ASTM F1925-22

Standard Specification for Semi-Crystalline Poly(lactide) Polymer and Copolymer Resins for Surgical Implants

ABSTRACT
This specification covers virgin poly(L-lactic acid) resin (PLLA resin) intended for use in surgical implants. This specification does not cover stereoisomeric compositions based on various D, L, or DL copolymer ratios. This specification addresses material characteristics of virgin poly(L-lactic acid) resin and does not apply to packaged and sterilized finished implants fabricated from this material. The virgin polymer shall be a homopolymer of L-lactide with the prescribed density. The molecular mass of the virgin polymer shall be indicated by relative solution viscosity (in chloroform). In addition, the weight average molecular mass and molecular mass distributions may be determined by gel permeation chromatography The virgin polymer shall be identified as a polylactide by infrared or 1H-NMR spectroscopy. Typical infrared transmission and 1H-NMR spectra are shown. The virgin polymer shall have a specific optical rotation (in dichloromethane) and residual monomer content within the prescribe values, and shall conform to the chemical and physical property requirements specified for: residual solvent, residual water, residual tin, heavy metals, and sulfated ash. The following test methods shall be used: (1) Karl-Fischer titration and (2) atomic absorption-emission (AA) spectroscopy or inductively coupled plasma (ICP) spectroscopy. Considerations for biocompatibility of the material from a human implant perspective is also given.
SCOPE
1.1 This specification covers virgin semi-crystalline poly(l-lactide) or poly(d-lactide) homopolymer resins intended for use in surgical implants. This specification also covers semi-crystalline resins of l-lactide copolymerized with other bioabsorbable monomers including, but not limited to, glycolide, d-lactide, and dl-lactide. The poly(l-lactide) or poly(d-lactide) based homopolymers and copolymers covered by this specification possess lactide segments of sufficient length to allow potential for their crystallization upon annealing.  
1.2 Since poly(glycolide) is commonly abbreviated as PGA for poly(glycolic acid) and poly(lactide) is commonly abbreviated as PLA for poly(lactic acid), these polymers are commonly referred to as PGA, PLA, and PLA:PGA resins for the hydrolytic byproducts to which they respectively degrade. PLA is a term that carries no stereoisomeric specificity and therefore encompasses both the amorphous atactic/syndiotactic dl-lactide based polymers and copolymers as well as the isotactic d-PLA and l-PLA moieties, each of which carries potential for crystallization. Inclusion of stereoisomeric specificity within the lactic acid based acronyms results in the following: poly(l-lactide) as PlLA for poly(l-lactic acid), poly(d-lactide) as PdLA for poly(d-lactic acid), and poly(dl-lactide) as PdlLA for poly(dl-lactic acid).  
1.3 This specification is applicable to lactide-based polymers or copolymers that possess isotactic polymeric segments sufficient in size to carry potential for lactide-based crystallization. Such polymers typically possess nominal mole fractions that equal or exceed 50 % l-lactide. This specification is particularly applicable to isotactic-lactide based block copolymers or to polymers or copolymers synthesized from combinations of d-lactide and l-lactide that differ by more than 1.5 total mole percent (1.5 % of total moles). This specification is not applicable to lactide-co-glycolide copolymers with glycolide mole fractions greater than or equal to 70 % (65.3 % in mass fraction), which are covered by Specification F2313. This specification is not applicable to amorphous polymers or copolymers synthesized from combinations of d-lactide and l-lactide that differ by less than 1.5 total mole percent (1.5 % of total moles) as covered by Specification F2579.  
1.4 This specification covers virgin semi-crystalline poly(lactide)-based resins able to be fully solvated at 30 °C by either methylene chloride (dichloromethane) or chloroform (tr...

