M.RAGHUVARAN
M.PHARM 1st SEM (PHARMACEUTICS)
UNIVERSITY COLLEGE OF PHARMACEUTICAL SCIENCES
KAKATIYA UNIVERSITY
What is sterilization?
Definitions
 Sterile: Free from any living
organisms
 Sterilization: Process of killing or
removing microorganisms from a
product to insure that it is sterile
Sterilizing Agents
 Type of agents
 Chemical
 Physical


Moist heat
Dry heat
 Most clinics use physical agents
Steam Sterilization: Autoclave
 Pressurized device that uses heat, steam and pressure to achieve
sterilization or decontamination
 Steam – Advantages
 Simple process: The only two parameters to control are
time and temperature. Highly reliable and easily
controlled.
 Widespread capability: All hospitals and many other
heath care facilities have steam sterilizers.
 Excellent process for reusable medical devices that are
not adversely affected by temperatures >121C (up to 135
C).
 Excellent process for liquids that are not heat sensitive.
 Steam – Disadvantages
 Comparatively high temperature required: Many
products and packaging materials cannot tolerate
temperatures of >121C.
 Generally not appropriate for most single use disposable
medical devices produced in high volumes and sold as
sterile.
Principles of Steam Sterilization
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Sterilization: the complete destruction of all
forms of microbial life, including bacterial spores
Steam under pressure reaches high temperatures
Principles of Steam Sterilization (cont.)
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The “killing power” of steam is due to its latent heat
of vaporization
 80 calories: 1 L water to boiling
 540 calories: 1 L boiling water to steam
Latent Heat of Vaporization
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:
For example
Action of Steam
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Steam contacts a cooler surface, condenses, causing
a huge decrease in volume and setting up a negative
pressure that draws more steam
Condensation occurs as long as there is a
temperature differential
Action of steam ensures: Surface heating,
penetration, and protein coagulation
Items that CAN be Autoclaved:
 Cultures and stocks of infectious material
 Culture dishes and related devices
 Discarded live and attenuated vaccines
 Contaminated solid items such as: petri dishes,
eppendorf tips, pipettes, gloves, paper towel
 Items for sterilizations such as; glassware media,
aqueous solutions
DO NOT Autoclave:
 Any liquid containing:



Toxic, volatile, or corrosive chemicals
e.x. bleach, formalin, glutaraldehyde
Check MSDS before hand
 Cancer drugs


Do not break down under high temperatures
Highly toxic
 Radioisotopes
Types of autoclaves
 Lumbers Room 120A
 Farquharson 227A
Parts of a Steam Sterilizer
 Control panel with graph
 Door handle
 Outer metal jacket-like chamber built around the
inner chamber
 Inner chamber
 Series of filters
 Temperature measurement of steam sensor
Components of a Steam Sterilizer



1.
2.
3.
Source of steam- generate own steam or rely on steam
from outside source
Preheat metal jacket build around chamber for outside
sources reduces total cycle time
Three main pipes
A pipe with inline filters to bring steam to the sterilizer
and the chamber
A drain pipe for steam, air and water from the chamber
A pipe to deliver filtered air to the chamber at eh end of
the cycle
Steam Jacket: Surrounds the inner chamber and stores
steam until pressure has been obtained.
Inner Chamber: Items to be sterilized are loaded into
this compartment without touching.
Construction of Steam Sterilizers
 Valves:
 Pressure regulating: Maintains the pressure of 15 to 20
psi in the jacket.
 Safety Valve: Prevents excess pressure build-up.
 Steam trap: If pressure to high, valve opens and releases
pressure.
Construction of Steam Sterilizers
 Gauges:
 Located on front of sterilizer.
 Reading chamber pressure
 Reading Jacket pressure.
Safety Steam-lock Door:
Located in front of chamber
Weakest part of sterilizer
How to Autoclave
Which cycle to use
2. Preparing your items for autoclaving
3. Loading the autoclave
4. Choosing the cycle settings
5. Unloading the autoclave
6. Aborting Autoclave
1.
How to Autoclave- Which cycle to
use

Autoclaves run 3 types of cycle programs

The type of cycle depends on what is being autoclaved:
Liquid/Slow exhaust
* For autoclaving liquids
* Prevents liquids from boiling over
Solid/Gravity
* Best for unwrapped solid items
(ie glassware)
Solid/Vacuum
* Best for wrapped solid items
How to Autoclave - Preparing your items
 Sign into log book
 Keeps track of autoclave use for
maintenance records
 Use personal protective equipment!
 Eye protection
 Heat resistant gloves
 Lab coat
How to Autoclave - Preparing your items
 Use a primary container
 Container comes into direct contact with the contaminated or nonsterilized material or fluid
 Do not fill more than 75% of holding capacity
How to Autoclave - Preparing your items
 Use a primary container (cont’d)
 Must NOT be a tightly sealed container (might explode)
 Primary container must permit heat (steam) penetration



