General Biocompatibility Testing Considerations 生物相容性测试注意事项总则

Test article preparation is a critical variable in the conduct of the biocompatibility tests. Therefore, it is important to understand how the test articles compare to the medical device in its final finished form (e.g., sterile, if applicable). The example test article documentation language included in Attachment F can be used to detail how any differences may or may not affect biocompatibility of the medical device in its final finished form.

测试样品的准备是进行生物相容性测试的关键变量。因此，了解测试样品与医疗器械最终成品形式（如适用）的比较情况（例如，是否无菌）非常重要。附件 F 中包含的示例测试样品文档语言可用于详细说明任何差异可能如何影响医疗器械最终成品形式的生物相容性。

Use of Medical Device in Final Finished Form or Representative Test Article 在最终成品形式下使用医疗器械或代表性测试样品

When biocompatibility testing is necessary, the Agency recommends testing medical devices in the condition that they will be used, whenever possible. This could include final, packaged devices, or as sterilized by an end user, if appropriate. If the medical device in its final finished form cannot be used for biocompatibility testing, a test article (e.g., coupons or “representative components”) may be considered. The representative test article should undergo the same manufacturing and sterilization processes, have the same chemical, physical, and surface properties, and have the same ratio of component materials as the medical device in its final finished form. In situations where differences exist between the medical device in its final finished form and the test article, additional information describing how these differences could impact study findings should be provided. For example, when testing an individual device component, a low-level tissue response could be observed, but when all of the components are tested within a medical device in its final finished form, a more robust tissue response could occur. If there are differences between the medical device in its final finished form and the representative test article, additional information may aid in determining the appropriateness of the selected test article. For example, extraction and surface characterization techniques may be appropriate to demonstrate that the surfaces are equivalent in geometry and surface properties, and that the chemicals leaching from the test article display the same kinetics, chemical identity and relative quantity as those eluting from the medical device in its final finished form. For example, for permanent or absorbable implants, FDA may request data from exhaustive extraction studies (per ISO 10993-12) and surface characterization information to support use of the representative test articles. See also Attachment F.

在进行生物相容性测试时，机构建议尽可能以医疗器械将要使用的状态进行测试。这可以包括最终包装好的设备，或者根据最终用户的需要进行灭菌。如果医疗器械在其最终成品形式下无法用于生物相容性测试，可以考虑使用一个测试样品（例如，样片或“代表性组件”）。代表性测试样品应经过相同的制造和灭菌过程，具有相同的化学、物理和表面性质，并且具有与医疗器械最终成品形式相同的组分材料比例。对于医疗器械最终成品形式与测试样品之间存在差异的情况，应提供描述这些差异可能如何影响研究结果的额外信息。例如，当测试单个器械组件时，可能观察到低水平的组织反应，但当所有组件在医疗器械最终成品形式内进行测试时，可能会出现更强的组织反应。如果医疗器械最终成品形式与代表性测试样品之间存在差异，额外的信息可能有助于确定所选测试样品的适用性。例如，提取和表面特性分析技术可能适用于证明表面的几何形状和性质是相等的，并且从测试样品中溶出的化学物质显示出与医疗器械最终成品形式中析出的化学物质相同的动力学、化学特性和相对含量。例如，对于永久性或可吸收性植入物，FDA 可能会要求进行详尽的提取研究（根据 ISO 10993-12）和表面特性信息，以支持使用代表性测试样品。另请参阅附件 F。

Testing of In Situ Polymerizing and/or Absorbable Materials 对原位聚合和/或可吸收材料的测试

For devices made from in situ polymerizing and/or absorbable materials, we recommend that test article preparation be representative of the device in its final finished form. In addition, we recommend that biocompatibility be evaluated for the medical device in its final finished form as well as at various time points over the course of polymerization and/or degradation to ensure that starting, intermediate, and final degradation products are assessed. Should biocompatibility assessment of the materials during degradation be needed, preparation of test articles using in vitro degradation methods may be considered with appropriate technical justification. Test articles degraded in vitro may be used for biological testing, and/or chemically analyzed to show that the material breaks down into intermediate or final degradation products that are known to be non-toxic at the levels present. However, depending on the materials of manufacture and the degradation testing conditions, accelerated degradation testing may not result in the same intermediate or final degradation products and therefore may not be acceptable.

