Micro-encapsulation

1. Presented By- Chetan Vishwanath Pawar
M. Pharmacy Sem –I
Guided By- Mrs. S. MUTHA
Department of Pharmaceutics
PDEA’s S.G.R.S. College of Pharmacy Saswad.
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2.  INTRODUCTION
 MICROENCAPSULATION TECHNIQUES
 CHEMICAL TECHNIQUES
 APLLICATIONS
 REFERENCE
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3.  DEFINATION
Microencapsulation are small particles that
contain an active agent or core material
surrounded by a coating or shell .
- The product obtained by this process is called as
micro particles, microcapsules.
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4.  Micro particles consist of two components -
a) Core material
b) Coat material
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FUNDAMENTAL CONSIDERATION:
Core material Coating material Vehicle
Liquid
Microencapsulation
Polymers
Waxes
Aqueous Nonaqueous
Resins
Proteins
Solid

6.  To Increase of bioavailability.
 To alter the drug release .
 To improve the patient’s compliance .
 To produce a targeted drug delivery.
 To convert liquid to solid & To mask the core taste.
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8.  Coacervation (2 – 1200 µm)
 Polymer-polymer incompatibility (0.5 –
1000 µm)
 Interfacial Polymerization
 In Situ Polymerization
 Solvent evaporation (0.5 – 1000 µm )
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9. COACERVATION PHASE SEPARATION:
A coacervate is a tiny spherical droplet of
assorted organic molecules (specifically, lipid
molecules) which is held together by
hydrophobic forces from a surrounding liquid.
Coacervates measure 1 to 100 micrometers
across, possess osmotic properties and form
spontaneously from certain dilute organic
solutions.
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 Two methods for coacervation are available,
namely simple and complex processes :-
• In simple coacervation, a desolation
agent is added for phase separation.
• Whereas complex coacervation involves
complexation between two oppositely
charged polymers.

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 Simple coacervation involves the use of either
a second more-water soluble polymer or an
aqueous non-solvent for the gelatin.
 Simple coacervation can be effected either by
mixing two colloidal dispersions, one having
a high affinity for water, or it can be induced
by adding a strongly hydrophilic substance
such as alcohol or sodium sulfate.

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Polymeric
Membrane
DropletsHomogeneous
Polymer Solution
Coacervate
Droplets
PHASE
SEPARATION
MEMBRANE
FORMATION
Schematic representation of the coacervation process.
(a) Core material dispersion in solution of shell polymer;
(b) Separation of coacervate from solution
(c) Coating of core material by micro droplets of coacervate;
(d) Coalescence of coacervate to form continuous shell
around core particles

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14.  Complex coacervation can be induced in
systems having two dispersed hydrophilic
colloids of opposite electric charges.
 Neutralization of the overall positive charges
on one of the colloids by the negative charge.
 separation of the polymer-rich complex
coacervate phase.
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 This method utilizes two polymers that are
soluble in a common solvent; yet do not mix
with one another in the solution.
 The polymers form two separate phases, one
rich in the polymer intended to form the
capsule walls, the other rich in the
incompatible polymer meant to induce the
separation of the two phases.

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18.  In Interfacial polymerization, the two
reactants in a polycondensation meet at an
interface and react rapidly.
 A unique feature of this technology is that
the capsule shell is formed at or on the
surface of a droplet or particle by
polymerization of reactive monomer.
 The multifunctional monomer dissolved in
liquid core material which will be then
dispersed in aqueous phase containing
dispersing agent.
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20.  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 about0.5μm/min.
Coating thickness ranges 0.2-75μm.
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21.  In this process no reactive agents are
added to the core material.
Application –
In situ polymerization is used
extensively to produce small (3 to 6 µm
diameter) capsule loaded with carbonless
paper inks or perfume for scented strips .
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22.  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.
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25.  Step 1:
Formation of a solution/dispersion of the
drug into an organic polymer phase.
 Step 2:
Emulsification of the polymer phase into an
aqueous phase containing a suitable stabilizer ,
thus, forming a o/w emulsion.
 Step 3:
Removal of the organic solvent from the
dispersed phase by extraction or evaporation
leading to polymer precipitation and formation of
the microspheres.
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26. B . SOLVENT EVAPORATUION (EMULSIFICATION
–evaporation )
1 . OIL-IN-WATER EMULSION
2 . MULTIPLE EMULSION : water-in-oil-in water
3 . NONAQUEOUS EMULSION
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MULTIPLE EMULSION : water-in-oil-in water

28.  The technology has been used widely in the
design of controlled release and sustained
release dosage forms.
 To mask the bitter taste of drugs like
Paracetamol, Nitrofurantoin etc.
 to reduce gastric and other G.I. tract
irritations.
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 Hygroscopic properties of core materials
may be reduced by microencapsulation e.g.
Sodium chloride.
 To improve the flow properties. e.g. Thiamine,
Riboflavine
 To enhance the stability. e.g. Vitamins
 To reduce the volatility of materials. e.g. Peppermint
oil, Methyl salicylate

30.  International Journal of Pharma and Bio Sciences
ISSN 09.75-6299 Vol 3/Issue 1/Jan – Mar 2012.
 Indo Global Journal of Pharmaceutical Sciences,
2012; 2(1): 1-20.
 Simon Benita , MICROENCAPSULATION Method And
Industrial applications , vol – 73.
 Wikipedia.
 www. Slideshare .com
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