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Steritech: A World Leader in Sterilisation and Decontamination
Ethylene Oxide (55%)
• Surface sterilant
• Typically 100%
• Sterilize under vacuum
• Process variables include
Temperature
RH
Time
Pressure
EO concentration
• Preconditioning / Aeration
Irradiation (45%)
• Penetrative sterilant
• Gamma
Cobalt 60
Alpha particles
High penetration
• Electron Beam
Accelerated electrons
Beta particles
Processing speed dependant on power(Kwatts)
Penetration dependant on energy /particle speed (MeV)
Main Sterilization Technologies
Steritech: A World Leader in Sterilisation and Decontamination
Method Comparison
Steritech: A World Leader in Sterilisation and Decontamination
• 1859 - First prepared in by Charles Wurtz
• Importance during W W1 as precursor to Ethylene Glycol coolant and mustard gas
• 1931- Theodore Lefort - prepared from Ethylene and Oxygen using silver as a catalyst
• 1938- patented for use in spice preservation by Lloyd Hall.
• Produced for use as a sterilant/fumigant
• Early 60’s - First used as a sterilizing agent for medical devices
• Currently ~ 50% of Medical Device sterilization market
• Accounts for < 2% of global EO usage
Ethylene Oxide History
Steritech: A World Leader in Sterilisation and Decontamination
Main Sterilization Technologies
Steritech: A World Leader in Sterilisation and Decontamination
Steritech: A World Leader in Sterilisation and Decontamination
An Ethylene Oxide Chamber
Steritech: A World Leader in Sterilisation and Decontamination
An Ethylene Oxide Chamber
Steritech: A World Leader in Sterilisation and Decontamination
An Ethylene Oxide Chamber
Traditional 3 Phases of Process
Preconditioning Sterilisation Post Conditioning
Steritech: A World Leader in Sterilisation and Decontamination
Preconditioning
The Initial Part of the process aims at bringing product humidity and temperature to optimal sterilisation conditions.
Within Sterilisation Chamber – ConditioningOrPartly done within room or cell outside sterilisation chamber
Steritech: A World Leader in Sterilisation and Decontamination
Sterilisation
The phase during which the load is safely exposed to EO under controlled environmental conditions for a pre determined time.
Steritech: A World Leader in Sterilisation and Decontamination
Aeration / Degassing
After sterilisation the process aims at removing as much EO residues as possible from the chamber and load.
Within sterilisation chamber and / or room/cell outside of sterilisation chamber where temperature and ventilation rate are high
Effects of conditions of EO residues
• Time The longer the exposure, the higher the absorption• Temperature The higher the temperature, the less the absorption• Humidity The higher the humidity, the higher the absorption• Gas concentration The higher the concentration, the higher the absorption• Gas composition Pure EO can result in higher absorption than EO in mixtures
radition EO Sterilisation Cycle
12 Hours Routine 12 Hours12 hours
Total Cycle Time 36 Hours
Steriliser Phase
0
100
200
300
400
500
600
700
800
900
1000
0 50 100 150 200 250 300 350 400 450 500 550 600 650 700
Time in Minutes
Pres
sure
in M
bar
6 hour Exposure
A tmospheric
E.T.OGas Concent rat ion 500 M g/ l @ 50 C
Twenty 10 Mbar Pul ses450 mbar - 460 mbar
wi th one mi nute peak dwel l
400
982
..
982
N2
50 Mbar Steam
Preconditioning Phase
0
10
20
30
40
50
60
70
80
90
100
0 120 240 360 480 600
Time in Minutes
Tem
pera
ture
& R
elat
ive
Hum
idity
Relat ive Humid ity(Cont ro lled Ramp Up)
Temperature
Degassing Phase
0
10
20
30
40
50
60
70
80
90
100
0 120 240 360 480 600 720
Time in Minutes
Tem
pera
ture
Temperature
Steritech: A World Leader in Sterilisation and Decontamination
Steritech: A World Leader in Sterilisation and Decontamination
iological Indicators
Positive BI Negative BI
Advantages of Ethylene Oxide
Steritech: A World Leader in Sterilisation and Decontamination
• Low Temperature (40 – 60oC)
• Minimal Damage to Materials
• Sterilization of Finished Goods
• EO can vaporize from materials quickly
• EO is highly diffusive: will penetrate deep
• EO low reactivity with materials (polymers) *
* The Effects of Sterlisation Methods on Polymers & Elastomers (2nd Edition)
Leisel K Massey – PDL Handbook Series
Disadvantages of Ethylene Oxide
Steritech: A World Leader in Sterilisation and Decontamination
• More expensive than steam
• Cycle Time
• Toxic & Explosive Gas
• Requirement for automation
• Requirement for Monitoring
• Lengthy & Complex Validation
• Residues May Remain
• May react with metals (copper, aluminum)
• Need to consider sources or spark (battery, static, etc.)
