1、Designation: F3087 15Standard Specification forAcrylic Molding Resins for Medical Implant Applications1This standard is issued under the fixed designation F3087; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers acrylic resins supplied invirgin form (typically pellets, powder, or granules) for medicalimplant app
3、lications. The co-polymers are limited to randomco-polymers. This specification provides requirements andassociated test methods for this thermoplastic when it isintended for use in manufacturing implantable medical devicesor components of medical devices.1.1.1 While a variety of co-monomers may be
4、used, thecomposition of the resin shall contain poly(methyl methacry-late) (PMMA) as its primary ingredient. Classification D788defines an acrylic molding compound as “having at least 70%of the polymer polymerized from methyl methacrylate.” Theterms PMMA and acrylic as used herein refer generically
5、toboth the homopolymer and to co-polymers as defined above.1.2 As with any material, some characteristics may bealtered by the processing techniques (such as molding,extrusion, machining, sterilization, and so forth) required forthe production of a specific part or device. Therefore, proper-ties of
6、fabricated forms of this resin should be evaluated usingtest methods that are appropriate to ensure safety and efficacyas agreed upon between the supplier, purchaser, and regulatingbodies.1.3 This specification allows for designation of acrylicresins for all medical implant applications. The actual
7、extent ofperformance and suitability for a specific application shall beevaluated by the medical device manufacturer and regulatingbodies.1.4 The properties included in this specification are thoseapplicable for both unfilled acrylic polymers and for formu-lated resins containing barium sulfate. Ind
8、icated properties(Table 1 and Table X3.1) are for unfilled injection moldedforms. Forms containing fillers other than barium sulfate,colorants, polymer blends that contain PMMA, or reclaimedmaterials are not covered by this specification.1.5 Compliance with this specification does not obviate thenee
9、d for functional testing of any device fabricated from theresin to demonstrate effectiveness in its intended application.1.6 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.7 This standard does not purport to address all of th
10、esafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D638 Test Method for Tensil
11、e Properties of PlasticsD695 Test Method for Compressive Properties of RigidPlasticsD788 Classification System for Poly(Methyl Methacrylate)(PMMA) Molding and Extrusion CompoundsD792 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementD1238 Test Method for Me
12、lt Flow Rates of Thermoplasticsby Extrusion PlastometerD1898 Practice for Sampling of Plastics (Withdrawn 1998)3F451 Specification for Acrylic Bone CementF748 Practice for Selecting Generic Biological Test Methodsfor Materials and Devices2.2 ISO Standards4ISO 10993-1 Biological evaluation of medical
13、 devices Part1: Evaluation and testing within a risk managementprocessISO 17025 General Requirements for the Competence ofTesting and Calibration Laboratories1This test method is under the jurisdiction of ASTM Committee F04 on Medicaland Surgical Materials and Devices and is the direct responsibilit
14、y of SubcommitteeF04.11 on Polymeric Materials.Current edition approved July 15, 2015. Published July 2015. DOI: 10.1520/F3087-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informat
15、ion, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM Inter
16、national, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.3 Other Reference:Klaus-Dieter Kuhn, “Up-to-Date Comparison of Physicaland Chemical Properties of Commercial Materials,” BoneCements, Springer, 2000.3. Terminology3.1 Definitions:3.1.1 formulated resin, n
17、materials, parts, or devices fab-ricated from virgin polymer resin in such a way as to containintentional or unintentional adjuvant substances.3.1.2 poly(methyl methacrylate) (PMMA), nhomopolymerof methyl methacrylate (MMA), or random copolymer ofMMA with other vinyl monomers in which MMA constitute
18、sthe majority of the final content.3.1.3 virgin polymer, nthe initially delivered form of thepolymer as synthesized from its monomers prior to anyprocessing or fabrication into a medical device. The resin istypically provided in the form of pellets, granules, or powderand is the material from which
19、fibers, tubes, rods, slabs, sheets,films, or specific parts and devices are fabricated.4. Significance and Use4.1 This specification identifies the composition and recom-mends test methods to establish a reasonable level of confi-dence concerning the performance of acrylic resins for use inmedical i
