Formulation of Advanced or Complex Medicines 5

Question 1

What is moist heat disinfection?

Answer 1

Temperature below 100C
- pasteurisation = 63C for 30 mins or 71C for 15 secs
- tyndallisation = intermittent heating

Question 2

What is moist heat sterilisation?

Answer 2

Temperature above 100C
- steaming
- steam under pressure to attain high temperatures
- autoclaving
- ultra-high temperature (UHT)
- 140C for 4 secs

Question 3

What are the three phases to moist heat sterilisation?

Answer 3

Heating up
- articles to be treated are raised to appropriate sterilisation temperature
Holding stage
- sterilisation
Cooling down

Question 4

What is saturated steam?

Answer 4

Steam is holding as much water as possible in the form of transparent vapour

Question 5

What is dry steam?

Answer 5

Does not contain water droplets

Question 6

What percentage of heat energy of steam is released in the form of latent heat when it contacts a cooler surface?

Answer 6

80%

Question 7

How does moist heat sterilisation work?

Answer 7

Denaturation of structural and functional proteins, nucleic acids and lipids
Coagulation of proteins and other components to cause cell death

Question 8

What happens during the heating up and exposure phase of moist heat sterilisation?

Answer 8

Sterilisation stage begins when operating and pressure are obtained e.g. 121C at 15 psig

Question 9

What happens during the drying or cooling phases of moist heat sterilisation?

Answer 9

Dressing packs and other porous loads may become dampened and must be dried before removal from the chamber
Achieved by steam exhaust and application of a vacuum
After drying, atmospheric pressure within the chamber is restored by admission of sterile filtered air

Question 10

What is the design of a moist heat steriliser?

Answer 10

Downward displacement steriliser
High pressure vacuum steriliser

Question 11

What two factors need to be controlled during moist heat sterilisation?

Answer 11

temperature and pressure

Question 12

What is parametric release?

Answer 12

Declaration that a product is sterile, based on records demonstrating that the process parameters were delivered within specified tolerances
Decision to release a load of processed devices is based on the results of physical measurements

Question 13

Do you have to prove a product is sterile?

Answer 13

No - just that the physical parameters have been met

Question 14

How is superheated steam produced?

Answer 14

Results from increase in temperature of dry saturated steam without an increase in pressure, or from reduction of pressure at constant temperature

Question 15

How is wet steam produced?

Answer 15

Results from decrease in temperature of dry saturated steam without decrease in pressure, or from increase of pressure at constant temperature

Question 16

What are the disadvantages of wet steam sterilisation?

Answer 16

Dry products (e.g. dressings) become wetted/soaked preventing good penetration of steam into porous material

Question 17

Why is it important to remove air during moist heat sterilisation?

Answer 17

It impedes the penetration of steam

Question 18

Why is steam purity important during moist heat sterilisation?

Answer 18

Water contaminants can be carried over in steam and deposited onto the products
- toxic effects
- damage

Question 19

What is steam purity determined by?

Answer 19

Quality of the water

Question 20

What cannot be destroyed during moist heat sterilisation?

Answer 20

Bacterial endotoxins

Question 21

What effects can organic contaminants have?

Answer 21

Pyrogens (bacterial toxins) - can induce fever
Amines - toxicity
Particulate materials - discolouration of packaging

Question 22

What effects can inorganic contaminants have?

Answer 22

Toxic metals (e.g. lead, mercury) - cumulative poisons
Calcium/magnesium - hardness deposits
Iron and chlorides - corrosion