tableting 1+2 Flashcards
what are tablets?
solid preparations each containing a single dose of one or more active ingredients and obtained by compressing uniform volumes of particles
what is tableting?
Compaction of powder or granules using compressive force
what is the drug dose for a single-dose solid oral dosage form for a conventional tablet?
dose of drug from 0.1 to 1000 mg
what weight can special tablets such as chewing tablets or effervescent tablets be?
up to 2g
what are the two type of tablets?
1-single-solid oral dosage form
2- intermediate for film coating
which of the two tablets can have markings for identification?
single solid oral dosage form
why are some tablets film coated?
for protective reasons- light sensitive, decomposition of drug in stomach acid
what are the types of film coatings?
- enteric coating
- modified release coating
why are tablets popular?
- can be produced from majority of substances
- dry-stability
- cheaper
- high dose content uniformity
- simple and easy admin- good compliance
- easy to pack/store/ transport
- adequate choice of excipients
what are the different types of tablets available?
Conventional tablets Chewable tablets Effervescent tablets Lozenges Sublingual tablets Buccal tablets Controlled release tablets Fast disintigrating tablets Liquisolid tablets Floating tablets
how can tablets be manufactured?
enteric tablet press single punch
single die
one pair punches
2- rotary press
- number of dies
set of punches
- 10,000/ min
what are the 3 stages of tableting?
Die filling -Flow of the powder, by gravity, from the hopper into the die
Tablet formation-Descending of the upper punch to entre the die -Compression of the powder and formation of tablets
Tablet ejection-The lower punch rises and the tablet is removed from the die
what are the 4 steps to produce a tablet on an eccentric tablet press?
- only upper punch compresses
- pressure drop from upper to lower punch due to friction
- per stroke one tablet (or one set for multiple dies)
- simple filling procedure
what is the general principle of the rotary tablet machine?
During compression both punches take part in the powder compaction process
what are the modern machines features?
two filling stations-1/2 tablet rotation per tablet
30-60 dies per tablet
-multiple bore dies for smaller tablet sizes
-up to 1 mil tabs per hour
what are the advantages of MR press-coated tablets prep?
–separation of incompatible drugs–no application of moisture or heat during coating–extended possibilities for manufacture of modified-release preparations–less variability in disintegration, when enteric press coat–machines require less space–less time and energy consumption
what are the advantages of multi-layer tablets?
–easier to produce than press-coated tablets
–separation of incompatible drugs
–manufacture of modified release preparations with various release-rates
what are the disadvantages of multilayer tablets?
–granules/powders should have small particle size distribution
–granule size must not be larger than 0.5×layer thickness
–binder must be the same in all layers
–sparse use of lubricant
what are the typical compositin of tablets?
- active component(s)
- filler/bulking agent
- binder
- disintegrant
- lubricant
- glidant
- wetting agent
- colours and flavours
what is the role of diluents for tableting?
bulking agents- to fill up the volume/mass / to gain a defined tablet size
some act as binder material
what is direct tableting?
diluent and drug must have similar particle size and particle size distribution
what are the requirements of the diluent if there is an insoluble drug>
diluent must be hydrophilic
what are some examples of diluents?
microcrystalline cellulose, lactose monohydrate, dicalciumphosphate dihydrate, pregelatinised starch
what are the role of disintegrates for tableting?
to break up tablets into individual granules/particles at contact with water
act mainly by swelling i.e. volume increase due to uptake of moisture. Examples: cross-linked polyvinyl pyrrolidone, carboxymethylcellulose sodium, sodium starch glycollate(insoluble in water)
how do disintegrants work?
swelling capillary (“wicking”) action i.e. providing pathways for moisture penetration into tablet. Examples: colloidal silicium dioxide, pregelatinise dstarch
what is a lubricant used for?
to reduce friction between powder and tableting tools
what is a glidant used for?
to increase powder flowability
what are typical lubricants?
magnesium stearate, calcium stearate, stearicacid, glyceryl monostearate, hydrogenated cotton seed oil, sodium stearyl fumarate, polyethylene glycol
what are typical glidants?
glidants: colloidal silicium dioxide, Talcum powder, all lubricants
what are examples of anti-sticking agents?
glidants, but not lubricants
what is diametral compression test?
it is the tablets tensile strength
- the way it cracks determines if it passes of fails
what is the chewing action?
stress on mandibular joints must not exceed 30-40 N
What are the threshold values for flexural tensile strength?
1
what is tablet fraibility?
to test mechanical resistance against attrition/abrasion
rotation of tablets in a drum for 4 min (100 revolutions)
why do we test the fraibility of a tablet?
important for transport, packing and film coating
what is the upper limit for film coating?
upper limit for film coating 0.5%
how do we measure disintigration?
break up of tablets at contact with water (37°C), so that all fragments pass a 2 mm aperture sieve
–up and down movement of disintegration basket in water to agitate immersed tablets
what is the max disintegration time for conventional tabs?
15 min
except for coated/ soluble or effervescent tablets
how much of the drug should be dissolved within 45 min of dissolution?
70%
what are the 3 types of tablet deformation?
- elastic deformation
- plastic deformation
- fragmentation
what is elastic material deformation?
elastic deformation (deformation during and recovery of original shape after compression)
what is ductile material deformation?
plastic deformation during compression (permanent change in shape)
what is brittle materials deformation?
deformation and fragmentation during compression (fragments retain their shapes after compression)
how do you know what type of material it is from the compressive strength/tensile strength/
ductile materials are aprox 2
brittle materials are greater than 1
what is the ratio for microcryst. cellulose and lactose monohydrate?
microcryst. Cellulose 6.70
Lactose monohydrate 11.27