steritech: a world leader sterilisation decontamination€¦ · • early 60’s - first used as a...

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


Method Comparison


• 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


Main Sterilization Technologies



An 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 – ConditioningOrPartly 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 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



iological Indicators

Positive BI Negative BI

Advantages of Ethylene Oxide


• 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


• 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.)


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


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.


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


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


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


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

• 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


Thank-you for listening.Any questions?


steritech: a world leader sterilisation decontamination€¦ · • early 60’s - first used as a...

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