‘Amino acid Derivative Reactivity Assay(ADRA)’ — an alternative test for skin sensitization is adopted in OECD test guidelines
Establishing the safety of Chemical Substances without Animal Testing
Skin sensitization testing now possible with only around 1/100th the concentration required for previous methods
June 20, 2019
Tokyo, June 20, 2019 — FUJIFILM Corporation (President: Kenji Sukeno) announces that Amino acid Derivative Reactivity Assay (ADRA), an alternative skin sensitization test developed by Fujifilm has recently been adopted in the OECD (Organization of Economic Cooperation and Development) test Guidelines*1 for evaluating the safety of chemical substances. It evaluates whether a chemical substance provokes an allergic reaction in skin without using animal testing. ADRA can evaluate a wider variety of chemical substances by making use of a reagent with high detection sensitivity developed with Fujifilm’s chemical synthesis and molecular design technology. The adoption of ADRA in the OECD test guidelines marks the international recognition of the method as a standardized method of evaluation, contributing to the more widespread use of an alternative test without conducting animal experiments.
Under the process of skin sensitization, chemical substances come into contact with the skin provoking allergic reactions and inflammation. Skin sensitization tests are conducted in order to ascertain the safety of the substance for various purposes; when developing new chemical substances, or when a company introduces a new chemical substance in its manufacturing process. Previously, these tests have been carried out on animals such as guinea pigs and mice, but in recent years, in accordance with the 3R principles*2 for minimizing animal testing, it has become increasingly common to evaluate skin sensitization by using a combination of multiple alternative methods that focus on the various symptoms of the allergic reaction process.
Up until now, the standard test for evaluating bonding between chemical substances and proteins has been the Direct Peptide Reactivity Assay (DPRA)*3 , which is an alternative method of conducting skin sensitization tests using peptides as a reagent to mimic the skin proteins. It evaluates the degree of inflammation caused by chemical substance by using ultraviolet rays to measure the concentration of peptides remaining unbound with the target substance. However, since DPRA has a low sensitivity for detecting peptide, highly concentrated chemical solution is required to conduct the testing. This could cause various problems including the precipitation of the chemical substance in reaction solution when preparing reagent or difficulties in separately measuring the peptide and chemical substance when analyzing reaction solution. As a result, this method is considered unsuitable for the skin sensitization predicting of certain chemical substances.
To address this issue, Fujifilm has harnessed the advanced chemical synthesis and molecular design technology acquired through long years of experience in R&D of photographic film in order to develop the new ADRA test. It uses, as the test reagent, a new amino acid derivative with a naphthalene ring, a reagent which can be detected with high sensitivity using ultraviolet light. This dramatically lowers the concentration of the chemical substance and reagent required to carry out the skin sensitization test. Not only does testing become possible with only around 100th of the respective concentration of chemical substance and reagent required for DPRA, it is also possible to maintain the stability of the chemical substance in reaction solution, ensuring that skin sensitization can be evaluated with high precision.
Furthermore, chemical substances that could not be evaluated accurately using DPRA, such as the salicylic acid used in pharmaceuticals, can be evaluated using ADRA, making it possible to accurately predict skin sensitization on a widely diverse range of different chemical substances.
ADRA demonstrated efficacy during validation experiments*4 conducted by Fujifilm between October 2016 and April 2017. In addition, specialists in various countries have recognized that the rapid international update of ADRA will contribute to the promotion of the 3R principles on animal testing. Thus, ADRA was able to achieve the adoption in the OECD test guidelines in around three years, which is comparatively a short period of time. Over the years to come, ADRA is expected to be widely used as it has now become a global standard, making further contributions to the development of new chemical substance with no-animal testing.
Dr. Hajime Kojima, President of the Japanese Center for the Validation of Alternatives Methods, an internationally authoritative in the field of alternatives to animal testing, “The alternative skin sensitization test ADRA will make a major contribution to safety evaluation of chemical substances or cosmetics without using animal testing. With the adoption in the OECD test guidelines, I expect ADRA to be widely used across the globe.”
Fujifilm has been involved in the construction of various safety evaluation methods for chemical substances with the aim of sustaining the environment and promoting human health, engaging in all stages of the development process from early product development through to commercialization. The technology and know-how are combined with the advanced technical capability held by a leading reagent manufacturer FUJIFILM Wako Pure Chemical Corporation to facilitate the development of the ADRA kit*5 . The ADRA kit has been sold globally by FUJIFILM Wako Pure Chemical Corporation since last September. Fujifilm remains committed to the active development and promotion of new evaluation technologies so as to guarantee the safety of chemical substances while also promoting the 3R principles of animal testing, working to develop frameworks for the evaluation of chemical substances that do not require animal testing.
The ADRA kit will be exhibited at the 46th annual meeting of the Japanese Society of Toxicology, to be held between June 26 and June 28 in Japan.