiple emulsions areoptimized by orthogonal experiments. The optimized preparation conditions: the firststirringrate1600rpm/min, the second stirringrate1800rpm/min, the first emulsifyingtime15min, the second emulsifying time40min and emulsifying temperature80℃. The best formula: paraffin oil concentration30wt%, monoglyceride concentration5.71wt%,SDS concentration6.82wt%, triethanolamine concentration2.5wt%, synephrineconcentration0.15wt%and deionized waterconcentration54.82%.