Manufacture & Testing of Tablets (M2)

Question 1

List 3 reasons why Tablets are so successful

Answer 1

1) They provide accurate dosage (Patient doesn’t measure)
2) They can control the release of drugs
3) They are easy to identify
4) Easy to transport and store
5) They are economical to produce
6) They are stable (do not need to be kept at certain temps)
7) Diversity of use (simple and effervescent forms)

Question 2

How does a sublingual tablet effectively transport the drug into the blood stream?
Does this favour lipophilic or hydrophilic drugs?

Answer 2

• The drug is placed under the tongue and rapidly absorbed into the veins found there
• Useful option for lipophilic drugs with a low molecular weight

Question 3

What are the different types of tablets you can put in your mouth?

Really quickly their main benefit

Answer 3

• Sublingual (fast acting)
• Buccal (dissolve slowly, slow release drugs)
• Chewable (breaks down tablet, large SA, fast acting)
• Lozenges (slowly dissolve, only small amount is released, localised effect)

Question 4

What is a multilayer tablet?

Answer 4

• Either a multi-layered tablet prepared by multiple compression
• Or a tablet core within a tablet shell, each containing a different API

Question 5

Why is it important that the API (active pharma ingredient) and excipient particles are the same before mixing?

Answer 5

• Differences in particle sizes causes segregation and mixing problems
• We want to API to be perfectly uniformly distributed in the excipient powder

Question 6

What is a diluent?

Answer 6

• Diluent is filler (dilutes the API), it is an inert ingredient in the tablet and the main excipient

Question 7

What are some basic requirements of the diluent

Answer 7

• Cheap (as we need a lot of it)
• Compressible into a strong tablet (be non-friable)
• Have good flow properties for mixing
• Rapidly disintegrate (digestion or in water)
• Stable (not go off) and inert
• Taste acceptable
• reasonably soluble

Question 8

What is the purpose of a granulating agent?

Answer 8

• A liquid solvent that is added to the diluent + API powder to cause it to stick together and form granules

Question 9

Name a few granulating agents

Answer 9

• Water, ethanol, isopropanol

Question 10

What is the purpose of a binding agent

Answer 10

• A binding agent is dissolved into the granulating agent
• When the granules are dried (granulating agent evaporated), the binding agents continue to hold the granules together

Question 11

What are the consequences of too much or too little binding agent?

Answer 11

• Too much: hard tablets that take too long to disintegrate
• Too little: Weak tablets that are friable and fall apart during the following process

Question 12

How are wet granules dired?

Answer 12

• baking in an oven
• or using a fluidised bed drier

Question 13

What are glidants and when are they added?

Answer 13

• Glidants are added to the dry granules
• Glidants are small particles that fill the tiny cracks in the granules making them smoother, improving friction and flow properties

Question 14

What are 2 glidants commonly used?

Answer 14

• Colloidal silica
• Talc

Question 15

What is the purpose of lubricants and when are they added?

Answer 15

• Added to the dry granules
• To prevent granules sticking to equipment (die wall and punch surface)
• Prevents a pitted appearance (a fault known as picking)

Question 16

What are some limitations of adding lubricants to stop granule sticking to machinery?

Answer 16

• Lubricants are hydrophobic and inhibit tablet disintegration in the GI tract
• can make tablets weaker

Question 17

What is the purpose of a disintegrant?

Answer 17

Allows the tablet to disintegrate/break up in the body

Question 17

There are 3 mechanisms by which disintegrants promote break down, what are they?

Answer 17

1) Swelling on contact with moisture, breaking apart the tablet
2) React with moisture with effervescence
3) Act as a Wetting or wicking agent (allow water to easily penetrate the tablet, to speed up)

Question 18

When are disintegrants added to the powder during tablet making?

Answer 18

• Half before granulation (help deaggregation of granules)
• Half after granulation (help disintegration of tablet into granules)

Question 19

When are colours and flavours added

Answer 19

Flavours: During the granulation stage

Colours: during powder blending, with the granulating agent (in aqueous form) or as a coating

Question 20

Recap the ingredients in a tablet

Answer 20

• API
• Diluent
• Adsorbent (only for liquid API)
• Granulating agent
• Binding agent
• Glidant
• Lubricant
• Disintegrant
• Colours and flavours