1、Designation: F619 03 (Reapproved 2008)F619 14Standard Practice forExtraction of Medical Plastics1This standard is issued under the fixed designation F619; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision.An
2、umber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers methods of extraction of medical plastics and may be applicable to other materials. This practiceidentifies a method
3、for obtaining “extract liquid” for use in determining the biological response in preclinical testing. Furthertesting of the “extract liquid” is specified in other ASTM standards. The extract may undergo chemical analysis as part of thepreclinical evaluation of the biological response, and the materi
4、al after extraction may also be examined.1.2 This practice may be used for, but is not limited to the following areas: partial evaluation of raw materials, auditing materialswithin the manufacturing process, and testing final products. This practice may also be used as a referee method for themeasur
5、ement of extractables in plastics used in medical devices.1.3 This practice was initially developed for extraction of medical plastics not intended to undergo degradation or absorptionduring normal medical device usage. When applied to the extraction of absorbable materials, additional consideration
6、s may benecessary in the selection of extraction procedures and fluids.1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information only and are not considered standard.1.5 This sta
7、ndard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 AS
8、TM Standards:2D543 Practices for Evaluating the Resistance of Plastics to Chemical ReagentsD570 Test Method for Water Absorption of PlasticsD1193 Specification for Reagent WaterD1239 Test Method for Resistance of Plastic Films to Extraction by ChemicalsD1898 Practice for Sampling of Plastics (Withdr
9、awn 1998)3F748 Practice for Selecting Generic Biological Test Methods for Materials and Devices2.2 Other Documents:USP NF 24 or current edition43. Definitions3.1 extraction vehiclea liquid specified for use in testing the plastic. Specific extraction vehicles are to be designated by theASTM standard
10、 that references this practice (see Section 7 for a list of standard extraction vehicles).3.2 extract liquidthat liquid which, after extraction of the specimen, is used in tests.3.3 specimen portionthe unit or units of plastic placed into the extraction vehicle.3.4 blankthe extraction vehicle not co
11、ntaining the specimen under test which is used for comparison with the extract liquid.1 This practice is under the jurisdiction of ASTM Committee F04 on Medical and Surgical Materials and Devices and is the direct responsibility of Subcommittee F04.16on Biocompatibility Test Methods.Current edition
12、approved Aug. 1, 2008March 1, 2014. Published August 2008April 2014. Originally approved in 1979. Last previous edition approved in 20032008 asF619 03.F619 03 (2008). DOI: 10.1520/F0619-03R08.10.1520/F0619-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Custome
13、r Service at serviceastm.org. ForAnnual Book ofASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.4 Available from U.S. Pharmacopeia (USP), 12601 Twinbrook Pkwy., Roc
14、kville, MD 20852-1790, http:/www.usp.org.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. Becauseit may not be technically possible to adequately depict all changes accurately, AST
15、M recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Summ
16、ary of Practice4.1 Standard-size specimens of the plastic, which may closely simulate the intended device depending upon the use, areimmersed in defined volumes of selected liquids (extraction vehicles) for the time and temperature specified.4.2 A choice is made, based on the end use, of the extract
17、ion vehicles (see Section 7) and one of the combinations of time andtemperature for the test (see Section 12).4.3 The resultant test liquids (extract liquids) are kept in glass containers suitable containers as described in 6.3 until used fortesting. The test liquids shall be stored tightly stoppere
18、d at normal room temperature. Test liquids for biological testing are keptin sterile glass containers. Consideration should be given as to whether the extraction should be done under aseptic conditions. Thetest liquids for biological testing should be used within 24 h.5. Significance and Use5.1 Thes
19、e extraction procedures are the initial part of several test procedures used in the biocompatibility screening of plasticsused in medical devices.5.2 The limitations of the results obtained from this practice should be recognized. The choice of extraction vehicle, durationof immersion, and temperatu
