benetti :( Flashcards by rachel c

What does it mean to have high bioburden?

Higher risk of contamination with viable microorganisms and pyrogens

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3 requirements for sterile product

Without microorganisms
Endotoxins inside limits
No detectable particles

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F concept equation for 121 degC for 15mins (Moist heat autoclave/gravity steriliser)

F0 = 15 x 10^(T-121/10)

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What is a sterilisation method suitable for a product that is heat sensitive and moisture sensitive?

Chemical sterilants (Ethylene oxide, peracetic acid, hydrogen peroxide, ozone, gas plasma)

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Sequence of lyophilisation

Freeze - Vacuum - Sublimation to remove water - Stoppering

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What is the end point for sublimation in lyophilisation process?

When temperature is rising, meaning all water has evaporated.

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Which sterilisation method uses 0.22 micron filter?

Aseptic filtration

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Why does membrane filtration sterility testing use 0.45 micron filter instead of 0.22 micron filter?

0.45 micron filter filters out other component except the bacteria and virus to be tested (if present). Using 0.22micron filter will filter out the microbe that we are trying to detect.

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Factors affecting efficacy of disinfection and sterilisation (7)

Number of microbes
Innate resistance of microorganism
Concentration and potency of disinfectants
Physical and chemical factors
Organic and inorganic matter
Duration of exposure
Biofilms

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How does hard water interfere with disinfection/sterilisation?

Cations present in hard water forms insoluble precipitates with disinfectant/sterilant.

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Examples of alcohol disinfectant (4) and why it makes a good hand sanitiser

Ethanol, propanol, isopropyl alcohol, ethyl alcohol
More viscous and increases contact time (gel form)

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Does aldehydes (formaldehyde, paraformaldehyde, ortho-phthalaldehyde OPA) work from inside out or work from outside in?

Inside out. It alters RNA, DNA and protein synthesis (alkylating agent).

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What does the residue left behind disinfection with chlorine compounds do?

Residue left behind increases contact time of surface to disinfectant and exert more prolonged bactericidal effect.

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What is the main application of peracetic acid?

Low temperature liquid sterilant for medical devices, flexible scopes and hemodialysers and also environmental surface sterilant

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What byproducts does peracetic acid leave behind and its toxicity?

Acetic acid and oxygen. Non toxic.

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What byproducts does peroxygens (e.g hydrogen peroxide) leave behind and its toxicity?

Water and oxygen

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Sporicidal disinfectants

Peroxygens (Hydrogen peroxide)
Peracetic acid
Formaldehyde (high conc.)?

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Should sporicidal activity of chemical be more important for disinfection or sterilisation?

Sterilisation

Metal compound used for disinfection?

Silver

Quaternary ammonium compounds are standard choice of disinfection for ___________

Ordinary environmental sanitation of non critical surfaces (floors, furniture, walls)
+ Clinical purposes (e.g. preoperative disinfection of unbroken skin)

2 Vapour-phase sterilants

Ethylene oxide, formaldehyde

To comply with GMP guidelines, one must rotate with 2 different disinfectants. Why?

To prevent germs from becoming immune to the germicide part.

What is MBC (Minimum Bactericidal Concentration)?

The lowest concentration of an antibacterial agent that causes at least a 3log10 reduction in the number of surviving cells

What is MEC (Minimum Effective Concentration)?

The lowest concentration of active ingredients at which the product is still effective

For suspension test, why is it important to neutralise the sample by diluting it until concentration is below MEC?

To prevent the test substance from functioning, so that results are not falsely positive.

Ideal vaccines should be: (6)

- 100% effective in all age groups - Long-term protection after single application - Should not have side effects - Should be stable in different conditions (heat, light, transport) - Easily accessible and inexpensive - Protect against more than one disease at the same time

How does formaldehyde work as a preservative in vaccines?

Kills or inactivates unwanted germs in vaccines

mRNA is enclosed in what type of particle to help it enter cell cytoplasm?

Lipid nanoparticle

2 disadvantages of mRNA delivery systems

- Needs to be refrigerated (Cold chain logistics) - Sterile filtration not always possible

Levels of QC of vaccine (5)

1. In depth review of registration file by medicines agencies 2. QC testing to adhere to approved specifications 3. GMP inspections before and after approval (every 2-3 years) 4. Pharmacovigilance 5. Additional QC testing by independent laboratory

Which of the following sentences are true regarding sterility testing: a. Turbidity is used as an indicator for microbial growth b. Turbidity is specific for microbial growth only and it cannot be caused by anything else c. Microbes should be identified to the species level d. Biological indicators can be used to validate sterility testing e. Suitability testing is not required for injectables.

a, c, d A and B: Microbial growth is not the only thing that causes turbidity, others include: precipitates, insoluble materials/excipients (these would need to be removed before doing microbial test) If don’t remove these excipients, unable to determine the reason of the turbidity and how the product got contaminated C: important to correctly identify the microbes to species level to find out which process needs to be reevaluated for sterility E: suitability testing always needed because otherwise cannot be sure of sterility test results

If you need to sterilise a liquid formulation in a closed container, why can't chemical sterilants be used?

Have to open the container as chemical sterilant can only work when in contact with formulation, but it will end up being present in the final formulation as a contaminant. Even if product is safe, it will still be considered contaminant and not sterile.

Why steam sterilisation instead of dry heat sterilisation?

Dry heat is less effective, used only when sterilisation by steam is not possible. And takes longer time.

How does steam sterilisation differ from dry heat sterilisation in terms of temperature uniformity?

Steam ensures that every part of the equipment is exposed to the desired temperature, more uniform in temperature.

Which ONE of the following statements CORRECTLY describe the step of neutralization in the testing of disinfectants? a. Neutralization involves introducing the inoculum of the selected strain b. Neutralization involves dilution of the sample prior to the regrowth c. Neutralization involves removal of the test substance

An endoscope turned out not to be sterile after treatment with ethylene oxide; increasing the time of the process seems not effective in correcting the issue. Which ONE of the following steps can be performed to correct the issue? a. Sterilization in dry heat at 120 degrees b. Add a second treatment with ozone c. Add a second treatment with moist heat using ethanol instead of water d. Wash the endoscope with sterile water e. Preliminary treatment with iodine

Ans: b A: High temperature sterilisation may not be suitable for equipment C: Ethanol is flammable → leads to explosion D: Sterile water won’t do anything E: Iodine won’t kill anything and poses potential contamininant

Which disinfectants can be used against MRSA? (best 2)

Chlorine compounds (hypochlorite), Hydrogen peroxide

If turbidity in test sample is comparable to positive control in suitability, it means that __________

Components do not affect microbial growth, and can go ahead with sterility testing

If components are shown to affect microbial growth, what should be done?

Neutralisation of this component

Passing criteria for light obscuration particle count test

Average number of particles present does not exceed 6000 per container equal to or greater than 10micron and does not exceed 600 per container equal to or greater than 25micron

Sterility testing use what growth medium? (2)

Fluid Thioglycollate Medium (FTM) or soybean casein digest medium

Incubation duration and temperature for sterility testing

14 days at 32.5degC and 22.5degC respectively

2 examples of biguanides

Chlorhexidine and Alexidine

When cleaning before disinfection, detergent must not foam. Why?

- Reduce contact of disinfectant with surface (blocked by bubbles) - Leave behind a residue that needs to be removed