Joint research results on skin irritation testing received the Chairman's Special Award
- Presented at the 37th Annual Meeting of the Japanese Society for Alternatives to Animal Experiments -
January 29, 2025
ROHTO Pharmaceutical Co., Ltd. (Headquarters: Osaka City, Osaka Prefecture; President: Masashi Sugimoto), together with five other companies - Kobayashi Pharmaceutical Co., Ltd., Sunstar Group, TOA Corporation, Mandom Corporation, and Japan Tissue Engineering Co., Ltd. (hereinafter referred to as J-TEC) - presented their collaborative research into alternative methods for skin irritation testing, one of the safety evaluation items, at the 37th Annual Meeting of the Japanese Society for Alternatives to Animal Experiments, and received the Conference Chairman's Special Award.
The Ministry of Health, Labour and Welfare issued guidance on the skin irritation evaluation system for quasi-drugs and cosmetics in April 2021, limiting the quasi-drug and cosmetic ingredients that can be used for testing to those expected to pose little risk of skin irritation. Therefore, with the aim of revising the guidance to expand the scope of ingredients that can be evaluated, we have been working to expand data on alternative methods to animal testing and improve testing conditions. We presented the results of this research at the 37th Annual Meeting of the Japanese Society for Alternatives to Animal Experiments, held at Light Cube Utsunomiya from Friday, November 29 to Sunday, December 1, 2024, and received the Conference Chairman's Special Award.
To achieve these research results, we received the 8th Research Grant for the Evaluation of Test Methods Aimed at Ensuring the Safety of Cosmetics, etc., sponsored by the Japanese Society for Alternatives to Animal Experiments. Furthermore, KOSÉ Corporation, SSCI-Net, and the Japan Cosmetic Industry Association participated as advisors, and we have had numerous discussions about the content of our research.
In the future, we aim to contribute to the cosmetics industry by further expanding data and improving test conditions together, and we would like to publish a database of the test results and knowledge we have obtained.
Background, results, and future developments of the six-company joint research
In the cosmetics industry, the use of alternative testing methods to animal testing is accelerating, and they are being used to evaluate cosmetics, quasi-drugs, and other products. For safety testing, official evaluation methods such as those outlined in the Quasi-drug Guidance issued by the Ministry of Health, Labour and Welfare are available, and for skin irritation evaluation, the "Guidance on the Skin Irritation Evaluation System for Safety Evaluation of Quasi-drugs and Cosmetics (PSEHB/PED Notification No. 0422-3)" (hereinafter referred to as "this Guidance") can be used. Our six companies have been working to compile a database of test results and findings related to skin irritation in order to revise this Guidance to make it easier to use.
With the support of the 8th Research Grant for the Evaluation of Test Methods Aimed at Ensuring the Safety of Cosmetics, etc., sponsored by the Japanese Society for Alternatives to Animal Experiments, we were able to obtain more detailed irritation data for 24 ingredients, including 6 of the 16 ingredients previously tested and 18 new ingredients, using J-TEC's 3D human cultured epidermis LabCyte EPI-MODEL24 (Figure 1). The OECD TG439 * test method guideline used in this guidance assumes the evaluation of undiluted ingredients, as its primary purpose is to evaluate ingredients in the event of accidental skin contact. It does not address test conditions for diluted ingredients, and dilution is not permitted in this guidance. Another issue is that even if a concentration that becomes non-irritating upon dilution is identified, there is still no clear concept for determining the final concentration that can be applied to determine skin irritation.
Currently, with the cooperation of collaborating institutions, we are working to confirm the correlation of human patch tests that will be conducted after OECD TG 439 for this guidance. We would like to obtain data by combining the results of tests using alternative methods to animal testing with the results of human tests, and use this data to provide data that can contribute to revising the guidance.
*OECD TG439: The Organization for Economic Co-operation and Development (OECD) has adopted the in vitro test method for skin irritation testing, "Test method using reconstructed human epidermis (RhE)," as OECD Test Guideline (TG) 439.
Rohto Pharmaceutical's efforts to develop safe and secure products using alternatives to animal testing
In addition to the above efforts, we are also promoting research and development activities that proactively utilize in silico toxicity prediction, which involves simulations and data analysis using computers and information technology, in vitro evaluation methods using cultured cells, and in chemico evaluation methods, which use analytical equipment to evaluate the reactivity of biological substances with chemical substances.
In order to continue providing products and services that contribute to the well-being of our customers, we will promote our efforts in research into alternatives to animal testing.