20、re of the test is necessarily arbitrary. The specification of these conditions provides a basis forstandardization and serves as a guide to investigators wishing to compare the relative resistance of various plastics to extractionvehicles.5.3 Correlation of test results with the actual performance o
21、r serviceability of materials is necessarily dependent upon thesimilarity between the testing and end-use conditions (see 12.1.2 and Note 4).5.4 Caution should be exercised in the understanding and intent of this practice as follows:5.4.1 No allowance or distinction is made for variables such as end
22、-use application and duration of use. Decisions on selectionof tests to be done should be made based on Practice F748.5.4.2 This practice was originally designed for use with nonporous, solid materials. Its application for other materials, such asthose that are porous, or absorptive, or resorptive,
23、should be considered with caution. Consideration should be given to alteringthe specified material to liquid ratio to allow additional liquid to fully hydrate the material and additional liquid or other methodsto fully submerge the test article. Additional procedures that fully remove the extract li
24、quid from the test article, such as pressureor physically squeezing the material, should also be considered as appropriate. Although no definitions are given in this practicefor the following terms, such items as extraction vehicle surface tension at the specified extraction condition and plastic sp
25、ecimenphysical structure should be taken into account.5.5 Test Methods D543, D570, and D1239 may be useful in providing supplemental information.6. Apparatus6.1 Autoclave, capable of maintaining a temperature of 12162.0C (249.863.8F) for at least 1 h and equipped with a displayof temperature and pre
26、ssure. A slow exhaust cycle is necessary. A rack to hold the extraction containers above the water level isalso necessary. Loss of fluid volume should be recorded.6.1.1 Sealed, unvented extraction vessels should not be removed until internal temperature and pressure have reached ambientconditions an
27、d the door can be opened. It is recommended that the extraction vessels be left undisturbed until any risk of boil overhas passed. When the extraction vessels are cool to the touch, the lids should be sealed.6.2 Heating Equipment:6.2.1 Ovens or incubators that will maintain temperatures of 37, 50, 7
28、0 6 2C (98, 122, 158 6 3F).6.2.2 Water baths capable of maintaining temperatures described in 6.2.1. Those with the ability to agitate the extraction vesselsare preferred.6.3 Extraction ContainersSuitable containers that protect the extract liquid from the biological and chemical contamination.They
29、should allow expansion of the liquid, but then be sealed to prevent evaporation. One suggested container is the screw-capculture test tube of borosilicate glass, unless a larger container is required for the size and shape of the material to be extracted.Screw caps, if used, shall have polytetrafluo
30、roethylene liners.6.4 Balance, accurate to 60.1 mg.6.4.1 Caution should be exercised when performing weighings in glassware. Depending upon the required accuracy, the relativehumidity should be the same for weighings at different times.6.5 Micrometers, capable of measuring dimensions of test specime
31、ns to 0.025 mm (0.001 in.).F619 1427. Reagents and Materials7.1 Purity of ReagentsReagent grade, or better, chemicals shall be used in all tests.5 Other grades may be used, provided itis first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accurac
32、y of the determination.7.2 Extraction VehiclesThe following list of standard extraction vehicles is intended to simulate the main constituents ofhuman body fluids. The extraction vehicles shall be:7.2.1 Sodium Chloride Injection, USP, containing by weight not less than 0.85 % and not more than 0.95
33、% sodium chloride.7.2.1.1 Other aqueous solutions shall be made with USP WFI (water for injection).7.2.2 Vegetable Oil:7.2.2.1 Sesame Oil, USP.7.2.2.2 Cottonseed Oil, USP.7.3 Other extraction vehicles as required, such as polyethylene glycol, DMSO, as specified in other standards. Vehicles shouldbe
34、chosen based on biotolerance, the test protocols to be used, and the ability to extract contaminants from the material to be tested.NOTE 1Depending upon the material under test and the users needs, extraction vehicles other than those in 7.2 and 7.3 may be used if the reasonsare justified.8. Samplin
