Granulation 2 Flashcards
What are the types of wet granulators?
high shear granulator
oscillating granulator
fluid bed granulator
What are the types of melt granulators?
melt granulation
What are the types of dry granulators?
slugging
roller compaction
How does the high shear granulator work?
has five stages
1 - powder mixing (mixed prior to granulation)
= powder is kept inside a stainless steel pan
2 - addition of granulation fluid
= is fed into the closed container via a spray nozzle
3 - wetting of the powder and nucleation
= Z-shaped rotor/motor rotates and mixes the material
= chopper rotates at the bottom of the pan to give uniform granules
4 - growth of granules
5 - granule attrition and breakage
How does the oscillating granulator work?
1 - moist mass is prepared in a mixer
= excipients, drug substance and granulation fluid are put in a mixer
2 - moist mass is added to the granulator
3 - oscillating arm moves up and down while rotating in half circles forcing the wet mass through the sieve screen to form granules
How does the fluid bed granulator work?
1 - powder particles are fluidised in a stream of air
= hot air is supplied from the bottom of the granulator and it carries the powder
2 - granulation fluid is sprayed from a nozzle onto the bed of powders
= particles become wet and sticky forming granules as they adhere together
3 - exhaust filter prevents the escape of fine particle
= minimises loss of material and prevents inhalation by operators
What is the purpose of extrusion/spheronisation? What are the steps?
purpose is to produce spherical particles with uniform size
1 - dry mixing
2 - wet massing
How do extrusion and spheronisation work?
extrusion
- wet mass is added to the hopper and forced though the dies to form a cylindrical shape
= produces extrudates of high density and similar lengths
spheronisation
- long cylindrical rods are changed into spheres via a spheroniser
= friction between particle-particle and particle-equipment results in rounding of the extrudate
then it is dried and screened
How does melt granulation work?
uses hot melt binder = thermosetting material
- hot melt binder is mixed with the other solids and the temperature of the mixture is raised
= the hot melt binder melts and is sprayed with the powder
What are different types of hot melt binder?
hydrophilic
- polyethylene glycol (PEG)
hydrophobic
- hydrophobic wax
= carnauba wax, hydrogenated castor oil
How does slugging work?
uses a conventional tablet machine to produce slugs (extra large tablets)
- has work hardening issues
= are difficult to recompact after being broken down into granules
How does roller compaction work?
two stainless steel cylinders rotate against each other as the powder is fed in
rotation of the rollers compress the powder in sheets and flakes
- sheets can break up into flakes
