Medical Design Briefs - November 2021 - 21

tion is not challenging enough to simulate
a worst-case representation.
Alternatively, some devices could
become over inoculated and create an
impossible challenge. Leveraging an
experienced partner's expertise can
help find the correct balance and save
time by avoiding costly retests.
Compromised Cleaning. After determining
an inoculation method that will
produce a worst-case simulated clinical
device, another parameter to adjust is
the cleaning process variables. Since
cleaning methods are unique to manufacturers
and device type, there is no
one straight answer on what cleaning
parameters to adjust for the validation
or by how much.
To demonstrate a worst-case cleaning
rigorous
method,
simulate the least
cleaning application that could happen
in the clinical setting, such as decreased
washing or
rinsing times, decreased
temperatures, or detergent concentrations.
As teams design or edit the cleaning
instructions, keep in mind that even
when adjusting multiple variables to
challenge the cleaning process, the
device must still meet the cleaning endpoint
acceptance criteria.
Measuring Residual Analytes. Testing
laboratories must identify the relevant
analytes that comprise the artificial soils,
which will be the basis for what they will
measure to prove adequate cleaning of a
device. In the past, log reductions of bacteria
were an ac -
ceptable primary
cleaning endpoint,
but regulatory advancements
have
shifted to
"
more
organically relevant
analytes. These analytes
can include
proteins, hemoglobin,
carbohydrates,
and total organic
carbon (TOC).
In some cases,
supplementing the
two analyte measurements
with bioburden
reduction may
be beneficial; however,
the bioburden
When laboratories go too far
- or not far enough - with
even just one variable, they
may compromise the testing,
cause delays in the validation
process, and prompt questions
during a regulatory
review.
EU MDR and U.S. FDA.
The EU Medical Device
Regulation (MDR) is challenging
the industry to push
the boundaries of evaluating
device safety, leading to more comprehensive
validation expectations than
those that were previously accepted for
reusable devices. This advancement of
regulation means that manufacturers
aiming for product approval under the
new terms, especially legacy products
with possibly dated submission packages,
may need to revalidate and
ensure that their technical files meet
the latest scientific trends. These
trends follow the latest published guidance
and standards from ISO, AAMI,
and U.S. FDA.
Manufacturers must present a successful
cleaning validation accomplished
by testing for at least two clinically
relevant analytes that comprise the
artificial soil along with the visual
inspection. By using scientifically justified
sample sizes, manufacturers can
show repeatability and reproducibility
of the process.
The worst-case
experimental design must
closely reflect the clinical
use scenario, so the
validation procedures
apply the soils correctly
to the proper locations in
relevant quantities.
"
reduction data can no longer be a primary
cleaning measurement. Finding
the correct balance between the artificial
soil, its application, and the cleaning
procedures is an intricate process.
Medical Design Briefs, November 2021
Cov
ToC
Embracing the
Best-Case
Scenario
Developing or re -
fining reprocessing
instructions can be
a big undertaking,
but those who recognize
the potential
difficulties that
may be ahead and
work with competent
partners when
validation is on the
horizon are less likely
to have unanticipated
testing outcomes.
Many testing
partners are willing
to engage in the development phase
and leverage feasibility testing to stay
ahead of risks. It is essential to keep
timelines on track by identifying
opportunities to strengthen the reprowww.medicaldesignbriefs.com
"
It
is a manufacturer's
responsibility to ensure that the
reprocessing instructions for reusable
devices are clear, comprehensive,
and effective.
"
cessing instruction before final reprocessing
validation.
Creating a safe, effective medical
device is an increasingly extensive
process. Proactively staying up to date
with guidance, validation principles,
and regulatory environment requires a
keen eye across the entire design verification
and validation process.
Companies can maintain productivity
in their projects through awareness
of testing risks, partnerships with testing
experts and compliance with the
latest scientific, industry and regulatory
expectations. For further details on
how to keep up with other new development
procedures, read the article " New
Regu lations, New Timelines: How
Chemistry Changed in Response to ISO
10993-18:2020, " in the January 2021
issue of MDB.3
References
1. FDA. (March 2015). " Reprocessing
Medical Devices in Health Care Settings:
Validation Methods and Labeling,
Guidance for Industry and Food and
Drug Administration Staff. " Guidance
document, https://www.fda.gov/
regulatory-information/search-fdaguidance-documents/reprocessingmedical-devices-health-care-settingsvalidation-methods-and-labeling
2.
AAMI, (August 10, 2011). " A Compendium
of Processes, Materials, Test
Methods, and Acceptance Criteria for
Cleaning Reusable Medical Devices,
Association of the Advancement of
Medical Instrumentation, " https://
webstore.ansi.org/standards/aami/
aamitir302011r2016
3. S. Schaible, " New Regulations, New
Timelines: How Chemistry Changed
in Response to ISO 10993-18:2020, "
Medical Design Briefs, 2021: 09-10, Vol. 11,
No. 1, January 2021, https://www.
medicaldesignbriefs.com/component/
content/article/mdb/features/articles/
38319
This article was written by Dan Fowler,
Principal Scientist at WuXi AppTec Medical
Device Testing, St. Paul, MN. For more
information, visit http://info.hotims.com/
79419-341.
21

https://www.fda.gov/regulatory-information/search-fda-guidance-documents/reprocessing-medical-devices-health-care-settings-validation-methods-and-labeling https://webstore.ansi.org/standards/aami/aamitir302011r2016 https://www.medicaldesignbriefs.com/component/content/article/mdb/features/articles/38319 http://info.hotims.com/79419-341 http://www.medicaldesignbriefs.com

Medical Design Briefs - November 2021

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