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3151 - nat > Sterile Products (IC4) > Flashcards

Sterile Products (IC4) Flashcards

1
Q

Definition of Sterility

A

Absence of any viable organisms

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2
Q

What is the Sterility Assurance Level (SAL)? What is the most common SAL?

A

SAL is the probability of one viable microorganism in a certain number of dug products. It is done by neutralising any preservative in the sterile product and testing the amount of bacteria present inside.

most common SAL is 10^-6, which means finding a microbe in one product out of 1 million products

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3
Q

What is the difference between SAL and log reduction?

A

Log reduction is the efficacy of one disinfectant

SAL is the sterility of the entire batch of disinfectants

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4
Q

2 risks of having a high bioburden

A

1) Contamination of viable microorganisms
2) Contamination of pyrogens produced by viable microbes

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5
Q

What is the most common pyrogen?

A

Endotoxin, an example of Lipopsaccharides produced by gram (-) bacteria eg. E.coli

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6
Q

3 requirements of a sterile product

A

1) No microorganisms
2) Endotoxin within limits
3) No detectable particles

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7
Q

What are 6 different sterilisation methods?

A

1) Dry heat
2) Moist heat in autoclave
3) Aseptic filtration
4) Gamma irradiation
5) Vapour phase sterilants (Ethylene oxide, Nitrous oxide, H2O2 fog)
6) Lyophilisation

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8
Q

Advantages and Disadvantages of Aseptic filtration

A

Adv: Can check filter integrity, ensure that filter does not rupture
can remove pyrogens

Disadv: Filter must be suitable for filtrate

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9
Q

Advantages and Disadvantages of Gamma irradiation

A

Adv: Containers and packaging can remain intact

Disadv: heat sensitive not suitable

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10
Q

Advantages and Disadvantages of gas sterilants (Ethylene oxide, Nitrous oxide, H2O2)

A

Adv: Less invasive. Suitable for heat sensitive disinfectants

Disadv: May cause contamination

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11
Q

Advantages and Disadvantages of Lyophilisation

A

Adv: Stable, Suitable for liquids

Disadv: Expensive, require sterile diluent

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12
Q

Describe Aseptic Process Simulation

A

Testing for the sterility of the manufacturing process AKA presence of microbes in EVERY step, using a growth medium and usual conditions

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13
Q

Is Aseptic Process Simulation (APS) enough to test the sterility of the product?

A

NO!
APS is not a Quality Assurance method.
QA method: Conducting sterility testing on the final product
We need BOTH QA and Aseptic Process Simulation (APS), cos APS might not be able to lapses during the manufacturing that can contaminate the final product of the disinfectant

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14
Q

Four types of Aseptic Filtration (what is the Acronym)

A

MUNRO
Microfiltration
Ultrafiltration
Nanofiltration
Reverse Osmosis

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15
Q

What do the four types of Aseptic Filtration block?

A

Microfiltration
Block bacteria

Ultrafiltration
Block virus

Nanofiltration
Block multivalent ions

Reverse Osmosis
Block monovalent ions

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16
Q

What can a 0.22 micron sterile filter (used in Aseptic filtration) remove?

A

Bacteria and moulds
Not all virus or mycoplasma (these need additional heat treatment)

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17
Q

What is Lyophilisation

A

Lyophilisation is the process of removing water from a product
1) Freeze the water to ice first
2) Placing the ice in a vacuum. Ice will be converted to vapour.

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18
Q

What are the 3 main steps of Lyophilisation?

A

1) Freezing
2) Sublimation
3) Desorption

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19
Q

When is the endpoint of sublimation

A

When the temperature of the product starts to rise, that’s when there is no more ice

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20
Q

Why does sublimation occur?

A

Cos its in vacuum

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21
Q

(From google) What is Desorption? And what does it produce?

A

Desorption: Removing water that is incorporated into the solid
Water content <1%

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22
Q

What is a product of lyophilisation?

A

Hygroscopic powders used for vaccines

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23
Q

How long should incubation take when testing for Sterility Assurance Level

A

14 days

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24
Q

What is the purpose of the suitability test?

A

To achieve sufficient neutralisation of the perservatives in my disinfectant

Once I know how to neutralise all the preservative in my sterile product, I can then proceed to conduct Sterility Assurance Testing and test the sterility of the rest of my sterile products and determine if my batch fulfils the SAL.

25
Q

How to conduct the Suitability test of the Sterility test?

A

1) Spike ALL samples with known quantities of microbes
2) Compare the Test with the Positive control and Negative Control
Positive control: Sterile product with NO preservatives
Negative control: Sterile product with preservative eg. formaldehyde
Success: Test is as turbid as Positive control → means preservative is neutralised fully!

26
Q

What are the 3 points that the Growth Promotion Test should achieve? (eg. Growth medium should…)

A

1) Growth medium must be able to grow microbe
2) Must be able to grow microbe consistently
3) Must be sterile, not introduce other microbes

27
Q

How do I ensure that my product is sterile and free from endotoxins?

A

1) Do SAL by incubating sterile product in growth medium, detect any microbes inside
2) Do Endotoxin test

28
Q

What is the most common Endotoxin test? What occurs during a positive test?

A

Limulus Amoebocyte Lysate Test
A reaction of lipopolysaccharide with Horseshoe Crab blood produces clotting

29
Q

What is Maximum Valid Dilution (MVD)

A

MVD is used when we dilute the test substance when testing for endotoxins

30
Q

Should I dilute close to the MVD? Why or why not?

A

Dont dilute too much, such that its too close to the MVD. In case we exceed the MVD and dilute too much, the sensitive of the sample will not give a positive result if there are endotoxins.

