This presentation consists of the info about the pharmaceutical emulsions , definition, types,preparations,methods,formulation,emulsifying agents .... this presentation is very useful for the b.pharm students for a brief idea ...

1. EMULSIONS
BY:
N JV S PAVAN
3RD BPHARM
L20PH02101
HINDUCOLLEGEOF PHARMACY

2. INTRODUCTION
Definition:- Emulsion is a biphasic liquid dosage form in which two immiscible liquids
are made miscible by converting one liquid into fine droplets finely distributed in other
liquid by using an emulsifier
▪ Normally two immiscible liquids cannot be dispersed for a longer period. So, an
emulsifying agent is added to the system.
▪ It forms a film around the globules in order to scatter them indefinitely in the
continuous phase, so that a stable emulsion is formed.
▪ The globule size in the emulsion varies from 0.25 to 25ϕm diameter
▪ There are two phases in an emulsion:-
1. DISPERSED OR INTERNAL PHASE
2. CONTINUOUS OR EXTERNAL PHASE

3. INTRODUCTION

4. Advantages:
▪ Medicaments having unpleasant taste and odour can be made
palatable
▪ Prevent reactions such as oxidation ,hydrolysis etc..When subjected
to open air
▪ Absorption of oils is improved when taken orally
▪ Supplements like carbohydrates , fats , vitamins , minerals etc,,.. Can
be made into emulsion preparations which are given intra venously
▪ Emulsions are also used in the diagnostic use as gels or creams

5. Classification of emulsions
▪ Simple emulsions(macroemulsions)
1. Oil-in-watero/w
2. Water-in-oilw/o
▪ Multiple emulsions
1. Oil-in-water-in-oilo/w/o
2. Water-in-oil-in-waterw/o/w
▪ Micro emulsions

6. Classification of emulsions…

7. Tests for identify the type of emulsions
1.Dilution test : The emulsion is diluted with water. In case the emulsion remains stable after its dilution it is
o/w emulsion. The w/o emulsion breaks on its dilution with water but remains stable when diluted with oil.
2.Dye test :if an oil-soluble dye (Scarlet red C or Sudan III) is added to an emulsion and the continuous phase
appears red, then it is w/o emulsion and viseversa…
3.Conductivity test : The conductivity test can be performed by dipping a pair of electrodes connected
through a low voltage bulb in the emulsion. If the bulb glows the emulsion is o/w type, because water is in the
continuous phase (good conductor) and viseversa.
4.Fluorescence test : Certain fixed oils possess the physical property of fluorescing in the presence of ultra
violet radiation. On microscopic observation of emulsion under ultraviolet radiation, the whole field fluorescence
indicates that oil is present in continuous phase ( w/o type emulsion) and droplets fluorescence indicates that oil
is present in dispense phase ( o/w type emulsion).

8. Formulation of Emulsion
1. Emulsifying agents
2. Preservation techniques
3. Antioxidants
4.Flavours

9. Emulsifying agents or Emulsifiers…
▪ The emulsifying agents reduce the interfacial tension between two phases i.e., oily
phase and aqueous phase and thus make them miscible with each other and form a
stable emulsion. Emulsifying agents are also known as ‘emulgents’ or ‘emulsifiers’ .
▪ it is very difficult to select a proper emulsifying agent for the development of a stable
emulsion.
▪ Griffin devised a useful method for calculating balanced mixtures of emulsifying agents
to provide a particular type of emulsion . It is called the Hydrophilic Lipophilic Balance or
HLB method. Every emulsifying agent is given a number on HLB scale, which is divided
into 18 units.
▪ emulsifying agents help in stabilizing an emulsion ”by reducing the interfacial tension or
surface energy between two liquids forming the emulsion by forming a film between the
medium and suspended particles”

10. Emulsifying agents or Emulsifiers…

12. Pharmaceutically, ideal properties of emulsifiers:
Be stable .
Be compatible with other ingredients .
Be non — toxic .
Possess little odor , taste , or color .
Not interfere with the stability of efficacy of the active agent .