20、mplant devices. The required properties are intendedto provide a means of ensuring consistent performance. Addi-tional testing should be considered in selecting a material inaccordance with specific end-use requirements.4.2 Acrylic resins may be considered for use in implantablemedical devices as we
21、ll as in non-implant medicalapplications, but this standard specifically covers resins usedfor implants. Resins meeting the requirements of this specifi-cation may be suitable for non-implant applications, but otheracrylic resins that do not conform to this standard may also besuitable for use in no
22、n-implant medical applications.4.3 Acrylic resins intended for use in implant applicationsare manufactured with more rigorous use of manufacturing ortesting controls, or both, to ensure consistency of properties,cleanliness, and biocompatibility. This is further elaborated in5.1.5. Classification5.1
23、 Acrylic resins meeting the requirements of this specifi-cation may be considered for use for either prolonged orpermanent medical implant applications. Resins classified forpermanent implant applications may require additional testingbeyond that required for prolonged use as agreed upon betweenthe
24、device manufacturer and regulating bodies. Use of resinsfor implant applications also implies a higher degree ofmanufacturing control. Implant grade resins shall be in com-pliance with the relevant aspects of Good ManufacturingPractices (GMPs), use of process validation, enhancedcontrols, and testin
25、g in a laboratory meeting the requirementsof ISO 17025. Acrylic resins classified for implantable devicesshall be evaluated for biological response in accordance withISO 10993-1 or Practice F748, Section 10, or both.NOTE 1Implant uses are medical applications implanted in the humanbody and devices t
26、hat are in contact with bodily fluids or tissues forgreater than 24 h; that is, prolonged (24 h to 30 days) or permanent ( 30days) exposure. Non-implant uses are medical applications in which thedevice is in contact with bodily fluids or tissues for 24 h or less (that is,limited exposure).5.2 The cl
27、ass and grade of unfilled acrylic plastic shall bedesignated in accordance with Classification D788.6. Chemical Composition6.1 The acrylic resin shall be a homopolymer of MMA or arandom co-polymer of MMA and other vinyl monomers whereMMAconstitutes the majority of the composition. No additivesother
28、than radiopaque fillers or stabilizers shall be used.6.2 The acrylic resin shall yield an infrared transmittancespectrum that exhibits major transmittance bands at the sameNOTE 1Spectrum courtesy of Wright Medical Technology, Memphis, TN. Nicolet Magna IR spectrometer, Attenuated Total Reflectance m
29、ode.FIG. 1 Poly(Methyl Methacrylate) Homopolymer Infrared SpectrumF3087 152wavelengths as shown in Fig. 1. The purpose of the infrared(IR) spectrum, as used in this specification, is to identify thePMMA present and does not necessarily indicate an acceptabledegree of material purity. The presence of
30、 additional bands inthe IR spectrum of a sample may indicate a co-polymerfraction, or impurities, or both.6.3 The acrylic resin (prior to formulation or molding) shallmeet the requirements of Table 1 as determined using avalidated method.6.4 The acrylic resin shall contain no more than 0.5 %residual
31、 monomer as determined using a validated method(typically gas chromatography or high performance liquidchromatography (HPLC).6.5 The molar mass of the acrylic resin shall be appropriateto the intended molding method (that is, injection molding,extrusion, etc.). The molar mass may be measured directl
32、ythrough use of size exclusion chromatography (SEC), intrinsicviscosity, etc., or indirectly through evaluation of the melt flowindex in accordance with Test Method D1238. The melt flowindex for injection molding of acrylic resins can usually bedetermined at 230C with a piston mass of 3.8 kg, but ot
33、herconditions may be required as agreed upon between the userand the supplier.7. Properties and Sampling7.1 Table X3.1 lists typical mechanical properties of non-sterilized fabricated forms molded from unfilled PMMA ho-mopolymer. Acrylic co-polymers typically have lower strengthand modulus values an
34、d higher elongations at break comparedto homopolymers. Specific requirements shall be as agreedupon between the resin supplier and the customer.7.1.1 The properties listed in Table X3.1 are determinedfrom specimens injection molded in accordance with the resinsuppliers process recommendations. Addit