Loosen screw caps or use self venting caps
Cap open containers with aluminum foil or muslin
If using plastic waste bags, leave a small opening
Small opening
Loosen screw caps
How to Autoclave - Preparing your items
 Use a secondary container
 Used to contain any spills
 The sides of the secondary container must be sufficiently high to
contain any spill that may occur
 Tray MUST be autoclave safe
For liquids add water
How to Autoclave - Preparing your items
 Do not over load primary or secondary containers
 Do not fill more than 75% to allow expansion without overflow
 Do not pack or compress contents
Unautoclaved
Autoclaved (regular)
Autoclaved (due to being
compressed & sealed)
How to Autoclave - Preparing your items
 Use temperature sensitive tape
 Will indicate that high temperature has been achieved
 Will not prove that decontamination or sterilization was successful
 Will assist in keeping track of autoclave and non autoclaved items
Before
After
How
to
Autoclave
Loading
the
autoclave
 NEVER autoclave liquid loads using a solid load cycle

liquids may boil over
 Be cautious if autoclave was recently used


Rack may be hot
Use heat protective gloves
 Make sure tray is locked on dolly

Rack may slide out unexpectedly if not locked
How to Autoclave - Loading the autoclave
 Farquharson:
 Tighten door so that prongs are
fully extended
 If noise and/or steam escapes,
abort the cycle and tighten the
door more
 Lumbers
 Keep the door button pushed until
the ready prompt is on the screen
How to Autoclave – Choosing the Cycle
 For Liquids:
 20 mins / litre of liquid, 5 mins per additional litre
 For Solids:
 Glassware (empty): 15 mins
 Instruments (utensils): 30 mins
 Biohazardous Garbage: at least 30 mins per full bag

Use biological test strips to optimize duration
How to Autoclave – Unloading autoclave
 Wait for autoclave to state END CYCLE
before opening door
 When opening, stand away from door
opening
 Make sure no one is standing by door
opening
How to Autoclave – Aborting
 Only qualified personnel should attempt to troubleshoot an autoclave
 Farquharson
 Large autoclave: push abort button
 Small autoclave: need to manually advance through the autoclave cycle
 Lumbers
 Push abort button
Autoclave: Performance
Indicators
 How to know if autoclave is functioning correctly:
Physical
- Annual testing by certified technician
- Pressure, Temperature, Cycle times, recorded on paper
Chemical
- Heat sensitive autoclave tape
- Not an indicator of successful sterilization, useful to keep track of
autoclaved and unautoclaved items
Biological
- Tests ability of autoclave to sterilize effectively
- Bacillus stearothermophilus spore strips often used because they
are resistant to steam sterilization.
- EZ Test (SGM Biotech) (Fisher Sci #29801 074)
- 3M Attest Rapid Readout Biological Indicators
- Steris Verify Integrator Laminated and EO Integrators
DART
- Daily Air Removal Test, verifies complete air removal and checks
for leaks.
Biological Indicator Controls/Spore
Tests
Bacillus Stearothermophilus:is used strictly for Steam
and dry heat sterilizers.
Tests ability of sterilizer to kill microorganisms.
Biological
Indicator
 Must be incubated:
 Follow manufacturers instructions
 Use correct temperature 131-140 degrees F.
 Use special incubator
 Incubate for 48 hours or follow manufacturers
instructions
Biological Indicator
 Record results:
 Negative- no color change from original.
 Positive- color changed is usually amber in color.
Take sterilizer out of service
 Report to supervisor
 Recall all items sterilized in sterilizer for
last 24 hour period

Types of Steam Sterilizers
 Gravity Air Displacement Sterilizer- using gravity to
remove air from the inner chamber
 Prevacuum Steam Sterilizer- uses vacuum in two
cycles to remove air from the inner chamber
Types of Steam Sterilizers
1.
Gravity displacement.
a. Definition: Gravity pushes air through the
packages and down through the drain. Sterilization
begins when steam passes the thermometer and
reaches the desired temperature.
Gravity Displacement
 Settings:
 Temperature- 250 degrees F. to 254 Degrees F.
 Pressure- 15 to 17 pounds per square inch(PSI)
 Exposure time- 30 minutes for wrapped instruments.
Minimum 15 minutes.
Gravity Displacement Uses
1. Metal ware
2. Glassware
3. Thermoplastics.
4. Linens.
5. Rubber.
•Pre-vacuum (high temperature)
Sterilizer
Definition: Air is completely evacuated from the
chamber by a vacuum. The steam-injector helps
eliminate the air out of packages. Steam then
penetrates the packages on all surfaces.
Pre-vacuum
Settings:
1. Temperature: 270 degrees F. to 276 degrees F.
2.
Pressure: 27 PSI
3. Exposure Time: 15 to 30 minutes.
Pre-vacuum Sterilizer
Uses.
Metalware
Rubber
Thermoplastics
Sterilization: How is it validated?
Steam
 IQ, OQ, PQ of steam sterilizer
 Temperature profiles of product during sterilization
cycles (using thermocouples)
 Fractional and/or half cycles with product & B.I.s (G.
stearothermophilus)
 Then sterility testing of product & B.I.s
References
 ANSI/AAMI/ISO standards and TIRs available at
www.aami.org
 USP 25 – order from www.usp.org
 PBL Compliance Guides
 Sterility Assurance Compliance
 Assessing Biocompatibility
 Online at www.pacificbiolabs.com
Thanks
 Comments?
 Questions?