Vaporized Hydrogen Peroxide For Medical Device
Sterilization
Vaporized hydrogen peroxide (VHP)
is the latest medical device sterilization
alternative to ethylene oxide (EtO) as the
industry seeks to limit potential harm from EtO
and increase total sterilization capacity.
A molecular model of hydrogen
peroxide (H2O2) [Illustration by petrroudny via Adobe
Stock]
Vaporized hydrogen peroxide (also
referred to as VH2O2 ) is the
FDA’s newest addition to its list of Established
Category A sterilization methods for medical devices.
Other Category A sterilization methods include EtO,
dry heat, moist heat and radiation.
Like the aqueous form of hydrogen
peroxide (HO), VHP (also referred to as VHO)
kills infection-causing bacteria, viruses and all
other microbial life by oxidizing amino acids and
proteins.
VHP has a similar effectiveness as
EtO, which is the most commonly used method for
medical device sterilization. Like EtO, VHP can
permeate many materials used for medical devices and
packaging without causing damage or leaving harmful
residue. And VHP can similarly be used to sterilize
medical devices in bulk.
But unlike EtO, VHP is not
flammable or explosive and is not considered by the
EPA to be a cancer risk when inhaled. VHP also
sterilizes at lower temperatures than EtO, which
reduces the risk of heat damage to device components
or materials.
Which medical devices can be
sterilized with vaporized hydrogen peroxide?
VHP is an effective sterilization
alternative to EtO for many medical devices, including
single-use and reusable surgical instruments,
endoscopes, implants and devices with electronics,
temperature-sensitive devices, combination delivery
devices, single-packaged complex devices, and complete
assemblies or devices with loose components.
VHP can also be used for
pharmaceutical sterilization, including containers,
pre-filled syringes and other parenteral drug delivery
systems.
VHP is “a safe and effective
alternative” to EtO sterilization, Stryker’s
Sustainability Solutions division said in a 2021
white paper as the world’s largest orthopedic
developer explained its migration from EtO to VHP.
That Stryker white paper - authored by Sterilization &
Microbiology Global Director Erick Gustin - explored
VHP’s use for medical device sterilization, covering
efficacy, temperature, processing cycles, emissions
and materials compatibility.
“Vaporized hydrogen peroxide
provides a safe alternate to ethylene oxide
sterilization of medical devices when specific
limitations of the technology are appropriately
addressed during process development,” Gustin wrote.
Vaporized hydrogen peroxide
sterilization processing
VHP can permeate most materials -
including seams, joints and plastic membranes - and is
an effective sterilant at low concentrations.
“Following established ISO guidelines, the VHP process
shows consistent repeatability and reproducibility for
medical device sterilization,” Gustin wrote.
VHP can sterilize at lower
temperatures than heat sterilization or EtO, with
typical processing cycles in the range of 75-100°F,
Gustin said. He reported efficient VHP sterilization
at temperatures as low as 39°F to minimize the risk of
damage to heat-sensitive materials.
Like EtO, VHP is applied in a
vacuum chamber, but VHP has relatively short
sterilization cycles, with less or no need for
extended product residual outgassing like EtO. VHP
also has low toxicity. Water and oxygen are the
byproducts of VHP sterilization, eliminating the toxic
emission risks of EtO. This all yields faster turn
times and increased chamber availability to maximize
sterilization throughput.
Vaporized hydrogen peroxide
materials compatibility
Medtech industry testing has found
VHP is compatible with most materials used to make
medical devices, including a wide range of metals
(such as stainless steel, aluminum, and titanium),
plastics (including polycarbonate, polyethylene and
polypropylene), silicones, glass, adhesives and
electronics. However, VHP may react with certain
uncoated reactive metals like copper and brass,
causing material degradation and/or discoloration.
“During design and development of
VHP sterile processing cycles, devices are inspected
both from a cosmetic and functional aspect post
exposure,” Gustin wrote. “Any materials or devices
that are found to not pass stringent requirements for
functionality and cosmetic appearance are not adopted
into the
VHP processing cycles.”
Another notable exception for VHP
materials compatibility is cellulosic material like
the paper or cardboard that’s commonly used in medical
device packaging and shipping. That’s a big
disadvantage compared to EtO, which can be used to
sterilize pallets worth of devices in cardboard
packaging because the gas permeates the packaging to
sterilize the contents within.
“Stryker’s Sustainability Solutions
division addresses this limitation by processing
devices only in their primary sterile barrier that is
VHP compatible and composed of non-cellulosic
materials (Tyvek, Mylar, various plastic polymers),”
Gustin wrote. “Following VHP processing, products are
packaged in secondary and shipping containers for
distribution.”
Stryker also warned of adsorption
and condensation difficulties with long lumen devices
and densely packed exposure loads.
“Poor cycle development which does
not consider potential dew point changes, gas
concentration and saturation levels and exposure
environment temperature will exhibit these processing
non-conformances,” Gustin wrote. “Stryker
Sterilization Engineers account for these conditions
and parameters during the developmental process of a
VHP cycle. Devices are seeded with appropriate
biological challenges to challenge the process and
achieve the desired sterility assurance levels to
avoid these anomalies.”
https://www.medicaldesignandoutsourcing.com/vaporizedhydrogen-peroxide-vhp-sterilization-medical-devices/. |