ISO 13781:2017

INTERNATIONAL ISO
STANDARD 13781
Second edition
2017-07
Implants for surgery —
Homopolymers, copolymers and
blends on poly(lactide) — In vitro
degradation testing
Implants chirurgicaux — Homopolymères, copolymères et mélanges
sur poly(lactide) — Essais de dégradation in vitro
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
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ii © ISO 2017 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Degradation evaluation . 3
4.1 General . 3
4.2 Apparatus and reagents . 4
4.3 Real-time degradation — Sample conditioning procedure . 5
4.3.1 Sample loading and placement. 5
4.3.2 Control of temperature . 5
4.3.3 Control of buffer solution . 5
4.3.4 Sample retrieval. 5
5 Physical, chemical and mechanical tests . 6
5.1 General . 6
5.2 Loss of sample mass . 6
5.2.1 Apparatus . 6
5.2.2 Number of test samples . 6
5.2.3 Procedure . 7
5.2.4 Reusability of test specimens. 7
5.3 Evaluation of molar mass . 8
5.3.1 Via inherent viscosity . 8
5.3.2 Via gel permeation chromatography/size exclusion chromatography . 8
5.4 Mechanical tests . 8
5.4.1 General. 8
5.4.2 Conditioning of test samples . 8
5.4.3 Test methods . 9
5.5 Additional evaluation methods for consideration . 9
6 Test termination . 9
7 Test report .10
Annex A (informative) Nomenclature of absorb, degrade and related terms .12
Annex B (informative) Additional analytic methods for consideration .13
Bibliography .14
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
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electrotechnical standardization.
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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
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URL: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 150, Implants for surgery, Subcommittee
SC 1, Materials.
This second edition cancels and replaces the first edition (ISO 13781:1997) and ISO 15814, which have
been technically revised.
The main change compared to the previous edition is as follows:
— the principle contents of ISO 15814 are incorporated into this document.
iv © ISO 2017 – All rights reserved

Introduction
With the development of absorbable polymers for use in implantable devices, there is a need to
define standard test methods to evaluate the behaviour of bulk material or devices under simulated
physiological environments. On the other hand, the behaviour of absorbable materials and devices in
situ depends on the conditions in which the material is implanted. These conditions differ, so that the
site-specific behaviour of the material or device can differ. The interpretation of in vitro test results
therefore needs to be considered carefully, taking into account any correlation of test results under
in vitro and in vivo conditions. Only functional in vivo tests with the final product can answer actual
degradation behaviour in situ.
INTERNATIONAL STANDARD ISO 13781:2017(E)
Implants for surgery — Homopolymers, copolymers and
blends on poly(lactide) — In vitro degradation testing
1 Scope
This document describes methods for the determination of chemical and mechanical changes in
poly(lactide)-based homopolymers, copolymers and/or blends induced under in vitro degradation
testing conditions. This document covers polymers based on L-lactide, D-lactide, and/or D, L-lactide
monomeric units.
The purpose of this document is to compare and/or evaluate materials or processing conditions. This
document also describes the fundamental physical and mechanical evaluations needed for an in vitro
degradation characterization of an absorbable poly(lactide) or other hydrolysable material or device.
This document is applicable to poly(lactide)-based homopolymers, copolymers and/or blends in bulk
or processed forms and used for the manufacture of surgical implants, including finished products
(packaged and sterilized implants).
The test methods specified in this document are also intended to determine the in vitro degradation
rate and related changes in material properties of polylactide-based copolymers and/or blends with
various other comonomers, such as glycolid, trimethylene, carbonate and/or ε-caprolactone. Unless
otherwise validated for a specific device, these in vitro methods cannot be used to definitively predict
device behaviour under in vivo conditions.
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 178, Plastics — Determination of flexural properties
ISO 180, Plastics — Determination of Izod impact strength
ISO 527-1, Plastics — Determination of tensile properties — Part 1: General principles
ISO 527-2, Plastics — Determination of tensile properties — Part 2: Test conditions for moulding and
extrusion plastics
ISO 527-3, Plastics — Determination of tensile properties — Part 3: Test conditions for films and sheets
ISO 604,Plastics — Determination of compressive properties
ISO 1628-1, Plastics — Determination of the viscosity of polymers in dilute solution using capillary
viscometers — Part 1: General principles
ISO 1805, Fishing nets — Determination of breaking force and knot breaking force of netting yarns
ISO 2062, Textiles — Yarns from packages — Determination of single-end breaking force and elongation at
break using constant rate of extension (CRE) tester
ISO 6721-2, Plastics — Determination of dynamic mechanical properties — Part 2: Torsion-pendulum method
ISO 13934-1, Textiles — Tensile properties of fabrics — Part 1: Determination of maximum force and
elongation at maximum force using the strip method
ISO 14130, Fibre-reinforced plastic composites — Determination of apparent interlaminar shear strength
by short-beam method
ISO 16014-1, Plastics — Determination of average molecular mass and molecular mass distribution of
polymers using size-exclusion chromatography — Part 1: General principles
ISO 16014-2, Plastics — Determination of average molecular mass and molecular mass distribution of
polymers using size-exclusion chromatography — Part 2: Universal calibration method
ISO 16014-3, Plastics — Determination of average molecular mass and molecular mass distribution of
polymers using size-exclusion chromatography — Part 3: Low-temperature method
ISO 16014-4, Plastics — Determination of average molecular mass and molecular mass distribution of
polymers using size-exclusion chromatography — Part 4: High-temperature method
ISO 16014-5, Plastics — Determination of average molecular mass and molecular mass distribution of
polymers using size-exclusion chromatography — Part 5: Method using light-scattering detection
ASTM D2990,Standard test methods for tensile, compressive, and flexural creep and creep-rupture of
plastics
ASTM D5296, Test method for molecular weight averages an
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