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Critical comparison of BMD and TD<sub>50</sub> methods for the calculation of acceptable intakes for N-nitroso compounds

Robert Thomas Orcid Logo, David J. Ponting Orcid Logo, Andrew Thresher Orcid Logo, Joerg Schlingemann Orcid Logo, John W. Wills Orcid Logo, George Johnson Orcid Logo

Archives of Toxicology, Volume: 99, Issue: 3, Pages: 983 - 993

Swansea University Author: George Johnson Orcid Logo

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Abstract

The tumorigenic dose 50 (TD50) is a widely used measure of carcinogenic potency which has historically been used to determine acceptable intake limits for carcinogenic compounds. Although broadly used, the TD50 model was not designed to account for important biological factors such as DNA repair and...

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Published in: Archives of Toxicology
ISSN: 0340-5761 1432-0738
Published: Springer Science and Business Media LLC 2025
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa68652
Abstract: The tumorigenic dose 50 (TD50) is a widely used measure of carcinogenic potency which has historically been used to determine acceptable intake limits for carcinogenic compounds. Although broadly used, the TD50 model was not designed to account for important biological factors such as DNA repair and cell compensatory mechanisms, changes in absorption, etc., leading to the development of benchmark dose (BMD) approaches, which use more flexible dose–response models that are better able to account for these processes. Using a nitrosamine dataset as a case study, we compare the impact of moving to a BMD-based limit as opposed to a TD50-based limit. Although there are differences in individual potency estimates between the two approaches for some compounds, we show that the key metrics such as the 5th percentile of the respective potency distributions, used when calculating class-specific default acceptable intakes, are not greatly affected. Furthermore, potency estimates for nitrosamine compounds relevant to read-across do not vary by more than a factor of 3, which is little in the context of the inherent variability in a biological response, in an overall landscape wherein potencies can vary by four orders of magnitude. This suggests a move to BMD-based limits is achievable without significant disruption to existing limits while utilising a more robust methodology.
Keywords: Nitrosamines; Acceptable intake; TD50; Benchmark dose (BMD); Dose–response modeling; Drug impurities
College: Faculty of Medicine, Health and Life Sciences
Funders: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Issue: 3
Start Page: 983
End Page: 993