ISO 10993-18:2020

Overview

ISO 10993-18:2020 - "Biological evaluation of medical devices - Part 18: Chemical characterization of medical device materials within a risk management process" defines a structured framework for identifying and, where necessary, quantifying chemical constituents of medical devices. The standard supports biological hazard identification and the estimation/control of biological risks from material constituents using a stepwise chemical characterization approach, including material composition, manufacturing-introduced substances, extractables (potential releases under laboratory extraction), and leachables (measured release under clinical conditions). It also guides characterization of degradation products and is applicable when devices or materials have direct or indirect body contact.

Key topics and requirements

• Stepwise chemical characterization process: establish device configuration and material composition, assess equivalence to clinically established materials, estimate hypothetical worst-case release, set an Analytical Evaluation Threshold (AET), perform extractables and leachables testing, and exit the process when risk is acceptable.
• Identification and quantification: use information gathering (supplier data, formulations) and information generation (analytical testing) as needed to identify constituents and contaminants (e.g., mould release agents, process contaminants, sterilization residues).
• Extractables vs. leachables: guidance on designing accelerated extraction studies (extractables) and clinical-condition leachables studies to characterize potential chemical release.
• Analytical considerations: selection and qualification of analytical screening and targeting methods, reporting thresholds, and documentation requirements. Annexes provide detail on extraction principles (Annex D), AET calculation and application (Annex E), and method qualification (Annex F).
• Integration with risk management: chemical characterization is carried out within the device’s overall risk management and biological evaluation process (references ISO 10993-1, ISO 10993-17, ISO 14971).

Practical applications and users

Who uses ISO 10993-18:

• Medical device manufacturers and component suppliers
• Material formulators and polymer suppliers
• Biocompatibility/toxicology specialists and regulatory affairs teams
• Analytical laboratories performing extractables/leachables studies
• Quality and risk management professionals

Common uses:

• Pre-market biological safety assessments and regulatory submissions
• Supplier qualification and material change control
• Defining safety testing strategy for new or modified devices
• Supporting toxicological risk assessments by identifying and quantifying potential chemical exposures

Related standards

• ISO 10993-1: Biological evaluation - evaluation and testing within a risk management process
• ISO 10993-17: Establishment of allowable limits for leachable substances
• ISO 10993-12: Sample preparation and reference materials
• ISO 14971: Application of risk management to medical devices

ISO 10993-18 is essential for anyone responsible for chemical safety, extractables/leachables testing, and the biocompatibility evaluation of medical device materials. Keywords: ISO 10993-18, chemical characterization, extractables, leachables, AET, medical device materials, biological evaluation, risk management.