CEN ISO/TS 11135-2:2008

SLOVENSKI STANDARD
01-november-2008
Sterilizacija izdelkov za zdravstveno nego - Etilenoksid - 2. del: Navodilo za
uporabo ISO 11135-1 (ISO/TS 11135-2:2008)
Sterilization of health care products - Ethylene oxide - Part 2: Guidance on the
application of ISO 11135-1 (ISO/TS 11135-2:2008)
Sterilisation von Produkten für die Gesundheitsfürsorge - Ethylenoxid - Teil 2: Leitfaden
zur Anwendung von ISO 11135-1 (ISO/TS 11135-2:2008)
Stérilisation des produits de santé - Oxyde d'éthylène - Partie 2: Directives relatives à
l'application de l'ISO 11135-1 (ISO/TS 11135-2:2008)
Ta slovenski standard je istoveten z: CEN ISO/TS 11135-2:2008
ICS:
11.080.01 Sterilizacija in dezinfekcija na Sterilization and disinfection
splošno in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION
CEN ISO/TS 11135-2
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
August 2008
ICS 11.080.01
English Version
Sterilization of health care products - Ethylene oxide - Part 2:
Guidance on the application of ISO 11135-1 (ISO/TS 11135-
2:2008)
Stérilisation des produits de santé - Oxyde d'éthylène - Sterilisation von Produkten für die Gesundheitsfürsorge -
Partie 2: Directives relatives à l'application de l'ISO 11135- Ethylenoxid - Teil 2: Leitfaden zur Anwendung von ISO
1 (ISO/TS 11135-2:2008) 11135-1 (ISO/TS 11135-2:2008)
This Technical Specification (CEN/TS) was approved by CEN on 8 June 2008 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.
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Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN ISO/TS 11135-2:2008: E
worldwide for CEN national Members.

Contents Page
Foreword.3

Foreword
This document (CEN ISO/TS 11135-2:2008) has been prepared by Technical Committee CEN/TC 204
“Sterilization of medical devices", the secretariat of which is held by BSI, in collaboration with Technical
Committee ISO/TC 198 "Sterilization of health care products".
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO/TS 11135-2:2008 has been approved by CEN as a CEN ISO/TS 11135-2:2008 without any
modification.
TECHNICAL ISO/TS
SPECIFICATION 11135-2
First edition
2008-08-01
Sterilization of health care products —
Ethylene oxide —
Part 2:
Guidance on the application of
ISO 11135-1
Stérilisation des produits de santé — Oxyde d'éthylène —
Partie 2: Directives relatives à l'application de l'ISO 11135-1

Reference number
ISO/TS 11135-2:2008(E)
©
ISO 2008
ISO/TS 11135-2:2008(E)
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ii © ISO 2008 – All rights reserved

ISO/TS 11135-2:2008(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Quality management systems . 2
4.1 Documentation. 2
4.2 Management responsibility . 2
4.3 Product realization. 3
4.4 Measurement, analysis and improvement — Control of non-conforming product . 3
5 Sterilizing agent characterization . 3
5.1 Sterilizing agent . 3
5.2 Microbicidal effectiveness . 3
5.3 Materials effects. 3
5.4 Environmental considerations . 3
6 Process and equipment characterization .4
6.1 Process characterization . 4
6.2 Equipment characterization. 4
7 Product definition . 5
7.1 General. 5
7.2 Product safety and performance. 8
7.3 Microbiological quality. 9
7.4 Documentation. 9
8 Process definition. 9
9 Validation. 12
9.1 Installation qualification. 13
9.2 Operational qualification. 14
9.3 Performance qualification. 15
9.4 Varying load configurations . 19
9.5 Review and approval of validation. 19
10 Routine monitoring and control . 20
10.1 General. 20
10.2 Parametric release. 21
11 Product release from sterilization. 22
12 Maintaining process effectiveness . 23
12.1 General. 23
12.2 Maintenance of equipment . 23
12.3 Requalification . 24
12.4 Assessment of change. 25
Annex A (informative) Guidance on ISO 11135-1:2007 Annex A Determination of process
lethality — Biological indicator/bioburden approach . 26
Annex B (informative) Guidance on ISO 11135-1:2007 Annex B Conservative determination of
lethal rate of the sterilization process — Overkill approach. 36
Bibliography . 38
ISO/TS 11135-2:2008(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
In other circumstances, particularly when there is an urgent market requirement for such documents, a
technical committee may decide to publish other types of document:
⎯ an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in
an ISO working group and is accepted for publication if it is approved by more than 50 % of the members
of the parent committee casting a vote;
⎯ an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical
committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting
a vote.
An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a
further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is
confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an
International Standard or be withdrawn.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO/TS 11135-2 was prepared by Technical Committee ISO/TC 198, Sterilization of health care products.
ISO/TS 11135-2, together with ISO 11135-1, cancels and replaces ISO 11135:1994 and
ISO 11135/Cor.1:1994, which have been technically revised.
ISO/TS 11135 consists of the following parts, under the general title Sterilization of health care products —
Ethylene oxide:
⎯ Part 1: Requirements for development, validation and routine control of a sterilization process for medical
devices
⎯ Part 2: Guidance on the application of ISO 11135-1
iv © ISO 2008 – All rights reserved

