Tablet Testing Flashcards
What are properties of an ideal tablet?
- should be acceptable to patient
- contain right drug content
- pleasing appearance
- consistent weight, size and shape
- release drug in reproducible and predictable manner
- good chemical, physical and microbiological stability
- suitable packaging
- strong enough to keep shape during manufacture, processing, packaging, shipping and use
- exempt of contaminants
What tests are performed on tablets?
- appearance; devoid of cracks, chipped edges and that colour is uniform
- thickness and diameter; should not exceed 5% of mean thickness
- diameter can vary by 3% for tablets with diameter above 12.5mm and 5% for tablets with diameters less than 12.5mm
- uniformity of weight
- uniformity of content
- hardness and friability
- disintegration
- dissolution
How is uniformity of dosage form measured?
- uniformity of mass
- uncoated, film-coated tablets if API content is over 25mg or contributes to over 25 wt%
- uniformity of content
- all others
What can excessive variation in mass be a result of?
- formulation
- process development
- equipment maintenance
Paracetamol tablets have been made in the following proportion:
- Paracetamol: 21
- Lactose: 37
- HPMC: 8
- Starch: 5
The weight of granules after drying was 80g. Moisture content of the dried granules was 8%.
5% w/w starch and 0.5% w/w magnesium stearate was added.
Calculate the fill weight (mg) to produce tablets containing 500mg paracetamol.
- work out % API
21/71*100 = 29.6% of dry powder mix is paracetamol
- work out w/w addition calculations
4g starch and 0.4g MgSt
- 4g material
- using moisture content, work out how much of granule mass is powder
- 6g of powder
- work out how much of this is API
- 6 x 21/71 = 21.77g
- do amount of API/total tablet mix as a ratio to work out fill weight
- 77g drug/84.4g tablet mix = 0.5g drug/answer
answer = 1938mg
What is wrong with a tablet that is too hard or soft?
too hard = may not disintegrate
too soft = will not sustain further processing, such as coating or shipping
What does friability measure and what is the requirement?
- attrition method measures tendency to chip or fragment
- mass loss should not exceed 1%
How do disintegrants work?
- enabling water entry (wicking)
- swelling
- releasing gaseous material
- effervescent tablets
Describe wicking in comparison to swelling.
wicking
- water uptake depends on
- wettability (surfactants help)
- pore size distribution
- disintegrant addition
- compression forces
swelling
- impact of porosity
- fluid absorbed, disintegrant size increased
What is intergranular and extragranular disintegrant addition?
intergranular - before granulation
extra - after granulation ; 20-50% wt/wt of disintegrant added
Why would there be a slow rate of drug dissolution?
no disintegrant used or conc too low
What are properties of disintegrants?
- small particle size for high SA
- hygroscopic material as water absorption is important
- gas liberating for effervescent tablets
Give exmaples of convential disintegrants and superdisintegrants
conventional
- starch 5-10%
- poorly compressible
- higher amount needed
- wicking low
- microcrystalline cellulose 5-10%
- wicking activity
superdisintegrants
- sodium starch glycolate 2-8%
- free flowing
- rapid swelling
- croscarmelose 1-5%
- rapid swelling
- wicking
- crospovidone 1-5%
- wicking activity high
What is dissolution testing?
determination of drug release rate
What is preformance of tablets disintegration test affected by?
- disintegration media used
- temp during the test
- formulation factors
