1、BRITISH STANDARD BS ISO 16428:2005 Implants for surgery Test solutions and environmental conditions for static and dynamic corrosion tests on implantable materials and medical devices ICS 11.040.40 BS ISO 16428:2005 This British Standard was published under the authority of the Standards Policy and
2、Strategy Committee on 10 June 2005 BSI 10 June 2005 ISBN 0 580 45920 9 National foreword This British Standard reproduces verbatim ISO 16428:2005 and implements it as the UK national standard. The UK participation in its preparation was entrusted by Technical Committee CH/150, Implants for surgery,
3、to Subcommittee CH/150/1, Materials for surgical implants, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this docu
4、ment may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract.
5、 Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for ch
6、ange, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to v, a blank page, pages 1 to 8, an inside back cover and a back c
7、over. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsReference number ISO 16428:2005(E) INTERNATIONAL STANDARD ISO 16428 First edition 2005-04-01 Implants for surgery Test solutions and enviro
8、nmental conditions for static and dynamic corrosion tests on implantable materials and medical devices Implants chirurgicaux Solutions dessai et conditions environnementales pour les essais statiques et dynamiques de corrosion sur les matriaux et dispositifs mdicaux implantables BS ISO 16428:2005ii
9、BS ISO 16428:2005iii Contents Page Foreword iv Introduction v 1 Scope 1 2 Normative references. 1 3 Terms and definitions. 1 4 Significance and application. 2 4.1 Significance of test solution 2 4.2 Application. 2 5 Environmental testing conditions. 3 5.1 Test solution 3 5.2 Testing temperature 3 5.
10、3 pH value. 3 5.4 Aeration 3 5.5 Volume of test solution 3 5.6 Circulation of the solution . 4 5.7 Test chamber. 4 6 Test specimens. 4 7 Evaluation and reporting 4 7.1 Evaluation of test results . 4 7.2 Test report. 4 Annex A (informative) Additional test solutions . 6 Annex B (informative) Consider
11、ations for surface preparation and test evaluation. 7 Bibliography . 8 BS ISO 16428:2005iv 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 o
12、ut 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 c
13、ollaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International
14、 Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elemen
15、ts of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 16428 was prepared by Technical Committee ISO/TC 150, Implants for surgery, Subcommittee SC 1, Materials. BS ISO 16428:2005v Introduction In many instances te
16、sting of medical devices and materials in a physiological environment is highly desirable for scientific purposes and development work as well as for the assessment of the performance of surgical implants and devices. The application of original physiological fluids is often difficult because of the
17、 rapid deterioration of such media. The application of artificial media is common, but there is the disadvantage that the compositions vary widely and testing results are often not comparable. This International Standard specifies basic reproducible environmental conditions using a test fluid of iso
18、tonic sodium chloride (NaCl) solution. This solution is appropriate because it is used for injections and irrigation in surgery and has an ion content similar to that of human body fluids. Of particular importance are the chloride (Cl ) ions because the corrosion resistance of most metals is very se
19、nsitive to them. Correspondingly, the isotonic NaCl solution is already widely used in the testing of medical devices. BS ISO 16428:2005blank BS ISO 16428:20051 Implants for surgery Test solutions and environmental conditions for static and dynamic corrosion tests on implantable materials and medica
20、l devices 1 Scope This International Standard specifies standard environmental conditions for the testing of metallic materials intended for implantation, surgical implants, and medical devices. The test conditions described simulate physiological conditions in a simplified manner controlling the te
21、st solution, the temperature, the gaseous atmosphere and the proportions of sample size and volume of solution. These environmental testing conditions can be employed where necessary in combination with various static or dynamic tests where the effect of the physiological environment is to be consid
22、ered. Typical applications are corrosion fatigue tests and selected fretting and wear tests, as well as general electrochemical tests. Typical articulating joint simulator tests and aspects particular to the dental field are not considered by this International Standard. Solutions that attempt to re
23、plicate the tribological properties of body fluids, such as those used in wear studies, are outside the scope of this International Standard. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited
24、 applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 3696, Water for analytical laboratory use Specification and test methods 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 c
25、orrosion fatigue testing assessment of corrosion fatigue behaviour where cyclic loading tests are carried out in an aqueous test solution which is related to the human physiological environment NOTE The test solution may either cause visible corrosion effects and/or acceleration of the fatigue proce
26、ss. 3.2 environmental testing conditions conditions under which a sample (specimen) is tested including the testing fluid, temperature, aeration, the pH, and the volume ratio and exchange of the fluid 3.3 isotonic sodium chloride solution aqueous solution of sodium chloride (0,9 % NaCl mass fraction
27、) which provides the same osmotic pressure in living tissues as the physiological fluid (blood serum) NOTE In surgical applications, it prevents the collapse of tissues and serves as an infusion solution. BS ISO 16428:20052 3.4 Ringers solution isotonic aqueous solution of NaCl with additional compo
28、unds which are constituents of the human body fluids (blood serum) NOTE See also Annex A. 3.5 static and dynamic test mechanical set-up of the test within the context of this International Standard NOTE This does not refer to electrochemical conditions. 4 Significance and application 4.1 Significanc
