This February ISO/TC 194 published the long-anticipated draft of ISO 10993-10
standard, named: “Biological evaluation of medical devices – Part 10: Tests for skin
sensitization”.

At first sight, a major change with respect to the previous version is the exclusion of
irritation from the current standard. Irritation will be described into a new document,
which is expected to be published as ISO/DIS 10993-23 later this year.

In this draft edition, there are some minor changes with respect to the methodologies
of the established in vivo methods (LLNA, GPMT and Buehler test), as well as the newly
introduced Annex ZC making reference to the relationship of this standard and the
General Safety and Performance Requirements of the upcoming Regulation (EU)
2017/745 (MDR).

The most important change in the standard is the clear introduction of the Integrated
Approaches to Testing and Assessment (IATA) methodology described in Annex C,
which comes in line with the requirements of ISO 10993-1 and ISO 10993-2, regarding
the reduction of unnecessary animal testing and includes: In chemico – In silico – In
vitro studies.

IATA are science-based approaches for chemical hazard characterisation that rely on
an integrated analysis of existing data coupled with the generation of new information
using testing. To predict the skin sensitization potential of chemicals in human,
alternative non-animal methods are either used in combination or with existing
relevant information to fully characterize the biological endpoint. The sensitization
endpoint can be determined by utilizing an integrated approach whereby all existing
and reliable information about a chemical or material are combined with data from in
chemico, in silico and in vitro methods to adequately predict the toxicity of the
material. Sometimes, the integrated approach may require additional data to be
generated using non-animal approaches to gain full acceptance as a predictor of a
specific toxicity endpoint.

A solid strategy to address sensitization potential is to combine in silico data from
chemical characterization with in vitro or in chemico testing addressing one of the first
3 Key Events:

Key Event 1: Covalent binding to skin proteins.
Key Event 2: Keratinocyte Response.
Key Event 3: Activation of Dendritic Cells.

The DPRA (OECD 442C) is an in chemico validated method that addresses the Key
Event 1 and quantifies the reactivity of a test chemical through its depletion of
synthetic peptides containing cysteine or lysine. Percent depletion values are
calculated and a prediction model categorizes the chemical as a sensitiser or nonsensitiser.

KeratinoSens™ (OECD 442D) is an in vitro validated method that addresses the Key
Event 2. The KeratinoSens™ assay makes use of an immortalised human keratinocyte
adherent cell line containing a luciferase reporter gene controlled by the antioxidant
response element (ARE) of the human AKR1C2 gene, which is known to be upregulated by skin sensitisers. Luciferase gene induction is determined quantitatively
by measuring luminescence produced by light-generating luciferase substrates.

Qualimetrix is one of the few laboratories which act in compliance with the
requirements of ISO 10993-1 and the principles of the 3Rs (Replacement, Reduction
and Refinement) for animal testing. Our laboratory is a state-of-the-art analytical and
bioanalytical laboratory, which employs cutting-edge technology, such as LCHRMS/MS, GC-MS, ICP-MS and cell-imaging multi-mode reader, combined with
sophisticated analytical knowledge and expertise, providing accurate and top-quality
results.

For more information, please fill out the enquiry form attached to this page.