Page 37 - Course Guide 2019

The table below listed some examples of emulsifying agents that could be used in
extemporaneous preparations:

Source Emulsifying agent Quantity Type of emulsion
Natural Acacia Based on O:W:A ratio Oil-in-Water
(Plant sources) Compound tragacanth powder 2-4 % w/v
Sodium alginate mucilage 1% w/v
Tragacanth mucilage 1.25% w/v
Tragacanth powder 0.2% w/v
Natural Methylcellulose 0.5 – 2% w/v Oil-in-Water
(Cellulose) Sodium 0.5 – 2% w/v
carboxymethylcellulose
Natural Gelatin Oil-in-Water
(Animal source) Beeswax Water-in-oil
Wool fat
Wool alcohol
Synthetic Soaps, sodium lauryl sulphate, Oil-in-Water
(Anionic) sodium cetosteryl
Synthetic Cetrimide Oil-in-Water
(Cationic)
Synthetic Span 20, Span 60, Span 80 Water-in-oil
(Non-ionic) Tween 20, Tween 60, Tween Oil-in-Water
80

For acacia-based emulsions, there are specific ratio called the O:W:A ratio to determine the
amount of each oil, water and acacia amount needed to form a primary emulsion. The ratio
could be summarized as follows:

Quantity for primary emulsion
Type of oil Example Oil Water Acacia
Fixed oil Almond oil
Arachis oil 4 2 1
Castor oil
Cod liver oil
Mineral oil Liquid paraffin
3 2 1

Volatile oil Turpentine oil
Cinnamon oil 2 2 1
Peppermint oil
Oleo-resin Male fern extract 1 2 1