Definition Types Formulation Preparation Stability of emulsion Identification test

1. EMULSION
BY: LIPANJALI BADHEI
(KIMSR, KEONJHAR)

2. CONTENT
1. DEFINATION
2. ADVANTAGES & DISADVANTAGES
3. TYPES
4. FORMULATION
5. EMULSIFYING AGENT
6. METHOD OF PREPARATION
7. TEST FOR IDENTIFICATION
8. PHASE INVERSION
9. STORAGE

3. EMULSION
“An Emulsion is a biphasic liquid dosage form in which two or more
immiscible liquid are made miscible by addition of emulsifying
agent.”
oil
wate
r
Emulsifying
Agent
Emulsio
n
DISPERSED PHASE: The liquid that is broken up into globules is called dispersed phase.
Always present in small quantity.
CONTINEOUS PHASE: The liquid in which globules are dispersed is called continuous
phase or external phase. Always present in more quantity.
Dispersed
Phase
Continuous
Phase

4. ADVANTAGES DISADVANTAGES
 Mask the unpleasant teste
 Economical
 Improve Bio-availability
 Absorption Rate increase
 Nutritional Supplement
 Short self-life
 Unstable soluble phase separate
slowly
 Storage condition affected
stability
 Difficulty in handling

5. TYPES OF EMULSION
Emulsion
Oil in water
(O/W)
Water in oil
(W/O)
Multiple
Emulsion
O/W/O W/O/W
Micro
Emulsion (size:
less then 0.1µ)

6. Oil in Water:
 Here dispersed phase is oil and dispersion medium is water.
 In this type of emulsion small amount oil is dispersed in water.
 These are non greasy & easily removable from skin.
 This is preferred for internal use as bitter test of oils can be masked.
 Eg: Castor oil emulsion
Water in Oil:
 Here dispersed phase is water and dispersion medium is Oil.
 This type of emulsion is mainly used for externally as lotion, cream etc.
 These are greasy & not water washable.
 The oil soluble drug are more quickly released from this type of emulsion.
 Eg: Cold Cream

7. FORMULATION OF EMULSION
Following ingredients are included in the formulation of emulsion.
1) Oil phase :- This phase medicament or vehicle is mode up of fixed oil. Eg: mineral oil,
volatile oil or also resin type that is used.
2) Aqueous phase:- Due to increased risk of microbial contamination freshly boiled and
cooled purified water are used.
3) Antioxidant:- It prevents the oil form getting oxidizing during Its shelf like hence It
enhance the stability of the oil phase in the emulsion.
4) Flavoring agent:- It enhances the palatability of the final product. Eg: pineapple, orange,
chocolate, and mint flavors are commonly used.
5) Coloring Agent:- It is used for identifying the preparation and enhancing its aesthetic
appeal. Erythrosine tartrazine etc. Colors approved by the food Drug and cosmetic act are
used as Coloring Agent.
6) Emulsifying Agent:-Emulsifying agents/emulsifiers/emulgent reduces the
interfacial tension between oil and water (oily and aqueous phase), thus make them
miscible with each other and form a stable emulsion.

8. IDEAL EMULSIFYING AGENT:
Qualities of ideal emulsifying agent:
1. It should be non toxic
2. If should be physically and chemically stable.
3. It should be compatible with the preparation.
4. It should reduce the interfacial tension between the two phases.
5. It should be capable of maintaining the required viscosity of the emulsion.
Classification of Emulsifying Agent:
Emulsifying agent are classified into six divisions.
I. Natural emulsifying agent from vegetable sources
II. Natural emulsifying agent from animal sources
III. Semi synthetic polysaccharides
IV. Synthetic emulsifying Agent
V. Inorganic emulsifying Agent
VI. Alcohols

9. I. NATURAL EMULSIFYING AGENT FROM VEGETABLE SOURCES
 These are anionic in nature and produce o/w emulsions. They act as primary emulsifying agent and
stabilizers.
Eg: a. Acacia: Mainly used for extemporaneous preparation.
b. Tragacanth: Rarely used because it gives very coarse and thick emulsion.
c. Agar: It is not a good emulsifying agent bcz it forms coarse and viscous emulsion.
d. Chondrus (Irish Moss): It occurs a yellowish mass obtained from dried seaweed of Chondrus
crispus. It is not used as emulsifying agent but as a thickening agent. It is used with acacia for the
emulsification of cod liver oil.
e. Pectin: It is a purified complex carbohydrate obtained from inner rind of citrus fruit and pulp of apple
and guava. It acts as emulsion stabilizer in acacia emulsion.
II. NATURAL EMULSIFYING AGENT FROM ANIMAL SOURCE
a. Gelatin: It is mainly used for emulsification of liquid paraffin.
b. Egg Yolk: it contains emulsifying agents like lecithin and cholesterol. It is rarely used in industrial
preparation because emulsions are spoiled during transportation.
c. Wool Fat: It consists of fatty acid esters of cholesterol and other sterols together with normal fatty
alcohols, It produces w/o emulsion.

10. III. SEMI SYNTHETIC POLYSACCHARIDES
 These produce o/w type of emulsion.
a. Methyl cellulose. It is a synthetic derivative of cellulose, used in pharmaceutical industry as
suspending, thickening and emulsifying agent.
b. Sodium carboxymethyl cellulose. It is not used as true emulsifier but is used as an emulsion stabilizer
in the concentration of 0.5 to 1.0 %.
IV. SYNTHETIC EMULSIFYING AGENT
a. Anionic. Its anionic part is responsible for emulsifying activity various alkali soaps, metallic soaps,
sulphated alcohols (sodium lauryl sulphate) or sulphonates (Dioctyl sodium sulphosuccinate) are used
as emulsifying agent. They produce o/w type.
b. Cationic. Its cationic part do the emulsification. It is mainly used for externally used preparation.
Quaternary ammonium compounds like cetrimide, benzalkonium chloride etc.
c. Non lonic. These are stable at wide range of pH and are not affected by addition of acids and
electrolytes. For example glycerol monostearate, polyethylene glycol, esters and ethers, sorbitan
monopalmitate etc.

