Sterilisation

Question 1

How do pathogens harm the patient?

Answer 1

Cause infectious disease

Question 2

How do microbes damage a product?

Answer 2

Degrade API, make dose unpalatable

Question 3

Which routes of administration have the greatest and least infection hazards?

Answer 3

• Parenteral has the greatest risk
• Then cream (skin is sensitive)
• Oral has the least risk - stomach acid kills bacteria

Question 4

Which order is microbe growth?

Answer 4

First order = logarithmic

Question 5

What does CFU stand for?

Answer 5

Colony forming unit = 1 live microbe

Question 6

What is Decimal Reduction Time (D)?

Answer 6

Time taken for a 10x reduction in microbes (i.e. 90% reduction in concentration)

Question 7

What is the sterility assurance level (SAL)?

Answer 7

• Level of sterility required for terminally sterilised products = 10^-6
• Therefore the probability of an item being non-sterile if selected at random should be 1 in 1,000,000

Question 8

How is sterilisation time for an item decided?

Answer 8

Based on decimal kill rate (D) value

Question 9

How is sterility tested?

Answer 9

1. Take a sample from the item (swab, liquid or filtrate)
2. Add to culture medium
3. If no growth after 14 days = non-sterile

Question 10

Define: Sterilsation

Answer 10

Totally killing all microbes on product/item

Question 11

Define: Sanitisation

Answer 11

Cleaning a surface

Question 12

What does a disinfectant do?

Answer 12

Kills microbes on a surface

Question 13

What does an antiseptic do?

Answer 13

Kills microbes on skin/tissue

Question 14

What does a microbicide do?

Answer 14

Kills microbes

Question 15

What does a bacteriostatic drug do?

Answer 15

Stops growth of bacteria

Question 16

List 2 methods by which heat is used as a sterilisation technique?

Answer 16

1. Steam
2. Dry heat

Question 17

List 2 advantages of using heat as a sterilisation technique?

Answer 17

1. Steam is very effective
2. Cheap

Question 18

List disadvantages of using heat as a sterilisation technique?

Answer 18

1. Wets product/dries product out
2. Can damage product

Question 19

What application is there for using filtration as a sterilisation technique?

Answer 19

Solutions for injection

Question 20

List 2 advantages of using filtration as a sterilisation technique

Answer 20

1. Good for liquids/solutions
2. Removes particles

Question 21

List 2 disadvantages of using filtration as a sterilisation technique

Answer 21

1. Only good for solutions
2. Costly

Question 22

What application is there for using chemical sterilisation?

Answer 22

Surfaces and equipment

Question 23

List 2 advantages of chemical sterilisation

Answer 23

1. Cheap
2. Very effective

Question 24

List 2 disadvantages of chemical sterilisation

Answer 24

1. Usually needs to be removed from the product afterwards
2. May damage product

Question 25

List **2 examples** of **irradiation** used for **sterilisation**

Answer 25

1. **Gamma** 2. **UV**

Question 26

List **2 appllications** of where **irradiation** can be used as a **sterilisation technique**

Answer 26

1. **Surfaces** 2. **Packed products**

Question 27

List **2 advantages** of **irradiation** as a **sterilisation technique**

Answer 27

1. **Quick and cheap** 2. **Penetrates packet**

Question 28

List **2 disadvantages** of **irradiation** as a **sterilisation technique**

Answer 28

1. **Surface only** 2. **Safety**

Question 29

What is the **disadvantage** of using **gas** as a **sterilisation technique**?

Answer 29

**Hazardous to workers**

Question 30

What **piece of equipment** is used for **steam sterilisation**?

Answer 30

**Autoclave**

Question 31

What are the **conditions** within the **autoclave**?

Answer 31

* **121°​C** * **High pressure** * **15-30 minutes**

Question 32

How does the **autoclave/steam kill bacteria**?

Answer 32

**Hydrolyses the proteins**

Question 33

What is **dry heat sterilisation** used for?

Answer 33

* Typically for **surgical instruments** * Hot enough to char off some components

Question 34

What are the **conditions** of **dry heat sterilisation**?

Answer 34

* **170°C** * **2 hours**

Question 35

Define: **Terminal sterilisation**

Answer 35

When the **product is sterilised** at the **start and at the end**

Question 36

Define: **Non-terminal sterilisation**

Answer 36

When product is **sterilised throughout** the **manufacturing process**

Question 37

List **3 chemicals** used for **sterilisation** and **how they work**

Answer 37

1. **Phenols** - disrupt membrane and denature proteins 2. **Alcohol** - denature proteins and dissolve membranes 3. **Aldehydes** - crosslinks biomolecules, one of the most effective disinfectants

Question 38

List **4 conditions** which influence the **effectiveness** of **antimicrobial agents**

Answer 38

1. **Type** of micro-organism 2. **Concentration** of micro-organisms 3. **Environmental conditions** (pH, viscosity) 4. **Temperature**

Question 39

Which is **harder to kill** - gram **negative** or gram **positive** bacteria?

Answer 39

**Gram negative**

Question 40

List **2 other processes** that occur during the **production of sterile products**

Answer 40

1. **Aseptic handling** 2. **Quality control and monitoring**