Microencapsulation is a process in which tiny particles or droplets are surrounded by a coating to give small capsules, with useful properties. In general, it is used to incorporate food ingredients, enzymes, cells or other materials on a micro metric scale.

2. INTRODUCTION
• MICROENCAPSULATION IS A PROCESS BY WHICH SOLIDS, LIQUIDS, OR EVEN GASES MAY BE ENCLOSED IN
MICROSCOPIC PARTICLES BY FORMATION OF THIN COATINGS OF WALL MATERIAL AROUND THE
SUBSTANCE.
• MICROENCAPSULATION IS DEFINED AS THE APPLICATION OF A THIN POLYMERIC COATING TO INDIVIDUAL
CORE MATERIALS (TINY PARTICLES OR DROPLETS OF LIQUIDS AND DISPERSIONS) THAT HAVE AN
ARBITRARY PARTICLE SIZE RANGE FROM 5-5000 ΜM TO GIVE SMALL CAPSULES WITH MANY USEFUL
PROPERTIES.
• MICROENCAPSULATION IS A MODIFIED FORM OF FILM COATING, DIFFERING ONLY IN THE SIZE OF THE
PARTICLES TO BE COATED AND THE METHOD BY WHICH THIS IS PRODUCED

3. ADVANTAGES
• PATIENTS TO CONSUME LOWER DOSES FOR THE SAME THERAPEUTIC EFFECT.
• LOWERS THE RISK OF SIDE EFFECTS.
• MASKING OF ODOR OR TASTE FOR CHEWABLE TABLETS, POWDERS AND SUSPENSIONS FOR CHILDREN'S
MEDICINES.
• PROLONG ACTION DOSAGE FORM AND CONTROLLED AND TARGETED DRUG DELIVERY.
• MODIFY THE PHYSICAL CHARACTERS OF A MATERIAL WHICH IS REQUIRED IN CERTAIN FORMULATIONS.
• PROTECT CHEMICALS AGAINST DEGRADATIVE REACTIONS SUCH AS OXIDATION, DEHYDRATION.
• DIAGNOSTICS AND MEDICAL EQUIPMENT DESIGN.
• LIQUIDS CAN BE HANDLED AS SOLIDS.
• SAFE AND CONVENIENT HANDLING OF TOXIC SUBSTANCES

4. DISADVANTAGES

5. APPLICATIONS OF MICROENCAPSULATION
• .

6. TYPE OF CORE MATERIALS, COTING
MATERIALS AND VEHICLES USED IN
MICROENCAPSULATION
• .

7. FUNDAMENTAL CONSIDERATIONS
A) CORE MATERIAL.
• THE SOLID CORE CAN BE MIXTURE OF ACTIVE CONSTITUENTS, STABILIZERS,
DILUENTS, EXCIPIENTS AND RELEASE-RATE RETARDANTS OR ACCELERATORS.
B) COAT OR WALL OR SHELLMATERIAL
•COMPATIBLE, NON REACTIVE WITH CORE MATERIAL
•PROVIDE DESIRED COATING PROPERTIES LIKE STRENGTH,FLEXIBILITY
,
IMPERMEABILITY, OPTICAL PROPERTIES, NON HYGROSCOPICITY, TASTELESS AND
STABLE.

8. CONT…
C) CORE MATERIAL
• THE MATERIAL TO BE COATED. IT MAY BE LIQUID OR SOLID OR GAS. LIQUID CORE
MAY BE DISSOLVED OR DISPERSED MATERIAL.
• COMPOSITION OF CORE MATERIAL:
• DRUG OR ACTIVE CONSTITUENT
• ADDITIVE LIKE DILUENTS STABILIZERS

9. TYPES OF COATING MATERIALS
WATERSOLUBLE RESIN WATERINSOLUBLE RESIN WAX& LIPID ENTERICRESIN
Gelatin, EthylCellulose, Paraffin, Shellac,
Gum Arabic, Polyethylene, Carnauba Wax, Zein,
PVP,
CMC,
Polymethacrylate,
Cellulose Nitrate,
Bees Wax,
StearicAcid,
CelluloseAcetate
Phthalate.
Hydroxyl Methyl
Cellulose,
Silicones. StearylAlcohol.
Arabino Galactan,
Polyvinyl Acrylate,
PolyacrylicAcid.