11. V. INORGANIC EMULSIFYING AGENT
 Several inorganic substance like milk of magnesia, magnesium oxide, magnesium aluminium
silicate and bentonite are used as emulsifying agent.
 They all except bentonite produces o/w emulsion.
 Bentonite can produce both o/w and w/o emulsion.
VI. ALCOHOLS
a. Cholesterol. It can also used as emulsifying agent like cetyl alcohol, stearyl glycerol monostearate.
It is rarely used due to availability of better emulsifying agent.
b. Carbowaxes. It act as non ionic emulsifying agents and is mainly used in the preparation of
ointments and creams.

12. METHOD OF PREPARATION
Method of
preparation
Trituration
Method
Dry Gum
Method
Wet Gum
Method
Bottle
Method
Continental or Dry Gum Method
 This method is also referred to as the 4:2:1 method because for every 4 parts by
volume of oil, 2 parts of water and 1 part of gum are added in preparing primary
emulsion.
In this method, the dry gum is triturated with the oil in a perfectly dry mortar until
thoroughly mixed.
After the oil and gum have been mixed, two parts of water are added all at once,
and the mixture is triturated immediately, rapidly, and continues until a crackling
sound is produces with creamy white Colour primary emulsion.
Finally filter the emulsion and make the volume up. Then bottling and
Labelling properly.

13. ENGLISH OR WET GUM METHOD
 By this method, the same proportions of oil, water, and gum are used as in the continental or
dry gum method, but the order of mixing is different, and the proportion of ingredients may
be varied during the preparation of the primary emulsion.
In this method, the gum is triturated with water first in a perfectly dry
mortar to form mucilage.
After the water and gum have been mixed, then gradually drop
wise added the oil and continuously triturate to until a crackling
sound is produces with creamy white Colour primary emulsion.
Remaining quantity of water is added and make the volume up.
Filter it and bottling and labelling properly.

14. BOTTLE METHOD
 The bottle method is helpful for the preparation of emulsions from volatile oils and oleaginous
substances of low viscosities.
Powdered gum is placed in a dry bottle.
Two oil parts are added, and the mixture is thoroughly shaken in the capped container.
A volume of water approximately equal to that of the oil is then added in portions and
the mixture is thoroughly shaken after each addition.
When all of the water has been added, the primary emulsion thus formed may be
diluted to the proper volume with water and make the volume up.
Filter it and bottling and labelling properly.

15. TEST FOR IDENTIFICATION
1.Dilution Test:
 Take few drops of emulsion and dilute it with 2-3 ml of water.
 If emulsion gets mixed with water, then it is o/w type but if water
separates then emulsion, is w/o type
 Similarly add few drops of oil. If emulsion gets mixed with oil then
it is w/o type and if oil separates then it is o/w type.
2.Conductivity test:
 Water is good conductor of electricity whereas oil is non
conductor of electricity.
 Therefore when water is present in continuous phase it conducts
electricity.
 Conductivity test is performed by dipping a pair of electrodes
connected through a low voltage lamp, in the emulsions.
 On passing the current, if the bulb glows, the emulsion is o/w but
if bulb dose not glow the emulsion is w/ 0.

16. 3. Dye Test :
 In this test two types of dyes are used:
a. Water soluble dye - e.g. Amarnath.
b. Oil soluble dye - e.g. Scarlet Red.
 First mix the emulsion with the amaranth dye.
 Place drop of it on microscopic slide and observe under microscope. If continuous phase appears red,
then it is o/w emulsion but if globules appear red then it is w/o emulsion.
 Then this test can be repeated with scarlet red. If continuous phase appears to be red, it is w/o
emulsion but if globules appears red and continuous phase is colourless it is o/w emulsion.

17. 4. Fluorescence Test.
 When oils are exposed to UV rays they produce
fluorescence under microscope then, it is w/o emulsion
and it show only spotty pattern then o/w type.
5. Cobalt Chloride Filter Paper Test (CoCl2).
 When a filter paper soaked in CoCl2 solution is dipped in an
emulsion and dried its turn blue to pink, indicates that
emulsion is o/w type.
 This test may fail if emulsion is unstable or break in presence
of electrolytes.

18. STABILITY OF EMULSION
Creaming:
 In creaming, the oil separates out, forming a layer on top of the emulsion, but it
usually remains in globules so that it can be redispersed on shaking.
 This is undesirable as the product appearance is poor and if the product is not
adequately shaken there is a risk of the patient obtaining an incorrect dose.
 Creaming is less likely to occur if the viscosity of the continuous
phase is increased.

19. Phase inversion:
 This is the process when an oil-in-water emulsion changes to a water-in-oil emulsion or vice
versa.
 Phase inversion can occur by the addition of an electrolyte or by changing the phase volume
ratio.
 For stability of an emulsion, the optimum range of concentration of dispersed phase is 30-60% of
the total volume.
 If the disperse phase exceeds this, the stability of the emulsion is questionable.
Cracking/Breaking:
 This is the term applied when the disperse phase coalesces and forms a separate layer.
 Redispersion cannot be achieved by shaking and the preparation is no longer an emulsion.
 Cracking can occur if the oil turns rancid (unpleasant) during storage.
 The acid formed contaminate (destroy the property) the emulsifying agent, causing the two
phases to separate.

20. STORAGE
“Store in a air tight container in a cool place but
refrigeration should avoided because the low
temperature affect the stability.”