35、ional or differenttreatments and processing steps (such as extrusion, molding,machining, sterilization, and so forth) may alter the materialproperties.7.2 The material shall be sampled in accordance withstandard sampling procedures such as those described inPractice D1898, unless otherwise agreed up
36、on between thecustomer and the supplier.7.3 Testing shall be conducted on specimens fabricatedunder the same relevant conditions used on the finishedproduct.7.3.1 Testing for lot acceptance purposes may be conductedon as-molded parts. Testing for device evaluation shall beperformed on materials that
37、 have been through all processingintended for the final product, including cleaning and steriliza-tion.8. Appearance8.1 The resin shall be inspected for particulate foreignmatter contamination using the following or an equivalentprocedure:8.1.1 Spread a 100-g sample of the resin onto a flat, whitesu
38、rface and visually inspect (20/20 corrected vision if neces-sary) at a distance of 18 to 20 in. No more than 4 visibleparticles smaller than 0.5 mm shall be allowed. No particlesgreater than 0.5 mm shall be allowed. It may not be possible toevaluate foreign matter contamination for opaque materialsu
39、sing this method.8.2 More sophisticated methods or stricter criteria, or both,for evaluating contamination may be agreed upon between thesupplier and the customer, including the use of lower limitsthan given in 8.1.9. Certification9.1 Material suitable for medical implant applications shallbe certif
40、ied as meeting the requirements of this specification.Additionally, certification shall be as indicated in the materialSpecification D788 unless otherwise agreed upon between thesupplier and the customer. Testing and certification may beperformed by either the resin manufacturer or the medicaldevice
41、 manufacturer.9.2 Melt flow rate and residual monomer concentration shallbe used to determine lot acceptance properties. These testresults shall be included on the certificate of analysis.However, a periodic check of other designated properties mayalso be agreed upon between the purchaser and the su
42、pplier,depending on the application. Agreement between the pur-chaser and the supplier may also include testing of otherdesignated properties for validation and certification, depend-ing on the application.9.3 The certification shall state that the material was manu-factured by a process in statisti
43、cal control and sampled, tested,and inspected in accordance with this specification, and that theaverage values for the lot meet the requirements of thisspecification.NOTE 2TheASTM Manual on Presentation of Data and Control ChartAnalysis provides detailed information about statistical process contro
44、l.10. Assessment of Selected Tissue Effects10.1 The assessment of selected tissue effects of implantdevices made using acrylic polymers meeting this specificationshall be determined in accordance with Practice F748 or theISO 10993 series, unless otherwise agreed upon between theimplant manufacturer
45、and regulating bodies. Biological testingshould be conducted on the finished product after it has gonethrough all processing steps, including sterilization.TABLE 1 Required Properties of Virgin ResinsProperty ASTM Test Method Property ValuesDensity, g/cm3D792 1.17 to 1.20Residual monomer, % Gas chro
46、matography or HPLC 0.5 % maxMelt flow index, g/10 min D1238 (typically at 230C and 3.8 kg;use other conditions as required.)As agreed upon between the user and the supplier.F3087 15310.2 Acrylic polymers meeting the requirements of Speci-fication F451, which consist primarily of PMMA but withsubstan
47、tially higher concentrations of residual monomer(MMA), have been used successfully as in-situ curing bonecements for over 35 years. A comprehensive listing of com-mercially available bone cements has been published thatincludes information on the co-monomers used, although thepercentages of the co-m
48、onomers are not given.5In-situ curedPMMA is characterized by a transient tissue response that hasbeen shown to be due to a combination of thermal damagefrom the exothermic curing reaction, and leaching of residualmonomer, which can be present in concentrations as high as 5%. Molded devices of PMMA h
49、ave residual monomer levels atleast an order of magnitude lower than that of bone cements,and are therefore inherently more biocompatible than an in-situcuring acrylic bone cement. Therefore, if it can be demon-strated through quantitative chemical analysis that the typesand amounts of co-monomers used in the synthesis of theinjection molding resin fall within the composition of an in-situcuring acrylic bone cement with a successful clinical history itmay not be necessary to conduct full biocompatibility testingon the molding resin. This information should be taken into
