1. PREPARED BY:- ATIK VAHORA 09PCT02 M.PHARM(SEM-II)
SEMINAR ON
Particle coating Technology
PREPARED BY:-
ATIK VAHORA
09PCT02
M.PHARM(SEM-II)
GUIDED BY:-
Mr D.M MODI
DEPT.OF PHARMACEUTICS
A.R. COLLEGE OF PHARMACY, V V NAGAR

2. Contents Introduction Application Types of coating Coating technique
Reference

3. Introduction
Coating is a very commonly applied technology to modify/improve the properties of materials. 
Recently, there has been increased interest in the use of dry particle coating technology due to its reduced negative environmental impact and potential cost effectiveness.

4. Properties improved by coating
Taste masking with modified release
Separation of incompatibilities
Conversion of liquids to solids
Sustained release
Flowability
Dispersibility
Hydrophilic/Hydrophobic Properties
Particle Size Distribution
Shape/Sphericity

5. Application of particle coating
Particle coating are widely used in industry
Cosmetics
Dyestuff
Toner
Pharmaceuticals
Food
Ceramics
Powder
Biochemical
Electromaterials
Fertilizer

6. Type of coating
Mainly 2 types
Wet coating
Dry coating

7. Types of coating technique
Microencapsulation
Spray Drying And Prilling
Fluidized Bed Coating Techniques
Extrusion And Spheronization
Thin Precision Coating Technique
Rotating Fluidized Bed Coater
Supercritical Fluid Technique
Magnetically Assisted Impact Coating
Rotating Fluidized Bed Granulator
Hybridizer
Dry Particle Coating

8. Microencapsulation Versatile for individual particles coating
The type and level of membrane applied is determined by release rate requirements, organoleptic features and the dosage form application.
Microcaps particles can be incorporated into different dosage forms including fast melt tablets, sachets, sprinkles and reconstitutable and temporary suspensions.

9. Spray Drying And Prilling
Inexpensive methods for coating particles.
In both of these processes, the particle to be coated is added to the melt or solution and during atomization the coating is done.
Smaller coating materials are separated in a subsequent step.
The Wurster process was developed for particle coating.
In this process, the particles to be coated are suspended in a fluid bed and a coating solution of dissolved polymer, sugar, inorganic salts, sol gels, or other dissolved materials is sprayed onto the fluidized particles and then dried.

10. Spray drying systems Closed spray drying system
Open spray drying system
Semi-closed spray drying system

11. Fluid bed coating techniques
Fluid bed processing involves drying, cooling, agglomeration, granulation and coating of particulate material.
A fluidized bed is a bed of solid particles with a stream of air or gas passing upward through the particles at a rate great enough to set them in motion.
It is possible to propagate wave motion, which creates the potential for improved mixing.
The fluid bed can be used to dry the wet product, agglomerate particles, improve flow properties, instantize the product, or produce coated particles for controlled release or taste masking.
There are 3 types
Top Spray Coater
Bottom spray coater
Wuster coater

12. Top Spray Coater
Coating liquid is sprayed down onto a bed of fluidized particles. This design of coater is ideal for coating large quantities of powders, crystals and pellets.

13. Bottom spray coater
Bottom spray coating of products such as powders, seeds, crystals and other small particulates takes place in a central column as the product is airborne upwards in the presence of a fine spray of coating liquid.

14. Thin Precision Coating Technique for Fine Powders
A high velocity jet (30 to 60 ft/sec) is established by accelerating a stream of air or inert gas with Swirl Accelerator.
Control of the accelerator geometry one can establish a laminar flow pattern at Reynolds numbers where turbulent flow would normally occur.
A gap between the inlet fluidizing plate and the bottom of the coating tube allows powder to be exposed to the high velocity gas stream.
Particles of powder are picked up at this interface and accelerated by the gas stream.
A fine spray (of the coating) is introduced into the bottom of the high velocity gas stream. The coating spray is moving faster than the solid particles so contact occurs and a coating is deposited.
The coating can be virtually any liquid material that will pass through the atomizing nozzle.

16. Dry Particle coating Equipments
HIGH INTENSITY MACHINES :
Hybridizer
Mechanofusion
Theta Composer
FLUIDIZATION BASED DEVICES :
Magnetically Assisted Impaction Coating ( MAIC)
Rotating Fluidized Bed coater ( RFBC)

17. DRY PARTICLE COATING

18. Disadvantages of wet coating
Coating is a very commonly applied technology to modify/improve the properties of materials and generally done with use of different solvents. 
The solution used in the process may be hazardous and requires post-treatment (which increases the cost). 
The solvent used may also be volatile and toxic to human health.

