Tablets 2 Flashcards

1
Q

Granules need to be ___ into tablets of correct weight, hardness and size

A

compressed

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2
Q

The tablets need to be ___ enough to withstand handling and shipping but must ___ and/or dissolve in a specific time

A

hard

disintegrate

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3
Q

What are the two kinds of available tablet presses?

A
  • single punch or multi-station rotary press
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4
Q

What is the process of compression?

A

process of pressing material to make it more firm and solid

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5
Q

The force pattern is complex, but may be considered an ___ force causing compression and a ___ force exerted by the die wall

A

axial

radial

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6
Q

___ force between granule mass and die wall resists consolidation

A

Frictional

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7
Q

What are the two main events of tableting? Describe them

A
  1. compression (reduction in bulk volume by elimination of air)
  2. 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
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8
Q

What are almost all tableting problems a result of?

A

poor granulation

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9
Q

Describe the “binding and sticking” tableting problem

A
  • 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
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10
Q

Describe the “picking” tableting problem

A

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
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11
Q

Describe the “capping” tableting problem

A

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
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12
Q

What is the uniformity USP 905 test?

A

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
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13
Q

What is the disintegration USP <701> ?

A
  • 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
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14
Q

What is the dissolution USP <711>?

A
  • 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
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15
Q

What is the friability USP <1216>

A
  • 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
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16
Q

What is the hardness test?

A
  • unofficial
  • a compression force when applied diametrically to a tablet just fractures it
  • unites may be kg or kN
  • usually tablet on an anvil and the force is transmitted to it by means of a moving plunger
  • tablet hardness assessed to determine ability of tablet to withstand shocks during handling and shipping
  • also correlates with disintegration and dissolution
17
Q

What is hardness a function of?

A
  • compression force during pressing, particle density and size, tablet shape and components of the formulation
  • established in house and frequently used as an in process assessment of disintegration
  • usual minimum hardness for an uncoated tablet is 5 kg
18
Q

What are the 3 categories of tablet coating?

A
  • sugar coating, film coating and compression coating
19
Q

What are the basic processes used for applying coating (2)?

A
  • pan coating and air suspension coating
20
Q

Wha is the purpose of coating tablets?

A
  • used to mask unpleasant doors and tastes
  • to protect an ingredient from decomposition
  • to improve product elegance
  • can be used to control release rate
21
Q

Describe sugar coating?

A
  • process may take several days - some partly automated systems are faster
  • must have good control of humidity, temperature and dust
  • variety of coating pans used and each must be equipped with hot and cold air inputs
  • tablets core must be an optimal convexity and be quite hard (have to withstand abrasive effect of coating)
    • finished tablet must still have the appropriate disintegration/dissolution properties and USP monographs provide these specific details for testing
22
Q

What are the different processes involved in sugar coating?

A
  • sealing
  • subcoating
  • syruping
  • finishing
  • polishing
23
Q

Tablet cores usually represent ___ by weight of the finished tablet

A

50%

24
Q

Describe film coating

A
  • accomplished by decomposition of one or more film forming polymers on the surface of the tablet
  • usually film represents less than 5% of the finished tablet weight
  • coating can be enteric or non-enteric
25
Q

What are the qualities that film forming material should have?

A
  • soluble in solvent suitable for processes
  • soluble in GI fluids
  • form a strong continuous film which is smooth and elegant
  • stable to heat, light, air, moist and drug in the product
  • have no appreciable taste, odor or color
  • able to support pigment or coating additives
  • non toxic
  • crack resistant (usually by inclusion of additive)
26
Q

What is the differences in coating between an enteric vs a non-enteric coating?

A
  • non- enteric materials- cellulose derivatives

- enteric materials- phthalate esters of cellulose

27
Q

What is used to prevent the film from chipping?

A
  • a plasticizer
28
Q

What are common solvents used in coating?

A
  • alcohols, esters, chlorinated hydrocarbons, acetone, and other ketones
29
Q

What kind of coating can be used to prevent damage to the environment?

A
  • aqueous based
30
Q

Describe compression coating

A
  • core placed in centre of a larger die and surrounded with coating material in the form of free flowing granules which is compressed into a final product
  • incompatible drugs may be formulated this way
  • may also be used for repeat action tablets where the first dose in the coating and a second dose in much slower disintegrating core
  • layered or laminated tablets are also common for these purposes