How to Perform a Sterility Test
Failure Investigation
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Sterility test is a mandatory product release
criteria for aseptically – filled products. Sterility test failure of a drug
product/substance is a stressful event, because it will raise concerns about manufacturers control over the process, practices and clean
room environment and finally it will landed up with customer and revenue losses.
All sterility failures in pharmaceuticals should
thoroughly investigated, because inadequately investigated sterility failures
can trigger regulatory action as it is evident from many of the FDA’s warning
letters to the manufacturers.
Investigating a sterility failure is just like
connecting the dots. The first challenge in a sterility
failure investigation is to confirm the reported result is real or false
positive.
As a part of investigation clean room data, such
as differential pressures, microbial monitoring, videos, gowning records,
cleaning records, maintenance records, sterilizer records, etc. are to be verified
to find evidence of contamination. Firms should review all recent
sterilization, depyrogenation, and decontamination cycle re-validations and
compare them to the original qualification experiments performed.
While
performing a sterility failure investigation it is important to find out how
the microbes goes in to the product
rather than merely finding the source of contamination.
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A sterility failure investigation must be
conducted in two phases
1. Laboratory Investigation (Sterility test
&testing environment)
2. Manufacturing Investigation (manufacturing
& filling Process)
In the event of a sterility failure following
activities to be initiated immediately parallel to the investigation program.
Immediate Action
As and when a sterility failure is reported, the
batch in question must immediately be put in quarantine, and a decision must be
taken to set the boundaries of the investigation and identify other batches
which may also be affected. Production activities shall be stopped in the manufacturing and filling
area where the contaminated batch was manufactured until the identification of
root cause and CAPA implementation.
Impact Analysis
Impact analysis is equally important as failure
investigation, because regulatory inspectors pay more attention to the pitfalls
in such assessments. In the event of sterility failure, a detailed impact
analysis to be performed by giving consideration to other batches filled on the
same filling line, filled in the same suite, using the same sterilizers, using
equipment sterilized in the same manner, sharing the same air handling system,
or using the same materials in formulation. A formalized risk assessment to be
initiated to evaluate the impacts of sterility failure in these batches with rationale
and scientific justification, because these are key area of focus in regulatory
inspections. These decisions may need to be reviewed in the light of further
information gained through subsequent investigation.
Investigation Procedure
1. Laboratory Investigation (Sterility test &testing
environment)
· Verify the negative control. If growth observed invalidate test
and repeat the analysis. If negative control does not showing growth proceed
with investigation.
· Carry out identification of the organism. The nature of the
organisms recovered in the sterility test may give some direction to potential
source, but care should be taken to ensure that the investigation remains
sufficiently broad to include all potential sources.
· Verify analyst technique, If possible interview the analyst and
gather the information about his knowledge and technique. Also verify the
results of finger dabs and personnel monitoring of the persons involved in
testing.
· Verify autoclaving record for sterilization accessories used for
the test like glass ware, garments, gloves to confirm that correct load pattern
and sterilization parameters were followed.
· Verify the deviations, which reported during the performance of
sterility test.
· Verify testing environment, be it a UDAF unit or isolator.
If an isolator was used, the leak testing and gassing process
should be reviewed. Validation, maintenance and cleaning status will need to be
confirmed as part of this review.
2. Manufacturing Investigation (manufacturing
& filling Process)
· Review trend analysis of viable and nonviable count in the
critical area immediately adjacent to it.
· Verify if processing batches involved in any deviations.
· Verify the trend of personnel monitoring results to find any
adverse trend.
· Verify if any untoward event occurred during processing &
was not reported earlier.
· Verify if there was any failure of utility, while batch was
being processed.
· Verify if there was any drop in differential pressure during
processing.
· Verify for the manufacturing history of the product or similar
product for any changes for process, personnel and equipment.
· Verify gowning records, cleaning records, maintenance records,
sterilizer records etc. to find evidence of contamination.
· Verify operator’s technique, If possible interview the operator
and gather the information about his knowledge and technique.
· Data from the most recent media fill to be verified. If the
investigation indicates that any interventions may have been the cause,
consideration should be made as to whether the interventions were included and
simulated during the media fill or if there were any concerns when the
intervention was simulated.
· Cleaning & disinfection records pertaining to the filling
room and filling zone to be evaluated. Such review should consider the effectiveness
of cleaning techniques and the expiry time of disinfectants used for cleaning.
· Poor
personnel practice
· Loss of
environmental control
· Flawed
operational design
Based up on the arrived root cause, a media fill study may
required to be performed before resuming
production activities to establish that the clean room is under control.