This document defines microencapsulation as a process where tiny liquid or solid particles are surrounded by a continuous polymeric film. It lists advantages like increased bioavailability and targeted drug delivery. Methods of preparation include physical techniques like air suspension and spray drying, and chemical techniques like solvent evaporation and polymerization. Microcapsules are evaluated based on properties like particle size, density, isoelectric point and in vitro release studies. Applications include improving flow properties, enhancing stability, and reducing gastric irritation.

1. By
Mr. Sunirmal Bhattacharjee
Mr. Anupam Saha
Assistant Professor ( Department of
Pharmaceutics)
M.Pharm (Pharmacology)
Email ID – sunirmal.pharma@gmail.com
MICROENCAPSULATION

2. CONTENTS:
 Definition
 Advantages
 Disadvantages
 Classifications
 Method of Preparations
 Evaluation Tests
 Applications
 References

3. Definition:
 Microencapsulation is a process by which very tiny
droplets or particles of liquid or solid material are
surrounded or coated with a continuous film of
polymeric materials.
 Particles having diameter between 3-800µm are
known as micro particles.

4. Advantages:
 To increase of bioavailability.
 To alter the drug release.
 To improve the patient’s compliance.
 To decrease evaporation rate of the core material.
 To produce a targeted drug delivery.
 To convert liquid to solid from.

5. Disadvantages:
 Difficult to achieve continuous and uniform film.
 Shelf life of hygroscopic drugs is reduced.
 Polymer may produce toxic effect.
 Costly.

6. Classifications:
 Microcapsules can be classified
on three type. As follow as-
 (1)Mono nuclear-Contain the
shell around the core.
 (2)Poly nuclear-Having many
cores enclosed with in shell.
 (3)Matrix type- Distributed
homogeneously into the shell
material.

7. Method Of Preparation:
 (1)Physical Method:
 (a)Air suspension
 (b)Coacervation phase Separation
 (c)Pan coating
 (d)Spray Drying
 (2)Chemical Method:
 (a)Solvent Evaporation
 (b)Polymerization

8. 1.a)Air suspension Method:
Fine solid core materials are suspended by a
vertical current of air
Evaporation of the solvent
The encapsulating material is deposited onto
the core material
Achieved the desired film thickness
The encapsulated product is dried by passing
the stream air

9. (b)Coacervation Phase Separation:
Core material phase is dispersed in the
solution of coating polymer
Solvent of polymer is vehicle the phase
Deposition of polymer solution onto the core
material
Deposition of liquid polymer occurs when the
polymer is absorbed
Microcapsule

10. (c)Pan Coating method:
Solid particles are mixed with a dry coating
material
Temperature is raised
The coating material melts and encloses the
core particles
Then is solidified by cooling
Microcapsule

11. (d)Spray drying:
Core particles are dispersed in a polymer
solution
Sprayed into a hot chamber
Shell material are solidifies onto the core
materials
Solvent evaporates
Microcapsule

12. 2.(a)Solvent Evaporation:
Core material
Coating polymer solution
Liquid manufacture vehicle phase
Evaporation of polymer solvent
Microencapsulation
Dissolved
With
Agitation
Heating

13. (b)Polymerization:
Active ingredient + Polymer + Volatile solvent
Formation of oil in water emulsion
Solvent increase
Particle formation by polymer
Recovery of polymeric micro particles
Addition
Temperature
increase

14. Evaluation Test:
 Particle Size and Shape: Light microscopy and electron
microscopy both are use to determine particle size and
shape.
 Density Determination: The density of the
microcapsule can be measured by using a multi volume
pychnometer.
 Isoelectric Point: The micro electrophoresis is an
apparatus used to measure electro phonetic mobility.
 Contact Angle: The angle of contact is measured to
determine the wetting property of microcapsule.
 In vitro release Studies: Release studies for
microcapsules can be carried out in different pH condition
like pH 1.2 and 7.4 using USP rotating basket.

15. Application of microencapsulation:
 To improve the flow properties.
E.g=Thiamine
 To enhances the stability.
E.g=Vitamins
 To reduced volatility of materials.
E.g =Methyl salicylate
 To mask the unpleasant taste and odour.
E.g=castor oil
 To convert liquids into solids.
 E.g=castor oil
 To reduce gastric irritation.
 E.g= endomethacin

16. Conclusion:
Microencapsulation means packaging an active ingredient
inside a capsule ranging in size from one micron to several
from its surrounding environment until an appropriate
time. Then, the material escapes through the capsule wall
by various means, including rupture, dissolution, melting
or diffusion. Microencapsulation is both an art and a
science.

17. References:
 Jackson L. S, Lee K, "Microencapsulationand the food
industry", LebensmittelWissenschaft Technologie, Retrieved
1991-02-02.
 Aulton ME. Pharmaceutics The science of dosage form
design. NewYork: Churchill Livingstone: 1988.605-13.
 James, S., “Encylopedia of Pharmaceutical Techonology ”,
3rd edition,Vol-, 1325-1333.
 Leon, L., Herbert A. L., Joseph, L. K; “ The Theory And
Practice Of Industrial Pharmacy” 3rd edition,1990 Varghese
Publishing House,412, 428.