对于使用原位聚合和/或可吸收材料制造的器械，我们建议测试样品的准备应代表器械的最终成品形式。此外，我们建议在聚合和/或降解过程中，对医疗器械的最终成品形式以及不同时间点进行生物相容性评估，以确保评估起始、中间和最终降解产物。如果需要在降解过程中进行材料的生物相容性评估，可以考虑使用体外降解方法制备测试样品，并提供适当的技术依据。经过体外降解的测试样品可以用于生物学测试，或进行化学分析，以展示材料降解为已知无毒的中间或最终降解产物。然而，根据制造材料和降解测试条件的不同，加速降解测试可能不会产生相同的中间或最终降解产物，因此可能不被接受。

For in vivo tests for devices made of in situ polymerizing or absorbable materials, the assessment time points would depend on the polymerization and degradation kinetics. We recommend that assessments be targeted to demonstrate how the device materials degrade over time and continue until the absorbable material and/or its degradation products are no longer present in the tissue (e.g., microscopically), if possible. Alternatively, it may be acceptable to provide a rationale for ending the study earlier, if the rationale includes an estimate of the percentage (%) of absorbable material remaining in the tissue, and confirmation that a steady state biological tissue response is achieved.

对于使用原位聚合或可吸收材料制造的器械的体内测试，评估时间点取决于聚合和降解动力学。我们建议评估旨在展示器械材料随时间的降解情况，并持续进行，直到可吸收材料和/或其降解产物不再存在于组织中（例如，通过显微镜观察）。如果可能的话，另一种可接受的做法是提供终止研究的理由，如果该理由包括估计组织中剩余可吸收材料的百分比（%），并确认达到了稳态的生物组织反应。

For in vitro biocompatibility tests conducted with extracts of an in situ polymerizing or absorbable device, chemical analytical testing of the extract may be useful to determine whether the extract is representative of leachables during the polymerization or degradation processes, and if multiple biocompatibility tests with different extracts are needed to represent different stages of the polymerization or degradation processes. If test articles are pre-polymerized prior to extraction, unreacted constituents that may be available during physiologic polymerization may or may not be available for extraction from a pre-polymerized test article. For systems that may not be polymerizable in traditional extraction media, alternative approaches may be necessary.

对于使用原位聚合或可吸收器械提取物进行的体外生物相容性测试，化学分析测试提取物可能有助于确定提取物是否代表聚合或降解过程中的可溶性物质，并且如果需要用不同提取物进行多个生物相容性测试以代表聚合或降解过程的不同阶段。如果在提取之前对测试样品进行预聚合，可能会有未反应的成分在生理聚合过程中可能可溶出，也可能无法从预聚合的测试样品中进行提取。对于在传统提取介质中可能无法聚合的系统，可能需要采用替代方法。

Biological Response Resulting from Device Mechanical Failure 由设备机械故障引起的生物反应

Although the scope of ISO 10993-1:2009 specifically excludes biological hazards arising from any mechanical failure, FDA believes this potential risk is important to consider when conducting biocompatibility evaluations. For some devices, it may be possible that mechanical failure could alter the biological response to the device. For example, if coating particles or wear debris are released from a device, those particles could lead to a biological response because of their material properties, such as geometric and/or physicochemical properties^[1]. In addition, coating delamination or component release or failure could expose the biological system to leaching of different chemicals, or to an increased level of chemicals from a substrate material. Another consideration is whether the surface topography could change with mechanical loading in such a way that the biological response changes. We recommend that your test article selection for any biocompatibility testing incorporate these considerations. If your biocompatibility evaluation does not include testing to evaluate potential biological hazards due to mechanical failure, your rationale for why such testing is not needed may include the results of other nonclinical tests, such as bench testing or in vivo animal studies. For example, inadequate surface treatment of nitinol devices might result in non-optimized passivation layers that can be further compromised by mechanical loading, such as during device placement. This could result in nickel, a known renal toxin, sensitizer, genotoxin and possible co-carcinogen, being released at levels that could be toxic. If processing includes an adequate passivation method, and corrosion testing confirms that an appropriate passivation layer exists, the risk for nickel toxicity is minimized, and testing to assess biological endpoints and/or nickel leaching may not be necessary.

