1
|
Lambré C, Barat Baviera JM, Bolognesi C, Chesson A, Cocconcelli PS, Crebelli R, Gott DM, Grob K, Mengelers M, Mortensen A, Rivière G, Steffensen I, Tlustos C, Van Loveren H, Vernis L, Zorn H, Dudler V, Milana MR, Papaspyrides C, Tavares Poças MDF, Colombo G, Comandella D, Lioupis A, Marano R, Munoz Guajardo IP, Savini E, Sfika V, Tsochatzis E, Volk K, Lampi E. Scientific Guidance on the criteria for the evaluation and on the preparation of applications for the safety assessment of post-consumer mechanical PET recycling processes intended to be used for manufacture of materials and articles in contact with food. EFSA J 2024; 22:e8879. [PMID: 39081816 PMCID: PMC11287194 DOI: 10.2903/j.efsa.2024.8879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2024] Open
Abstract
In the context of entry into force of Regulation (EU) 2022/1616, EFSA updated the scientific guidance to assist applicants in the preparation of applications for the authorisation or for the modification of an existing authorisation of a 'post-consumer mechanical PET' recycling process (as defined in Annex I of Regulation (EU) 2022/1616) intended to be used for manufacturing materials and articles intended to come into contact with food. This Guidance describes the evaluation criteria and the scientific evaluation approach that EFSA will apply to assess the decontamination capability of recycling processes, as well as the information required to be included in an application dossier. The principle of the scientific evaluation approach is to apply the decontamination efficiency of a recycling process, obtained from a challenge test with surrogate contaminants, to a reference contamination level for post-consumer PET, set at 3 mg/kg PET for a contaminant resulting from possible misuse. The resulting residual concentration of each surrogate in recycled PET is then compared to a modelled concentration in PET that is calculated using generally recognised conservative migration models, such that the related migration does not give rise to a dietary exposure exceeding 0.0025 μg/kg body weight (bw) per day. This is the lowest threshold for toxicological concern (TTC) value, i.e. for potential genotoxicity, below which the risk to human health would be negligible. The information to be provided in the applications relates to: the recycling process (i.e. collection and pre-processing of the input, decontamination process, post-processing and intended use); the determination of the decontamination efficiency by the challenge test; the self-evaluation of the recycling process. On the basis of the submitted data, EFSA will assess the safety of the mechanical PET recycling process.
Collapse
|
2
|
Snodin DJ, Trejo-Martin A, Ponting DJ, Smith GF, Czich A, Cross K, Custer L, Elloway J, Greene N, Kalgutkar AS, Stalford SA, Tennant RE, Vock E, Zalewski A, Ziegler V, Dobo KL. Mechanisms of Nitrosamine Mutagenicity and Their Relationship to Rodent Carcinogenic Potency. Chem Res Toxicol 2024; 37:181-198. [PMID: 38316048 DOI: 10.1021/acs.chemrestox.3c00327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
A thorough literature review was undertaken to understand how the pathways of N-nitrosamine transformation relate to mutagenic potential and carcinogenic potency in rodents. Empirical and computational evidence indicates that a common radical intermediate is created by CYP-mediated hydrogen abstraction at the α-carbon; it is responsible for both activation, leading to the formation of DNA-reactive diazonium species, and deactivation by denitrosation. There are competing sites of CYP metabolism (e.g., β-carbon), and other reactive species can form following initial bioactivation, although these alternative pathways tend to decrease rather than enhance carcinogenic potency. The activation pathway, oxidative dealkylation, is a common reaction in drug metabolism and evidence indicates that the carbonyl byproduct, e.g., formaldehyde, does not contribute to the toxic properties of N-nitrosamines. Nitric oxide (NO), a side product of denitrosation, can similarly be discounted as an enhancer of N-nitrosamine toxicity based on carcinogenicity data for substances that act as NO-donors. However, not all N-nitrosamines are potent rodent carcinogens. In a significant number of cases, there is a potency overlap with non-N-nitrosamine carcinogens that are not in the Cohort of Concern (CoC; high-potency rodent carcinogens comprising aflatoxin-like-, N-nitroso-, and alkyl-azoxy compounds), while other N-nitrosamines are devoid of carcinogenic potential. In this context, mutagenicity is a useful surrogate for carcinogenicity, as proposed in the ICH M7 (R2) (2023) guidance. Thus, in the safety assessment and control of N-nitrosamines in medicines, it is important to understand those complementary attributes of mechanisms of mutagenicity and structure-activity relationships that translate to elevated potency versus those which are associated with a reduction in, or absence of, carcinogenic potency.
