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Validation of
Sterilization Process
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Mr
Sanjay Shah
Unikal Consultants
QUALITY MANAGEMENT
SYSTEM: ISO 9001 & ISO 13485; CE, USFDA 510k,
WHO-GMP & TECHNOLOGY CONSULTANTS |
Validation is a documented procedure for obtaining,
recording, and interpreting the results needed to show
that a process will consistently yield a product
complying with predetermined specifications. This
article includes explanations, definitions and
procedures related to effective validation with
special reference to Ethylene Oxide Sterilization.
PURPOSE
The purpose of the validation of sterilization process
is to provide objective evidence that a process
consistently produces a result that meets
specification. It is performed by
establishing equipment parameters as per required
settings or conditions.
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Definitions
Validation - Objective evidence that a
process consistently produces a result that meets
specification. Performed by setting equipment at different
settings or conditions
Validation protocol - how each individual process
validation will be completed
Validation is a documented procedure for obtaining,
recording, and interpreting the results needed to show
that a process will consistently yield a product complying
with predetermined specifications.
INPUT DOCUMENTS
FMEA, Product specification, Equipment / software
qualifications, Historical validations, Processes,
Component characterization, Process characterization
(Design of Experiments)
REQUIREMENTS
Document controlled processes
Trained operators / assemblers
Calibrated equipment and gauges
Traceable / accepted components
Clearly documented test results
FACTORS TO CONSIDER
FMEA Type
Validation scope
Critical process inputs
Process output and specification
Critical process parameters and ranges
FIRST STEP IN PROCESS
The effectiveness of any sterilization process is
dependent upon the amount of bioburden on the item.
Bioburden is defined as the number of microorganisms on a
contaminated object. Bioburden adversely affects the
sterilization process in four basic ways:
1) Some organisms have hard shells surrounding them
which makes them difficult to penetrate
2) the number of microorganisms may be in excess of
the amount of sterilant required to kill them
3) the amount and type of soil may act as a shield to
protect the organism
4) device may have cracks and crevices in which
microorganisms hide
ETHYLENE OXIDE
EtO gas has been the predominate choice for low
temperature sterilization since the 1960s. EtO has
excellent product penetration and material compatibility.
EtO is an alkylating agent, increases the pH greater than
7, which reacts with the DNA of the microorganism and
destroys the cells’ ability to metabolize or reproduce.
To design an effective validation and routine control
program for a sterilization process, the bioburden on the
product and packaging must be considered.
Bioburden is defined as “the population of viable
microorganisms on a product and/or a package” and is
characterized in terms of number, identity, and
resistance. A validated test method must demonstrate that
it can consistently and adequately remove the bioburden
from the product and packaging.
Microbial death relating to the gaseous sterilization
of healthcare products is an exponential function
typically defined as the probability of a nonsterile item
existing per a given number of units in a batch.
This probability, called the sterility assurance level
(SAL), defines the “probability of a viable microorganism
being present on a product unit after sterilization.”
While sterilization can reduce the bioburden on a given
product to a very low number, that probability can never
be reduced to zero.
Therefore, in order to achieve the desired bioburden
levels, it is critical to design a validation program that
provides a high degree of confidence for consistent
sterilization.
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