10. MICROSPHERES
• MICROSPHERES ARE CHARACTERISTICALLY FREE FLOWING POWDERS CONSISTING OF
PROTEINS OR SYNTHETIC POLYMERS WHICH ARE BIODEGRADABLE IN NATURE AND IDEALLY
HAVING A PARTICLE SIZE LESS THAN 200 ΜM.
a. b.

11. MICROPARTICLES
• MICRO PARTICLES ARE DEFINED AS PARTICULATE DISPERSIONS OR SOLID
PARTICLES WITH A SIZE IN THE RANGE OF 1-1000 ΜM. THE DRUG IS DISSOLVED,
ENTRAPPED, ENCAPSULATED OR ATTACHEDTO A MICRO PARTICLE MATRIX.
Schematic
Representation of
Micro particle

12. DIFFERENCE BETWEEN MICROSPHERES AND
MICRO PARTICLES
AS WE KNOW MICROENCAPSULATION IS A TECHNOLOGY USED TO ENTRAP SOLIDS,
LIQUIDS, OR GASES INSIDE A POLYMERIC MATRIX OR SHELL.
 TWO GENERAL MICRO MORPHOLOGIES OF MICRO PARTICLES CAN BE
DISTINGUISHED- MICROCAPSULES AND MICROSPHERES.

13. METHODS OF PREPARATION
• .

14. I] PHYSICAL OR PHYSICO-
MECHANICAL METHODS
•AIR SUSPENSION APPARATUS.

15. CONT…
• IT CONSIST OF DISPERSING THE SOLID PARTICULATE CORE MATERIAL IN SUPPORTING AIR STREAM AND BEING
COATED WITH COATING MATERIAL (USUALLY POLYMERIC SOLUTION)
• IN THIS, THE FINE CORE MATERIALS ARE SUSPENDED IN A VERTICAL CURRENT OF AIR AND SPRAYED WITH THE
COATING MATERIAL
• AFTER EVAPORATION OF SOLVENT, A LAYER OF ENCAPSULATING MATERIAL IS DEPOSITED ON CORE
• GIVES IMPROVED CONTROL AND FLEXIBILITY AS COMPARED TO PAN COATING.
• DURING EACH PASS THROUGH THE COATING ZONE, THE CORE MATERIAL RECEIVES AN INCREMENT OF COATING
MATERIAL.
• THE CYCLIC PROCESS IS REPEATED, PERHAPS SEVERAL HUNDRED TIMES DURING PROCESSING, DEPENDING ON
THE PURPOSE OF MICROENCAPSULATION THE COATING THICKNESS DESIRED OR WHETHER THE CORE MATERIAL
PARTICLES ARE THOROUGHLY ENCAPSULATED.
• THE SUPPORTING AIR STREAM ALSO SERVES TO DRY THE PRODUCT WHILE IT IS BEING ENCAPSULATED.
• DRYING RATES ARE DIRECTLY RELATED TO THE VOLUME TEMPERATURE OF THE SUPPORTING AIR STREAM.

16. CENTRIFUGAL EXTRUSION
 LIQUIDS ARE ENCAPSULATED USING A ROTATING
EXTRUSION HEAD CONTAINING CONCENTRIC NOZZLES.
 THIS PROCESS IS EXCELLENT FOR FORMING PARTICLES 400–2,000 ΜM IN
DIAMETER.
 SINCE THEDROPS ARE FORMED BYTHE BREAKUP OF A
LIQUID JET, THE PROCESS IS ONLY SUITABLE FOR LIQUID OR SLURRY.
 A HIGH PRODUCTION RATE CAN BE ACHIEVED, I.E.,UP TO
22.5 KG OF
• MICROCAPSULES CAN BE PRODUCED PER NOZZLE PER HOUR PER HEAD.
 HEADS CONTAINING 16 NOZZLES ARE AVAILABLE.

17. PAN COATING
 OLDEST INDUSTRIAL PROCEDURES FOR FORMING SMALL, COATED PARTICLES OR
TABLETS.
 THE PARTICLES ARE TUMBLED IN A PAN OR OTHER DEVICE WHILE THE COATING
MATERIAL IS APPLIED SLOWLY.
 SOLID PARTICLES GREATER THAN 600 MICRONS IN SIZE ARE GENERALLY
CONSIDERED ESSENTIAL FOR EFFECTIVE COATING.
 MEDICAMENTS ARE USUALLY COATED ONTO VARIOUS SPHERICAL SUBSTRATES
SUCH AS NONPAREIL SUGAR SEEDS, AND THEN COATED WITH PROTECTIVE
LAYERS OF VARIOUS POLYMERS.

