ISO 19671:2018

Additional lubricants for male natural rubber latex condoms - Effect on condom strength

This document specifies a method of assessing the effect or compatibility of an additional or personal lubricant with lubricated male natural rubber latex condoms. It also applies to topical medicines and any other substances that come into contact with such condoms. It describes the measurement of changes in physical properties of the condoms after exposure to the test substance (i.e. lubricant, topical medicine, etc.) and specifies the pass/fail criteria for such changes. This document is not applicable to the assessment of the compatibility of lubricants applied to a condom at the time of manufacture. It is not directly applicable to the assessment of the compatibility of a particular condom with lubricants or other substances. It is not directly applicable to tests using female condoms, although similar principles can apply. The test methods are applicable to condoms made from natural rubber latex and from synthetic materials, but a pass/fail criterion is only stipulated for natural rubber latex.

Lubrifiants supplémentaires pour préservatifs masculins en latex de caoutchouc naturel — Effet sur la résistance du préservatif

General Information

• Status: Published
• Publication Date: 30-Oct-2018
• ICS: 11.200 - Birth control. Mechanical contraceptives
• Technical Committee: ISO/TC 157 - Non-systemic contraceptives and STI barrier prophylactics
• Drafting Committee: ISO/TC 157/WG 15 - Additional lubricants
• Current Stage: 9092 - International Standard to be revised
• Start Date: 27-Sep-2024
• Completion Date: 13-Dec-2025

Overview

ISO 19671:2018 - "Additional lubricants for male natural rubber latex condoms - Effect on condom strength" specifies a laboratory method to assess how an additional/personal lubricant, topical medicine or any substance coming into contact with a lubricated male natural rubber latex condom affects its physical strength. The standard describes controlled exposure, conditioning and measurement of changes in tensile (force and elongation at break) and inflation (airburst) properties, and sets pass/fail criteria for natural rubber latex condoms.

Key topics and technical requirements

• Scope and limits
  • Applies to additional/personal lubricants, topical medicines and similar substances; not for lubricants applied during manufacture.
  • Intended for male condoms; not directly applicable to female condoms.
  • Test methods are applicable to synthetic materials, but pass/fail criteria are only stipulated for natural rubber latex.
• Principal variables
  • Force at break is the principal and most sensitive indicator; percent elongation at break and inflation/airburst properties are also measured.
  • Exposure time: 60 minutes contact followed by conditioning (heated to ~body temperature).
• Sample and controls
  • Use three distinct commercially available natural latex condom brands (different factories/companies), smooth and straight-walled, mean thickness 0.055–0.07 mm.
  • Control group uses distilled water (negative control); positive controls include liquid paraffin and cyclomethicone D5 (specified viscosity and specific gravity).
  • Minimum sample size for tensile testing: 30 condoms per group.
• Apparatus & procedure highlights
  • Environmental chamber/oven at (40 ± 2) °C, tensile tester with roller grips, ring-cutting die, inflation tester per ISO 4074.
  • Lubricant dosing for inflation testing: (1.5 ± 0.15) ml per condom (topical medicines: one normal dose).
• Results and criteria
  • Measurement methods are in Annex A; statistical treatment and pass/fail criteria appear in Clauses 10–11 and Annex B.

Applications and who uses it

• Lubricant manufacturers - pre-market compatibility screening for personal lubricants and topical formulations.
• Condom and medical device manufacturers - supplier validation, quality assurance, product development.
• Independent testing and regulatory labs - conformity assessment and consumer safety screening.
• Clinical researchers and public health agencies - evaluating risk of condom weakening when used with specific products.

Related standards

• ISO 4074:2015 - Natural rubber latex male condoms - requirements and test methods (referenced for inflation/airburst testing and condom requirements).

Keywords: ISO 19671:2018, condom compatibility testing, lubricant compatibility, natural rubber latex condom strength, tensile testing, inflation testing, positive control, ISO 4074.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 19671
First edition
2018-11
Corrected version
2020-02
Additional lubricants for male natural
rubber latex condoms — Effect on
condom strength
Lubrifiants supplémentaires pour préservatifs masculins en latex de
caoutchouc naturel — Effet sur la résistance du préservatif
Reference number
©
ISO 2018
© ISO 2018
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
ii © ISO 2018 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
6 Materials . 3
7 Samples and tests . 3
7.1 Sample overview . 3
7.2 Condom sample groups . 4
7.3 Sample size . 4
7.4 Quantity of test substance . 4
7.4.1 Inflation testing . 4
7.4.2 Tensile testing . 4
8 Procedure. 4
8.1 General . 4
8.2 (Negative) control testing . 5
8.3 Inflation testing . 5
8.4 Tensile testing . 5
9 Positive control testing . 6
10 Pass/Fail criteria . 6
11 Expression of results . 8
Annex A (normative) Determination of force and elongation at break of test pieces of condoms .9
Annex B (informative) Determination of the confidence interval for the ratio of two means.12
Bibliography .15
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 157, Non-systemic contraceptives and STI
barrier prophylactics.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
This corrected version of ISO 19671:2018 incorporates the following corrections:
— specifications for viscosity and specific gravity of positive control in 6.2;
— specifications for viscosity and specific gravity of positive control in Clause 9;
— “test substance” has been replaced by “lubricant” in A.3.3;
— subscript in Formula (B.4).
iv © ISO 2018 – All rights reserved