31
Q

What is the concept of Bioburden / IPC testing?

A

Bioburden testing is testing microbial load before the sterile filtration step
Bioburden cannot exceed 10 CFU/100ml, if not the subsequent sterile filtration step cannot ensure that the final product is sterile.

32
Q

4 components to test for Sterility Assurance Level (SAL)

A

Sterility test (of the final product) + Suitability tests before
1a) Suitability test
1b) Growth promotion test

Endotoxin test
Rabbit pyrogen test
Monocyte activation test
Limulus amoebocyte lysate test
Recombinant Factor C test

Bioburden test (before sterile filtration)

Visible / non visible test

33
Q

What is the similarity and difference between Aseptic Process Simulation (APS) and Bioburden testing?

A

Similarity
Aseptic Process Simulation and Bioburden testing both test product / processes at various points during manufacturing for the presence of microbes

Differences
1) APS tests the manufacturing process (machines, surfaces), Bioburden testing tests the sterile product

2) APS must be aseptic, the process cannot allow any microbial growth.
Bioburden testing allows microbes, up to a certain limit (eg. No More Than 10 CFU/100ml)

34
Q

Purpose of Bioburden testing (2 points)

A

1) Assess the microbial load before sterile filtration step, ensure that the final product will be sterile / any contamination is at acceptable levels. Hence subsequent sterilisation methods can result in a sterile product

2) Can alert if any sterilisation methods prior / upstream have gone wrong eg. filter break

35
Q

How to detect sub-visible to visible particles?

A

1) Light Obscuration Particle Count test
amount of laser blocked or scattered

2) Microscopic Particle Count test

36
Q

4 Examples of Pyrogen tests

A

Rabbit Pyrogen Test
Monocyte Activation test
Limulus Amoebocyte Lysate (LAL) test
Recombinant Factor C

37
Q

What is Gamma radiation used for?
What is not suitable for Gamma radiation?

A

Used for packaging
Not suitable for polyethylene plastic

38
Q

What is ozone used for

A

Drinking water disinfectant

39
Q

What is the MOA of ozone
Downside of ozone

A

Oxygen with a loosely bound oxygen atom, readily available to attach and oxidise other molecules
Short half life 22 mins

40
Q

What is Moist Heat sterilisation

A

Exposure to direct steam contact

41
Q

Four parameters of Moist Heat sterilisation

A

1) High temperature
2) High pressure
3) Steam
4) Time (minimum exposure period)

42
Q

What parameter do we use to compare for Moist Heat sterilisation?

A

D value.
Time taken for one log reduction to occur

43
Q

What is F value?

Pharmacopoeia recommendation: 121 deg for 15 mins.

A

Equivalent time for a given standard

eg. 121 deg for 15 mins.

If I change the temperature (126 deg) for the same time (15 mins), what is the duration I should expose 121 deg for to achieve the same sterilisation?

44
Q

2 Pros and 2 Cons of using Dry heat over Moist heat

A

Pros:
for substances that may be damaged by Moist heat, or impenetrable to moist heat

Can remove pyrogens

Cons: Slower than Moist heat
Less uniform in temperature control

45
Q

2 types of Dry heat sterilisation

A

Static - air
Forced - air

46
Q

What are the methods that can remove pyrogens

A

1) Aseptic filtration
2) Dry heat sterilisation

47
Q

3 types of pyrogens

A

Endotoxin
Lipopolysaccharides from Gram (-) bacteria

Non Endotoxin
Gram (+) bacteria, virus
Yeasts and fungi

Non microbial
Rubber particles
Microscopic plastic particles
Metal compounds

48
Q

3 methods of Chemical Sterilisation

A

H2O2 gas plasma
Ethylene oxide (ETO)
Peracetic acid

49
Q

Conditions for H2O2 gas plasma sterilisation (where, temp and time)

A

Under deep vacuum, 37-44 deg for 75 mins

50
Q

MOA of Ethylene Oxide (ETO)

A

Alkylating agent, attack proteins, nucleic acid and other organic compounds

51
Q

Caution for ETO

A

Flammable and explosive
Carcinogenic
Irritable, can cause eye pain, sore throat, difficulty breathing etc.

52
Q

MOA of peracetic acid

A

highly biocidal oxidising agent
Can work despite organic contaminants

53
Q

Pros and Cons of Dry heat sterilisation

A

Pros: Destroys pyrogens

Cons: Heat sensitivity

54
Q

Pros and Cons of Moist heat sterilisation

A

Pros: Use biological indicator to verify sterilisation
(Biological indicator: worst case bioburden scenario, hardest microbe to kill eg. spores)

Cons: Heat sensitivity

55
Q

Which methods can test both Endotoxins and Non-endotoxin pyrogen?

A

Rabbit pyrogen test
Monocyte activation test

56
Q

Which methods specific to Endotoxins only

A

Recombinant Factor C test
Bacterial endotoxin test

57
Q

What is the theory behind Recombinant Factor C test

A

Recombinant Factor C is a genetically engineered protein found in LAL.
Factor C will react with endotoxin + marker to produce a quantifiable, fluorescent product

58
Q

What are 2 methods for preparing sterile powders

A

1) Sterile recrystalisation
Drug dissolved into solvent, sterilised using 0.22 micron filter. Add anti-solvent to crystalise drug particles and filter, dry

2) Spray drying
Solution is prayed with hot steam of sterile gas (80-100 deg)
Economic, scalable, fast

59
Q

Which methods use which size filter? To sterilise VS To test sterility

A

To sterilise: use 0.22 micron filter
To test sterility: use 0.45 micron filter

3151 - nat (22 decks)

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