PHA 327 - Exam 2 - Emulsions 6
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What are the four methods for preparing an emulsion?
- Wet gum method (English method)
- Dry Gum method (Continental Method)
- Bottle method
- Beaker Method
Describe the process of the wet gum method:
- Viscous mucilage of gum is made w/ little water
- Oil is added with rapid trituration
- Water is added as needed to reduce viscosity
How is the dry gum method performed?
- Primary emulsion is formed using all the oil (4:2:1 oil:water:emulsifier)
- Trituration is continued until “crackling/snapping” sound is heard
- Rest of aqueous phase is added by trituration
How is the bottle method performed?
Same as dry gum method but with bottle rather than mortar and pestle
What type of emulsion is the Bottle method suitable for?
Emulsions with volatile oils
What emulsion preparation would you use if your preparation contained a volatile oil?
How is the Beaker method performed?
- Put aqueous phase and oil phase in separate beakers
- Dissolve the emulsifier in the one in which it is most soluble
- Heat both beakers to 70 degrees C
- Add the internal to the external phase while stirring
What four parts of an emulsion should you evaluate after preparation?
- Phase separation
- Particle size distribution
How should you inspect for phase separation of an emulsion?
- Visually observe
- Sample from both top and bottom of the emulsion
Why do you need to evaluate the viscosity of an emulsion?
A decrease in viscosity can indicate an increase in particle size due to coalescence
What property of an emulsion indicates an increase in particle size due to coalescence?
What type of electrokinetic evaluation needs to be performed on an emulsion?
Measure the zeta potential
What does a decrease in zeta potential indicate?
A decrease in what indicates flocculation?
In the Dry Gum Method of emulsion preparation, what is the ratio of oil:water:emulsifier in the primary emulsion?
What would you like to do?
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