18. FIGURE OF PAN COATING
• .

19. SPRAY DRYING
 IN MODERN SPRAY DRYERS THE VISCOSITY OF THE SOLUTIONS TO BE
SPRAYED CAN BE AS HIGH AS 300MPA.S
 SPRAY DRYING AND SPRAY CONGEALING- DISPERSING THE CORE
MATERIAL IN A LIQUEFIED COATING SUBSTANCE AND SPRAYING.
 SPRAY DRYING IS EFFECTED BYRAPID EVAPORATION
OF A SOLVENT IN WHICH THE COATING MATERIAL IS
DISSOLVED.
• THE EQUIPMENT COMPONENTS OF A STANDARD SPRAY DRYER INCLUDE
1. AN AIR HEATER,
2. ATOMIZER,
3. MAIN SPRAY CHAMBER,
4. BLOWER OR FAN,
5. CYCLONE AND
6. PRODUCT COLLECTOR.

20. FIGURE OF SPRAY DRYING
• .
Spray Drying:
The coating solidification effected by
rapid evaporating of solvent in which coating material is dissolved.
Spray Congealing:
The coating solidification is effected by thermally congealing a
molten coating material. The removal of solvent is done by
sorption, extraction or evaporation technique
Steps:
1Core particles are dispersed in a polymer solution and sprayed
into a hot chamber.
2The shell material solidifies onto the core particles as the
solvent evaporates.
- The microcapsules obtained are of polynuclear or matrix type.

21. VIBRATIONAL NOZZLE
 THE PROCESS WORKS VERY WELL FOR GENERATING DROPLETS BETWEEN
• 100–5,000 ΜM
 UNITS ARE DEPLOYED IN INDUSTRIES AND RESEARCH MOSTLY WITH
CAPACITIES OF 1–10,000 KG PER HOUR AT WORKING TEMPERATURES OF 20–1500
C.
 NOZZLES HEADS ARE AVAILABLE FROM ONE UP TO SEVERAL HUNDRED
THOUSAND ARE AVAILABLE

22. CONT…
• .

23. II] PHYSICO-CHEMICAL
METHODS
• IONOTROPIC GELATION
 CHEMICAL REACTION BETWEEN SODIUM ALGINATE AND CALCIUM CHLORIDE OR
OTHER COUNTER ION SOLUTION SUCH AS BARIUM CHLORIDE.
 EG: VERAPAMIL HYDROCHLORIDE CAUSES GASTRIC IRRITATION ON SUDDEN RELEASE. IT IS
USUALLY ADMINISTERED AS CONVENTIONAL TABLETS CONTAINING 40-120 MG, 3 TIMES A DAY.
DUE TO ITS READY SOLUBILITY IN WATER AND SHORTER HALF-LIFE.
 MICRO PARTICULATE SYSTEM OF VERAPAMIL HYDROCHLORIDE FOR PROLONGED RELEASE
DELIVERYSYSTEM.

24. A) COACERVATION-PHASE
SEPARATION
 THREE STEPS CARRIED OUT
UNDER CONTINUOUS
AGITATION:
1) FORMATION OF THREE
IMMISCIBLE CHEMICAL PHASES
2) DEPOSITION OF THE COATING
3) RIGIDIZATION OF THE COATING
(a) Core material dispersion in solution of shell polymer;
(b) Separation of coacervate from solution;
(c) Coating of core material by microdroplets of coacervate;
(d) Coalescence of coacervate to form continuous shell around core
particles.

25. III] CHEMICAL PROCESS
• SOLVENT EVAPORATION
 IN THE CASE IN WHICH THE CORE MATERIAL IS DISPERSED IN THE POLYMER SOLUTION,
POLYMER SHRINKS AROUND THE CORE. IN THE CASE IN WHICH CORE MATERIAL IS DISSOLVED
IN THE COATING POLYMER SOLUTION, A MATRIX - TYPE MICROCAPSULE IS FORMED.
 THE CORE MATERIALS MAY BE EITHER WATER – SOLUBLE
OR WATER - INSOLUBLE MATERIALS.
 A VARIETY OF FILM - FORMING POLYMERS CAN BE USED ASCOATINGS.

26. CONT…
Step1: Formation of a solution/dispersion
of the drug into an organic polymer phase.
Step2: Emulsification of the polymer
phase into an aqueous phase containing a
suitable stabilizer, thus, forming a o/w
emulsion.
Step3: Removal of the organic solvent
from the dispersed phase by extraction or
evaporation leading to polymer
precipitation and formation of the
microspheres.

