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About Using Steam For
Sterilization
The use of steam for sterilization
is fairly widespread; however, steam is seldom used as a
sterilization method by the medical device industry. Most
disposable plastic devices are terminally sterilized by ethylene
oxide (EtO) or radiation. These processes provide low temperatures
that most plastics can tolerate. Steam, however, is the most
commonly used sterilization method in many healthcare facilities.
Despite its use of high
temperatures, steam is a simple and inexpensive sterilization
method with many benefits. It yields little waste (entropy is its
only by-product). It is also efficacious in terms of its ability
to kill microbial organisms.
With the growing complexity of
medical device and drug combinations, it is essential to consider
steam. These combination devices, such as drugs in syringes, drugs
on catheters, and drug-eluting stents, often require steam
sterilization because EtO cannot sterilize liquids and irradiation
breaks down many drug compounds.
Steam sterilization has long been
used in hospitals as well as in the pharmaceutical, aseptic
processing, and food industries. Its simplicity and low capital
cost make it an inexpensive, attractive, and viable sterilization
method. Typical steam sterilization equipment costs less than
one-third as much as an EtO chamber system and controller. It
costs less than one-fourth as much as gamma or E-beam equipment
and facilities.
Sterilization exposure times can
range from as short as 3 minutes at 134°C to as long as 3 hours at
101°–111°C, depending upon the bioburden (see Table I). Hospitals
use steam at 134°C for 3 minutes for flash sterilization in
emergency situations and 121°C for 15 minutes on a routine basis.
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