This document discusses specialized pharmaceutical emulsions. It defines emulsions as unstable systems where one liquid is dispersed as globules in another liquid stabilized by emulsifying agents. The two main types are oil-in-water and water-in-oil emulsions. Multiple emulsions contain both water-in-oil and oil-in-water emulsions. Various methods are described for producing emulsions including mechanical and solvent evaporation techniques. Emulsifying agents lower the interfacial tension between the liquids to form stable emulsions. Potential applications include drug delivery, vaccines, and products for pulmonary, dermal, and oral administration.

1. SPECIALIZEDSPECIALIZED
PHARMACEUTICALPHARMACEUTICAL
EMULSIONEMULSION
By
MARIA HANIF
(Mphil Pharmaceutics)
(2014-2016)

2. INTRODUCTION
An emulsion is thermodynamically unstable
system in which one phase is uniformally
distributed as globules in other phase and is
stabilized by the addition of emulsifying
agents.
The emulsions can be divided up into:
1. Oil in water (O/W) emulsions and
2. Water in Oil (W/O) emulsions.

3. 2. W/O Emulsion:
By dispersion of water into oil the
water drops are the
Inner, dispersed phase. Oil is the outer,
continuous phase.
Oil phase
Aq phase
Oil phase

4. Methods of Preparation of Emulsions
1) Continental or Dry Gum Method:1) Continental or Dry Gum Method:
"4:2:1" Method
4 parts (volumes) of oil
2 parts of water
1 part of gum
Dry gum method is used to prepare
the initial or primary emulsion from
oil, water, and a hydrocolloid or

5. 2) Bottle or Forbes Bottle Method:
useful for extemporaneous preparation
of emulsion from volatile oils or
oleaginous substance of low viscosity.
powdered acacia
+ Dry
bottle
2 parts of oil
This method is not suitable for

6. 3) English or wet Gum Method:
4 parts (volumes) of oil
2 parts of water
1 part of gum

7. 4) Auxiliary4) Auxiliary method
An emulsion prepared by other
methods can also be improved by
passing it through a hand
homogenizer, which forces the
emulsion through a very small
orifice, reducing the dispersed droplet
size to about 5 microns or less.

8. In situ soap methodIn situ soap method
wCalcium Soap :
w/o emulsions contain oils such as
oleic acid , in combination with lime
water ( calcium hydroxide solution,
USP).
Prepared by mixing equal volumes of
oil and lime water.
/o emulsions contain oils such as

9. Stability Issues:
Emulsions are, by nature, physically
unstable; that is, they tend to separate
into two distinct phases or layers over
time.
 Creaming occurs when dispersed oil
droplets merge and rise to the top of
an o/w emulsion or settle to the
bottom in w/o emulsions. In both
cases, the emulsion can be easily
redispersed by shaking.

10. Coalescence (breaking or cracking) is
the complete and irreversible
separation and fusion of the dispersed
phase.
Phase inversion or a change from w/o
to o/w (or vice versa) may occur.

11. Emulsion Type and Means of
Detection:
1) Dilution Test:
- o/w emulsion can be diluted with
water.
- w/o emulsion can be diluted with oil.
2) Conductivity Test:
Continuous phase water > Continuous
phase oil.

12. 3) Dye-Solubility Test:
- water soluble dye will dissolve in
the aqueous phase.
- oil soluble dye will dissolve in the
oil phase.
4)Cobalt Chloride test:
Cobalt Chloride solution is used for
identification of Emulsion. It is water
soluble so it changes colour when

13. 5:Fluorescence test:
Oils give fluorescence under UV light,
while water doesn’t.
Therefore, O/W emulsion shows spotty
pattern when observed under UV.
while W/O emulsion fluoresces.

