ED 3

Question 1

Define ‘Solutions’

Answer 1

Homogenous liquid preparations containing one or

more dissolved substances

Question 2

What factors should be considered when preparing a solution ?

Answer 2

• Solubility of solid constituents
• Which solvents to use ?
• Temperature
• pH (affects stability of final product)
• Colourings, flavourings and preservatives

Question 3

During preparation of a solution, in what order do you add the soluble ingredients ?

Answer 3

Ascending order (least to most soluble)

Question 4

Define ‘Suspensions’

Answer 4

Preparations where one or more active constituent is suspended in the disperse phase

Question 5

Some formulas may or may not contain suspending agents. TRUE or FALSE

Answer 5

TRUE

Question 6

Why is it important for non-soluble constituents to be re-suspended for long enough ?

Answer 6

Allows patient to measure an accurate dose

Question 7

Give for examples of Suspending agents

Answer 7

1) Tragacanth BP
2) Compound Tragacanth Powder BP
3) Xanthan gum
4) Methylcellulose

Question 8

What is Compound Tragacanth Powder BP made out of ?

Answer 8

• Acacia BP 20%
• Tragacanth BP 15%
• Starch BP 20%
• Sucrose BP 45%

Question 9

About how many %w/v Tragacanth BP is used in suspensions ?

Answer 9

0.2%

Question 10

About how many %w/v Compound Tragacanth Powder BP is used in suspensions ?

Answer 10

2%

Question 11

Compound Tragacanth Powder BP is said to be too sticky for external products. TRUE or FALSE

Answer 11

TRUE

Question 12

About how many %w/v Xanthan gum is used in suspensions ?

Answer 12

2%

Question 13

About how many %w/v Methylcellulose is used in suspensions ?

Answer 13

b/wn 0.5 - 2%

Question 14

Is Xanthan gum highly soluble in hot or cold water ?

Answer 14

Cold water

Question 15

Methylcellulose is a semi-synthetic polysaccharide. TRUE or FALSE

Answer 15

TRUE

Question 16

Name 4 other types of suspending agents

Answer 16

1) Guar gum
2) Sodium alginate
3) Hydromethylcellulose
4) Sodium carboxymethylcellulose

Question 17

How many weeks expiry do ‘Freshly prepared’ solutions and suspensions have ?

Answer 17

Two weeks

Question 18

How many weeks expiry do ‘Recently prepared’ solutions and suspensions have ?

Answer 18

4 weeks

Question 19

When should ‘freshly prepared’ solutions and suspensions be prepared ? (according to BP 2018 recommendations)

Answer 19

‘No more than 24 hrs before it is issued for use’

Question 20

When is deterioration likely to occur for ‘recently prepared’ solns and suspensions ? (According to BP 2018 recommendations) ?

Answer 20

Likely to occur if preparation is stored for longer than 4 weeks at 15 - 25 degrees celcius

Question 21

Define ‘Trituration’

Answer 21

• Incorporation of finely divided insoluble powders or liquids into a base

Question 22

Define ‘Levigation’

Answer 22

• Incorporation of coarse insoluble powders into a base

Question 23

Define ‘Fusion’

Answer 23

• Melting of bases before the addition of other ingredients

Question 24

During ‘Fusion’ process, why does the melting points of ingredients need to be known ?

Answer 24

Because you start with the ingredient with the highest melting point

Question 25

What is the standard expiry for Creams and Ointments

Answer 25

3 months from date of manufacture

Question 26

Why do creams/ointments have a long expiry ?

Answer 26

Because the cream/ointment bases contain

preservatives in their formulae

Question 27

What is the expiry for Diluted creams ?

Answer 27

1 month from date of manufacture

Question 28

Why do diluted creams have shorter expiry ?

Answer 28

Because creams are generally diluted with aqueous

cream and the aqueous environment is more susceptible to bacterial growth

Question 29

Do diluted ointments also have a shorter expiry like that of diluted creams ?. YES or NO

Answer 29

NO