35、g8.1 The application of this practice may be in various areas. Therefore, although some well-known quality sampling methodsmay be used, a statistician might be consulted to ensure a statistically valid sampling plan.8.2 Practice D1898 may also be consulted.9. Test Specimen9.1 This practice is design
36、ed primarily for application to materials in the condition in which they are used. The material shouldbe exposed to all conditions and substances as during a production run, such as washing, packaging, and sterilization. Theextraction may be done on the end-use item, specimen portions thereof, or re
37、presentative molded or extruded test specimens ofthe formulated compound that are preconditioned by the same processing.NOTE 2Changes to a plastic formulation, specifically additives, such as plasticizers, stabilizers, antioxidants, pigments, and lubricants are perhapsmore prone to produce differenc
38、es in the extract liquid than the polymer itself.9.2 Specimen SizeUse a specimen size as described in the following sections. Suitable-size containers will allow a 20-mLextraction vehicle volume for each of the following specimen sizes:9.2.1 The total surface area of a specimen (both sides) is equiv
39、alent to 120 cm2 (18.6 in.2) when the specimen thickness is 0.50mm (0.020 in.) or less, or equivalent to 60 cm2 (9.3 in.2) when the thickness is greater than 0.50 mm (0.020 in.).9.2.2 An alternative for specimens of intricate geometry or those specimens with a thickness greater than 1.0 mm (0.039 in
40、.)is a specimen whose weight is 0.2 g/ml.9.2.3 Specimens shall be of such dimensions as to conveniently fit within the extraction container and their total surface areashall be completely covered by the extraction vehicle.9.2.3.1 To ensure full submersion of a large or bulky specimen, it may be nece
41、ssary to cut the specimen to provide for fullimmersion of its component pieces in the extraction vehicle. Under no circumstances shall such cutting be allowed to reduce theappropriate sample extraction ratio as determined in 9.2.1 or 9.2.2. If the specimen cannot be cut, coupons known to possess the
42、same surface characteristics and sized to deliver the same overall surface area as the original test specimen can alternately beutilized.9.2.4 It may be necessary to subdivide the specimen, utilize inert and noncontaminating spacers or weights or both, or initiallyagitate the extraction vehicle to e
43、nsure the entire specimen surface is contacted.9.3 Number of Specimen PortionsIn both procedures set forth in Section 12, test at least three specimen portions with eachextraction vehicle to account for variability.10. Preparation of Apparatus10.1 Clean all reusable glassware thoroughly with a chrom
44、ic acid cleansing mixture, or if necessary, with hot nitric acid,followed by prolonged rinsing with tap water and then at least two rinses with distilled water.10.2 Clean cutting devices by an appropriate method, for example, successive cleaning with suitable solvents prior to use insubdividing the
45、sample.5 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For Suggestions on the testing of reagents not listed bythe American Chemical Society, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States
46、Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.F619 14310.3 Clean all other equipment by thorough scrubbing with a suitable detergent and prolonged rinsing with tap water and thenat least two rinses with distilled water.10.4 Render containers and device
47、s used for extraction and in transfer and administration of the extract liquids, sterile and dryby a suitable process.NOTE 3If ethylene oxide is used as the sterilizing agent, allow adequate conditioning for complete degassing. Ethylene oxide residuals may varyamong different material formulations.1
48、1. Specimen Portion and Conditioning11.1 Biological Response ExtractionSelect and cut to size, as in 9.2 and 9.3, at least three specimen portions for eachextraction vehicle to be used. Aseptic precautions should be used if the extract liquid is to be used in a test requiring aseptictechnique or if
49、the extract is to be stored for more than a few hours before use.12. Procedure12.1 Biological Response Extraction:12.1.1 Prepare a set of four 20-mL portions of each extraction vehicle. Place one appropriate specimen portion in each of threecontainers; the extraction vehicle in the fourth container will serve as a blank. Secure the cap on each container.12.1.2 Extraction ConditionsEmploy one of the following conditions in accordance with the specified requirements. Sufficienttime, in addition to that specified, should be allowed for the liquid to reach the
