Formulation of Advanced or Complex Medicines 16 SODF4

Question 1

Why is lactose used as a diluent in tablets and capsules?

Answer 1

Available in a variety of forms
- crystalline
- amorphous
- spray dried forms used for direct compression

Question 2

Give examples of sugars or sugar alcohols used in tablets and capsules for their taste properties

Answer 2

Sucrose
Glucose
Mannitol
Sorbitol

Used in chewable tablets and lozenges

Question 3

Give examples of starches used as diluent in capsules

Answer 3

Maize
Potato starch
Rice starch

Depends what is easy to grow locally

Question 4

Why are modified starches used in both tablets and capsules?

Answer 4

Pre-gelatinised
- add water and heat to starch
- increase hydrogen sites
- better flow properties
Starch 1500
- physically processed maize starch to improve flow

Question 5

What inorganic molecules are used as diluents in tablets and capsules?

Answer 5

Calcium phosphate
- dicalcium phosphate dihydrate and anhydrous
- non-hygroscopic
- insoluble but hydrophilic
- readily wetted
- tribasic calcium phosphate
Calcium carbonate

Both used as a calcium source in nutraceuticals
- calcium supplement

Question 6

What organic molecules are used as diluents in tablets and capsules?

Answer 6

Cellulose
Microcrystalline cellulose
- produced by acid hydrolysis of alpha-cellulose followed by spray drying
Powdered (microfine) cellulose
- produced by purification followed by size reduction of alpha-cellulose obtained from pulp
Both have good compaction properties
- large change in volume with compression force

Question 7

How can tablets and capsules be made stronger than if they were just made of the active pharmaceutical ingredient and diluent?

Answer 7

Use a binder in the formulation

Question 8

What is the purpose of a binder in tablets and capsules?

Answer 8

To form granules
- either dry or in solution

Adhesive materials that hold the granules together

Question 9

Give two examples of binders used in tablets and capsules

Answer 9

Wet binders
- typically aqueous preparation
- sometimes added to dry mix then wetted during granulation
Dry binders
- materials with good compaction properties added to formulation to improve the compact strength
- e.g. microcrystalline cellulose

Question 10

Give examples of wet binders in tablets and capsules

Answer 10

Povidone
- PVP
- polyvinylpyrrolidone
Cellulose derivatives
- hydroxypropyl methylcellulose
- hypromellose (HPMC)
- hydroxypropylcellulose (HPC)
Gelatine
Maltitol
Maltodextrin
Starch paste
- heat starch suspension above 60C
- wall paper paste
Polyethylene glycol
Water principle solvent
- if cannot be used then replaced with
- ethanol
- isopropanol
- flammable
- venting - no sparks

Question 11

Give examples of dry binders used in tablets and capsules

Answer 11

Materials that deform plastically and fill voids in tablet mass
- microcrystalline cellulose

Question 12

How can the solubility of an active pharmaceutical ingredient be improved so oral dosage forms disintegrate in the GI tract?

Answer 12

Use disintegrants in your formulation

Question 13

What is the function of a disintegrant?

Answer 13

Break tablets apart and disrupt powder plug in capsules

Question 14

Give examples of super-disintegrants

Answer 14

Sodium starch glycolate
- swells extensively
- 10x normal volyme
- usage level 2 - 4%
- need to use much less for same effect
Crospovidone
- recovers shape with little swelling
- wicks water inside tablet
- usage level 2 - 4%
Croscarmellose sodium
- fibre which bends/knots when dry
- swells radially and straightens out when wet
- wicks water inside tablet
- usage level 4 - 6%

Question 15

How can pharmaceutical powder/granule mixes be prevented from sticking to the surfaces of machinery?

Answer 15

Use lubricants in your formulation

Question 16

Why is a lubricant used in tablets and capsules?

Answer 16

Stop materials from adhering to moving metal parts on tabletting and capsule filling machines