Steritech: A World Leader in Sterilisation and Decontamination
Ethylene oxide sterilisation is growingEthylene oxide processing is getting increasingly complexDesigning a cycle is about making compromises
Future Of Ethylene Oxide Sterilisation
Criteria to Consider
Steritech: A World Leader in Sterilisation and Decontamination
Qualification• Set out in ISO11135
• Typically takes 8-12 weeks
• Protocol needs to take into considerationLoad configuration
Placement of internal BI’s
EO residuals
Product functionality
Number of samples
• Changes to product / load configuration
• Generally re-qualified every 1-2 years
• Review of
• Process history
• Product / packaging changes
• Equipment changes
• Long validation lead time
• Complex validation
• Extra validation activity to accommodate scale up.
Steritech: A World Leader in Sterilisation and Decontamination
Processing Costs• By Chamber (e.g. 10 Pallets)
• Cycle price dictated by cycle length
• Expensive for small volume loads
• Extra costs may include
Extra aeration
BI’s
Other testing
• Factor in WIP cost due to longer lead times
Process Time• Typically 7-10 days
Processing : 20-48 hours
BI testing : 2 – 7 days
Aeration : 0-5 days
Some products may require post sterilizationprocessing
• Parametric Release may shorten turnarotime by elimination of BI’s
• Long turnaround times result in increaseWIP
Steritech: A World Leader in Sterilisation and Decontamination
Process Release• Up to 7 days
• Review of Batch record
Cycle parameters within specification
BI results
Aeration Complete
• Parametric release an option for quicker release
Risk• Batch Process – 1-32 pallets
• Multiple parameters to be controlled and monitored
• Multiple sterilization capability recommended
• Only option is to reprocess or scrap
Steritech: A World Leader in Sterilisation and Decontamination
Residuals• EO & ECH levels on product must meet limits set out in ISO10993-7.
• Can result in increased processing time to get limits below required limits
• Influenced by
Aeration temperature
Materials
Product design
Layers of packaging
Product Material Compatibility• Product design
Tortuous pathway
Dead legs
Coatings
• Most materials compatible
• May be issue where product is temperaturesensitive
• EO / ECH residuals
Steritech: A World Leader in Sterilisation and Decontamination
Packaging• Porous to EO
• May need post sterilization activity of product is RH sensitive• Packaging validation needs to take pressure changes into consideration.• Ideally need to minimize layers to facilitate EO penetration
Electrical Components• Increased risk of source of ignition
• Cycle can be designed outside flammable zo
• May result in longer cycle leading to higher processing costs
Steritech: A World Leader in Sterilisation and Decontamination
Safety / Environmental• Hazardous Gas
• Occupational exposure
• Facility design
Atex
Fail Safe
• Emission Control
Steritech: A World Leader in Sterilisation and Decontamination
Points to Keep in Mind
Steritech: A World Leader in Sterilisation and Decontamination
• Consider Sterilisation Early in Product Development• Choice of Sterilisation Method
• Packaging Design
• Product Design
• Capability of Product to be Re-sterilized
• Time to Validate
• Am I using the most suitable sterilization method for my product ?
Was it selected based on availability at the time ?
Are there other materials that would be irradiation compatible ?
Has anything changed to make my product capable of using an alternative sterilization method ?
• Can I change to a different sterilization method ?
Is my product compatible ?
What are the regulatory requirements ?
How long will it take ?
Will it be worth the while – Financially and operationally ?
• Am I considering the sterilization method early enough in the product design phase ?
Questions to Ask Yourself
Steritech: A World Leader in Sterilisation and Decontamination
Thank-you for listening.Any questions?
Steritech: A World Leader in Sterilisation and Decontamination