Study On The Preparation Of Multiple-emulsions And It's Insulin Entrapment Property

The control release properties of multiple emulsions provide the potential for many usefulapplications in medical, cosmetic, food and other personal care products. However, the unstable nature of multiple emulsions have limited their development. .The stability of multiple emulsions(W/O/W) have been studied by many people in recent years. The object of this study was to optimize the preparation conditions of a multiple emulsion, which would provide stability. The microencaplatoin and delivery of insulin was chosen as a system for development of a stable multiple emulsion.This research compared defferent preparation conditions for a multiple emulsion. Ultrasonic, pressure homogenizaton, and high-shear homogenization were used to prepare primary emulsion. The second or multiple emulsion was prepared with high-shear homogenization. The results indicated that a multiple emulsion which was prepared with high-shear homogenization for primary emulsion and high-shear homogenization for the multiple emulsion was more stable than with the use pressure homogenization for the first stage. The property of the insulin in the inner aqueous phase was not affected by this preparation proceudure. High-shear homogenization was selected to prepare primary emulsion.The effect of the components on the stability of the multiple emulsion was studied. The components were the inner aqueous phase, the middle lipid phase, outer aqueous phase, the inner emulsifier (I), and outer emulsifier II. Paraffin was found to be the best lipid. The optimized inner aqueous phase was NaCl 0.08%, Xanthan gum 0.2%, with a pH 2. Blends of Span80 and Tween80 with different HLB values were found to be effective for the two emulsifier systems needed for the two interfaces. For the inner interface (I) an HLB value of 5.4 was the most effective. This was prepared with a 9:1 mixture of Span80 to Tween80 and making an 18% (w/w) solution of this emulsifier blend with the paraffin and them emulsifying the inner aqueous phase in the paraffin and emulsifier blend. For the outer interface (II), the best HLB value was 7.5. This was prepared with a 7:3 ratio of Span80 to Tween80. This blend was then dissolved in the outer aqueous phase and the inner emulsion was emulsified into the outer aqueous phase. Xanthan gum (0.2%) was used as a stabilizer in the outer phase. Xanthan gum increased the viscosity of the outer phase and this decreased the rate of separation of the multiple emulsion droplets. The fittest ratio of primary emulsion to outer water phase is 1:1. Multiple emulsions kept unchanged in the centrifugal condition (3000 r/min 15min).