27. POLYMERIZATION
ARELATIVELY NEW MICROENCAPSULATION METHOD UTILIZES
POLYMERIZATION TECHNIQUES TO FROM PROTECTIVE MICROCAPSULE
COATINGS IN SITU.
THE METHOD INVOLVE THE REACTION OF MONOMERIC UNIT LOCATED AT THE
INTERFACE EXISTING BETWEEN A CORE MATERIAL SUBSTANCE AND
CONTINUOUS PHASE IN WHICH THE CORE MATERIAL IS DISPERSE.
THE CORE MATERIAL SUPPORTING PHASE IS USUALLY A LIQUID OR GAS, AND
THEREFORE POLYMERIZATION REACTION OCCUR AT LIQUID-LIQUID, LIQUID-GAS,
SOLID-LIQUID, OR SOLID-GAS INTERFACE.
E.G. IN THE FORMATION OF POLYAMIDE (NYLON) POLYMERIC REACTION
OCCURRING AT LIQUID-LIQUID INTERFACE EXISTING BETWEEN ALIPHATIC
DIAMINE & DICARBOXYLIC ACID HALIDE.

28. CONT…
1) INTERFACIAL POLYMER
• IN INTERFACIALPOLYMERIZATION, THE TWO REACTANTSIN A POLY
CONDENSATION MEET AT AN INTERFACE AND REACT RAPIDLY.
2) IN-SITU POLYMERIZATION
• IN A FEW MICROENCAPSULATION PROCESSES, THE DIRECT POLYMERIZATION OF A
SINGLE MONOMER IS CARRIED OUT ON THE PARTICLE
SURFACE.
• E.G. CELLULOSE FIBERS ARE ENCAPSULATED IN POLYETHYLENE WHILE IMMERSED IN
DRY TOLUENE. USUAL DEPOSITION RATES ARE ABOUT 0.5ΜM/MIN. COATING THICKNESS
RANGES 0.2-75ΜM.
3) MATRIX POLYMER
• IN A NUMBER OF PROCESSES, A CORE MATERIAL IS IMBEDDED IN A POLYMERIC MATRIX
DURING FORMATION OF THE PARTICLES.
• PREPARES MICROCAPSULES CONTAINING PROTEIN SOLUTIONS BY INCORPORATING
THE PROTEIN IN THE AQUEOUS DIAMINE PHASE.
• NATIONAL LEAD CORPORATION- UTILIZING POLYMERIZATION TECHNIQUES

29. POLYMERIZATION TECHNIQUE

30. EVALUATION PARAMETERS
• MICROMERETIC PROPERTIES
a. ANGLE OF REPOSE
b. TAP DENSITY
c. BULK DENSITY
d. CARR’S INDEX
e. HAUSER'S RATIO
• PERCENTAGE YIELD
• PERCENT DRUG ENTRAPMENT
• PERCENT BUOYANCY
• FLOATING TIME
• IN-VITRO DRUG RELEASE
• IN-VIVO DRUG RELEASE
• EX-VIVO DRUG RELEASE

31. REFERENCE
• LEON, L., HERBERT A. L., JOSEPH, L. K; “ THE THEORY AND PRACTICE OF INDUSTRIAL
PHARMACY”, 3RD EDITION (1990), VARGHESE PUBLISHING HOUSE, PAGE NO.- 412-428.
• S.S. BANSODE, A REVIEW ON “MICROENCAPSULATION”, INTERNATIONAL JOURNAL OF
PHARMACEUTICAL SCIENCES REVIEW AND RESEARCH, VOLUME 1, ISSUE 2, MARCH –
APRIL 2010; ARTICLE 008; ISSN 0976 – 044X, PAGE NO.- 38-43.
• N.K. SACHAN, A REVIEW ON “CONTROLLED DRUG DELIVERY THROUGH
MICROENCAPSULATION”, MALAYSIAN JOURNAL OF PHARMACEUTICAL SCIENCES,
VOLUME 4, NO. 1, PAGE NO.- 65–81 (2006).
• H. UMER, A REVIEW ON “MICROENCAPSULATION: PROCESS, TECHNIQUES AND
APPLICATIONS”, INTERNATIONAL JOURNAL OF RESEARCH IN PHARMACEUTICAL AND
BIOMEDICAL SCIENCES, VOL. 2 (2) APR – JUN 2011, ISSN: 2229-3701, PAGE NO.-447-481.