虽然 ISO 10993-1:2009 的范围明确排除了由于任何机械故障而产生的生物危害，但 FDA 认为在进行生物相容性评估时应考虑此潜在风险的重要性。对于某些器械而言，机械故障可能会改变对器械的生物反应。例如，如果设备释放出涂层颗粒或磨损颗粒，这些颗粒可能由于其材料特性（如几何和/或物理化学特性）而导致生物反应。此外，涂层剥离、组件松动或故障可能会使生物系统暴露于不同化学物质的淋漓，或使基板材料释放出更高水平的化学物质^[1:1]。另一个考虑因素是在机械载荷下表面拓扑结构是否会发生改变，从而使生物反应发生变化。我们建议在进行任何生物相容性测试时，选择测试样品时要考虑这些因素。如果您的生物相容性评估不包括评估由于机械故障而可能导致的生物危害的测试，您为什么认为不需要进行此类测试的理由可以包括其他非临床测试的结果，例如台架测试或体内动物研究。例如，对于氮化钛设备，如果表面处理不充分，可能导致未经优化的钝化层在设备放置期间受到机械加载等因素的进一步损害。这可能导致镍（已知的肾毒素、致敏剂、基因毒性物质和可能的共诱变剂）被释放到可能具有毒性的水平。如果处理过程包括充分的钝化方法，并且腐蚀测试确认存在适当的钝化层，那么镍毒性的风险将被最小化，因此可能不需要进行评估生物终点和/或镍淋漓的测试。

Submicron or Nanotechnology Components 亚微米或纳米技术组件

It is now generally accepted[^33][34] that there can be unique properties associated with submicron(<1 micron) or nanotechnology components such as aggregation, agglomeration, immunogenicity, or toxicity. Medical devices with submicron components may require specialized techniques if characterization and biocompatibility testing is needed. [^35] Limitations may apply when using chemical leachates-based ISO 10993-12 test conditions for the analysis of submicron component biocompatibility assessments. The sponsor should consult relevant literature and standards during the development of test protocols for device-specific submicron or nanotechnology component biocompatibility assessments, and contact the respective Center and review division prior to initiation of any tests.

目前普遍认为[^33][34]，亚微米（<1 微米）或纳米技术组件可能具有独特的特性，如聚集、凝聚、免疫原性或毒性。如果需要对具有亚微米组件的医疗器械进行表征和生物相容性测试，可能需要使用专门的技术[^35]。

For biocompatibility assessment of devices with submicron components, you should consider the following:

对于具有亚微米组件的器械的生物相容性评估，您应考虑以下几点：

Careful characterization of the test article. 对测试样品进行仔细的表征。
Selection of extract conditions (e.g., solvent type) that avoid testing artifacts. 选择提取条件（例如溶剂类型），以避免测试中的人为因素。
Assurance that the test article used is representative of the device that is intended to be used clinically. 确保所使用的测试样品代表了拟临床使用的器械。

For test selection, the following items are also important:

对于测试选择，以下几点也很重要：

Consideration of standard biocompatibility tests in the context of contemporary literature regarding the validity of individual tests for assessment of devices with submicron components. 在考虑使用标准生物相容性测试时，要参考当代文献，了解各个测试方法对于评估具有亚微米组件的器械的有效性。
Assurance that the submicron components will not interfere with the conduct of a chosen test. 确保亚微米组件不会干扰所选择测试的进行。
Consideration of any additional toxicity issues that might be relevant to submicron particles, such as absorption, distribution, and accumulation into organs, potential metabolism, and elimination, since there are greater concerns associated with submicron particles that cannot be readily detoxified and/or eliminated from the body. 考虑与亚微米颗粒相关的任何额外毒性问题，例如吸收、分布和积累到器官中的潜在代谢和排泄。因为与亚微米颗粒相关的担忧更大，这些颗粒可能不能很容易地被解毒和/或排出体外。

Kunzmann, A., et al., “Toxicology of engineered nanomaterials: Focus on biocompatibility, biodistribution and biodegradation.” Biochim Biophys Acta, 2011, 1810(3): 361-373.
Rivera, G.P., et al., " Correlating physico-chemical with toxicological properties of nanoparticles: the present and the future." ACS Nano,2010,4(10):5527-5531.
For example, ASTM F1903 “Standard Practice for Testing For Biological Responses to Particles In Vitro,” or ASTM F1904 " Standard Practice for Testing the Biological Responses to Particles in vivo . "

Test Article Preparation for Extract Testing 提取测试中的测试样品准备

For biocompatibility testing conducted using extracts of the test article^[2], we recommend that you:

