Excipients

Question 1

What is the use of saccarin and aspartame in oral formulations?

Answer 1

Sweeteners

Question 2

What is the degradation product of aspartame?

Answer 2

Phenylalanine - so should not be ingested by patients with the condition phenylketonuria (because they don’t have the enzyme that breaks it down)

Question 3

A decrease in the number of OH groups in an organic compound increases its sweetness. True or false?

Answer 3

False - an increase in the number of OH groups

Question 4

Hydrophobic diluents can increase the rate of absorption. True or false?

Answer 4

False - hydrophilic

Question 5

What is the aim of a diluent (filler)?

Answer 5

To increase bulk of a tablet, especially for low dose potent drugs

Question 6

How can a diluent increase the rate of dissolution of a poorly soluble drug?

Answer 6

As the diluent is hydrophilic, particles of it will dissolve in the GI fluid, leaving a porous mass of drug where GI fluids are able to penetrate. This way SA and hence dissolution rate is increased

Question 7

Name a diluent

Answer 7

Mannitol
Lactose 
Sucrose
Glucose
Sorbitol

Question 8

How do disintegrants work?

Answer 8

When they come into contact with intestinal fluids, the absorb liquid and start to swell, dissolve and form gels. This causes the tablet structure to rupture and disintegrate, increasing SA and enhanced dissolution of drug

Question 9

What are the four mechanisms that disintegrants are able to function by?

Answer 9

Wicking
Swelling
Deformation
Repulsion

Question 10

What is the difference between non-ionic and anionic polymer disintegrants?

Answer 10

Non-ionic are natural or physically modified polysaccharides

Anionic are mainly chemically modified cellulose products or low-crosslinked polyacrylates

Question 11

PVP is an anionic polymer disintegrant. True or false?

Answer 11

False - non-ionic

Question 12

Disintegrants don’t have an effect on drug bioavailability. True or false?

Answer 12

False - they are able to regulate bioavailability

Question 13

What do lubricants do?

Answer 13

They reduce the frictional forces between particles and between particles and metal contact surfaces

Question 14

How do boundary lubricants work?

Answer 14

Adhere to solid surfaces to reduce friction

Question 15

How do fluid film lubricants work?

Answer 15

Melt under pressure and create a thin fluid film around particles, but resolidify after pressure is removed

Question 16

How do liquid lubricants work?

Answer 16

They are released from granules under pressure and create a fluid film. They do not resolidify when pressure is removed but are reabsorbed and redistributed through the tablet matrix

Question 17

Lubricants are often hydrophilic and aid dissolution. True or false?

Answer 17

False - hydrophobic and retard liquid penetration into the capsule - so reduce dissolution

Question 18

What is magnesium stearate?

Answer 18

A lubricant

Question 19

What is a binder?

Answer 19

A binder causes agglomeration of powder into granules during mixing with a granulating fluid, by altering inter-particle adhesion

Question 20

Which excipient ensures that tablets can be formed with the required mechanical strength?

Answer 20

Binders

Question 21

Binders can be natural polymers, synthetic polymers or sugars. Name a binder

Answer 21

Sucrose
Starch
PVP

Question 22

Name a chelator and outline its role

Answer 22

EDTA - forms soluble stable complexes with metal ions, removing the ions from solution and so preventing them from reacting with other elements and/or precipitating

Question 23

Chelators are only used in oral formulations. True or false?

Answer 23

False - used in oral, parenteral and topical formulations

Question 24

Name an antioxidant

Answer 24

Sodium sulfate

Question 25

A buffering agent does not contribute charges to the formulation. True or false?

Answer 25

False - contributes charges, this may affect flocculation behaviour and ionisation state of other components

Question 26

Parabens are anti-microbial preservatives used in oral formulations. True or false?

Answer 26

False - used in topical and parenteral formulations

Question 27

Name two anti-microbial preservatives used in oral formulations

Answer 27

sorbic acid

benzoic acid

Question 28

What is benzalkonium chloride and what is it used it?

Answer 28

Anti-microbial preservative - used in eye drops

Question 29

Benzalkonium chloride is an anionic surfactant. True or false?

Answer 29

False - cationic

Question 30

What are viscosity enhancing agents used for?

Answer 30

To ease pouring
Palatability
Slow down rate of sedimentation of dispersed particles

Question 31

An increase in viscosity leads to a decrease in rate of dissolution. True or false?

Answer 31

True

Question 32

Viscosity enhancing agents are used to stabilise disperse systems. True or false?

Answer 32

True

Question 33

Viscosity enhancing agents are colloidal sol particles. True or false?

Answer 33

True

Question 34

Wetting agents are typically surfactants above their critical micelle concentration. True or false?

Answer 34

False - below their cmc

Question 35

What is sodium sulifte and in which preparations is it used?

Answer 35

Antioxidant and high pH

Question 36

What is sodium bisulfite and in which preparations is it used?

Answer 36

Antioxidant used in neutral pH preparations

Question 37

What is sodium metabisulfite and in which preparations is it used?

Answer 37

Antioxidant used in preparations with a low pH