Microencapsulation is a process where tiny particles or droplets of a core material are surrounded by a coating to form capsules in the micrometer to millimeter range called microcapsules. Various techniques are used to produce microcapsules including air suspension, pan coating, coacervation, solvent evaporation, and polymerization. Microencapsulation offers advantages like taste masking, sustained release, and protection of materials. Microcapsules find applications in pharmaceuticals for controlled drug delivery and replacement of non-oral therapeutics. Some commercial products that use microencapsulation technology include Lupin Cefadroxil, ZORprin CR, and Glipizide SR.

1. MICROENCAPSULATION
By
SANA TABASSUM
(B.Pharm)
Under the guidance of
Mrs.Ch.S VIJAYA VANI,M.Pharm.
Associate Professor,
Department of Pharmaceutics.
A
Presentation
On
CMR COLLEGE OF PHARMACY

2. DEFINITION
Microencapsulation is the
process by which tiny solid
particles or droplets of
liquid are surrounded or
coated with a continuous
film of polymeric material to
produce capsules in the
micrometer to millimeter
range. The product obtained
by this process is called as
microcapsules.1
Microcapsule

3. MICROCAPSULES
Microcapsules in
blood stream
Microscopic view
of microcapsules

4. Advantages of microencapsulation
Masking of bitter taste drugs. Eg: Ofloxacin.
Conversion of liquid to pseudo solid.
Eg: Eprazinone.2
Environmental protection.
Eg: Vit.A.Palmitate.
 Reduction of hygroscopicity .Eg: NaCl.
 Reduction of vaporization of volatile drugs.
Eg: Methyl salicylate.
Prevention of incompatibilities among drugs.
Eg: Aspirin and Chlorpheniramine maleate .2

5. Disadvantages of Microencapsulation.
Possible cross reaction between core and
shell material.
Difficult to achieve continuous and uniform
film.
Shelf life of hygroscopic drugs is
reduced.
More production costs.
More skill and knowledge is required.2

6. MECHANISMS OF DRUG RELEASE
Degradation
controlled
monolithic
system
Diffusion
controlled
monolithic
system
Diffusion
controlled
reservoir
system
Erosion

7. MECHANISMS OF DRUG RELEASE
1)Degradation controlled monolithic
system-Drug releases on degradation
of matrix.
2)Diffusion controlled monolithic
system-Drug released by diffusion
then degradation of matrix occurs.
3)Diffusion controlled reservoir
system-Drug from capsule diffuses
then rate controlling membrane
erodes.
4)Erosion-Due to pH and enzymatic
hydrolysis.2

8. CLASSIFICATION OF MICROCAPSULES2
Mononuclear Polynuclear Matrix Mononuclear
with
multiple
shells

9. MATERIALS INVOLVED IN FORMULATION
A)Core Material:
Specific material to be coated.
It may be liquid or solid.
Liquid core may be dissolved or dispersed
material.3

10. Core Material Purpose Final
Product
Form
Acetaminophen Taste masking Tablet
Potassium
chloride
Reduces
gastric
irritation
Capsule
Isosorbide
dinitrate
Sustained
release
Capsule
Examples of core material

11. B)Coating Material: Inert substance
which coats on core with desired
thickness.
Composition of coating solution
•Inert polymer.
•Plasticizer- Triethylcitrate, glycerin
•Solvents- Water,cyclohexane.
•Co solvents-Glycerol, sorbitol.

12. Examples of various coating material 3
Category of Coating
Material
Examples
Water soluble resins Gelatin,
Polyvinylpyrrolidone(PVP).
Water insoluble resins Ethyl cellulose, Polyethylene.
Waxes and lipids Paraffin, Carnauba, Beeswax.
Enteric resins Shellac, Zein.

13. TECHNIQUES TO MANUFACTURE
MICROCAPSULES
S.No Physical Methods Chemical Methods
A) Air Suspension Solvent Evaporation
B) Pan Coating Polymerization
C) Coarcervation Phase
Separation
 Interfacial
Polymerization
 In-situ PolymerizationD) Multi-orifice
Centrifugal Process
E) Spray Drying & Spray
Congealing
F) Fluidized Bed
Technology

14. A)Air Suspension(Wurster Method)
Within the coating chamber, particles are
suspended on an upward moving air stream.
Spraying of coating material on the air suspended
particles.
The cyclic process is repeated depending upon
purpose of microencapsulation.
Air stream serves to dry the product.3

15. Advantages: Disadvantages:
Various
coating
material can be
used.
Applicable only
to solid core
material.
Capacity is
more
Agglomeration
of the particles
WURSTER APPARATUS

16. B) Pan Coating
The particles are tumbled in a pan while
the coating material is applied slowly as
solution or atomized spray to the core.
To remove the coating solvent, warm air is
passed over the coated materials or dusting
of talc is done.

17. Medicaments are usually coated onto
nonpareil sugar seeds and then coated with
polymers.3
Advantages: Disadvantages:
Suitable to
larger particles.
Time consuming.
Sustained
release
preparations.
High material
loss.

