Controlling Contamination Flashcards
What are the two types of sources of contamination? Give examples
Non viable : particulates :foreign material e.g. Clothing fibers, skin flackes
Microbial products: toxins, metabolites, pyrogens eg LPS
Viable: bacteria, fungi, viruses
Definition of sterile
And its mathematical characters.
Free from all viable forms of life
Sterilisation proceeds like a first order chemical reaction. A population exposed to sterilisation process decreases exponentially but never reaches zero
What is bioburden?
This is how many bacteria are in the product before sterilisation
What’s SAL and PNSU stands for?
SAL: Sterility assurance level (batch)
PNSU: probability of a non sterile unit (single unit)
What is the minimum required standard for PNSU in most of pharmaceutical products?
= 1 in 10^6
1 in a million
Methods of sterilisation
And conditions/ agents that are used
Moist heat 120C Dry heat 180C Radiation gamma ray Gaseous ethylene oxide or formaldehyde Filtration REMOVES instead of killing bacteria
Which sterilisation process to use depends on… 4 factors
Stability nature of product
Scale of production
Type and level of contamination
Cost
What if process degrades product?
Adapt different sterilisation process
Reformulate product to increase stability
Reduce initial bioburden - shorter time it needs to be sterilised
Whats D value
Is it applicable for heat AND radiation method?
Decimal reduction time: time needed to reduce population by a factor of 10 (1 log, or kill 90%)
Can be used for both heat and radiation
What’s Z value?
Is it applicable for heat AND radiation method?
Increase in temp needed to reduce D value by 10 fold
Used in heat sterilisation only (unit Celsius)
Types of sterilisation…
Destruction (Flaming)
Killing (heat, radiation, gas)
Removal (filtration)- bio pro: insulin
