This document discusses various techniques for emulsification. Emulsification involves dispersing one liquid within another to form an emulsion using an emulsifying agent and applying shear. Common emulsification equipment includes mixing impellers, colloid mills, homogenizers, and ultrasonic devices. Mixing impellers produce emulsions quickly using shear from a high speed impeller. Colloid mills use rotors and stators to subject materials to impact, shear, and hydraulic forces to reduce particle size. Homogenizers use high pressure to force materials through a small clearance to produce emulsions. Ultrasonic devices generate emulsions using vibrations from piezoelectric crystals, magnetostriction, or hydrodynamic wedges.

1. Emulsification
Lecture VI
Industrial Pharmacy

2. Emulsification is the dispersion of one liquid (oily phase) within another
(water phase) to form emulsion.
Emulsification
Definition
It is produced by subjecting the liquids containing an emulsifying agent to high
shear to reduce the interfacial tension between them and thus facilitate
subdivision and dispersion of the internal phase.
Principle
Emulsion is composed of:
1. Dispersed phase.
2. Continuous phase.
3. Emulsifying agent
Emulsifiers are mixers of high speed > 20,000 rpm which produce
high shearing rate.
Emulsifiers

3. Emulsifiers 1. Mixing Impellers
2. Colloid Mills
a. Single stage
b. Double stage
3. Homogenizers
4. Ultrasonic
Devices
a.Piesoelectric
emulsator
b.Magnetostriction
generator
5- Hydrodynamic
generator
EMULSIFICATION EQUIPMENT

4. EMULSIFICATION EQUIPMENT
It consists of
a) motor mounted above the homogenizing
head which fixed by stator rods
b) A shaft extends from the motor and carries
on its lower end the turbine which rotates.
c) A deflector
How does it work?
• The homogenizing head is immersed in the
tank that contains the materials to be
emulsified.
• The turbine rotates at high speed creating
pressure difference between the bottom of
turbine and the surface of material
• It is subjected to intense shear force
(Impaction and shearing) and thus broken
to small particles.
• A deflector is used to prevent vortex
formation
1. Mixing Impellers: (Homo-mixer)

5. ADVANTAGES:
 It gives a homogeneous dispersion in a short period of
time.
 It is simple.
 No vortex is formed due to the presence of a deflector,
so minimum amount of air is incorporated.

6. 2. COLLOID MILLS
A. Single stage colloid mill
• It is composed of a rotor and a
stator.
• The clearance between the rotor
and the stator can be controlled to
give a specific particle size.
• The driving shaft rotates at 2000 -
3000 rpm.
The materials are fed through the
hopper where it is subjected to three
forces:
1) Impact by the rotor leading to
changes of the discontinuous phase
into globules.
2) Mechanical shear due to the
corrugated surface of the rotor.
3) Hydraulic shear due to passage
between the rotor and the stator.

7. USES
1) Preparation of cortisone suspension.
2) Preparation of milk of magnesia.
3) Preparation of paints.
4) Preparation of hand lotions and cold creams.
Advantages:
1) Low energy consumption.
2) Low cost.
3) It gives uniform products.
4) It can be used for preparation of relatively viscous
materials.
Disadvantages:
1) Heat may be generated during the operation which
could break the emulsion again
2) Disperse air in the system and increase oxidation.

8. B. Double stage colloid mill.
It contains cooling water jackets to absorb the heat generated
through the emulsification process.
Advantages:
1) Heat generated during
the process will be
absorbed by the cooling
water.
2) More efficient than the
single stage colloid mill
because of the two
rotating cones

9. 3. HOMOGENIZERS
Gaulin Homogenizer
It consists of:
• A pump which provides high
pressure to force the introduction
of the feed.
• A spring loaded homogenizing
valve with an adjustable clearance
between the valve and the
emulsifier seat.
How does it work ?
 The material, at high pressured by pump.
 Enters through the homogenizing valve passes through the clearance
between valve and seat.
 The material impinges against the impact ring surrounding the clearance
region and then discharged .
 The clearance between the valve seat and the impact ring controls the
particle size of the produced emulsion.

10. Uses
preparation of emulsions, suspensions and for
dispersion of pigments.
Advantages:
1) No incorporation of air through the operation.
2) It has high capacity.
3) It is continuous in production.
Disadvantages:
1) High energy consumption.
2) A small rise in temperature may happened.

11. 4. ULTRASONIC DEVICES:
 Ultrasonic waves are used for preparation of
emulsion. They're used on small scale only
• The material is placed in a tube
and then dipped in a liquid in
which quartz crystal is immersed.
• Alternation of electric potential is
applied to quartz, it will produce
ultrasonic waves in the liquid.
• Vigorous agitation produce high
vibrations leading to
emulsification of material .
A ) Piesoelectric emulsator (emulsifier):

12. B. Magnetostriction generator :
• When a magnetic field is applied to
Nickel, ultrasonic waves generated .
• Vibration as a result of ultrasonic
waves leading to emulsification of
material.
5- Hydrodynamic generator
(sonolator)
• The emulsion components are
introduced under high pressure, pass
from small orifice with high velocity.
• They impinge with a resonating wedge
which cut the globules leading to
dispersion
Advantages:
1) It is simple.
2) Low initial cost.
3) Low operating cost
4)Premixing is not required.
5) Rapid.
6)No incorporation of air.