19. Nanoparticle Applications by Dry Particle Coating Technology
In dry coating techniques, materials with relatively large particle size ( microns) form a core and these core (“host”) particles are mechanically coated with guest nanoparticles.
Dry particle coating can be applied to a wide variety of situations to improve particle performance.
Material properties which can be improved by dry particle coating include flowability, dispersability, wettability, coloring, flavor/taste, electrostatic, electric, magnetic and optical characteristics, and solid phase reactivity.
With the expected development of an enormous variety of new guest nanoparticles, we believe that dry particle coating can be a successful coating technology for extensively industrial applications.

20. Rotating Fluidized Bed Coater
This newly developed coating device operates on the principle of a rotating fluidized bed.
The host and guest powder mixture are placed into the rotating bed and is fluidized by the radial flow of gas through the porous wall of the cylindrical distributor.
Due to the high rotating speeds, very high centrifugal and shear forces are developed within the fluidized gas-powder system leading to the break-up of the agglomerates of the guest particles.
The very large flow of gas needed to fluidize the particles at high rotating speeds and the motion of bubbles when operating the bed above minimum fluidization conditions creates strong mixing and hence good coating is achieved.
The RFBC also has the capability of being operated in a continuous mode, by feeding guest particles in with the fluidizing gas and operating the RFBC in a vertical position so that host particles can be continuously fed into and removed from the device by gravity

21. Rotating Fluidized Bed Coater

22. Magnetically Assisted Impact Coating
The oscillating magnetic field generated by the coil is used to accelerate and spin the large magnetic particles mixed with the host and guest particles promoting collisions between the particles and with the walls of the vessel.
Since the magnetic particles ‘‘fluidize’’ the host and guest powders, ‘‘soft’’ coating occurs by powder impaction.
Magnetically Assisted Impact Coating (MAIC, pronounced mace), coats particles onto particles by a peening process.
By adding a small coating particle and a large core particle into an assembly of small oscillating magnets, the small particles are readily coated onto the core particles.
Materials that have been used in this process include glasses, pigments, metals, metal oxides, polymers, organic and inorganic powders.

23. Magnetically Assisted Impact Coating

24. Rotating ( Centrifugal ) Fluidized Bed Granulator/Coater
The rotating fluidized bed consists of a chamber and a porous cylindrical air distributor made of stainless sintered mesh.
The horizontal cylinder (air distributor) rotates around its axis of symmetry inside the chamber.
There is a stationary concentric cylindrical metal filter inside the air distributor to retain any elutriated fine powder.
Coating procedure includes following steps:
(1) The powder sample was fed into the cylindrical air distributor (vessel).
(2) The air distributor was rotated and fluidization air was supplied.
(3) Coating liquid was sprayed onto the powder bed.

26. Hybridizer
The hybridizer consists of a very high-speed rotating rotor with six blades, a stator and a powder re-circulation circuit made with ceramic or stainless steel.
The powder (host and guest particles) placed in the processing part of the vessel is subjected to high impaction and dispersion due to the high rotating speed of the rotor.
The particles undergo many collisions, and this allows for break-up of fine agglomerates and powder coating due to the embedding or filming of the guest particles onto the surface of the host particles.  
Very short processing times are required to achieve coating.
The rotor of the hybridizer can rotate anywhere from 5000 rpm to rpm. Due to the strong forces applied to the materials at these high rpm, very short processing times are required to achieve coating.

28. Theta Composer
Slow revolution of outside vessel: Promotion of favourable bulk mixing
High speed rotation of inside rotor: high shear stress required for coating.
Elliptical Shape: Stress & relaxation

29. Mechanisms of the dry particle coating process

30. Hot air coating technique a method to produce microparticles
This technique, called hot air coating (HAC), was developed to overcome the drawbacks of the conventional spray-congealing technique.
Consists of a special venturimeter, deliberately designed to prevent any hindrance along the axial path through which the powder is conveyed.
In HAC technology, the raw material is a solid, generally small granules, which is aspirated through the "Venturi effect" and accelerated in a flux of hot air to soften and then to melt the excipient, especially on the particle surface.
The microparticles then solidify during falling in air at room temperature.

31. References
Michelle Ramlakhan, C.-Y. Wu, Satoru Watano, R.N. Dave, Robert Pfeffer, Dry particle coating using magnetically assisted impaction coatings: modification of surface properties and optimization of system operating parameters, Powder Technology 112 (2000) 137–148.
P. Singh, T.K.S. Solanky, R. Mudryy, R. Pfeffer, R.N. Dave, Estimation of coating time in the magnetically assisted impaction coating process, Powder Technology 121 (2–3) (2001) 159–167.
Nethersole, Douglas C.; Dudley, Michael A.; Parthasarathy, Mellapalayam R.; United States Patent
Powder Coater’s Manual 1/98
www. biophan - nanotechwire_com - the online resource for nano technology and research
www. ventilex.htm
www. caleva.co.uk
www. coating place, inc.htm

32. Thank You