Microencapsulation

Microencapsulation topic.
B. Pharmacy sem 7th

1. Microencapsulation Introduction, Advantages and disadvantages, Methods of encapsulation - Snehal Jagtap

2. Introduction -

3. Types -

4. Theory of encapsulation-

5. Core material (API)

6. Coating material

7. Advantages-

8. Disadvantages -

9. Methods of microencapsulation -. Physicomechanical methods Physicochemical methods Chemical methods

10. A] Physicochemical methods Air suspension Centrifugal extrusion Pan coating Spray drying – co-current - counter current - mix flow 5. Vibrational nosal method

11. B] Physicochemical methods Ionotropic gelatin Coacervation C] Chemical methods Solvent evaporation Polymerization - interfacial - in situ - matrix method

12. [A] Physicomechanical methods 1]Air suspension coating Developed by Prof. Dale E. Wurster. Factors to be considered….. Properties of drug material and coating material Concentration of coating material Coating material application rate Amount of coating of coating material Inset and outlet pressure operative maintenance

13. Air suspension

14. Process-

15. 2] Centrifugal extrusion Centrifugal extrusion is  a liquid coextrusion process utilizing nozzles consisting .  of a concentric orifice located on the outer circumference of a rotating cylinder .  i.e., the head . Centrifugal extrusionLiquids are encapsulated using a rotating extrusion head containing concentric nozzles. This process is excellent for forming particles 400-2,000 µm in diameter Since the drops are formed by the 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.

16. 3] Pan coating Pan Coating process is  used for solid particles greater than 600 microns in size . The coating is applied as a solution, or as an atomized spray, to the desired solid core material in the coating pan.

17. 4] Spray drying Process….

18. Instruments of spray dryer Air heater Automizer (used to reduce molecularsize ) Main chamber Cyclon Blender / fan Product collector

19. Co-current flow In a co-current flow spray dryer,  the spray is directed into the hot air entering the dryer and both pass through the chamber in the same direction

20. Counter current In counter-current spray drying,  the material to dry and the air are injected at opposite location in the drying chamber

21. Mixed flow It combines both co-current and counter current flow.

22. 5] Vibration nozzel method A fluid stream of liquid core and shell material is pumped through concentric tubes and forms droplets under the influence of vibration. Particle size 100-500 micrometer Capacity is 1 - 10,000 kg/ hr

23. [B] Physicochemical methods 1]Ionotropic gelation Ionotropic gelation (IG) is  a technique that allows the production of nanoparticles and microparticles by electrostatic interactions between two ionic species under certain conditions . At least one of the species has to be a polymer. Example .. Chemical reaction between sodium algenate or barium chloride with verapamil, reduces the gastric irritation of Verapamil (antihypertensive)

24. 2] Co-acervation Coacervation can be defined as  the separation of a macromolecular solution into two immiscible liquid phases: a dense coacervate phase and a dilute equilibrium one .

25. Process- Core material dispersion in solution of shell polymer; separation of coacervate from solution; coating of core material by microdroplets of coacervate; Coacervance of coacervate to form continuous shell around core particles.

26. [C] Chemical methods 1] Solvent evaporation In the solvent evaporation method,  the drug is dissolved, dispersed, or emulsified into an organic polymer solution, which is then emulsified into an external aqueous or oil phase . The microspheres are formed after solvent diffusion/evaporation and polymer precipitation.

27. 2] Polymerization i) Interfacial ii) In-situ iii) Matrix

28. i) Interfacial polymerization Interfacial polymerization is a type of step-growth polymerization in which polymerization occurs at the interface between two immiscible phases (generally two liquids), resulting in a polymer that is constrained to the interface.

29. ii) In-situ polymerization In some Polymerization processes, direct Polymerization of single monomer is carried out on the particle surface.

30. iii) Matrix Polymerization A core material is imbedded in a polymeric matrix during formation of particles.