Collapse
Affiliation(s)
| | - Alejandra Trejo-Martin
- Gilead Sciences Inc. Nonclinical Safety and Pathobiology (NSP), Foster City, California 94404, United States
| | | | - Graham F Smith
- AstraZeneca, Imaging and Data Analytics, Clinical Pharmacology and Safety Sciences, Research and Development, CB2 0AA Cambridge, U.K
| | - Andreas Czich
- Sanofi, Research and Development, Preclinical Safety, 65926 Frankfurt, Germany
| | - Kevin Cross
- Instem, Conshohocken, Pennsylvania 19428, United States
| | - Laura Custer
- Bristol-Myers Squibb, Nonclinical Safety, New Brunswick, New Jersey 08903, United States
| | - Joanne Elloway
- AstraZeneca, Safety Sciences, Clinical Pharmacology and Safety Sciences Research and Development, CB2 0AA Cambridge, U.K
| | - Nigel Greene
- AstraZeneca, Imaging and Data Analytics, Clinical Pharmacology and Safety Sciences, Research and Development, Waltham, Massachusetts 02451, United States
| | - Amit S Kalgutkar
- Medicine Design, Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
| | | | | | - Esther Vock
- Boehringer-Ingelheim Pharma GmbH & Co., KG, 88397 Biberach an der Riss, Germany
| | - Adam Zalewski
- Bayer AG, Pharmaceuticals, Genetic and Computational Toxicology, 13342 Berlin, Germany
| | - Verena Ziegler
- Bayer AG, Pharmaceuticals, Genetic and Computational Toxicology, 13342 Berlin, Germany
| | - Krista L Dobo
- Drug Safety Research and Development, Global Portfolio and Regulatory Strategy, Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| |
Collapse
|
3
|
Yang C, Rathman JF, Ribeiro JV, Batke M, Escher SE, Firman JW, Hobocienski B, Kellner R, Mostrag A, Przybylak KR, Cronin MTD. Update of the Cancer Potency Database (CPDB) to enable derivations of Thresholds of Toxicological Concern (TTC) for cancer potency. Food Chem Toxicol 2023; 182:114182. [PMID: 37951343 DOI: 10.1016/j.fct.2023.114182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/03/2023] [Accepted: 11/03/2023] [Indexed: 11/13/2023]
Abstract
The purpose of this study was to update the existing Cancer Potency Database (CPDB) in order to support the development of a dataset of compounds, with associated points of departure (PoDs), to enable a review and update of currently applied values for the Threshold of Toxicological Concern (TTC) for cancer endpoints. This update of the current CPDB, last reviewed in 2012, includes the addition of new data (44 compounds and 158 studies leading to additional 359 dose-response curves). Strict inclusion criteria were established and applied to select compounds and studies with relevant cancer potency data. PoDs were calculated from dose-response modeling, including the benchmark dose (BMD) and the lower 90% confidence limits (BMDL) at a specified benchmark response (BMR) of 10%. The updated full CPDB database resulted in a total of 421 chemicals which had dose-response data that could be used to calculate PoDs. This candidate dataset for cancer TTC is provided in a transparent and adaptable format for further analysis of TTC to derive cancer potency thresholds.
