1. Emulsions Emulsion suitable for intravenous injection.
Balm: Water in oil emulsion
Sodas: Oil in Water emulsion
Milk: Oil in Water emulsion
Dodecane droplets in a continuous phase of water/glycerol mixture.
Mayonnaise: Oil in Water emulsion

2. Outline Introduction Types of emulsions Emulsifying agents
Tests for emulsion types
Emulsion Stability
Phase Inversion, Creaming
Emulsion Breaking

3. Introduction
Emulsion – Suspension of liquid droplets (dispersed phase) of certain size within a second immiscible liquid (continuous phase).
Classification of emulsions
- Based on dispersed phase
Oil in Water (O/W): Oil droplets dispersed in water
Water in Oil (W/O): Water droplets dispersed in oil

4. Emulsions encountered in everyday life!
Metal cutting oils
Margarine
Ice cream
Pesticide
Asphalt
Skin cream
Stability of emulsions may be engineered to vary from seconds to years depending on application

5. Emulsifying Agents
Stable suspensions of liquids constituting the dispersed phase, in an immiscible liquid constituting the continuous phase is brought about using emulsifying agents such as surfactants .

6. W/O vs. O/W emulsions Bancroft's rule
Emulsion type depends more on the nature of the emulsifying agent than on the relative proportions of oil or water present or the methodology of preparing emulsion.
The phase in which an emulsifier is more soluble constitutes the continuous phase
In O/W emulsions – emulsifying agents are more soluble in water than in oil.
In W/O emulsions – emulsifying agents are more soluble in oil than in water.

7. 1) Size distribution of droplets
Emulsion with a fairly uniform size distribution is more stable than with the same average droplet size but having a wider size distribution
2) Phase volume ratio
As volume of dispersed phase  stability of emulsion 
(eventually phase inversion can occur)
3) Temperature
Temperature , usually emulsion stability 

8. General Guidelines Some General Ratios of Emulsions
Vinaigrette = 3:1 oil to vinegar
Mayonnaise = 6:1 oil per egg yolk
Hollandaise = 3:1 clarified butter per yolk
There are three types of emulsions: stable, semi-permanent and unstable.
To create a stable emulsion an emulsifying agent must be added.
Most common emulsifier is Lecithin (found in egg yolks, garlic, mustard)