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Flashcards in Excipients Deck (37):
1

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

Sweeteners

2

What is the degradation product of aspartame?

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

3

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

False - an increase in the number of OH groups

4

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

False - hydrophilic

5

What is the aim of a diluent (filler)?

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

6

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

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

7

Name a diluent

Mannitol
Lactose
Sucrose
Glucose
Sorbitol

8

How do disintegrants work?

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

9

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

Wicking
Swelling
Deformation
Repulsion

10

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

Non-ionic are natural or physically modified polysaccharides
Anionic are mainly chemically modified cellulose products or low-crosslinked polyacrylates

11

PVP is an anionic polymer disintegrant. True or false?

False - non-ionic

12

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

False - they are able to regulate bioavailability

13

What do lubricants do?

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

14

How do boundary lubricants work?

Adhere to solid surfaces to reduce friction

15

How do fluid film lubricants work?

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

16

How do liquid lubricants work?

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

17

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

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

18

What is magnesium stearate?

A lubricant

19

What is a binder?

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

20

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

Binders

21

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

Sucrose
Starch
PVP

22

Name a chelator and outline its role

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

23

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

False - used in oral, parenteral and topical formulations

24

Name an antioxidant

Sodium sulfate

25

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

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

26

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

False - used in topical and parenteral formulations

27

Name two anti-microbial preservatives used in oral formulations

sorbic acid
benzoic acid

28

What is benzalkonium chloride and what is it used it?

Anti-microbial preservative - used in eye drops

29

Benzalkonium chloride is an anionic surfactant. True or false?

False - cationic

30

What are viscosity enhancing agents used for?

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

31

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

True

32

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

True

33

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

True

34

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

False - below their cmc

35

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

Antioxidant and high pH

36

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

Antioxidant used in neutral pH preparations

37

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

Antioxidant used in preparations with a low pH