对于使用测试样品的提取物进行生物相容性测试^[2:1]，我们建议您：

Determine the appropriate amount of test article as outlined in ISO 10993-12 or another FDA-recognized standard (e.g., ASTM F619 “Standard Practice for Extraction of Medical Plastics”), using surface area to extract volume ratios. Mass to extract volume ratios should only be used if surface area cannot be calculated, or if use of mass will result in a test article with a larger surface area to extract volume ratio than recommended by ISO 10993-12. If there is a need for an alternate extraction ratio, appropriate justification should be provided. For example, for fluid path devices or components (where fluids contact the channels in the device or component, and then the fluid enters the body), the fluid path can be filled to capacity. If the ISO 10993-12 recommended surface area to extract volume cannot be achieved, the fluid contacting surface area and extraction volume should be noted in the test report. This approach can be used for both static and dynamic extractions. For some test systems, there may be standardized alternatives for test-specific extraction conditions that provide a different level of extraction (e.g., guinea pig maximization testing per ISO 10993-10"Biological evaluation of medical devices-Part 10: Tests for irritation and skin sensitization," Annex E).
根据 ISO 10993-12 或其他 FDA 认可的标准（例如 ASTM F619 “Standard Practice for Extraction of Medical Plastics”）确定适量的测试样品，使用表面积与提取体积的比例。只有在无法计算表面积或使用质量会导致测试样品的表面积与提取体积比例大于 ISO 10993-12 推荐值时，才应使用质量与提取体积的比例。如果需要使用其他提取比例，应提供适当的理由。例如，对于液体通路器械或组件（其中液体接触器械或组件中的通道，然后进入体内），可以将液体通路填满。如果无法达到 ISO 10993-12 推荐的表面积与提取体积比例，应在测试报告中注明接触液体的表面积和提取体积。这种方法可用于静态和动态提取。对于某些测试系统，可能存在针对特定测试的标准替代提取条件，提供不同水平的提取（例如，按照 ISO 10993-10 "Biological evaluation of medical devices-Part 10: Tests for irritation and skin sensitization"的附录 E 进行的豚鼠最大化测试）。
Use both polar and nonpolar solvents, such as those described in ISO 10993-12. In some cases, other solvents may be used, where appropriate. For example, a mixed polarity solvent (e.g., cell culture medium with 5-10% serum for cytotoxicity testing) is appropriate to extract both hydrophilic and lipophilic chemicals. Also, where devices do not have direct contact with the body but only have indirect contact via a polar solution (e.g., assessment of the inner channel material of a cardiovascular catheter where the inner channel is only used for the infusion of saline), a rationale for waiving testing with a non-polar solution should be provided. For some tests such as material-mediated pyrogenicity, where the extract is injected intravascularly, a polar extract is sufficient.
使用极性和非极性溶剂，例如 ISO 10993-12 中所描述的溶剂。在某些情况下，可以使用其他适当的溶剂。例如，混合极性溶剂（例如细胞培养基中含有 5-10%血清用于细胞毒性测试）适用于提取亲水性和亲脂性化学物质。此外，对于与体内直接接触，但只通过极性溶液（例如评估心血管导管的内部通道材料，其中内部通道仅用于注入盐水）间接接触的器械，应提供放弃使用非极性溶液进行测试的理由。对于一些测试，例如材料介导的发热性测试，其中提取物是静脉内注射的，使用极性提取物就足够了。
Use extraction conditions that are adequate for testing of extractables and leachables from the device given its intended use. Traditional biocompatibility extraction methods, such as those in ISO 10993-12:2012 (e.g., 37 C for 72 hours; 50 C for 72 hours; 70 C for 24 hours; or 121 C for 1 hour ) are acceptable for many biocompatibility tests. For prolonged contact devices and those categorized as permanent implants, extraction at 37 C may not be sufficient to obtain an extract that represents the chemicals extracted over the duration of device use. However, in some cases, temperatures above 37 C result in chemicals that may not occur in clinical use and may result in adverse biological responses not representative of the medical device in its final finished form. For example, for devices that contain heat labile or heat sensitive materials (e.g., drugs, biomolecules, tissue-derived components), which may have the potential to undergo deformation or material configuration/structural change at high temperature, extraction at 37 C per ISO 10993-12 is recommended, but some additional information on how the chemistry of the device will change over time may also be needed. In all cases, a justification for the selected extraction conditions should be provided.
使用适合设备预期用途的可提取物和可溶出物测试的提取条件。对于许多生物相容性测试，传统的生物相容性提取方法，例如 ISO 10993-12:2012 中描述的方法（例如 37 摄氏度提取 72 小时；50 摄氏度提取 72 小时；70 摄氏度提取 24 小时；或 121 摄氏度提取 1 小时）是可以接受的。对于长期接触设备和被归类为永久植入物的设备，在 37 摄氏度下的提取可能无法获得代表设备使用期间提取的化学物质的提取物。然而，在某些情况下，高于 37 摄氏度的温度会导致在临床使用中不会出现的化学物质，并可能导致与最终成品形式的医疗器械不符的不良生物反应。例如，对于含有热敏感材料（例如药物、生物分子、组织来源的成分）的器械，这些材料可能在高温下发生变形或物质构型/结构变化的情况下，建议按照 ISO 10993-12 在 37 摄氏度下进行提取，但可能还需要一些关于设备化学性质随时间变化的其他信息。在所有情况下，应提供所选择提取条件的理由。
Describe the condition of the test extract (e.g., color, presence of any particles), and describe any changes in the extraction solvent (pre-and post-extraction) and explain the source of these changes (e.g., test article degradation).
描述测试提取物的状态（例如颜色、是否有颗粒），并描述提取溶剂的任何变化（提取前和提取后），并解释这些变化的来源（例如测试样品的降解）。
Use the extracts without additional processing (e.g., no filtration, centrifugation, or other methods to remove particulates; no pH adjustment), unless otherwise justified.
除非有合理理由，否则在使用提取物时不进行其他处理（例如无过滤、离心或其他去除颗粒的方法；无 pH 调节）。
If test article extracts are not used immediately, we recommend that you use them within the time frame outlined in ISO 10993-12 or an equivalent method. We recommend that you describe the details of storage conditions for the test extract, and explain why storage will not affect your test results (i.e., as stated in ISO 10993-12:2012,“stability and homogeneity of extract under storage conditions shall be verified”).
如果测试样品提取物不立即使用，建议您在 ISO 10993-12 或等效方法中规定的时间范围内使用它们。建议您描述测试提取物的存储条件的详细信息，并解释为什么存储不会影响您的测试结果（如 ISO 10993-12:2012 所述，“在存储条件下提取物的稳定性和均匀性应予以验证”）。