ISO/TS 11135-2:2008(E)
Introduction
This Technical Specification describes some of the methods that may be employed to achieve the
requirements contained in ISO 11135-1. This document is not intended as a checklist for assessing
compliance with ISO 11135-1, rather it is intended to promote a uniform understanding and implementation of
ISO 11135-1 by providing explanations and possible methods for achieving compliance with specified
requirements. It highlights important aspects and provides examples.
This Technical Specification addresses ethylene oxide (EO) sterilization in both the industrial and health care
facility settings, and it acknowledges the similarities and differences between the two applications.
Among the similarities are the common need for quality systems, staff training, and proper safety measures.
The major differences relate to the unique physical and organizational conditions in health care facilities, and
to the initial condition of re-usable devices being presented for sterilization.
Health care facilities differ from medical device manufacturers in the physical design of processing areas, in
the equipment used, and in the availability of personnel with adequate levels of training and experience. The
primary function of the health care facility is to provide patient care; medical device reprocessing is just one of
a myriad of activities that are performed to support that function.
In terms of the initial condition of medical devices, medical device manufacturers generally sterilize large
numbers of similar devices that have been produced from virgin material. Health care facilities, on the other
hand, must handle and process both new medical devices and re-usable medical devices of different
descriptions and with varying levels of bioburden. They are therefore faced with the additional challenges of
cleaning, evaluating, preparing and packaging a medical device prior to sterilization. In this document,
alternative approaches and guidance specific to health care facilities are identified as such.
In general, moist heat sterilization (also known as steam sterilization) is the method of choice for medical
devices and supplies that are sterilized in health care facilities. However, EO gas and its mixtures are effective
sterilants that are primarily used for heat- and moisture-sensitive medical devices that cannot be steam
sterilized.
For ease of reference, the numbering in this technical specification corresponds to that in ISO 11135-1.

TECHNICAL SPECIFICATION ISO/TS 11135-2:2008(E)

Sterilization of health care products — Ethylene oxide —
Part 2:
Guidance on the application of ISO 11135-1
1 Scope
This Technical Specification provides guidance for the requirements in ISO 11135-1:2007. It does not repeat
the requirements and is not intended to be used in isolation.
The exclusions in ISO 11135-1 apply also to this Technical Specification.
For ease of reference, the clause numbering in this Technical Specification corresponds to that in
ISO 11135-1:2007. Further guidance for the requirements given in ISO 11135-1 is also included in Annex C of
ISO 11135-1:2007 and should be used in conjunction with this Technical Specification.
This guidance document is intended for people who have a basic knowledge of the principles of EO
sterilization but may need help in determining how to best meet the requirements contained in ISO 11135-1.
This document is not intended for people lacking a basic knowledge of the principles of EO sterilization.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 11135-1:2007, Sterilization of health care products — Ethylene oxide — Part 1: Requirements for
development, validation and routine control of a sterilization process for medical devices
ISO 11138-2:2006, Sterilization of health care products — Biological indicators — Part 2: Biological indicators
for ethylene oxide sterilization processes
ISO 11140-1:2005, Sterilization of health care products — Chemical indicators — Part 1: General
requirements
ISO 11737-1, Sterilization of medical devices — Microbiological methods — Part 1: Determination of a
population of microorganisms on products
ISO 13485:2003, Medical devices — Quality management systems — Requirements for regulatory purposes
ISO 17664, Sterilization of medical devices — Information to be provided by the manufacturer for the
processing of resterilizable medical devices

