Tablets 2 Flashcards
Granules need to be ___ into tablets of correct weight, hardness and size
compressed
The tablets need to be ___ enough to withstand handling and shipping but must ___ and/or dissolve in a specific time
hard
disintegrate
What are the two kinds of available tablet presses?
- single punch or multi-station rotary press
What is the process of compression?
process of pressing material to make it more firm and solid
The force pattern is complex, but may be considered an ___ force causing compression and a ___ force exerted by the die wall
axial
radial
___ force between granule mass and die wall resists consolidation
Frictional
What are the two main events of tableting? Describe them
- compression (reduction in bulk volume by elimination of air)
- increase in mechanical strength of mass due to particle/particle interactions (consolidation)
- bonds form during consolidation and on decompression some break due to elastic properties of the mass
- if sufficient bonds remain tablet formed
What are almost all tableting problems a result of?
poor granulation
Describe the “binding and sticking” tableting problem
- tablets ejected with difficulty often accompanied by a grunting sound
- inadequate or uneven lubrication of the granules
- granules too dry or too wet
- die dirty or scratched
- worn die
Describe the “picking” tableting problem
granules material sticks to the punk faces leaving the tablet with a pitted surface
- inadequate or uneven lubrication of the granules
- granules under dried
- -scratched or damaged punch face
Describe the “capping” tableting problem
on decompression, top of tablet becomes detached
- worn tooling
- compression speed too fast
- excess fines
- punch fits too tightly into die
- excessive pressure
- insufficient or ineffective binder
- over dried granules
- crystal habit of drug may have changed
What is the uniformity USP 905 test?
may be determined by weight variation if:
- tablets are uncoated
- contain more than 50 mg of active drug and
- if the active component provides more than 50% of the total weight
- otherwise content uniformity testing must be done
- weight variation
- for tablets meeting the criteria, weigh 10 tablets and -calculate the contents of active ingredient in each based on assay results
- -(assume homogenous distribution, all tablets must contain 85-115% of the labeled amount and the relative standard deviation must not exceed 6%)
- of one unit is outside of these limits, a further 20 tablets are weighed
- requirements for test are met if no more than 1 unit out of the 30 is outside the 85-115% range and the RSD of the thirty tested does not exceed 7.8%
- if tablets do not meet criteria, content uniformity done by assay of 10 units individually and proceed as above
What is the disintegration USP <701> ?
- time required for tablet to disintegrate in a specified test fluid at a specified temperature
- limitations in extrapolating to bioavailability so dissolution testing usually required
- USP test consists of an apparatus into which 6 tablets are placed each into a cylindrical tube which is covered at the bottom by a 0.025 square inch wire screen
- tubes are raised and lowered through a distance of 5.3 to 5.7 cm 29-32x per minute
- plastic disks may or may not be required
- disintegration complete when no solid material with a palatable core remains on the mesh
- if 1 or 2 tablets fail, a further 12 tablets are tested
- the conditions of the test are met if no more than 2 tablets of the 18 tablets fail
What is the dissolution USP <711>?
- time required for a tablet to dissolve in a specified test fluid at a specified temperature
- some correlation to bioavailability
- apparatus is of 2 types
- types 1 apparatus consists of a 1000 mL glass vessel, a motor with a shaft and a cylindrical basket made of a metal screen (40 mesh)
- mesh must be stainless steel or gold plated
- type 2 apparatus same except that a paddle is used in place of the basket
- glass vessel is filled with the fluid and held at the specified temperature
- a tablet placed into each of the baskets or into the vessel if the paddle is used
- rotation speed is specified in the monograph and the time required for dissolution is specified in the monograph
- the quantity of drug which must be in solution (Q) within that time period is also specified in the monograph
What is the friability USP <1216>
- used to assess how tablet will withstand handling and general wear and tear
- uses an apparatus with a revolving drum which drops the tablet a specified distance a specified number of times
- tablets (5-20) are weight, places in the apparatus, tested and then reweighed
- weight loss of more than 0.8% is usually the limit
- test is now in the process of becoming an official test