M.RAGHUVARANM.PHARM 1st SEM (PHARMACEUTICS)

UNIVERSITY COLLEGE OF PHARMACEUTICAL SCIENCES

KAKATIYA UNIVERSITY

What is sterilization?

DefinitionsSterile: Free from any living

organisms

Sterilization: Process of killing orremoving microorganisms from aproduct 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 easilycontrolled. 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 135C). Excellent process for liquids that are not heat sensitive.

Steam – Disadvantages Comparatively high temperature required: Many

products and packaging materials cannot toleratetemperatures of >121C. Generally not appropriate for most single use disposable

medical devices produced in high volumes and sold assterile.

Principles of Steam Sterilization

u Sterilization: the complete destruction of allforms of microbial life, including bacterial spores

u Steam under pressure reaches high temperatures

Principles of Steam Sterilization (cont.)

u The “killing power” of steam is due to its latent heatof vaporization

80 calories: 1 L water to boiling540 calories: 1 L boiling water to steam

Latent Heat of Vaporization

u For example:

Action of Steamu Steam contacts a cooler surface, condenses, causing

a huge decrease in volume and setting up a negativepressure that draws more steam

u Condensation occurs as long as there is atemperature differential

u 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

Lumbers Room 120A

Farquharson 227A

Types of autoclaves

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 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 pipes1. A pipe with inline filters to bring steam to the sterilizer

and the chamber2. A drain pipe for steam, air and water from the chamber3. A pipe to deliver filtered air to the chamber at eh end of

the cycle

Steam Jacket: Surrounds the inner chamber and storessteam until pressure has been obtained.

Inner Chamber: Items to be sterilized are loaded intothis 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 releasespressure.

Construction of Steam Sterilizers Gauges: Located on front of sterilizer. Reading chamber pressure Reading Jacket pressure.Safety Steam-lock Door:

Located in front of chamberWeakest part of sterilizer

How to Autoclave1. Which cycle to use2. Preparing your items for autoclaving3. Loading the autoclave4. Choosing the cycle settings5. Unloading the autoclave6. Aborting Autoclave

How to Autoclave- Which cycle touse

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 non-

sterilized 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

Loosen screw capsSmall opening

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 beingcompressed & 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 thedoor 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 CYCLEbefore opening door

When opening, stand away from dooropening 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: PerformanceIndicators 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 ofautoclaved and unautoclaved items

Biological - Tests ability of autoclave to sterilize effectively- Bacillus stearothermophilus spore strips often used because theyare 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 checksfor leaks.

Biological Indicator Controls/SporeTests

Bacillus Stearothermophilus:is used strictly for Steamand 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 manufacturersinstructions

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 thepackages and down through the drain. Sterilizationbegins when steam passes the thermometer andreaches 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 ware2. Glassware3. Thermoplastics.4. Linens.5. Rubber.

•Pre-vacuum (high temperature)Sterilizer

Definition: Air is completely evacuated from thechamber by a vacuum. The steam-injector helpseliminate the air out of packages. Steam thenpenetrates the packages on all surfaces.

Pre-vacuumSettings:

1. Temperature: 270 degrees F. to 276 degrees F.

2. Pressure: 27 PSI

3. Exposure Time: 15 to 30 minutes.

Pre-vacuum SterilizerUses.

MetalwareRubberThermoplastics

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 atwww.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?