ISO 21726 and the Application of ISO 10993-1:2019
ISO 21726:2019 Biological evaluation of medical devices -- Application of the threshold of toxicological concern (TTC) for assessing biocompatibility of medical device constituents - is a new standard to aid the application of risk analysis chemical characterisation to information.
Biocompatibility testing is now a risk based process which requires chemical knowledge of devices and delivery systems. This information can be gathered from the production process and input materials. It can also be transferred between products in the same family. The chemical information goes into a toxicity risk analysis.
One of the factors considered in this is the Threshold of Toxicological Concern. TTC values have been determined by the ICH and these are applied to medical devices in ISO 21726. The table in the standard details the levels below which most materials are considered not to be carcinogenic or mutagenic.
If full chemical information is not available and analysis of residuals and leachables is required, then the table is also very useful in helping to decide which materials are worthy of investigation. Extractables and leachables testing will inevitably identify a number of materials, which are unexpected and difficult to identify. Those with abundances below the TTC can be eliminated from investigation almost regardless of their identity.
Medical Engineering Technologies provides complete biological evaluation services, including analytical chemistry and risk analysis.