Overview
EN ISO 10993-17:2023/A1:2025 (Amendment 1 to ISO 10993-17:2023) updates guidance for the toxicological risk assessment of medical device constituents. This amendment clarifies exposure calculations, terminology and tables used to derive toxicological screening limits (TSLs) and worst‑case estimated exposure doses. It also aligns cross‑references to ISO 10993‑18 (chemical characterization) and clarifies the document’s relationship to Regulation (EU) 2017/745 (EU MDR).
Key topics and technical changes
- Cumulative exposure dose (TQ_max): The amendment emphasizes the use of the maximum total quantity (TQ_max, µg) - the cumulative exposure dose - when calculating risk metrics.
- Units and formulas: Corrections include unit changes (e.g., g/d → µg/d) and clarified formula variables: the meaning of D (minimum assumed duration in days) and SF (scaling factor relating maximum device contact to the extraction study).
- Toxicological screening limits (TSLs): Updates to Annex B refine how TSLs are calculated (Formula B.1) and specify when toxicological screening limits shall not apply (for prolonged/long‑term use in infants/neonates, and certain constituent types).
- Extraction and release data interpretation: New text in Annex E clarifies when extraction/quantification results can be treated as conservative and used as worst‑case cumulative exposures for hazard calculations (EED, HQ).
- Tables and examples: Revisions to Table B.1, Table F.3 and multiple examples improve consistency in exposure-period assumptions and scaling scenarios.
- Regulatory alignment: Annex ZA maps the standard’s provisions to General Safety and Performance Requirements of EU MDR (Regulation (EU) 2017/745).
Practical applications and users
Who uses this amendment:
- Medical device manufacturers preparing biological evaluation files and toxicological risk assessments.
- Regulatory affairs and quality teams demonstrating conformity with ISO 10993 series and EU MDR.
- Toxicologists and safety assessors calculating TSLs, HQ, and EED using extraction or release‑kinetics data.
- Testing laboratories interpreting extraction studies and reporting conservative constituent quantities.
How it is used:
- To establish safe exposure limits for constituents released from devices.
- To scale extraction results to worst‑case patient exposure using SF and D parameters.
- To document and justify biocompatibility risk decisions in clinical evaluation and technical files.
Related standards
- ISO 10993‑17:2023 (base document)
- ISO 10993‑18:2020 and its amendment on uncertainty factors - referenced normatively for chemical characterization and uncertainty considerations.
- Other parts of the ISO 10993 series for biological evaluation and testing.
Keywords: ISO 10993-17, toxicological risk assessment, medical devices, TQ_max, toxicological screening limit, extraction study, EU MDR, ISO 10993-18.
