Tabletting technologies Flashcards
What are some disadvantages of tablets?
manufacture requires a series of unit processes – product loss at each stage, drug absorption is dependent on gastric emptying rate, compression difficulties due to powder physical properties
What is the definition of excipient?
an inert substance that is used as a diluent or vehicle for preparing a drug product
What are some advantages of tablets?
Improves patient compliance
- Convenient and safe way of administration
- Easy to carry multiple doses
- Accurate and reproducible doses
- Aesthetically pleasing
- Easy to store and dispense
- Solid dosage forms have better chemical and physical stability
- Ease of low cost mass production
- Possible to modify release and performance characteristics
- Possible to mask unpleasant taste and appearance
- Different tablet forms available
What is the minimum and maximum tablet weight?
< 800 mg max
50mg min
High dose tablets require a filler. True or false?
false
low dose - <5mg tablets
The filler used in tablets should be hygroscopic, True or false?
false, non-hygroscopic as you don’t want it to absorb water as they make bulk of tablet
Why is a filler needed in a low dose tablet?
For ease of manufacturing and handling
What is the need for a disintegrant in a tablet?
to ensure the tablet breaks up into smaller fragments (it’s primary particles)
What is the role of a binder in a tablet?
added to ensure that the tablet can be formed with the required mechanical strength
What is the role of a glidant in a tablet
to improve flowability of the powder – either for direct compaction of for granulation
What is the role of a lubricant in a tablet?
to ensure that tablet formation and ejection can occur with low friction between the tablet and the die
Why would you want to minimise the amount of lubricant in a tablet, although it helps with tablet formulation?
because they are usually lipophilic and so will hinder the dissolution and disintegration of the tablet if too much is used
What is the role of an antiadherent in tablet?
to reduce the adhesion between the powder and the punches which could otherwise lead to uneven tablet surface
What is tensile strength used to measure?
Adhesive/cohesive properties
What is meant by tensile strength?
how easy it is to introduce a breakage in the tablet
What does a high angle of repose indicate?
High cohesive forces
When the angle of inclination is greater than the frictional force, does the powder slide or stop sliding?
Slide
How can powder flow be improved?
increase the particle size eg by granulation, alter surface forces – controlled temp, humidity etc. Formulation additives eg glidants, lubricants, change process conditions – vibration assisted hoppers, force feeders
What is granulation?
primary powder particles are made to adhere to form larger multi-particle entities called granules
Why use granulation?
granules flow better than powder, prevent segregation of ingredients, improve compaction, ease of transport as they are less dense than powder and so occupy less vol/unit weight
What is the mechanism of granulation?
3 steps
Nucleation, transition (nuclei growth), granule growth
Wet granulation is suitable for temperature and moisture sensitive material. True or false?
False
Dry granulation is
What are some advantages of dry granulation?
Economical - less energy costs, low equipment costs, easy to scale up
Bulk density affects die filling. True or false?
True
How many tablets should be tested for uniformity of content?
More than 5 to be representative
What are the accepted % limit for API in uniformity of content test?
90-110%
There is a direct correlation between uniformity of content and tablet weight. True or false?
True
In tablet weight testing, no more than 2 tablets should have a mass difference of more than 20%. True or false?
10%
What happens to a tablet that is ingested but doesn’t disintegrate in the body?
Excreted
How many tablets need to fail the disintegration test for it to be repeated on a second full batch?
2 tablets
What is the definition of dissolution?
the transfer of molecules or ions from the solid state into solution
If a reaction is exothermic, will dissolution be favoured by an increase in temperature?
No