18. C) Coacervation Phase Separation:
Simple coacervation Complex coacervation
A desolvation agent is
added for phase separation
It involves complexation
between two oppositely
charged polymers.
Steps involved in this process are:-
1)Formation of three immiscible phases.
2)Deposition of liquid coating material upon
the core material.
3)Rigidization of coating.

19. Coacervation process

20. Various methods to obtain three immiscible phases:
1) Temperature change
2) Incompatible Polymer Addition
3) Non-Solvent Addition
4) Salt Addition
5) Polymer-Polymer Interaction(Complex Coacervation)

21.  Temperature change:
Temperature-composition
phase diagram for a binary
system of a polymer and a
solvent.
TEMPERATURE
POLYMER CONCENTRATION %
X
A
B
C D
E
F G
•Point X represents –single phase.
The phase-boundary curve indicates
that with decreasing temperature.
One phase
becomes
polymer rich.
Other phase
becomes polymer
poor.
Eg: N-acetyl p-amino phenol.4

22. Non-Solvent Addition:
A liquid that is a non-solvent
for a given polymer can be added to
a solution of the polymer to induce
phase separation.
Eg: Addition of isopropyl ether to
CAB dissolved in methyl ethyl
ketone.
Core: Methyl scopolamine HBr.4
A
B
C
D
E
SOLVENT
100%
100%
POLYMER
100%
NON
SOLVENT
Phase diagram for
phase-separation/
coacervation induced by
Non Solvent Addition

23. Salt Addition
Soluble inorganic salts can
be added to aqueous
solutions of water-soluble
polymers .
Eg: Sodium sulfate,
Core-Vitamin in corn oil.4

24. Polymer-Polymer Interaction (Complex
Coacervation):
Steps involved:4
1. Formation of an O/W emulsion
2. Formation of the coating
3. Stabilization of the coating
A
C
B
WATER
100%
100
%
P -
100%
P+
Ternary Phase
diagram
X

25. D) Multi-orifice Centrifugal Process
Advantages:
Encapsulates both solid and liquid materials.
Production rate is more.
It utilizes centrifugal forces to hurl a core material particle
through an enveloping microencapsulation membrane .4

26. E) Spray Drying and Spray Congealing:

27. Spray Drying Spray Congealing
Coating solidification
effected by rapid
evaporation of solvent in
which coating material is
dissolved.
Coating solidification is
effected by thermally
congealing a molten
coating material.4
Advantages:
Low bulk density product.
Porous nature capsules.
Free flowing particles.

28. F) Solvent Evaporation
Advantages:
Encapsulation of hydrophobic and hydrophilic drug.
Simple technique.
Encapsulation of solid and liquid drug.

29. G) Polymerization
Interfacial Polymerization In-situ Polymerization

30. NOVEL METHODS
A) Vibration Technology
A fluid stream of liquid
core and shell materials
is pumped through
concentric tubes and
forms droplets under the
influence of vibration. 1

31. B) Jet Cutter Technology
A solid jet of fluid coming out of a nozzle by means of
rotating cutting wires is cut into cylindrical segments
which then form beads due to surface tension on their way
to a hardening device.1

32. C) Rapid Expansion Of Super Critical
Solution(RSS)
Core and the shell material are maintained at high pressure
and then released at atmospheric pressure through a small
nozzle.
Sudden drop in pressure causes desolvation of the shell
material.1

33. APPLICATIONS
To reduce gastric and other GIT irritations.
Eg: Aspirin preparations.
Prolonged release dosage forms preparation.
 Preparation of enteric-coated dosage forms .
Replacement of therapeutic agents (not taken
orally like insulin), gene therapy and in use of
vaccines for treating AIDS, tumors, cancer and
diabetes.
Delivery of DNA vaccines.
Prodrug approach. Eg: Minocycline HCl.
Biodegradable and biocompatible microparicles
preparations.Example: Risperidone or testosterone.5

34. Marketed formulations prepared using
microcapsules5
S.No Brand
Name
Generic
Name
Category
of drug
1. Lupin Cefadroxil Antibiotic
2. ZORprin CR Aspirin Anti-arthritic
3. Glipizide SR Glucotrol Anti diabetic

35. REFERENCES
1. http://www.authorstream.com/Presentation/vivekchauhan-
1147305-microencapsulation.
2. Hammad umer et.al,” International Journal of Research in
Pharmaceutical and Biomedical Sciences” ISSN: 2229-
3701.
3. S. S. Bansode et.al,” Institute of Pharmaceutical Education
And Research”, Volume 1, Issue 2, March –April 2010;
Article 008 .
4. Lachman LA, Liberman HA, Kanig JL. The Theory and
Practice of Industrial Pharmacy. Mumbai, India: Varghese
Publishing House; 3:414-415.
5. http://www.authorstream.com/Presentation/thokesagar-
1295371-shree/