Introduction
Weakening of natural rubber latex is known to occur after contact with certain lubricants, particularly
petroleum-based products. This procedure was developed as a screening method for lubricant
manufacturers to determine whether or not a particular personal lubricant or topical medicine has
a significant effect on the tensile and airburst properties of condoms. It is also applicable to topical
medicines and other chemicals that might come in contact with vulval, vaginal or rectal tissues, and
hence with condoms.
The method is designed for use on male condoms that meet the criteria of ISO 4074. While the test
method can be effective for male condoms made of other raw materials, there is no evidence upon
which to base pass/fail criteria for these materials.
This test method does not determine the safety of either the test substance or the condom.
This test method is to be used only to determine if the tensile or airburst properties of the condom have
been significantly affected by the test substance.
INTERNATIONAL STANDARD ISO 19671:2018(E)
Additional lubricants for male natural rubber latex
condoms — Effect on condom strength
1 Scope
This document specifies a method of assessing the effect or compatibility of an additional or personal
lubricant with lubricated male natural rubber latex condoms. It also applies to topical medicines
and any other substances that come into contact with such condoms. It describes the measurement
of changes in physical properties of the condoms after exposure to the test substance (i.e. lubricant,
topical medicine, etc.) and specifies the pass/fail criteria for such changes.
This document is not applicable to the assessment of the compatibility of lubricants applied to a condom
at the time of manufacture. It is not directly applicable to the assessment of the compatibility of a
particular condom with lubricants or other substances. It is not directly applicable to tests using female
condoms, although similar principles can apply.
The test methods are applicable to condoms made from natural rubber latex and from synthetic
materials, but a pass/fail criterion is only stipulated for natural rubber latex.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 4074:2015, Natural rubber latex male condoms — Requirements and test methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4074 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
personal lubricant
additional lubricant intended for application by the user at the time of condom use
3.2
positive control
test substance (3.3) which is known to cause deterioration in the physical properties of a condom
3.3
test substance
lubricant (3.1), topical medicine (3.4) or other material which is being tested for compatibility with
condoms
3.4
topical medicine
medicine intended to be used vaginally or rectally, and which might come into contact with a
condom in use
4 Principle
This test method measures the change in tensile properties and inflation properties of condoms, after
60 min of contact with a lubricant or other test substance to which this document refers. Force at break
is the principal and most sensitive variable used in assessing the effect of test substances.
For tensile testing, rings cut from condoms are exposed to the test substance, heated to body
temperature, cleaned of excess test substance, and tested for force at break and percent elongation at
break in accordance with Annex A. Those properties are compared to control rings that are subjected
to the same procedures using distilled water instead of the test substance.
For inflation testing, the parts of the condoms which are subject to inflation are exposed to the test
substance and are then heated to body temperature. They are then subjected to inflation testing as
prescribed in ISO 4074 or ISO 23409. The results are compared to control condoms that are subjected
to the same using distilled water instead of the test substance.
5 Apparatus
5.1 Environmental chamber or oven, capable of maintaining (40 ± 2) °C.
5.2 Specimen containers for inflation testing, capable of holding one condom and sealing volatile
components of the test substance, so they cannot escape into the atmosphere. The excess space in the
container should be kept to a minimum.
NOTE A glass jar is a suitable container.
5.3 Specimen containers for tensile testing, capable of holding one tensile sample and sealing
volatile components of the test substance, so they cannot escape into the atmosphere. The excess space
in the container should be kept to a minimum.
NOTE A glass jar is a suitable container.
5.4 Tensile tester and roller grips, capable of testing ring specimens according to Annex A.
5.5 Ring-cutting die, mechanical press, and replaceable cutting surface, for cutting ring specimens
from condoms, compliant with Annex A.
5.6 Mounts, suitable for holding ring samples while they are being coated with test substance. These
mounts may be two cylindrical rollers about 15 mm in diameter, placed with their axes about 50 mm
apart, over which the samples are stretched. Refer to Annex A.
5.7 Soft paintbrush, suitable for spreading the test substance on the condoms. A width of
approximately 10 mm and thickness 5 mm to 10 mm, is recommended.
5.8 Cylindrical mounts, suitable for coating and storing condom samples for inflation testing. These
can be glass test tubes 32 mm to 38 mm in diameter, or plastic rods with approximately hemispherical
ends, mounted in such a way that the condoms can easily be unrolled onto them.
NOTE The tubes are intended to produce a smooth condom surface for applying the test substance, and also
to allow easy removal of the condom after coating. The dimensions are not critical.
5.9 Inflation tester, suitable for testing condoms in accordance with ISO 4074:2015, Annex H.
5.10 Syringes or pipettes, for dosing 1,5 ml and 0,2 ml of the substance under test.
2 © ISO 2018 – All rights reserved

