Irritation tests according to ISO 10993-23

“In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method”

As part of the biological evaluation of medical devices, irrespective of the nature of body contact or its duration, irritation is one of the endpoints that has always to be assessed according to ISO 10993-1. When insufficient data is available also testing for irritation must be done and for a long time this was only performed in animals, typically rabbits.

In January 2021 a new standard, ISO 10993-23, covering tests for irritation was issued that prescribes the use of in vitro test methods before considering any in vivo tests, all to fulfil the 3R principle of replacement, reduction, and refinement of animal tests. The standard contains a detailed description of the in vitro test method in reconstructed human epidermis models, which is built on the long-established test method for chemicals in the OECD test guideline 439 “In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method”. With a successful validation of testing polar and nonpolar extracts of medical devices, the adjusted test method is now the central test method of the ISO 10993-23 standard.

ICCR has for many years performed tests for skin irritation according to the OECD 439 guideline and began already at the end of 2019 to develop a protocol also for testing extracts of solid medical devices. When the ISO 10993-23 standard was issued, ICCR was well-prepared to offer the new test method and has since gained considerable experience in testing both solid and non-solid medical devices under GLP and its accreditation and recognition according to ISO/IEC 17025.