13. TYPES OF EMULSIFIERS:-
Natural
A) Vegetable source:-
Gum acacia ,Tragacanth, Agar, Pectin, Starch etc…
B) Animal Source
Wool fat, Egg yolk, Gelatin etc…
Semi Synthetic polysaccharides
Methyl Cellulose , Sodium Carboxy Methyl Cellulose
Synthetic
Anionic, Cationic, Non-ionic
Inorganic
Milk of magnesia ,magnesium oxide, magnesium trisilicate, Bentonite etc…
Alcohols
Carbowaxes ,Cholesterols , Lecithins

14. Preservation techniques
1.Use thoroughly cleaned equipment.
2. Use ingredients of standard quality.
3. Maintain the prescribed ratio of oil, water and gum while preparing emulsions.
4. Use freshly boiled and cool water to destroy microorganisms.
5. Use containers and closures of good quality. The closure should fit well on the containers.
6. Maintain the prescribed pH of the emulsion.
Benzoic acid ( 0.1-0.2%), methyl paraben and propyl paraben (0.1-0.2%), chloroform ( 0.25%),
Chlorocresol (0.1%), cetrimide ( 0.002 to 0.01%) and phenylmercuric nitrate ( 0.004 to 0.01%)
are some of the commonly used preservatives in emulsions.
Antioxidants :
During storage of emulsions, the fats obtained from vegetable and animal sources and
emulsifying agents ( such as wool fat, wool alcohol ) undergo oxidation by atmospheric
oxygen. This can be avoided by using antioxidants such as tocopherol, gallic acid, propyl
gallate and ascorbic acid

15. Preparation methods of emulsions
1. Dry gum method
2. Wet gum method
3. Bottle method
4. Other methods

16. 1. Dry gum method :
a). Measure the required quantity of oil in a dry measure and transfer it into a dry mortar.
b). Add calculated quantity of gum acacia into it and titrate rapidly so as to form a uniform mixture.
c). Add required quantity of water and titrate vigorously till a clicking sound is produced and the
product becomes white or nearly white due to total internal reflection of light.
The emulsion produced at this stage is known as primary emulsion.
d) Add more of water to produce required volume.
2.Wet gum method :
In this method, the preparation of oil : water : gum for preparing the primary emulsion is the same as
given in the table
1. Calculate the quantity of oil, water and gum required for preparing the primary emulsion .
2. Powder the gum acacia in a mortar. Add water and triturate it with gum so as form a mucilage.
3. Add the required quantity of oil in small portions with rapid trituration until a clicking sound is
produced and the product becomes white or nearly white. At this stage the emulsion is known as
primary emulsion.
4. Add more of water in small portions to the primary emulsion with trituration to produce the
required volume. Stir thoroughly so as form a uniform emulsion.
5. Transfer the emulsion to a bottle, cork, label and dispense.

17. Bottle method:
Bottle method is used for the preparation of emulsions of volatile and non-viscous oils.
The proportion of oil : water : gum is 2 : 2 : 1.
1). Measure the required quantity of the oil and transfer into a large bottle. Add the required
quantity of powdered gum acacia.
2). Shake the bottle vigorously, until the oil and gum are mixed thoroughly.
3). Add the calculated amount of water all at once.
4). Shake the mixture vigorously to form a primary emulsion.
5). Add more of water in small portions with the constant agitation to produce the required volume.
OTHER METHODS:
Various blenders and homogenisers are used for
preparing emulsions.
• Hand homogenizer,
• Silverson mixer homogenizer and
• Colloidal mill

21. Stability of
emulsions
1. Cracking
2. Creaming
3. Phase inversion
Cracking : Cracking means the separation of two
layers of disperse and continuous phase, due to
coalescence of dispersed phase globules which are
difficult to re-disperse by shaking.
Creaming : Creaming may be defined as the
upward movement of dispersed globules to form a
thick layer at the surface of the emulsion. Creaming
is a temporary phase because it can be re-
distributed by mild shaking or stirring to get again a
homogenous emulsion. As far as possible creaming
of an emulsion should be avoided because it may
lead to cracking with complete separation of two
phases.

22. Phase inversion : Phase inversion means the change
of one type of emulsion into the other type i.e., oil
in water emulsion changes into water in oil type and
vice versa. It may be due to following reasons :
1. By the addition of an electrolyte
2. By changing the phase volume ratio
3. By temperature change
4. By changing the emulsifying agent.