for medical and dental undergraduates

1. EMULSIONS
Emulsion is a liquid medicament containing two immiscible liquids one which is broken down
into minute globule, each globule being surrounded by a film of emulsifying agent and then
dispersed throughout the other liquid.
Naturally occurring emulsions: milk, egg yolk, butter
Phases of emulsion
1) Internal, dispersed or discontinuous phase is that which is broken down into globules.
2) External, dispersion or continuous phase is that which surrounds the globules.
3) Intermediate phase or interphase is that which covers the globules & prevents
coalescence. It is also known as emulsifying agent or emulgent.
Types: Oil in water (o/w) & Water in oil (w/o)
Differences
Oil in water (o/w) Water in oil (w/o)
1 Free dilution by external phase i.e. with
water
Free dilution with oil
2 The continuous phase is stained by
methylene blue
The continuous phase is stained by sudan
III
3 It has milky white appearance It has a waxy and translucent appearance
4 It is a good conductor of electricity It is a bad conductor of electricity
5 Water soluble emulsifying agents are used
e.g. acacia, casein saponins egg yolk and
soaps formed from monovalent base.
Fat soluble emulsifying agents are used
e.g. wool fat resins & soaps formed from
divalent base(ca++, Mg++, Zn++)
6 It has uniform fluorescence e.g. Cod liver
oil emulsion & castor oil emulsion
It has spotty fluorescence e.g. Cold cream
Emulsifying agents:
They form an intermediate phase between the dispersed & the continuous phase. They usually
reduce the interfacial tension between oil & water and thus aid in dispersion of one liquid in the
other. They are added to ensure uniform dispersion & to provide stability to preparation.
1) Gums: Acacia , tragacanth
2) Proteins: casein, egg yolk
3) Carbohydrates: starch mucilage, malt extract
4) Soaps: soft soaps, hard soaps

2. Stability of emulsion
A stable emulsion is one in which the globules retain their initial character & remain
uniformly distributed throughout the continuous phase. Any deviations from the above, result
in unstable emulsion. Physical instability in an emulsion may lead to:
(i) Cracking or breaking or separation of emulsion:
It means destruction of the emulsion system, coalescence of the dispersed globules &
separation of the two phases into two layers.
(ii) Creaming or sedimentation of an emulsion:
It occurs when oil / fat arise on the surface but still remains in the form of globules.
Hence the instruction “shake well before use” should be written on the label. It is
minimized by decreasing the size of globules & increasing the size of the external
phase.
Causes of failure to make a good emulsion:
1) By using wrong mortar & pestle.
2) By not using a dry measuring cylinder.
3) Using incorrect proportion of ingredients.
4) Diluting the primary emulsion before it is perfectly formed.
5) By improper trituration.

3. Cod liver oil emulsion
Object: To prepare & dispense 30 ml of Cod liver oil emulsion
Prescription:
Dr. Kanav Sharma,
MBBS, MD
Reg. No: 12345
Address: A 45, Malviya
Nagar, Jaipur
Mob. No: 9887123456
Email: kanav23@gmail.com
Amit 10 years Male
Diagnosis- Rickets
RX
Cod liver oil 6ml
Gum acacia 1.5gm
Aqua ad 30ml
M.ft: Mix and prepare an emulsion. Send such 30 ml.
Signa: 1) Shake well before use.
2) One tablespoonful to be taken twice a day after meals.
09/04/2019 Kanav
Method of preparation of emulsions :-
1) Wet gum method
2) Dry gum method
Wet gum method:
Weigh 1.5 gm of gum acacia, add 3 ml of water in mortar & triturate it until a mucilage is
formed, then add cod liver oil drop by drop while triturating till primary emulsion is formed. Add
water upto 10ml to primary emulsion with constant trituration, transfer it to the measuring

4. cylinder & adjust it to the required volume by adding water. Dispense it to the dispensing bottle.
Cork it & label it.
Label
30 ml
Cod liver oil emulsion
Shake well before use
Amit 10 years Male
Direction: one dose to be taken twice a day after meals.
09/04/2019 Kanav
Pharmacy Lab.
Dept. of Pharmacology
SMS Medical College &Hospital, Jaipur
Uses of Cod liver oil emulsion:
1) As a prophylactic for infants & children to prevent rickets.
2) As a dietary supplement in infants & children for promoting growth & nutrition.
3) As a curative in rickets, osteomalacia & in defective calcification.
4) Given to undernourished children with tuberculosis & other wasting diseases like caries
of bones, chronic joint diseases for promoting growth.
5) As a tonic to a convalescent person.
Action of individual ingredients:
1) Cod liver oil: pale yellow liquid, contains glycerides & unsaturated fatty acids. It is
obtained from liver of cod fish (Gaddus callarias). One gram of cod liver oil contains 85
units of vitamin D & 600 units of Vitamin A.
2) Gum acacia: It is a dried gum exudate obtained from branches of Acacia Arabica tree. It
acts as an emulsifying & suspending agent.
Advantages (of its being used as an emulsifying agent): It is used in preparing most of O/W
type of emulsions. No preservative is required. As it is tasteless & has good covering property it
makes the emulsion palatable.

5. Disadvantages: It cannot be used for preservation of W/O emulsion or emulsion used for
external use because here water is in internal phase & drying will cause stretching of skin.
Viva questions:
1) Define emulsion & its types?
2) What are emulsifying agents? Which is the most commonly used emulsifying agent &
why?
3) What is creaming & breaking of emulsion?
4) What is the daily requirement, various sources & indications of Vitamin D?
5) What is Hypervitaminosis D?
6) What is the daily requirement, various sources & indications of Vitamin A?
7) What is Hypervitaminosis A?