Inclusion of Multiple Components or Materials in a Single Test Article 在单个测试样品中包含多个组件或材料的器械

For devices that include components with different lengths of contact (e.g., categorized as limited, prolonged, or permanent), we recommend that any extract-based biocompatibility testing be conducted separately.^[3] If the components are combined into a single test article, this will dilute the amount of component materials being presented to the test system and may not accurately identify potentially toxic agents that would have been found if the components were tested separately. For example, we recommend testing implants separately from delivery systems or other kit components.

对于包含具有不同接触时间的组件（例如，被归类为有限、长期或永久的组件）的器械，我们建议将基于提取物的生物相容性测试单独进行。如果将这些组件组合成一个单一的测试样品，将会稀释呈现给测试系统的组件材料的数量，并且可能无法准确识别出如果这些组件分别进行测试可能会发现的潜在有毒物质。例如，我们建议将植入物与输送系统或其他套件组件分开进行测试。

For devices or device components that contain multiple materials with differing surface areas or differing exposure to the body, if one or more materials is new (i.e., not used before in devices with the same type and duration of contact), it may also be necessary to test the new material component(s) separately as well, to further understand the potential toxicity of this component. For example, for a catheter-based delivery system that contains a new balloon material, tests of the delivery system separate from the balloon may be necessary to ensure adequate assessment of each of the materials.

对于包含具有不同表面积或在体内接触程度不同的多种材料的器械或器械组件，如果其中一个或多个材料是新材料（即，在具有相同类型和持续时间接触的设备中尚未使用过的材料），可能还需要单独测试新材料组件，以进一步了解该组件的潜在毒性。例如，对于含有新的气囊材料的导管式输送系统，可能需要对输送系统和气囊分别进行测试，以确保对每种材料进行充分评估。

FDA’s " Guidance for Industry and FDA Staff : Preparation and Review of Investigational Device Exemption Applications (IDEs) for Total Artificial Discs" available at https://www.fda.gov/regulatory-information/search-fda-guidance-documents/preparation-and-review-investigational-device-exemption-applications-ides-total-artificial-discs requests that wear particles, which result from dynamic device loading during use, be assessed “to evaluate the local and systemic responses (e.g., biocompatibility, neurologic response, tissue response, and toxicity) to the wear debris.”
FDA 的“针对行业和 FDA 人员的指南：全人工椎间盘置换 IDE 申请的准备和审查”要求评估由使用过程中动态设备加载引起的磨损颗粒，以评估对磨损颗粒的局部和全身反应（如生物相容性、神经反应、组织反应和毒性）。 ↩︎ ↩︎
For biocompatibility testing, extracts could include leachable residuals at the surface of test articles or extractables migrating from the bulk of test articles. ↩︎ ↩︎
In many cases , it is acceptable to combine components with limited ( < 24 hour ) use , with an appropriate supporting rationale. However, separate assessments of devices with prolonged (24 hour to 30 day) or permanent 30 day) duration of contact are recommended.
在许多情况下，结合具有有限（<24 小时）使用时间的组件是可以接受的，并且需要提供合理的支持理由。然而，我们建议对与长期（24 小时至 30 天）或永久（30 天以上）接触持续时间相关的器械进行单独评估。 ↩︎