Granulation Flashcards
Granulation
Powder to granules, to form oral granules tablets and capsules
Four granulating steps
- Fluidised bed granulators
- High speed shear granulators
- Spray driers
- Extrnsion spheronisation
Disadvantages of High speed sheer graulators
- Optimisation
- Check up on size
- Sensitive to raw particle materal
Advantages of High speed sheer granulated
- One step process (Massing/granulator/drying)
- Short processing time
- Less binder than FBG
- Works on highly cohesive granules
Advantages of FBG
- One step process
- Homogenous particles made
- Free flowing particles
Disadvantages of FBG
- Expensive
- Optimisation
Spray driers
- All components are dried into a liquid and go through a hot chamber
Advantages of spray driers
- Rapid process
- One step process
- Heat sensitive process
Disadvantages of spray driers
- Size
- Low thermal efficiency
Exrension spheronisation advantages
- High coperation of drug
- Used for immediate and controlled release dugs
Exrension spheronisation disadvantages
- Labour extensive
Exrension spheronisation - how it works
1) wet mass
2) wet pass compressed via dye
3) Material gets extruded on the other side
4) Puts into the drum and rotation size breaks material down and makes it spherical
Fluidised bed granulator (FBD) - how it works
Spraying granules with binder on the fluidised bed
High speed granulator (HSG) - how it works
Chopper - Breaks down particles
Impeller - Shear and compression
Wet excipients
- Binder
- Lubricant
Dry excipients
- API
- Disintegrant
- Filler
Wet granulation advantages
- Low pressure and energy required
- Less dust and contamination
- Dissolution rate increased for hydrophobic drugs
Wet granulation disadvantages
- Loss of material
- Time consuming
- Requires more material than dry granulator
- Stability of heat and moisture API
Drying problems
Solute migration
Hydrates
Solute migration
Water evaporates stays at the top can affect uniformity and loss off API
-Intergranular migration of colour and binder
Hydartes
Water evaporates from solid , causes crystallisation of solid and in affect causes polymorphism
Drying techniques
1) Convection ( tray drier/ fludized bed(dynamic)
2) Conduction (vacuum oven / vacuum tumbling
3) Radiation (infa /microwave)
Dry granulation advantages
- Ideal for moisture and heat soluble material
- Ideal for heat sensitive material
- Ideal for improved disintegration (no binder)
Dry granulation disadvantages
- Specialised heavy duty machine
- Poor colour and distribution and uniformity
- Creates more dust and increases the potential of contamination
- Can cause polymorphism due to high temperature and pressure
- No binder easier to disintegrate
Point to consider when drying
- Heat sensitivity
- Physical character of the material
- Nature of the liquid to be remove d
- The scale of the operation
- Available heat sources
Two methods for dry granulation compression
1) Large tablet slug via a heavy duty tabletting press (slugging)
2) Powder is squeezed between two counter rotating rollers to produce a continuous sheet or ribbon of materials
Factors affecting slugging
Compressibility or cohesiveness of the material Compression ratio of the powder Destiny of the powder Machine type Punch and die size Slug thickness Speed of compression Pressure used to produce slug
