various gas used for sterilization and new technology plasma sterilization

1. GASEOUS STERILIENT
AND
PLASMA STERILIZATION
Dr. JOICE . P .
JIJI
PERIO DEPT,

2. Gases used
for
Sterilization
Formaldehyde
Gas
Ethylene
Oxide
Beta
Propiolactone
Ozone
Chlorine
Dioxide
Nitrogen
Oxide

3. FORMALDEHYDE GAS
• Used in Operation Theater, Ward. Lab, Bedding,
Furnitures etc.
• KMNO4 + FORMALIN Heating Formaldehyde Gas
• Sterilization achieved by codensation of gas onexposed
surface
• Broad Spectrum Biocidal Activity
• Gas is toxic and irritant
• Rooms should be sealed and left unopened for 48 hrs

4. • Colorless liquid
• Boiling Point 10.7 Degree celsius
• Highly penetrating Gas
• Sweet Ethereal smell
• Effective against all micro organisms including Spores and
Viruses
• Non corrosive
ETHYLENE OXIDE

5. ETHYLENE OXIDE (contd)
• Used plastic and rubber articles, Respirator, Heart - Lung
machines
• Sutures, Dental equipment and Clothing
• Highly explosive (more than 3% in air)
• Potential toxicity to Human Beings including Mutagenecity and
Carcinogenecity
• Cycle takes more than 14 hrs
• Relatively high annual costs for maintenance and service

6. BETA PROPIOLACTONE
• This is a condensation product of Ketane and Formaldehyde
• Boiling point 168 Degree C
• Rapid action and Broad Spectrum activity
• More efficient than formaldehyde
• Also used for inactivation of vaccines
• Low Penetrating power and carcinogenic

7. OZONE
• Ozone is nothing more than three oxygen molecules
electrically bound together, unlike stable oxygen you
breathe, ozone has extremely greate oxidative power and
very ready to react to germs, virus and a host of micro
organism that are known to cause illness
• Today ozone sterilization is a hot topic for disinfection for
food and water

8. OZONE (contd)
• Ozone is said to be 50% more powerful and acts 3000
times faster than Chlorine at 100 times the strength
• One advantage of an ozone system in food processing
is that it provides the user an opportunity to re-use
water
• It is cost effective and doesn’t leave any residue

9. OZONE (contd)
Air based Water based
2 Types of
Sterilizer
Machines

10. CHLORINE DIOXIDE
• Commonly used to disinfect drinking water
• When used in small quantity, it is safe and
doesnt lead to any health risks
• Higher dose can damage RBC’s and
lining of GIT
• Toxic gas

11. NITROGEN DIOXIDE
• Nitrogen dioxide is a sterilant gas that is used in terminal
sterilization of medical instruments.
• Bactericidal
Advantages :
1. Low sterilant concentration
2. Rapid Microbial activity
3. Operates at room temperature
4. Rapidly penetrates since it is a gas and not a vapour.
5. Minimal sterilant residual on processed articles
6. Non carcinogenic, non inflammable, but toxic

12. NITROGEN DIOXIDE (contd)
Polyurethane, nylon,
polyacetal and some
cellulose based papers
are not compatible with
nitrogen dioxide

13. Gas Plasma Sterilization
• Newer Technology
• Plasma 4th State of Matter
• Ionised gas consisting of positive ions and free electrons
• Vapourised hydrogen peroxide
• Low heat sterility cycle
• Now exclusively used by large manufacturers as the end
line process for in house sterilization

14. Who found it ?
• 1879 Sir William Crookes - Founder
• 1928 Irving Langmuir coined the term as
Plasma sterilization
• 1987 - Patented
• 1993 - US started marketing

15. Mechanism of action
• Free radicle interaction
• UV / Vaccum UV Radiation
• Volatization

16. Steps in Gas Plasma Sterilization
Vaccum Phase
The chamber is
evacuated, reducing
internal pressure in
preparation for
subsequent reaction
Injection Phase
Measured amount of
liquid peroxide is
injected into the
chamber, evaporating
the aqueous hydrogen
peroxide solution and
dispersing into the
chamber where it kills
the bacteria on any
surface it can reach
Diffusion Phase
The hydrogen peroxide
permeates the chamber,
exposing all load
surfaces to the sterliant
and rapidly sterilize
devices and materials
without leaving any toxic
residue at the completion
of this phase, chamber
pressure is reduced and
plasma discharge is
initiated

17. Steps in Gas Plasma Sterilization
PLASMAPhase
An electromagnetic field is
created in which Hydrogen
peroxide vapours break
apart producing a low
temperature plasma cloud
that contains UV and free
radicals. Following the
reaction, the activated lose
high energy and recombine
to form oxygen and water
VENT Phase
The chamber is vented to
equalize the pressure
enabling the chamber door
to be opened. There is no
need for aeration or cool
down. Devices are ready
for immediate use

19. Uses of Gas Plasma in Hospital
• Materials and devices that cannot tolerate high
temperature and humidity such as plastics, electric device,
corossion susceptible metal alloys can be sterilized
• Compatible with most medical devices and materials tested

20. Gas Plasma Sterilization
Advantages
 Materials and device compatibility
 Rapid turn around time
 In house control of sterilization process
 Lower inventory requirement
 Safe, non toxic, dry, low temperature
sterilization
 By products are water and oxygen
Disadvantages
 Cannot be used on paper,
cellulose or linen
 Small chamber
 Liquid, powder, strong
absorbers and some lumen
restriction
 It may corrode some materials

21. BIOLOPGICAL INDICATOR FOR QUALITY
CONTROL
• BACILLUS
ATROPHAEUS
SPORES
• BACILLUS
STEROTHERMOPHILI
S