This document discusses various methods for microencapsulation, including physical methods (air suspension coating, pan coating, spray drying), physiochemical methods (ionotropic gelation, co-accervation), and chemical methods (solvent evaporation, polymerization). It provides details on the procedures and processing variables for each method. Physical methods involve applying coating material to solid core materials using air streams or moving pans, while chemical methods use polymerization or solvent evaporation to form microcapsule shells around core materials dispersed in solution.

1. Novel Drug Delivery System
Presented By :- VIJAY C. JADHAV
B Pharm Final Year
Shri Sambhaji Collage Of Pharmacy
Khadkut, Nanded
Methods of Microencapsulation

2. Contents :
PHYSICAL
METHODS
Air
Suspension
Coating
Pan Coating
Spray Drying
PHYSIO-
CHEMICAL
METHODS
Ionotropic
Gelation
Method
Co-
Accervation
Method
CHEMICAL
METHODS
Solvent
Evaporation
Method
Polymerization
Method

3. PHYSICAL METHODS
Air Suspension Coating ( Wurster Process )
 It Is Also Known As Fludized Bed Method
 It is Applicable For Only Solid Material From The Size Ranging
From 35 – 5000 um
 The Capacity Of This Equipment Should Be 1 Lb – 990 Lb
 The Basic Principle Of This Process is That Dispersing Of Solid
Core Material With The Help Of Air Stream By Spray Coating
To Air Suspended Particles
 Micron Or Submicron Particles Can Be Effectively Encapsulated
By This Technique

5. Procedure :
 When Core Material Feed From Pipe Into Process Chamber It Get
Suspended Into Air Due To The Air Supply From Perforated Plate
 Spraying Nozzle Can Spray The Coating Material/Solution Onto The
Expension And Segregation Zone
 In This Zone Coating Material Contact With Core Material And
Polymer Coat Apply On It
 This Cyclic Process Repeat Until Uniform Coat Apply On Particle
 After Uniform Coating This Particle Should Be Settle Down And
Collected From Discharge Pipe At Bottom
 In This Technique We Can Apply Coating Solution From Both Side
i.e. Top or Bottom
 High Velocity Of Air Help For The Drying Of The Coating Solution
To Avoid Sticking Of The Particles.

6. Processing Variables :
Density, Surface Area,
Melting Point,
Solubility, Friability
And Flowability Of
Core Material
Coating Material
Concentration
Coating Material
Application Rate
Volume Of Air
Required To Support
And Fludizes the core
material
Amount of coating
material required
Inlet and outlet
Operating
Temperature

7. Pan Coating
INTRODUCTION
 It is The Oldest Industrial Procedure For Preparation Of Small
Coated Particles Or Tablets
 In This Process Microcapsules Are Obtained By Spraying A Coating
Solution On To Moving Core Material In Standard Coating Pan
 Solid Particles Greater Than 600 Micron In Size Are Generally
Consider For The Effective Coating
 Usually Warm Air is Passed Over The Coated Material For The
Avoidance Of Sticking And Uniform Coating Of Coated Material

8. Fig : PAN COATING
Mechanism :

9. Procedure :
Microcapsules Formed
Then Solidified By Cooling
The Coating Material Melts And Encloses The Core Material/Particles
Temprature Is Raised
Solid Core Material Mixed With Dry coating Material

10. Spray Drying
INTRODUCTION
 It Is Most Accepted and Widely Used Technique For
Microencapsulation
 This Method Involves Production Of Dry Powder Form Of
Active Component From Liquid Slurry By Rapid Drying With
Air / Gas
 Spray Drying Is Effected By Rapid Evaporation Of Solvent In
Which Coating Material Is Dissolved
 Atomizer Helps To Make Uniform Size Of Liquid Droplets

11. Fig : Spray Drying

12. Procedure :
Solid Core Particles Dispersed In The Polymer
( Coating ) Solution
This Solution Feed From Atomizer Into Hot
Chamber Where Heated Gas Present
Shell ( Coated ) Material Solidifies Onto Core
Material Due To Heated Air
Solvent Evaporate
Microcapsule Formed Which Is Seprated By
Clone Seprator And Collected

13. Process Variables :
1. Viscosity Of Feed Solution
2. Concentration Of Core And Coating Material
3. Feed Rate
4. Degree Of Atomization
5. Drying Rate

