D5

Question 1

What are the different types of liquid medicines

Answer 1

Solution
Suspensions
Emulsions

Question 2

Solution

Answer 2

All ingredients are dissolved and therefore present as single molecules within the liquid

Question 3

Suspension

Answer 3

Insoluble solid particles dispersed in the liquid

Question 4

Emulsions

Answer 4

Insoluble liquid droplets dispersed in another liquid

Question 5

What can be a stabiliser

Answer 5

Preservatives
Antioxidants
Buffers

Question 6

What can make medicines more appealing

Answer 6

Sweeteners
Flavours
Colours

Question 7

Things that can be specific to a certain type

Answer 7

Solubility enhancers
Thickening agents
Emulsifying agents

Question 8

What can the vehicle ( the main liquid ingredient) be

Answer 8

Water : must be purified and meet the bp quality / water for injection should be sterile and particle free
Thick sweet liquids : palatable and easier to pour
Other liquids like alcohol and ethers are mainly for external use

Question 9

Why do we need to use stabilisers ( preservatives)

Answer 9

To inhibit the growth of micro organisms
For medicines containing water to prevent
1 food poisoning
2 contamination of medicines
3. Micro organism degrading the medicine 

Question 10

Stabilisers ( antioxidants)

Answer 10

They react with dissolved oxygen
They are oxidised more easily than drugs or excipients
Terminate oxidation and free radical reactions

Question 11

Chelating agents

Answer 11

Form complexes with heavy metal ions
Reduce there ability to catalyse oxidation reaction

Question 12

Buffers

Answer 12

Control the ph of medicines

Question 13

How do buffers work

Answer 13

They are mixtures of a weak acid and it’s salt or a weak base and it’s salt
Most effective in ph values of +/- 1 of their Pka

Question 14

Common sweeteners

Answer 14

Sugars
Glycerol
Sugar alcohols
Artificial sweeteners

Question 15

Why do we use flavouring

Answer 15

To taste mask the drugs
Can be natural , natural identical or artificial

Question 16

Issues with colours

Answer 16

Not essential
Many undesirable effects of synthetic colours ( gradually withdrawn from food and medicines in the EU)
Natural colours are safer but they are
Less chemically stable
Mught cause food allergy

Question 17

What are solubility inhancers

Answer 17

Help solubilising the drugs

Question 18

What are suspensions

Answer 18

Liquid medicines in which insoluble solids (drug usually) are dispersed as fine particles

Question 19

What are the issues with suspensions

Answer 19

The have poor physical stability
Can separate
Caking ( particles bound together and difficult to separate)
Some bits can have low drug content (ineffective)
Some bits will have high drug content which can cause overdose

Question 20

How can we prevent separation and caking

Answer 20

Shake the medicine
Decrease size of particles suspended by grinding and sieving
Increase the thickness of the vehicle
Flocculate ( adjust surface charge)
Improve the wetting of suspended particles (add a surfactant)

Question 21

Thickening agents

Answer 21

Increase the thickness of vehicle and slow down the fall of the suspended particles
Can be used to increase the residence retime of external medicines at sight of action ( ex; eye drops )