Material compatibility with sterilization methods is a pivotal concern for medical device manufacturers and sterile processing professionals. Effective sterilization must not compromise the integrity of medical products or their packaging, as ensuring safety without sacrificing functionality is paramount. To address this, the Association for the Advancement of Medical Instrumentation (AAMI) has released updated guidance in AAMI TIR17:2024 - Compatibility of Materials Subject to Sterilization.
This revised guidance introduces critical insights into how various sterilization modalities—from ethylene oxide (EO) to vaporized hydrogen peroxide—interact with diverse material types such as polymers, ceramics, and metals. Focusing on novel scientific data, the document also offers detailed guidance on material selection, processing, testing, and aging programs.
On January 16, 2025, the FDA officially recognized this version of TIR17:2024. The FDA has added 4 AAMI sterilization guidance documents to its Recognized Consensus Standards Database.
In this interview with Infection Control Today® (ICT®), Jami McLaren, PhD, cochair of AAMI’s working group responsible for TIR17 (STWG96) and sterility assurance fellow at Boston Scientific, explains the practical applications of TIR17, why it was updated, and its impact on advancing sterilization science and ensuring patient safety.
ICT: What prompted the revision of AAMI TIR17 after 6 years, and what key gaps did the update address?
Jami McLaren, PhD: AAMI TIRs are automatically revised/reaffirmed every 3 years. In 2020, the AAMI working group acknowledged that TIR17 could benefit from reorganizing and streamlining the material related to accelerated aging, adding additional material on assessing material compatibility when considering sterilization modality changes or process optimization, and refreshing the information in the material compatibility annexes. Specifically, guidance on assessing material compatibility when dealing with sterilization modality changes and newer sterilization modalities were identified as needed updates.
ICT: Can you elaborate on the significance of the new material compatibility annexes and how the scientific data supporting them were gathered?
JM: The working group conducted an informal survey at the beginning of the revision process, and one of the clear outcomes of the survey was that the material compatibility annexes are the most frequently used/referenced sections of the TIR. While the material compatibility tables in previous revisions of the TIR were widely used, the working group realized that some of the information in these tables was subjective, not easily traceable, and inconsistent with known experience and other sections of the TIR. This prompted a complete overhaul of the information in these tables, with the most significant change being a new criterion for generating compatibility ratings.
The new criteria are based on 1) peer-reviewed literature, 2) known history of use of a material in the given sterilization modality, 3) the presence or absence of a known degradation pathway (Ie, mechanism of interaction) between the material and modality, and 4) white papers and/or datasheets. Each material rating in the revised tables clearly states how the rating was determined based on these criteria and references where the information originated, if applicable.
ICT: What are some specific challenges manufacturers and sterile processing professionals face when selecting and qualifying materials for sterilization?
JM: The challenge faced by manufacturers is knowing that the product that they are designing will be able to be sterilized while still performing its intended function, and understanding the compatibility of commonly used materials subject to sterilization is a good starting point for material selection. At a basic level, the materials comprising a sterile medical device enable the device to deliver its intended care to the patient.
As devices become more complex and new sterilization modalities become available, the potential sensitivity to sterilization processes could increase. Sterilization processes or modalities that have historically been compatible with a company’s devices may negatively impact the functionality of materials in new devices.
Understanding how these materials interact with sterilization is critical to ensuring sterile devices function as intended. Without this knowledge and information, companies could spend significant time and resources in design iterations to produce a device that is compatible with sterilization.
ICT: The revised TIR17 includes 70 material types. How does it help users understand their interactions with sterilization modalities?
JM: The materials listed in the compatibility tables are those most commonly used in medical devices, as determined by the working group. The number of materials is approximately the same as in the previous revision. However, effort was undertaken to ensure the same list of materials was consistently included in each compatibility table in the new revision. The TIR also provides basic information about the conditions that materials experience in 10 different sterilization modalities (eg, temperature, pressure, exposure to ionizing radiation, etc).
ICT: How will the new guidance on accelerated aging programs impact the testing and qualification of medical devices and packaging materials?
JM: The revised TIR contains more streamlined, better-organized information on accelerated aging and is more specifically related to material compatibility than previous revisions. Additional guidance has been provided for assessing the risks of alternate sterilization modality evaluations for previously qualified products where the materials were well characterized and the materials and aging effects were well understood. The new revision guides how accelerated aging and real-time data can be utilized with a risk-based assessment of the materials to inform the rationale for device-level testing plans.
ICT: What are the practical implications of the revised material compatibility ratings for professionals working with polymers, ceramics, and metals?
JM: The revised ratings provide accurate, traceable, and consistent information, which provides device designers/manufacturers with a critically valuable tool to understand how device materials will interact with sterilization. Accurate ratings of the compatibility of these materials with sterilization can help drive material selection during device development.
ICT: How do you envision the updates to AAMI TIR17 influencing industry standards and practices for sterilization moving forward?
JM: By providing accurate, traceable, and consistent compatibility information, the revised TIR17 has the potential to enable a more efficient and informed sterile product design process.