ISO/TS 11135-2:2008(E)
3 Terms and definitions
For the purposes of this document, the terms and definitions in ISO 11135-1 and the following apply.
3.1
dunnage
material used to mimic all or part of a sterilization load
3.2
health care facility
set of physical infrastructure elements intended to support the delivery of specific health-related services
3.3
processing group
collection of products or product families that can be sterilized in the same EO sterilization process
NOTE All products within the group have been determined to present an equal or lesser challenge to the sterilization
process than the challenge device for that group.
3.4
EO product family
collection of products that are determined to be similar or equivalent for validation purposes
3.5
re-usable medical device
medical device designated or intended by the manufacturer as suitable for reprocessing and re-use
NOTE This is not a medical device that is designated or intended by the manufacturer for single use only.
3.6
single use medical device
medical device that is designated or intended by the manufacturer for one-time use only
3.7
sterilization specialist
person with knowledge of the sterilization technology being utilized and its effects upon materials and
microorganisms
NOTE This level of knowledge has been obtained by both practical and theoretical means and the person does not
require guidance on the basic principles of the technology involved.
4 Quality management systems
4.1 Documentation
4.1.1 No guidance offered.
4.1.2 No guidance offered.
4.2 Management responsibility
4.2.1 Each organization should establish procedures for identifying training needs and ensure that all
personnel are trained to adequately perform their assigned responsibilities.
4.2.2 No guidance offered.
2 © ISO 2008 – All rights reserved