General Information

• Status: Published
• Publication Date: 31-Jan-2022
• ICS: 11.040.40 - Implants for surgery, prosthetics and orthotics
• ICS: 83.080.20 - Thermoplastic materials
• Technical Committee: F04 - Medical and Surgical Materials and Devices
• Drafting Committee: F04.11 - Polymeric Materials

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F1925 −22
Standard Specification for
Semi-Crystalline Poly(lactide) Polymer and Copolymer
1
Resins for Surgical Implants
This standard is issued under the fixed designation F1925; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope massfraction),whicharecoveredbySpecificationF2313.This
specification is not applicable to amorphous polymers or
1.1 This specification covers virgin semi-crystalline poly(L-
copolymers synthesized from combinations of D-lactide and
lactide)orpoly(D-lactide)homopolymerresinsintendedforuse
L-lactide that differ by less than 1.5 total mole percent (1.5 %
in surgical implants. This specification also covers semi-
of total moles) as covered by Specification F2579.
crystalline resins of L-lactide copolymerized with other bioab-
sorbable monomers including, but not limited to, glycolide,
1.4 This specification covers virgin semi-crystalline
D-lactide, and DL-lactide. The poly(L-lactide) or poly(D-lactide)
poly(lactide)-based resins able to be fully solvated at 30 °C by
based homopolymers and copolymers covered by this specifi-
either methylene chloride (dichloromethane) or chloroform
cation possess lactide segments of sufficient length to allow
(trichloromethane). This specification is not applicable to
potential for their crystallization upon annealing.
lactide:glycolide copolymers that possess glycolide segments
sufficient in size to deliver potential for glycolide-based
1.2 Since poly(glycolide) is commonly abbreviated as PGA
crystallization, thereby requiring fluorinated solvents for com-
for poly(glycolic acid) and poly(lactide) is commonly abbre-
plete dissolution under room temperature conditions (see
viated as PLA for poly(lactic acid), these polymers are com-
Specification F2313).
monly referred to as PGA, PLA, and PLA:PGA resins for the
hydrolyticbyproductstowhichtheyrespectivelydegrade.PLA
1.5 Within this specification, semi-crystallinity within the
isatermthatcarriesnostereoisomericspecificityandtherefore
resin is defined by the presence of a DSC (differential scanning
encompasses both the amorphous atactic/syndiotactic DL-
calorimetry) crystalline endotherm after annealing above the
lactide based polymers and copolymers as well as the isotactic
glass transition temperature. While other copolymeric seg-
D-PLAand L-PLAmoieties, each of which carries potential for
ments may also crystallize upon annealing (for example,
crystallization. Inclusion of stereoisomeric specificity within
glycolide), specific characterization of crystalline structures
the lactic acid based acronyms results in the following:
other than those formed by lactide are outside the scope of this
poly(L-lactide) as PLLA for poly(L-lactic acid), poly(D-lactide)
specification.
as PDLAfor poly(D-lactic acid), and poly(DL-lactide) as PDLLA
1.6 This specification addresses material characteristics of
for poly(DL-lactic acid).
the virgin semi-crystalline poly(lactide)-based resins intended
1.3 This specification is applicable to lactide-based poly-
foruseinsurgicalimplantsanddoesnotapplytopackagedand
mers or copolymers that possess isotactic polymeric segments
sterilized finished implants fabricated from these materials.
sufficient in size to carry potential for lactide-based crystalli-
1.7 As with any material, some characteristics may be
zation. Such polymers typically possess nominal mole frac-
altered by processing techniques (such as molding, extrusion,
tions that equal or exceed 50 % L-lactide. This specification is
machining, assembly, sterilization, and so forth) required for
particularly applicable to isotactic-lactide based block copoly-
the production of a specific part or device. Therefore, proper-
mers or to polymers or copolymers synthesized from combi-
ties of fabricated forms of this resin should be evaluated
nations of D-lactide and L-lactide that differ by more than 1.5
independently using appropriate test methods to ensure safety
total mole percent (1.5 % of total moles). This specification is
and efficacy.
not applicable to lactide-co-glycolide copolymers with gly-
colide mole fractions greater than or equal to 70 % (65.3 % in
1.8 Biocompatibility testing is not a requirement since this
