SDF Flashcards
A good tablet must have?
- Accurate dosing
- Stability of the active drug
- Uniformity
- Consistent performance
- Appropriate disintegration & dissolution
- Withstand packaging, transport & handling without breaking
- Mask taste and odour
- Pharmaceutically elegant
Types of tablets?
- Compressed (uncoated) - Advil
- Filmed coated - erythromycin
- Enteric coated - aspirin
- Effervescent - paracetamol
- Sublingual/buccal-buprenorphine/hydrocortisone
What are the types of excipients in a tablet?
- Dilutants
- Lubricants
- Glidants
- Disintegrants
- Binders
Function and example of Dilutants?
Function:
It is a bulking agent, compression and flow aid
Example:
- lactose BP
- microcrystalline cellulose
Function & example of lubricants?
Function:
- Prevent adherence of granules/powders to punch die/faces
- hydrophobic
Example:
Magnesium stearate
What happens if there is a lack of lubricant?
Sticking problems
What happens if there is too much lubricant?
Affects tablet hardness & dissolution
Function & example of Glidants?
Function:
Aids flow
Example:
Colloidal SiO2
Function & example of Disintegrants?
Function:
Causes rapid break up of tablet upon exposure of moisture
Example:
Sodium starch glycolate
Function & example of Binders?
Function:
Act as an adhesive to bind powders/granules
Example:
PVP (polyvinyl pyrrolidone)
How does a tablet disintegrate?
Saliva causes the disintegration agent to swell - creating channels for the saliva
Fast dissolving granules dissolve and the tablet disintegrates
Which route is used for heat & moisture sensitive drugs?
Dry granulation or slugging
Advantages of Dry Granulation?
- Less equipment & space
- No need for binder solution, heavy mixing equipment
- No need for costly and time-consuming drying step (needed for wet granulation)
Slugging is good for:
- Moisture sensitive material
- Heat sensitive material
- Improved disintegration, as powder particles are not bonded together by binder
Disadvantages of Dry Granulation
- Heavy duty tablet press is required to form slug
- Lack of uniform colour distribution
- Press creates more dust than wet granulation, causing contamination
What is the role of Binders in wet granulation?
- Good binder distribution
- Chemical affinity between binder and host
For good binding characteristics: similarity of surface free energy (surface tension) between host and binder
What are the mechanisms involved in Wet granulation?
Pendular state - granules contain 0-14% liquid in pores
Funicular state - granules contain 14-100% liquid in pores
Capillary state - granules may contain 100% liquid in pores
Droplet state- granules contain >100% liquid in pores
Disadvantages of Wet granulation?
- expensive process
- requires a lot of labour, time, equipment, energy and space
- loss of material
- stability concern (for moisture sensitive drugs)
- complex (multiple steps)
Methods for testing the End point of wet granulation?
- hand test
- power consumption
- Mixer Torque Rhinometry
What is the End Point of the MTQR
Funicular/capillary stage
Young’s Modulus?
Reflects how resistant a material is to elongation. The higher the YM, the more force needed to deform the material
What is elastic deformation?
Applying force will cause deformation, removing force will return it to its original state
What is plastic (ductile) deformation?
When force applied it soo high, the material will deform
Tablet formulations required?
Elasticity - low-medium
Plasticity - medium
Brittleness - medium
Steps for roller compression method - dry granulation?
- Feed the material into the hopper of the machine, it if further moved along to the roller system.
- At the roller system, 2 rollers are used to compress the material in a ribbons
- The ribbons will be of a specific size/shape. There is a sieve which only allow the granules to pass through.
Any granules let behind will, the machine will recirculate them back to step 1 and 2.
