Micro-encapsulation

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 . Micro-encapsulation 1

2. INTRODUCTION MICROENCAPSULATION TECHNIQUES CHEMICAL TECHNIQUES APLLICATIONS REFERENCE CONTENTS 2

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. INTRODUCTION 3

4. Micro particles consist of two components - a ) Core material b ) Coat material 4

5. 5 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. 6 ADVANTAGES :-

7. 7 MICROENCAPSULATION TECHNIQUES :-

8. Coacervation (2 – 1200 µm ) Polymer-polymer incompatibility ( 0.5 – 1000 µm) Interfacial Polymerization In Situ Polymerization Solvent evaporation ( 0.5 – 1000 µm ) 8 Chemical Techniques

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. 9

10. 10 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.

11. SIMPLE COACERVATION : 11 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.

12. 12 Polymeric Membrane Droplets Homogeneous Polymer Solution Coacervate Droplets PHASE SEPARATION MEMBRANE FORMATION Schematic representation of the coacervation process. Core material dispersion in solution of shell polymer; Separation of coacervate from solution Coating of core material by micro droplets of coacervate; (d) Coalescence of coacervate to form continuous shell around core particles

13. 13 Complex Coacervation :

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. 14

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16. Polymer –Polymer Incompatibility : 16 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. 18 Interfacial polymer :-

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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. 20 In-situ polymerization

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 . 21

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. 22 Solvent Evaporation :-

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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. 25

26. B . SOLVENT EVAPORATUION (EMULSIFICATION –evaporation ) 1 . OIL-IN-WATER EMULSION 2 . MULTIPLE EMULSION : water-in-oil-in water 3 . NONAQUEOUS EMULSION 26

27. 27 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. 28 APLLICATIONS

29. 29 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 30 REFERENCE