29、e of test solution The described environmental conditions are intended for applications where a testing environment for metallic medical devices or materials is required that relates to physiological conditions. The isotonic NaCl solution is used for injections 3and for flushing and cleaning in surg
30、ery. Its ion concentration is similar to that of human body fluids. Of particular significance are the Cl ions because they have corrosive effects on metals, in particular on such metals and alloys which form passive films that protect against corrosion. 4.2 Application 4.2.1 General The test condit
31、ions described are applicable for static and dynamic mechanical tests to assess the potential susceptibility to corrosion effects related to the physiological environment. 4.2.2 Testing under static conditions The environmental conditions described are suitable for static immersion tests to study, f
32、or example, special corrosion effects such as pitting or crevice corrosion, leaching, or the performance of special surface treatments. Such tests may include uniform mechanical loading. NOTE On highly corrosion resistant metallic implant materials, no visible surface deterioration might be detectab
33、le in purely static immersion tests. The environmental conditions described might show only effects under more stringent polarized conditions or mechanical loading and/or dynamic conditions. 4.2.3 Testing under loaded dynamic conditions The environmental conditions described are added to mechanical
34、test arrangements which are commonly carried out in air. They are applied, for example, in fatigue testing to assess the susceptibility to corrosion fatigue, or in selected fretting and friction tests where corrosion and wear effects are of concern. This International Standard is not applicable to t
35、ypical articulating joint simulator tests and aspects particular to the dental field nor that attempt to replicate the tribological properties of body fluids, such as those used in wear studies. In short-term handling tests (e.g. clamping), where friction or fretting are of concern, the test solutio
36、n(s) (5.1) may be employed while some of the other environmental conditions (Clause 5) are neglected depending on the issue. 4.2.4 Electrochemical studies In general, the environmental conditions described are applicable to electrochemical testing. However, depending on the type of tests some more s
37、tringent conditions may be required by certain test protocols. BS ISO 16428:20053 5 Environmental testing conditions 5.1 Test solution For the preparation of an isotonic aqueous 0,9 % (mass fraction) sodium chloride solution, 9 g of NaCl of analytical quality is added to purified water in accordance
38、 with ISO 3696. This results in 1 000 ml of test solution (for additional information see Reference 3). If a test solution other than the isotonic NaCl has been used in the testing, this shall be reported indicating some rationale. There may be specific reasons to use a modified isotonic NaCl soluti
39、on for the intended testing, for example a phosphate-buffered solution. The latter would have to be applied with technical care. There are various compositions known as “Ringers solutions” which contain additions that are constituents of the body fluids; in Annex A, a common composition is given und
40、er A.1. Under A.2, a modified solution with low pH is given, in case more stringent testing conditions are desired. Additional acceptable test solutions related to the human physiological environment include those identified in ASTM F 2129:2003, Annex X2 8 . 5.2 Testing temperature During the test,
41、the temperature of the solution is kept stable thermostatically at (37 1) C. 5.3 pH value The test solution has nearly a neutral pH value. During long-term testing the pH value shall be recorded on a regular basis. Smaller shifts of the pH may be caused by air (CO 2 ). Significant changes of the pH
42、value may indicate deterioration of the testing solution. This may be caused by degradation products (such as corrosion products or wear debris) from the test samples or possibly from parts of the test chamber. As soon as the test solution deteriorates, for example indicated by shifting of the pH or
43、 by discoloration, the test solution shall be exchanged and the test chamber washed out prior to the refill. If the degradation products and/or their effects are to be investigated, the test solution may remain unchanged, but this should be recorded and an explanatory note should be included in the
44、test report. 5.4 Aeration For defined conditions, reproducibility, and assessment of the corrosion behaviour, the test solution shall be flushed with pure gases: a) with pure oxygen to allow for passivation of the metal surface; or b) with pure nitrogen to reduce the passivating effect of dissolved
45、oxygen on the specimen surface for more stringent testing. Depending on the purpose of the investigation, it may be necessary to carry out tests with both gases to investigate the effect on the passivity of the metal surface. For certain tests it may suffice to flush with air. The conditions of aera
46、tion shall be reported. 5.5 Volume of test solution The ratio of the volume of the test solution to the exposed surface area of the specimen shall be at least 10 ml/cm 2 1 . BS ISO 16428:20054 5.6 Circulation of the solution If the specimen undergoes cyclic loading and the test solution is purged wi
47、th gas, the agitation of the solution will normally suffice. If there is suspicion that portions of the test solution stagnate at certain specimen areas, additional agitation or pumping in connection with a reservoir vessel may be indicated. For test series which are intended for comparison, the cir
48、culation conditions of the test solution shall be the same. 5.7 Test chamber Adjust the test chamber to the type of test carried out. The test chamber typically consists of a suitable glass or polymer vessel. For electrochemical or corrosion testing, the relevant test protocols shall be observed. In
49、 general, the mounting of the test specimens and the chamber should be such that erroneous test results are prevented. Thus, metallic mounting components should be avoided or should be of such material and design that galvanic corrosion is avoided. Care should also be taken to avoid crevice corrosion that could be caused by certain mounting conditions or at recesses of the test specimen. 6 Test specimens The test specimens may represent typical material samples d