ISO/TS 11135-2:2008(E)
4.3 Product realization
4.3.1 Purchasing procedures in a health care facility should ensure that re-usable medical devices are
supplied with validated instructions for cleaning, disinfection, sterilization and aeration as specified in
ISO 17664.
4.3.2 For those facilities that do not fully comply with ISO 13485, such as health care facilities, procedures
for identification of product and maintenance of traceability, should include the labelling of each item or
package prior to sterilization with a lot control identifier that includes the following information:
a) the sterilizer ID or code;
b) the date of sterilization;
c) the cycle number (i.e. the cycle run of the day or sterilizer).
It is recommended that the identity of the person who assembled the pack also be included on the identifier, to
allow for further investigation if a problem should arise.
Lot identification information enables personnel to retrieve items in the event of a recall and to trace problems
to their source.
4.3.3 No guidance offered.
4.4 Measurement, analysis and improvement — Control of non-conforming product
No guidance offered.
5 Sterilizing agent characterization
5.1 Sterilizing agent
EO is a highly penetrative gas that will permeate most packaging materials and polymeric materials. Widely
recognized compositions include 100 % EO and blends with carbon dioxide or nitrogen. The storage
conditions for EO should be in accordance with the EO manufacturer’s recommendations and all applicable
regulations.
5.2 Microbicidal effectiveness
No guidance offered.
5.3 Materials effects
No guidance offered.
5.4 Environmental considerations
5.4.1 EO is toxic, flammable and explosive; therefore, extreme caution should be used during its storage,
handling and use.
5.4.2 Effluent gas should be discharged through an EO-gas treatment system, such as a catalytic oxidiser,
wet acid scrubber or thermal oxidiser.
When choosing a diluent, its ozone depleting potential should be taken into consideration.
ISO/TS 11135-2:2008(E)
6 Process and equipment characterization
In health care facilities, process and equipment characterization are generally the responsibility of the sterilizer
manufacturer. The management of the health care facility should have controls in place to ensure that its
equipment purchases conform to national, regional and local regulations and are suitable for the products
intended to be sterilized. The management of the health care facility should ensure the facility has the
infrastructure necessary to operate the sterilizing equipment and to achieve sterilization of medical devices.
6.1 Process characterization
No guidance offered.
6.2 Equipment characterization
6.2.1 The following factors should be considered when characterizing the equipment.
Preconditioning equipment characterization
Preconditioning may be performed in a separate preconditioning area (chamber, cell or room). The
preconditioning area (if used) should have the following performance and monitoring capabilities:
⎯ air circulation system: adequate air circulation to ensure the uniformity of temperature and humidity in
the usable space, and to ensure that uniformity is maintained in a fully loaded room or chamber;
⎯ airflow detection equipment, alarm systems or indicators monitoring the circulation system to ensure
conformance to predetermined tolerances;
⎯ means of monitoring temperature and humidity;
⎯ means of controlling temperature and humidity;
NOTE Temperature and humidity sensor control systems may utilize redundant sensors for temperature and humidity
determination in the room.
⎯ a time clock or other means of recording time of load entry into and removal from the preconditioning
area, if applicable.
Sterilization chamber equipment characterization
The sterilization chamber should have the following performance and monitoring capabilities:
⎯ means of monitoring chamber pressure, temperature and humidity (if humidity additions are
controlled by sensor readings);
⎯ means of controlling chamber pressure, temperature and humidity, if humidity additions are
controlled by sensor readings [when sensors are fixed on the equipment, ensure that a correlation is
made during installation qualification (IQ) or operational qualification (OQ) at the coldest location];
⎯ if parametric release is used, instrumentation for the direct analysis of humidity during conditioning
and EO concentration during sterilant exposure time;
⎯ a system controlling that gaseous EO was admitted to the chamber. This can be done by measuring
the temperature of the EO gas flowing from the vaporizer to the sterilizer chamber or monitoring the
pressure rise during EO injection. This system may control EO concentration during sterilant
exposure time.
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ISO/TS 11135-2:2008(E)
Aeration equipment characterization
An aeration area (chamber, cell or room) may be used to remove EO residuals from product/packaging.
Temperature uniformity, fresh air make-up and air re-circulation throughout the area are important to ensure
consistent and reproducible results. The aeration area should have the following:
⎯ airflow detection equipment, alarm systems or indicators monitoring the air handling system to
ensure that it operates within specified parameters and maintains adequate airflow in a fully loaded
room or chamber;
⎯ equipment to re-circulate air;
⎯ means of monitoring room temperature;
⎯ means of controlling room temperature.
Prior to removing product from a sterilizer, precautions should be taken to ensure that operators are not
exposed to high levels of EO due to the outgassing of the load.
The equipment specification should be reviewed to ensure that regulatory and safety requirements are met,
technical specifications are appropriate, and services and infrastructure necessary to operate the equipment
are available.
6.2.2 Humidification by steam injection is required in ISO 11135-1, because humidifiers that operate by
dispersion of unheated water as an aerosol (e.g. spinning disc humidifiers and nebulizers) can be potent
sources of microbial contamination.
6.2.3 No guidance offered.
6.2.4 If there is an undetected failure of a control or monitoring function, a sterilization load could be
released without having met its required processing parameters. To prevent this from happening, it is general
practice to have redundant sensors for many critical process parameters. The common options for utilizing
these redundant sensors include:
a) use one sensor for control, and another sensor for monitoring and reporting;
b) use two sensors, or their average value, for both monitoring and control; this system needs to generate
