ain Sterilization Technologies 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)
Method Comparison
thylene Oxide History 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
ain Sterilization Technologies
n Ethylene Oxide Chamber
n Ethylene Oxide Chamber
n Ethylene Oxide Chamber
Traditional 3 Phases of Process Preconditioning Sterilisation Post Conditioning
Preconditioning The Initial Part of the process aims at bringing product humidity and temperature to optimal sterilisation conditions. Within Sterilisation Chamber Conditioning Or Partly done within room or cell outside sterilisation chamber
Sterilisation The phase during which the load is safely exposed to EO under controlled environmental conditions for a pre determined time.
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 Temperature Humidity Gas concentration Gas composition The longer the exposure, the higher the absorption The higher the temperature, the less the absorption The higher the humidity, the higher the absorption The higher the concentration, the higher the absorption Pure EO can result in higher absorption than EO in mixtures
adition EO Sterilisation Cycle 100 90 Preconditioning Phase 1000 900 982 Steriliser Phase 982 A t mo sp heric 100 90 Degassing Phase Temperature & Relative Humidity 80 70 60 50 40 30 Relative Humidity (Controlled Ramp Up) Temperat ure Pressure in Mbar 800 700 600 500 400 300 N2 E.T.O Twenty 10 Mbar Pulses 50 Mbar Steam 450 mbar - 460 mbar with one minute peak dwell 6 hour Exposure Gas Concent rat ion 500 Mg/l @ 50 C 400 Temperature 80 70 60 50 40 30 Temp erat ure 20 200 20 10 100.. 10 0 0 120 240 360 480 600 Time in Minutes 0 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 Time in Minutes 0 0 120 240 360 480 600 720 Time in Minutes 12 hours 12 Hours Routine 12 Hours Total Cycle Time 36 Hours
iological Indicators Positive BI Negative BI
Advantages of Ethylene Oxide Low Temperature (40 60 o C) 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 (2 nd Edition) Leisel K Massey PDL Handbook Series
Disadvantages of Ethylene Oxide 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.)
Future Of Ethylene Oxide Sterilisation Ethylene oxide sterilisation is growing Ethylene oxide processing is getting increasingly complex Designing a cycle is about making compromises
riteria to Consider
Qualification Set out in ISO11135 Typically takes 8-12 weeks Protocol needs to take into consideration Load 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.
rocessing 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 sterilization processing Parametric Release may shorten turnaro time by elimination of BI s Long turnaround times result in increase WIP
Process Release Up to 7 days Review of Batch record Cycle parameters within specification BI results Aeration Complete Risk Batch Process 1-32 pallets Multiple parameters to be controlled and monitored Multiple sterilization capability recommended Only option is to reprocess or scrap Parametric release an option for quicker release
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 temperature sensitive EO / ECH residuals
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
Safety / Environmental Hazardous Gas Occupational exposure Facility design Atex Fail Safe Emission Control
Points to Keep in Mind Consider Sterilisation Early in Product Development Choice of Sterilisation Method Packaging Design Product Design Capability of Product to be Re-sterilized Time to Validate
Questions to Ask Yourself 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?
Thank-you for listening. Any questions?