specification is not intended to cover fabricated devices.
1.9 The values stated in SI units are to be regarded as
1
This specification is under the jurisdiction of ASTM Committee F04 on
standard. No other units of measurement are included in this
Medical a
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F1925 − 17 F1925 − 22
Standard Specification for
Semi-Crystalline Poly(lactide) Polymer and Copolymer
1
Resins for Surgical Implants
This standard is issued under the fixed designation F1925; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This specification covers virgin semi-crystalline poly(L-lactide) or poly(D-lactide) homopolymer resins intended for use in
surgical implants. This specification also covers semi-crystalline resins of L-lactide copolymerized with other bioabsorbable
monomers including, but not limited to, glycolide, D-lactide, and DL-lactide. The poly(L-lactide) or poly(D-lactide) based
homopolymers and copolymers covered by this specification possess lactide segments of sufficient length to allow potential for
their crystallization upon annealing.
1.2 Since poly(glycolide) is commonly abbreviated as PGA for poly(glycolic acid) and poly(lactide) is commonly abbreviated as
PLA for poly(lactic acid), these polymers are commonly referred to as PGA, PLA, and PLA:PGA resins for the hydrolytic
byproducts to which they respectively degrade. PLA is a term that carries no stereoisomeric specificity and therefore encompasses
both the amorphous atactic/syndiotactic DL-lactide based polymers and copolymers as well as the isotactic D-PLA and L-PLA
moieties, each of which carries potential for crystallization. Inclusion of stereoisomeric specificity within the lactic acid based
acronyms results in the following: poly(L-lactide) as PLLA for poly(L-lactic acid), poly(D-lactide) as PDLA for poly(D-lactic acid),
and poly(DL-lactide) as PDLLA for poly(DL-lactic acid).
1.3 This specification is applicable to lactide-based polymers or copolymers that possess isotactic polymeric segments sufficient
in size to carry potential for lactide-based crystallization. Such polymers typically possess nominal mole fractions that equal or
exceed 50 % L-lactide. This specification is particularly applicable to isotactic-lactide based block copolymers or to polymers or
copolymers synthesized from combinations of D-lactide and L-lactide that differ by more than 1.5 total mole percent (1.5 % of total
moles). This specification is not applicable to lactide-co-glycolide copolymers with glycolide mole fractions greater than or equal
to 70 % (65.3 % in mass fraction), which are covered by Specification F2313. This specification is not applicable to amorphous
polymers or copolymers synthesized from combinations of D-lactide and L-lactide that differ by less than 1.5 total mole percent
(1.5 % of total moles) as covered by Specification F2579.
1.4 This specification covers virgin semi-crystalline poly(lactide)-based resins able to be fully solvated at 30°C30 °C by either
methylene chloride (dichloromethane) or chloroform (trichloromethane). This specification is not applicable to lactide:glycolide
copolymers that possess glycolide segments sufficient in size to deliver potential for glycolide-based crystallization, thereby
requiring fluorinated solvents for complete dissolution under room temperature conditions (see Specification F2313).
1.5 Within this specification, semi-crystallinity within the resin is defined by the presence of a DSC (differential scanning
calorimetry) crystalline endotherm after annealing above the glass transition temperature. While other copolymeric segments may
1
This specification is under the jurisdiction of ASTM Committee F04 on Medical and Surgical Materials and Devices and is the direct responsibility of Subcommittee
F04.11 on Polymeric Materials.
Current edition approved Dec. 15, 2017Feb. 1, 2022. Published January 2018February 2022. Originally approved in 1998. Last previous edition approved in 20092017
as F1925 – 09.F1925 – 17. DOI: 10.1520/F1925-17.10.1520/F1925-22.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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F1925 − 22
also crystallize upon annealing (for example, glycolide), specific characterization of crystalline structures other than those formed
by lactide are outside the scope of this specification.
1.6 This specification addresses material characteristics of the virgin semi-crystalline poly(lactide) based poly(lactide)-based
resins intended for use in surgical implants and d
...