an automatic fault condition if the difference between the two sensors exceeds a defined value;
c) use dual element sensors for both monitoring and control; this system needs to generate an automatic
fault condition if the difference between the two elements exceeds a defined value.
7 Product definition
7.1 General
Product definition involves documentation of essential information about the medical device to be sterilized (i.e.
the new or modified product).
7.1.1 Product definition for a medical device includes the medical device itself, the primary package
containing the device, and any accessories, instructions, or other items included in the primary package. It
also includes a description of the intended functionality of the medical device, and the available manufacturing
and sterilization processes. The product definition process should also consider whether this is a new design,
or whether it is part of an existing EO product family.
The following should be considered as part of product definition:
a) physical description of the medical device (composition and configuration);
b) intended use of the medical device;
ISO/TS 11135-2:2008(E)
c) whether the medical device is intended for single use or for multiple use;
d) design characteristics that would affect the choice of sterilization process (e.g. batteries, fibre-optics,
computer chips);
e) raw materials/manufacturing conditions that could affect microbiological quality (e.g. materials of natural
origin);
f) required sterility assurance level (SAL);
g) packaging;
h) loading pattern; requirements for a specific load or mixed loading patterns, or range of acceptable loading
patterns;
i) compatibility with the sterilant gas or gas mixture and EO processing conditions (preconditioning,
sterilization and aeration processes).
7.1.2 A technical review should be performed to compare the new or modified product to the validated
product and/or process challenge device (PCD) that was used to validate the existing EO process. The
construction and configuration of the new or modified product should be carefully examined for any features
that could present obstacles to the penetration of EO, heat or humidity. For medical device manufacturers, this
comparison should also involve an examination of factors that could affect the initial bioburden on the product,
including the location of the manufacturing facilities, the types of raw material used, the sources of these
materials and production methods. For new re-usable products, this comparison should include the evaluation
of the cleaning efficacy for this product.
If a new or modified product is demonstrated to be equivalent to an existing medical device or PCD for which
sterilization characteristics are already known, the new or modified product might be considered to be part of
an EO product family or a processing group.
[10]
NOTE AAMI TIR28 is a useful guide for minimizing the risk of introducing a new or modified product that presents
a greater challenge to the sterilization cycle than was previously validated.
As part of the technical review the following questions should be considered. If the answer to any of the
following questions is “yes,” further evaluation of the new or modified product might be necessary to determine
if it is more difficult to sterilize than the previously validated product:
a) With respect to the previously validated product, does the new or modified product:
1) have more restricted passageways or inner chambers;
2) have fewer openings;
3) have more internal surfaces;
4) have more mated surfaces;
5) have more closures;
6) have longer or narrower lumens;
7) include changes or differences that could reduce the transfer of heat, moisture or sterilant gas;
8) have a bioburden number or resistance significantly higher than that of the reference product (due to
manufacturing conditions, handling, cleaning process or materials used) or
9) contain materials or structures that could be adversely affected by the proposed processing or
sterilization method?
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ISO/TS 11135-2:2008(E)
b) With respect to the previously validated product, does the packaging of the new or modified product:
1) have any changes in packaging elements, including instructions or protective barriers;
2) have any additional impermeable protective barriers, e.g. container, case, template, that would
restrict or interfere with sterilant or humidity penetration or removal;
3) have a change in the porosity of the packaging material (e.g. basis weight, coating, treatment –
adhesive or coating on paper);
4) have a decrease in the surface area of the venting material or underlying opening, e.g. application of
tape or secondary label, change in size of label;
5) increase the bioburden level of the product or
6) change the number of barrier layers?
c) With respect to the previously validated product, does the load configuration of the new or modified
product:
1) differ significantly from the validated load configuration of the reference load;
2) differ significantly in the amount of absorptive materials;
3) differ significantly in density from that of the reference load or
4) differ significantly in total load volume?
7.1.3 No guidance offered.
7.1.4 No guidance offered.
7.1.5 A means of demonstrating equivalence is the comparison of the relative rates of inactivation of BIs
placed in the most difficult-to-sterilize location within the new or modified product and previously validated
product when both are exposed to a fractional cycle.
A PCD is a device or test pack into which a microbiological challenge is located. Examples of ways to develop
PCDs for use in the demonstration of equivalence include, but are not limited to:
a) placement of a microbiological challenge between rings, lands, grommets or ribs of a syringe stopper;
b) placement of a microbiological challenge in the middle of the lumen of a tube that is then reconnected
using a solvent bond agent or a connector to restore product integrity;
c) placement of a microbiological challenge in an interface;
d) placement of a microbiological challenge in a series of envelopes or packages.
Several PCD designs have been recommended for use in health care facilities.
[13] [11] [12]
NOTE 1 For further information see EN 1422 , ANSI/AAMI ST41 and AS/NZS 4187 .
To prepare the PCD, the microbiological challenge can be inoculated on the product either directly or indirectly.
Direct inoculation is accomplished by applying a liquid suspension of the spores on the product. Indirect
inoculation is accomplished by placing an inoculated carrier either within the package or in/on the product.

