Microencapsulation - Part 2
Monday, February 14, 2011 - 15:03
pancoating
- This process is suitable for the microencapsulation of large particles(4).
- the Particle size ranges from 600- 5000 u.
- It is applied for solids.
- This process involves application of coating as solution or atomized spray to the desired solid core material in coating pan.
- Warm air is passed simultaneously over the coated material to remove coating solvent(4).
solvent evaporation
- This process is applicable for solids and liquids.
- the Particle size ranges from 5-5000 u.
Procedure: Firstly Core Material and Coating Material are dissolved into Water immiscible volatile organic solvent ,then core - coating material mixture is dispersed into Liquid manufacturing vehicle phase. After that solvent is evaporated, Solid microcapsules are then formed
- Thickness of the microcapsule coat can be adjusted from less than 1 um to 200 um by changing the amount of coating material from 3 to 30% of total weight.
- the Particle size ranges from 5-5000 u.
Procedure: Firstly Core Material and Coating Material are dissolved into Water immiscible volatile organic solvent ,then core - coating material mixture is dispersed into Liquid manufacturing vehicle phase. After that solvent is evaporated, Solid microcapsules are then formed
- Thickness of the microcapsule coat can be adjusted from less than 1 um to 200 um by changing the amount of coating material from 3 to 30% of total weight.
interfacial polymerisation
- This process involves dispersion of organic phase containing core material into liquid manufacturing vehicle containing monomers, where by the monomer react at a liquid/ liquid interface to form a coating(4).
- A cross- linking agent is added to the continuous phase to affect polymerization at the interface.
- This method suits for low melting point solids or poorly soluble organic liquids.
- This process involves dispersion of organic phase containing core material into liquid manufacturing vehicle containing monomers, where by the monomer react at a liquid/ liquid interface to form a coating(4).
- A cross- linking agent is added to the continuous phase to affect polymerization at the interface.
- This method suits for low melting point solids or poorly soluble organic liquids.
Spray Drying and Spray Congealing:
- spray drying and spray congealing processes are similar, both involves dispersion of core material in a liquid coated substance and spraying or introducing the core- coating mixture into some environmental condition, there by relatively rapid solidification of the coating is affected.
- Spray drying: this method involves dispersion of core material into coating solution (core material must be insoluble in coating solution). Then spraying the mixture as in the form of atomized spray into air stream. The air is usually heated, which provides the latent heat of vaporization required to remove solvent from the coating material, resulting in formation of microencapsulated product(4).
- Spray congealing: General process and conditions are same as spray drying except that core material is dispersed into coating solution melt rather than a coating solution. Microencapsulation is achieved by spraying the hot mixture in a cool air stream.
- Both processes are applicable for solids and liquids.
- the Particle size ranges from 5 to 600 u.
- spray drying and spray congealing processes are similar, both involves dispersion of core material in a liquid coated substance and spraying or introducing the core- coating mixture into some environmental condition, there by relatively rapid solidification of the coating is affected.
- Spray drying: this method involves dispersion of core material into coating solution (core material must be insoluble in coating solution). Then spraying the mixture as in the form of atomized spray into air stream. The air is usually heated, which provides the latent heat of vaporization required to remove solvent from the coating material, resulting in formation of microencapsulated product(4).
- Spray congealing: General process and conditions are same as spray drying except that core material is dispersed into coating solution melt rather than a coating solution. Microencapsulation is achieved by spraying the hot mixture in a cool air stream.
- Both processes are applicable for solids and liquids.
- the Particle size ranges from 5 to 600 u.
Multi orifice- Centrifugal Process:
- This method of producing microcapsule utilises centrifugal forces in order to hurl a core material particle through an enveloping microencapsulation membrane, which results in the formation of microcapsules.
- Coating material which is in molten or solution form passes through coating material inlet tubes to upper and lower grooves, located circumferentially around a cylinder.
- The intermediate grooves have counter sunk, where spaces number of orifices closely & circumferentially surround the cylinder(4).
- The ridges of the coating material grooves, serves as a weir over which the coating material overflows when the volume of upper & lower grooves is exceeded by volume of material pumped into system.
- The coating material which is under centrifugal force imparted by the cylinder rotation flows outwardly along the side of the immediate groove into the counter sunk portion and forms a film across the orifice.
- A counter rotating disk mounted within cylinder, atomizes or disperse the core material, fed through the core material inlet. This rotating disk flings the core material (liquid droplet or solid particles) towards orifices.
- The core material arrives at orifices and encounters the coating material membrane. The impact and centrifugal force, generated by rotating cylinder, hurls the core material through the enveloping coating membrane, which is immediately regenerated by the continually overflowing coating material. The embryonic microcapsules, upon leaving the orifices, are congealed or hardened by a variety of means.
- This method is applicable for solid and liquid core materials.
- the Particle size ranges from 1 to 5000 u(4).
- This method of producing microcapsule utilises centrifugal forces in order to hurl a core material particle through an enveloping microencapsulation membrane, which results in the formation of microcapsules.
- Coating material which is in molten or solution form passes through coating material inlet tubes to upper and lower grooves, located circumferentially around a cylinder.
- The intermediate grooves have counter sunk, where spaces number of orifices closely & circumferentially surround the cylinder(4).
- The ridges of the coating material grooves, serves as a weir over which the coating material overflows when the volume of upper & lower grooves is exceeded by volume of material pumped into system.
- The coating material which is under centrifugal force imparted by the cylinder rotation flows outwardly along the side of the immediate groove into the counter sunk portion and forms a film across the orifice.
- A counter rotating disk mounted within cylinder, atomizes or disperse the core material, fed through the core material inlet. This rotating disk flings the core material (liquid droplet or solid particles) towards orifices.
- The core material arrives at orifices and encounters the coating material membrane. The impact and centrifugal force, generated by rotating cylinder, hurls the core material through the enveloping coating membrane, which is immediately regenerated by the continually overflowing coating material. The embryonic microcapsules, upon leaving the orifices, are congealed or hardened by a variety of means.
- This method is applicable for solid and liquid core materials.
- the Particle size ranges from 1 to 5000 u(4).
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vijay m.pharm bcop
Thu, 02/17/2011 - 09:18
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What are all the variables in
m.sandhyasravya
Fri, 02/18/2011 - 13:23
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hello
m.sandhyasravya http://www.pharmainfo.net/msandhyasravya/biography