The International Standards Organisation (ISO) recently published a new technical standard, ISO/TS 21726:2019 Biological evaluation of medical devices – Application of the threshold of toxicological concern (TTC) for assessing biocompatibility of medical device constituents.
The TTC is a recognized tool for evaluating the biological risks of impurities when they are present at low levels and when toxicity data are not available. This technical standard describes the use of the TTC for a constituent present in a medical device or released from a medical device. The TTC values presented in this document are considered protective for carcinogens, systemic toxicants, and reproductive toxicants.
As compared to ISO 10993-1:2018 Table A.1 Annex A, the duration of contact categories for the TTC values are consistent with the ICH M7(R1) contact categories and are divided into ≤1 month, > 1 month to 12 months, > 1 years to 10 years, and > 10 years.
For more information, you can follow this link, or see your national ISO member body.