sterilisation Flashcards
There are two general approaches to produce sterile products. what are they?
- produce under clean conditions then terminally sterilise in the final container
(limit the no. of MO’s during the manufacturing process - best way) - produce and assemble under conditions free of MO’s and other particulates. (ASEPTIC)
Why is Aseptic processing the best way to produce a sterile product?
you are sterilising a product in one container and only using one container.
Which type of material out of synthetic and natural have a greater microbial count?
Natural
Synthetic have a low count - usually MO’s on synthetic materials are derived from the manufacturing process (the machines they are put under.)
Does the population count and type of MO’s present depend on the natural product itself?
YES
what are the three factors associated with the manufacturing process that can cause MO’s to appear on a product?
raw materials, water and the manufacturing environment
what does the manufacturing environment include?
AIR (spores and endospores)
PERSONNEL (ourselves, we carry a host of MO’s)
EQUIPMENT AND FACILITIES (moving parts)
What are the sources of MO’s?
organisms can either be resident or transient
Give examples of where resident organisms come from
soil (gram+, endospore forming, fungi)
water (gram-, yeasts and moulds)
Animals and humans (gram-, obligate anaerobes, gram+)
Plants (yeasts and moulds)
Give examples of where transient organisms come from
they are carried by water and air.
they are harder to control
may already packaged up with the product inside
what does sterile mean?
free of viable micro-organisms; ZERO MO’s present
There are different sterilisation methods: killing or removal of all viable MO’s
KILLING: heating - dry heat and moist heat chemical - EtO radiation - gamma REMOVAL: filtration (sieves the cells out, doesn't damage them)
AN antibiotic solution will be placed in a vial with a stopper - how are these three components sterilised?
solution: filter
vial: steam sterilisation
stopper: EtO sterilisation
then bring the 3 components into the clean room to be assembled together to form a packaged sterile product
Is water destroyed by high temperatures?
NO
What are sterilisation standards used for?
- to control the number of M/O’s in the manufacturing environment
- to validate the sterilising agent
- to validate the sterilisation process
- to monitor the sterilisation process
who are the sterilisation standards regulated by? Are they consistent across all countries?
European Networks
FDA
no, they can differ between continents/countries, therefore, if a drug wants to be sold in America BUT was created and tested against the sterilisation standards in England, it needs to be repeated in America, against their standards before being sold.
Inactivation kinetics summary (4 points)
- first order kinetics
- affected by temperature
- infinite probability of survival
- organism specific
Why is bioburden estimation important?
inital number required to specify sterilisation parameters - to know what the pop. count is or what the pop. looks like in order to kill them
What is the bioburden estimation?
A population of viable micro-organisms on or in a product and/or packaging - the packaging is part of the overall product
At what stage would you conduct indirect treatment to the product?
after transfer to the test laboratory
What does indirect treatment include to estimate the bioburden on a product?
- contact with eluent
- physical treatment
- Then transfer to culture medium
In which cases would you use indirect treatment?
a multi-component product: indirect route would break the product apart
what do you have to be sure to do before using an eluent on a product?
look in the pharmacopoeia to see if the eluent you are using does not affect the vialbility of the cells you are handling
What are the physical treatment measures you can undergo on your product to extract the MO’s?
after using a eluent
add a mild detergent to identify them and help remove them from the surface
treat them with a swab/ultrasound - need to consider frequency
extract via glass beads - shake the product with the glass beads, the smaller the size of the beads the better.
What is the direct technique of estimating the bioburden count?
direct transfer to culture medium (also need to consider which culture medium will be used, as there are so many different types.)
selection of a removal technique considerations (indirect method)
- ability to remove microbial contamination
- effect of removal method on microbial viability
- types and location of MO’s present on product
- nature of product
culture conditions (in which the MO’s will be in contact with after)
is there a universal growth medium?
NO
the type of MO’s likely to be encountered upon depend on what?
the nature of the product
method of manufacture
potential sources of microbial contamination (operator, packaging)
what are the stages involved in bioburden estimation?
sample selection collection of items for test transfer to test lab treatment (if required) transfer to culture medium incubation enumeration and characterisation interpretation of data
process operation - what are the three factors involved in this?
- cycle development
- cycle validation
- cycle monitoring
what is the definition of process validation?
high degree of assurance provided for a specific process consistently producing a sterile product every time (the process meets its pre-determined specifications)
performance qualification can be assessed in two different ways - what are these?
physical qualification
micro-biological qualification
are physical or micro-biological measures more reliable in assessing performance qualification?
physical measures, they can be measured/monitored e.g. the amount of radiation the product is being exposed to
microbiological measures are open to change. biological indicators are used to often validate physical qualification
Are physical and microbiological qualification methods, means of assessing the physical validation of a sterilisation process?
YES
what is the definition of biological indicators?
An inoculated carrier contained within its primary pack ready for use and providing a defined resistance to the specified sterilisation process
what does it mean if the sterilisation process can kill endospores?
the sterilisation process is good
when are biological indicators used?
used for validation of steam, dry heat, radiation EtO. only used routinely to monitor EtO.
What is the sterility assurance level?
10-6. this is used when using BI’s as a means of measure for performance validation. if the process can reduce the no.i of BI’s to this level or more then it is good.
What factors govern the choice of BI’s used?
stability
resistance (high in comparison to product bioburden.)
non-pathogenic (endospores should be non-pathogenic)
recoverability
What are the recommended BI’s to be used for the different sterilisation processes, to assess whether they meet the sterility assurance level at least?
Filtration - Brevundimonas Diminuta Moist - Bacillus Stearothermophilus Dry - Bacillus Subtilus EtO - Bacillus Subtilus Radiation - Bacillus pumilus
When is the choice of sterilisation method made?
often at the design/developmental stage of the process
Which is better - terminally sterilising the product in the final container or aseptic processing?
terminally sterilisation (product in its container with its label) - but this is not always possible, in which case you would use aseptic processing!
What are factors of the sterilisation method that should be followed?
shouldn’t leave any toxic residues;
agent should be in contact with all parts of the product
process variables are controlled and monitored
process does not present hazards to the operators or the environment
