New irritation test standard published by ISO

The International Standardisation Organisation (ISO) has now published a new standard in the biocompatibility series ISO 10993 that specifies the use of laboratory-grown skin for irritation testing, as an option to animal testing.

The new standard is ISO 10993-23:2021, titled ‘Biological evaluation of medical devices — Part 23: Tests for irritation’, which replaces the irritation test sections of current standard ISO 10993-10:2010.

As stated in the Introduction to the new standard: “The irritation potential of a medical device or its components can be predicted either by an in vivo animal irritation test or by an in vitro irritation test if qualified for use with medical devices”. Previously, only in vivo animal test have been required by the ISO standard, so the new standard adds the option of carrying out the necessary tests on laboratory-grown skin – also known as in vitro reconstructed human epidermis (RhE).

The standard explains further: “This document describes tests to determine the irritancy of medical devices, materials or their extracts either by in vitro tests or in vivo tests. In vitro tests have preference over in vivo tests when appropriately validated and providing equally relevant information to that obtained from in vivo tests”.

The standard includes:
— pre-test considerations for irritation, including in silico and in vitro methods for dermal exposure;
— details of in vitro and in vivo irritation test procedures;
— key factors for the interpretation of the results.