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 material. Why to do it? How? what are its applications?

1. Type of Core materials, Coating
materials and Vehicles used in
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 material.
Components:
a) Core
b) Shell
Reasons of Microencapsulation:
1. Protect reactive substances from
environment.
2. Separate incompatible components.
3. Mask bad taste or odor.
4. Increase of bioavailability.
5. Produce a targeted drug delivery.
6. Protect GIT from drug irritant effects.
7. Control delayed release
or sustained release.
Microencapsulation Techniques:
Depend on the physical and chemical
properties of the material to be encapsulated.
Examples:
1. Chemical technique:
Solvent Evaporation:
The core material is dispersed/ dissolved in the
polymer solution.
2. Physico-chemical technique:
Ionotropic gelation:
Microparticulate system of verapamil
hydrochloride for prolonged release delivery
system.
3. Physical technique:
Air-suspension coating:
Wurster process by dispersing
the core materials in a supporting
air stream and spray-coating
the suspended particles.
Pharmaceutical Applications:
1. Aspirin controlled release version ZORprin
CR tab.s for relieving arthritis symptoms.
2. Quinidine gluconate CR tab.s for treating
and preventing abnormal heart rhythms.
3. Niaspan CR tab.s for improving cholesterol
levels and thus reducing risk of heart attack.
4. Glipizide SR is an anti diabetic medicine
used to control high blood pressure.