ISO/TS 11135-2:2008(E)
Listed below are various ways to prepare a PCD.
⎯ Inoculated product: the product to be sterilized is used to prepare the PCD and is inoculated directly or
indirectly.
⎯ Inoculated simulated product: a simulated product is used to prepare the PCD and is inoculated directly
or indirectly. The simulated product consists of portions of a medical device or a combination of
components that are known to represent the greatest challenge to the process while still adequately
representing all products within an EO product family.
⎯ Inoculated carrier: a carrier such as a paper strip, disc or other substrate is used to prepare the PCD and
is directly inoculated. The resistance of the inoculated carrier should be correlated with the resistance of
the inoculated product, simulated product or natural product to use the inoculated carrier for the
determination of process lethality.
NOTE 2 Inoculation with a spore suspension can result in variable resistance of the inoculated product because of
surface phenomena, other environmental factors and the occlusion of the spores on or in the product. Therefore, it is
important to provide scientific rationale or validation for this practice to ensure that the resistance of the inoculated
simulated product is reasonably correlated to the natural product. The inoculum recovery must also be validated if
[14] [22]
resistance is measured by plate count techniques. See Gillis and Schmidt , West , and ISO 11737-1 for additional
information.
7.2 Product safety and performance
7.2.1 The demonstration that the specified sterilization process does not affect the correct functioning of the
product may be accomplished by performing functionality tests, or other appropriate tests, on the medical
device and packaging following sterilization. These tests may range from a simple visual inspection to a
battery of specialized tests.
Elements that could affect safety, quality or performance include:
a) cycle pressure changes that could affect seal integrity;
b) effects of EO exposure time, temperature, humidity and, if applicable, any inert gases present in the
intended sterilization blend;
c) inclusion of new materials known to retain higher EO residuals;
d) packaging characteristics;
e) the presence of lubricants, especially within mated surface areas;
f) whether the medical device requires disassembly or cleaning;
g) safety hazards (e.g. leachable materials, or batteries or sealed liquids that could leak or explode);
h) number of sterilization cycles.
Medical devices containing a potential source of ignition (e.g. a battery) should be sterilized using a process
that does not contain an explosive mixture of EO in any part of the cycle.
7.2.2 When multiple sterilization cycles are permitted, the evaluation of the product should include biological
safety.
For re-usable medical devices, the manufacturer’s reprocessing instructions should be available and followed.
The instructions should include the recommended sterilization parameters and the limits to the number of
sterilization cycles. If applicable, testing and inspection should be performed to assess functionality of the re-
usable medical device following sterilization. The medical device manufacturer’s claims for the number of
allowable cycles should be considered to be the maximum. A system should be in place which will provide
notification if the maximum number of cycles is reached.
NOTE See ISO 17664 for more information.
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ISO/TS 11135-2:2008(E)
7.2.3 No guidance offered.
7.2.4 Proper aeration is essential to control EO residues in medical devices after EO processing. If
information regarding aeration time for a medical device is not available from the manufacturer, the health
care facility should establish the aeration time for that device. Using either data or knowledge of the product
and its material and design, the aeration time should be established based upon the most difficult-to-aerate
product or medical device. It is not feasible to test residues on each individual item that has been sterilized.
[1]
NOTE See ISO 10993-7 for more information.
7.3 Microbiological quality
7.3.1 No guidance offered.
7.3.2 In health care facilities, attention to microbiological quality will comprise having strict procedures for
collection and handling of used, re-usable medical devices, and for validation and control of the cleaning
processes for re-usable medical devices in accordance with the medical device manufacturer’s instructions.
[5],[6],[7],[8]
NOTE See ISO 17664 and the ISO 15883 series of documents for more information.
7.4 Documentation
Upon completion of the product definition the following should be documented.
a) The sterilization specification for the product. This specification should fully describe the product
configuration and how it is to be presented to the EO process (packaging and load configuration). The
specification should also include or reference the required SAL, as well as evidence for, or assessment of,
the compatibility of the product with the process.
b) The result of the comparison between the new or modified product and the existing validated product(s).
This result should clearly demonstrate that product complexity, materials, packaging and load
configuration were assessed.
c) Evidence or assessment of the bioburden of the product and its resistance relative to the biological
indicator (BI).
d) The documented conclusion that the new or modified product is suitable for adoption into the EO product
family/processing group specifically referenced in the current validation study to achieve the specified
SAL. This conclusion should include or reference any results from additional tests performed to
supplement the existing validation study and any further testing performed for confirmation/qualification
for routine release of product from the existing validated cycle (i.e. residual testing, functional testing).
This documentation should be:
1) approved by the sterilization specialist and other individuals as required by the normal change control
practices within the organization;
2) retained for at least as long as the medical device is in use, or for at least as long as required by
regulatory agencies or facility policies, whichever is longer;
3) retrievable.
8 Process definition
8.1 During process definition, a manufacturer will use microbiological testing and other analytical tools to
help establish an appropriate sterilization process for a medical device. For re-usable medical devices that will
be reprocessed in the health care facility, the manufacturer is expected to provide validated reprocessing
ISO/TS 11135-2:2008(E)
instructions, which are based in part on the process definition. It is then the health care facility’s responsibility
to review this documentation and confirm that it can follow the medical device manufacturer’s instructions
using its own equipment and sterilization cycles. The health care facility's purchasing procedures should
require that, prior to the purchase of an EO-sterilizable medical device, the reprocessing instructions be
evaluated to confirm that the device is compatible with
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