14. MULTIPLE EMULSIONS:
Multiple emulsion are complex system
which consist of both w/o and o/w at
the same time.
There are potential matrices for the
encapsulation of biactive compounds
and for the controlled release
compounds
w/o/w multiple emulsion are system
where small water droplets are
entrapped within larger oil droplets and

15.  This is made possible by double
emulsification hence the systems are
also called as “Double emulsions”.
 These are also called as “Liquid
membrane systems” as the liquid film
which separates the liquid phases acts
as a thin semipermeable film through
which solute must diffuse in order to
transverse from one phase to another.
Multiple emulsions are
thermodynamically unstable.
They are often stabilized by using a

16. TYPES:
 With optical microscopy method,
multiple emulsions are classified as,
1. coarse (>3 micrometer in diameter)
2. Fine (1-3 micrometer in
diameter)
3. Micro-multiple emulsions
(<1 micrometer in diameter)

17. W/O/W Type of emulsionW/O/W Type of emulsion

18. O/W/O type of emulsionO/W/O type of emulsion

20. Multiple emulsions can also be formulated by using eitherMultiple emulsions can also be formulated by using either
oo11/o/o22/o/o11 systems or osystems or o11/o/o22/w formulations are possible./w formulations are possible.
Examples of both are shown in FigureExamples of both are shown in Figure

21. Multiple emulsion w/o/w contain two
emulsifiers:
1 Low HLB surfactant
(Hydrophobic in nature)
2 High HLB surfactant
(Hydrophilic in nature)
Low HLB surfactant use in disperse
phase
High HLB surfactant use in
continuous phase.

22. EMULSIFYING AGENTS
Emulsifier or surface active agent
[SAA] is molecule which has two
parts, one is hydrophilic and the other
is hydrophobic. Upon the addition of
SAA, it tends to form monolayer film
at the oil/ water interface.

23. SURFACTANTS
Anionic
Sodium oleate
Pottasium
oleate
Glyceryl
monostearate
Cationic
Benzalkoniu
m
 chloride
Non ionic
span 80
span20
Tween 2
Tween 6
Tween 8

25. Mechanism of release of drug:
1. Primary interface lying between the
inner w/o phase contains the low
HLB surfactant.
2.Secondary interface lying between
droplets and continuous aqueous
phase. Low and high HLB
surfactant present in it. When
hydrophilic surfactant in the
continuous aqueous phase exceed its

26. METHOD OF PREPARATION
1) Solvent evaporation method
2) Two step emulsification.
3) Phase inversion technique.

27. SOLVENT
EVAPORATION
TECHNIQUE

28. TWO STEP
EMULSIFICATION/
DOUBLE
EMULSIFICATION

30. APPLICATONS
Multiple emulsions finds wide range
of applications in controlled or
sustained drug delivery, targeted
delivery, taste masking,
bioavailability enhancement, enzyme
immobilization, etc.
It will be able to provide a novel
carrier system for drugs, cosmetics

31. 1. Hemoglobin multiple emulsion having specified
properties is suitable for provision of oxygen as a
blood substitute and other oxygen transfer processes.
2. W/O/W multiple emulsions are systems of potential
interest in the oral administration of insulin.
Although it has been shown that a single oral
administration of insulin-loaded W/O/W multiple
emulsion to diabetic rats led to the significant
decrease of blood glucose.
3. (w/o/w) multiple emulsions and polymeric
nanoparticle formulations containing influenza virus
surface antigen hemagglutinin (HA) are thought to
be suitable carriers for a vaccine delivery system.

32. 4. Using a water-in-oil-in-water multiple emulsion
system developed for pulmonary drug targeting,
the effectiveness of tetrandrine as an antifibrotic
agent.
5. To develop a prolonged and sustained
release preparation , an albumin micro-sphere-
in-oil-in-water emulsion was prepared.
Tegafur was used as a model drug.
6. Vitamin c has been widely used in
formulations of skin care products.
7. Multiple emulsions are also used in topical
application ex… a w/o/w emulsion of
Metronidazole.

33. REFERENCESREFERENCES
1) Pharmaceutical Emulsions and Suspensions, edited by Francoise
Nielloud Gilberte Marti-Mestres.
2) Pharmaceutical Dosage Forms: Disperse systems, vol.3, second
edition, Edited by Herbert A.Liberman, Martin M. Rieger and
Gilbert S. Banker.
3) some studies on Multiple Emulsions by G.Vishwanadham, (Ph.D
thesis, KU)
4) Advances in Controlled and Novel Drug Delivery Systems,
Edited by N.K. Jain.
5) Targeted and controlled Drug Delivery Novel Carrier Systems
by -S.P. Vyas and R.K. Khar.
 http://www.aapsj.org/view.asp
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 http://iufost.edpsciences.org