5.11 Small beaker or cylindrical container, about 30 mm in diameter, for storing the test substance
and for moistening paintbrushes.
6 Materials
6.1 Condoms, complying with ISO 4074, to which the test substance is applied. The condoms shall
be smooth and parallel-sided. The mean thickness of the condoms used, when measured according to
ISO 4074 shall be between 0,055 mm and 0,07 mm. The mean force at break of the negative control
condoms shall be between 70 N and 100 N.
6.2 Liquid paraffin, for positive control testing, meeting the current requirements of the US, European
or British pharmacopeia, with a specific gravity of 0,83 to 0,85 at (25 ± 2) °C, and a kinematic viscosity
-5 2 -5 2
of 4·10 m /s to 5·10 m /s at 40 °C. The liquid paraffin is expected to cause significant degradation in
natural rubber condom physical properties when the test method is properly performed.
6.3 Cyclomethicone D5, for positive control testing, meeting the current requirements of the US,
European or British pharmacopeia. The cyclomethicone D5 is expected to cause significant reversible,
short-term degradation in natural rubber condom physical properties when the test method is properly
performed.
6.4 Distilled water, for negative control testing.
6.5 Solvents, including water, isopropanol (IPA), and mild detergent, for cleaning laboratory
equipment and supplies after each test substance group has been tested.
6.6 Cornstarch, or similar inert powder, to assist in dimensional measurements and tensile testing
(optional).
6.7 Low-lint laboratory-grade paper towels, for removing test substance from test samples after
oven conditioning.
7 Samples and tests
7.1 Sample overview
7.1.1 This test method shall be performed on three distinct, commercially available natural latex
condoms made in different factories and belonging to different independent companies. The products
shall be chosen from among leading brands in the country or countries where the test result is to be
applied or, in the case of internationally branded products, three major international brands. The mean
thickness for each product as determined in accordance with ISO 4074 shall be in the range 0,055 mm to
0,07 mm.
7.1.2 Each brand of condom should be lubricated, straight-walled, smooth condoms from a single
finished lot.
7.1.3 All natural rubber latex condoms shall meet the requirements of ISO 4074.
It is acceptable to purchase condoms that are stated to conform to ISO 4074 from retail outlets or
wholesalers.
7.2 Condom sample groups
7.2.1 Each of the three distinct brands of condoms shall be divided into two groups and tested for
physical properties in the following order:
a) Control group: Condoms are tested according to 8.3 and 8.4, but the tensile samples/condoms
are lubricated with distilled water. All other handling and testing of the control tensile samples/
condoms shall be exactly the same as for the test substance group. There is no contact with the test
substance in the control group.
b) Test substance group: Condoms are tested in accordance with Clauses 8 and 9 with a substance for
which condom compatibility is unknown.
7.2.2 For staff training and for periodic re-validation of the method, a third group of products exposed
to a positive control (with short or long-term effects) shall be tested, either instead of or after, the test
substance group.
7.3 Sample size
The sample size for tensile testing shall not be less than 30 condoms per group.
7.4 Quantity of test substance
7.4.1 Inflation testing
a) Lubricants: Each condom shall be exposed to (1,5 ± 0,15) ml of lubricant.
b) Topical medicines: Each condom shall be exposed to one normal dose of the medicine. Where
necessary to achieve even spreading over the sample, the medicine may be dissolved or dispersed
in a minimum quantity of distilled water at a temperature of up to 45 °C prior to application.
7.4.2 Tensile testing
a) Lubricants: Each ring sample shall be exposed to (0,2 ± 0,02) ml of lubricant.
b) Topical medicines: Each ring sample shall be exposed to (12 ± 1) % of one normal dose of the
medicine. Where necessary to achieve even spreading over the sample, the medicine may be
dissolved or dispersed in a minimum quantity of distilled water at a temperature of up to 45 °C
prior to application.
8 Procedure
8.1 General
The negative control test shall be performed first, and be followed immediately by the test on the
test substance. Additional substances may be tested thereafter, provided all equipment is thoroughly
cleaned of the previous test substance beforehand. Provision is made for testing positive controls,
liquid paraffin and cyclomethicone D5, to train operators and validate techniques.
NOTE Some regulatory bodies might require positive control results to be submitted along with the results
for the test substances.
Tests performed using natural latex condoms shall apply to claims of compatibility with natural latex
condoms only.
Tensile testing shall be conducted in accordance with Annex A.
4 © ISO 2018 – All rights reserved

8.2 (Negative) control testing
For both inflation and tensile testing, a control test shall be conducted immedia
...