MICROENCAPSULATION PROCESS IN PHARMACEUTICAL INDUSTRY

In this process small particles of liquids, solids, as well as gases may be encapsulated into microscopic size, ranging from 1µ to 5000µ in size, through the progression of thin coating of coating materials around the substance being encapsulated.

Purpose

l       Controlling the release characteristics or availability of coated materials

l       To keep an environmental protection

l       Alteration of colloidal and surface properties

l       Convertion of  liquids to solid

Types of methods

l       Air suspension

l       Coacervation phase separation

l       Mutiorifice centrifugal

l       Pan coating

l       Solvent evaporation

l       Spray drying & congealing

Table: Applicability’s of these methods

Microencapsulation Process	Applicable core material	Approx. particle size (µm)
Air suspension	Solids	30-5000
Coacervation phase separation	Solids & liquids	2-5000
Mutiorifice centrifugal	Solids & liquids	1-5000
Pan coating	Solids	600-5000
Solvent evaporation	Solids & liquids	5-5000
Spray drying & congealing	Solids & liquids	600

Air Suspension Method

Basically the process consists of:

·         The dispersing of solid particulate core constituents in a supporting air stream.

·         Sprayin coating materials on the air suspended particles.

Coacervation-Phase Separation

This process is done by three steps:

Ø      Formation of 3 immiscible phases

Ø      Deposition of the coating material on the core

Ø      Rigidization of the coating material

Application

·         To mask the bitter test of  drugs. Eg. Acetaminophen Tab.

·         To facilitate selective sorption.EG. activated charcoal.

·         To prepare sustained action dosage forms. Eg. Progesterone.

·         For separating the incompatible ingredients.eg. Aspirin Tablet.

·         To prevent volatilization of volatile substances. Eg. Menthol.

·         To protect drugs from moisture and oxidation. Eg.  encapsulated Vit A palmitate.

·         In stabilization by conversion of dosage form.

·         i.e. liquid to solid [ Liquid crystal]

·         In new formulation concepts for ointments, aerosols,creams, dressings, suppositories, plasters, and injectables.

·         In various pharmaceutical related areas such as hygiene, diagnostic aids and medial equipment design. [ BaSO₄ for X-rays]

·          Reduction of  gastric irritation. [KCI]

·         In selectivity of enzyme substrate and reaction products. [Urease]

·         Sustained normalization of diabetic condition [Islets of Langerhans]
ETIOLOGYAND MECHANISM OF ATROPHY