14. PHYSIO-CHEMICAL METHODS
Ionotropic Gelation
 In This Method Synthesize The Micro-particles
Or Nanoparticles Based On Electrostatic
Interaction Between the Ions With Different
Charges

15. Procedure :
 All The Required Material Weighed Accurately
i.e. Core Material , Sodium Alginate (2%) , CaCl2 (3%)
 In A Beaker Take Weighed Quantity Of Sodium Alginate Along
With Water To Make Aq. Mucilage Solution
( Heat For 5 – 10 Minutes )
 This Solution Is Stirred In A Magnetic Stirrer At Suitable
Speed For 30 Min.
 Then Drug ( Core Material ) Is Dispersed Into It And Stirred
 In Another Beaker Take Weighed quantity Of CaCl2 & Make
Solution By Adding Distilled Water

16.  Microcapsule / Micro-particles Are Formed By Dropping
Bubble Free Dispersion Through Syringe With The Help Of
Needle ( No.22 ) Into The CaCl2 Solution
 Filter And Wash The Micro-particles With Distilled Water
 Dry This Microcapsule In Hot Air Oven At 50°c For 2-4 Hr

17. Co-Accervation
Co-Accervation : It Is The Process Of Sepration Of The
Macromolecular Solution Into Two Immiscible Liquid Phases
STEPS OF CO-ACCERVATION MICROENCAPSULATION
Step 1 : Formation Of Three Immiscible Phases
Step 2 : Deposition Of Coating Material
Step 3 : Regidization Of Coating Material

18. Fig : Co-Accervation

19. Procedure :
 In This Method Coating Material Is First Dissolved In
Suitable Solvent And Then Core Material Is Uniformly
Dispersed In It.
 By Incresing Temprature Co-Accervate Can Be Formed
i.e. There is Formation Of Three Immiscible Phase
( Solvent,Core Material,Coating Material )
 After Sepration Of Coating Material From Solution They
Get Deposited On The Core Material
 By Continous Agitation And Decresing Temprature This
Coating Material Uniformly Applied Over Core Material
And Make Rigid Microcapsule

20. Methods For Achieving Co-Accervation
1. Temprature Change
2. Incompatible Polymer Addition
3. Non Solvent Addition
4. Salt Addition
5. Polymer–Polymer Interaction

21. CHEMICAL METHODS
Solvent Evaporation
 This Technique Is Used For The Poorly Water Soluble Drugs
 This Technique is Carried Out In The Liquid Manufacturing
Vehicle ( O/W Emulsion ) Which Is Prepared By Agitation Of
Two Immiscible Liquids
 This Process involves Dissolving Microcapsule Coating
( Polymer ) In Volatile Solvent Which Is Immiscible With The
Liquid Manufacturing Vehicle Phase
 Core Material To Be Encapsulated Is Dissolved Or Dispersed In
Coating Polymer Solution

22. Procedure :
Step 1 : Preparation Of Organic Phase
Step 2 : Preparation Of Aqueous Solution Of Surfactant / Surface
Stabilizer

23. Step 3 : Emulsification
Step 4 : Evaporation Of Solvent And Precipitation Of Nanoparticles

24. Step 5 : Ultracentrifugation
 The Nanoparticles Are Collected By The
Ultracentrifugation And Washed With Distilled Water To
Remove Stabilizer Residue Or Any Free Drug
Step 6 : Lyophilization ( Freeze Drying )

25. Polymerization ( In Situ )
A. Dispersion Of Liquid To Be Encapsulated In Water
 In Stirred Tank Liquid To Be Encapsulated Is Dispersed In Water
The Size Of Droplets Obtained Is Regulated By Speed Of Stirrer
B. Introduction Of Monomer A & B Into Solution
 Monomers Which Are Small Molecules Are Introduced Into Stirred Tank
They Will Form Polymer By Polymerization Reaction

26. C. Initiation Of Polymerization Process
 The Polymerization Reaction Is Initiated By PH Changes And
Temperature Can Be Accelarated By The Use Of Catalyst
 The Polymer Formed Is Deposited Around The Drops Which Leads To
Encapsulation
D. Stabilization Of Polymer Structure
 The Polymer Is Then Consolidated By Changes In PH, Temperature Or
Addition Of Additives
This Leads To Better Isolation Of Encapsulated Assest