Collapse
Affiliation(s)
- Chihae Yang
- Molecular Networks GmbH, Nuremberg, Germany; Altamira LLC, Columbus, OH, USA; The Ohio State University, Columbus, OH, USA
| | - James F Rathman
- Molecular Networks GmbH, Nuremberg, Germany; Altamira LLC, Columbus, OH, USA; The Ohio State University, Columbus, OH, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Magurany KA, English JC, Cox KD. Application of the threshold of toxicological concern (TTC) in the evaluation of drinking water contact chemicals. Toxicol Mech Methods 2023:1-17. [PMID: 38031359 DOI: 10.1080/15376516.2023.2279041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 10/30/2023] [Indexed: 12/01/2023]
Abstract
The Threshold of Toxicological Concern (TTC) is an approach for assessing the safety of chemicals with low levels of exposure for which limited toxicology data are available. The original TTC criteria were derived for oral exposures from a distributional analysis of a dataset of 613 chemicals that identified 5th percentile no observed effect level (NOEL) values grouped within three tiers of compounds having specific structural functional groups and/or toxic potencies known as Cramer I, II and III classifications. Subsequent assessments of the TTC approach have established current thresholds to be scientifically robust. While the TTC has gained acknowledgment and acceptance by many regulatory agencies and organizations, use of the TTC approach in evaluating drinking water chemicals has been limited. To apply the TTC concept to drinking water chemicals, an exposure-based approach that incorporates the current weight of evidence for the target chemical is presented. Such an approach provides a comparative point of departure to the 5th percentile TTC NOEL using existing data, while conserving the allocation of toxicological resources for quantitative risk assessment to chemicals with greater exposure or toxicity. This approach will be considered for incorporation into NSF/ANSI/CAN 600, a health effects standard used in the safety evaluation of chemicals present in drinking water from drinking water contact additives and materials certified to NSF/ANSI/CAN 60 and 61, respectively.
Collapse
Affiliation(s)
| | | | - Kevin D Cox
- Water Toxics Unit, Michigan Department of Environment, Great Lakes and Energy (EGLE), Lansing, MI, USA
| |
Collapse
|
5
|
Tennant RE, Ponting DJ, Thresher A. A deep dive into historical Ames study data for N-nitrosamine compounds. Regul Toxicol Pharmacol 2023; 143:105460. [PMID: 37495012 DOI: 10.1016/j.yrtph.2023.105460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/09/2023] [Accepted: 07/19/2023] [Indexed: 07/28/2023]
Abstract
Mutagenicity data is a core component of the safety assessment data required by regulatory agencies for acceptance of new drug compounds, with the OECD-471 bacterial reverse mutation (Ames) assay most widely used as a primary screen to assess drug impurities for potential mutagenic risk. N-Nitrosamines are highly potent mutagenic carcinogens in rodent bioassays and their recent detection as impurities in pharmaceutical products has sparked increased interest in their safety assessment. Previous literature reports indicated that the Ames test might not be sensitive enough to detect the mutagenic potential of N-nitrosamines in order to accurately predict a risk of carcinogenicity. To explore this hypothesis, public Ames and rodent carcinogenicity data pertaining to the N-nitrosamine class of compounds was collated for analysis. Here we present how variations to the OECD 471-compliant Ames test, including strain, metabolic activation, solvent type and pre-incubation/plate incorporation methods, may impact the predictive performance for carcinogenicity. An understanding of optimal conditions for testing of N-nitrosamines may improve both the accuracy and confidence in the ability of the Ames test to identify potential carcinogens.
Collapse
Affiliation(s)
- Rachael E Tennant
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds, West Yorkshire, LS11 5PS, UK.
| | - David J Ponting
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds, West Yorkshire, LS11 5PS, UK
| | - Andrew Thresher
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds, West Yorkshire, LS11 5PS, UK
| |
Collapse
|
6
|
Snodin DJ. Mutagenic impurities in pharmaceuticals: A critical assessment of the cohort of concern with a focus on N-nitrosamines. Regul Toxicol Pharmacol 2023; 141:105403. [PMID: 37116739 DOI: 10.1016/j.yrtph.2023.105403] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/20/2023] [Accepted: 04/25/2023] [Indexed: 04/30/2023]
Abstract
The TTC (Threshold of Toxicological Concern; set at 1.5 μg/day for pharmaceuticals) defines an acceptable patient intake for any unstudied chemical posing a negligible risk of carcinogenicity or other toxic effects. A group of high potency mutagenic carcinogens, defined solely by the presence of particular structural alerts, are referred to as the "cohort of concern" (CoC); aflatoxin-like-, N-nitroso-, and alkyl-azoxy compounds are considered to pose a significant carcinogenic risk at intakes below the TTC. Kroes et al.2004, derived values for the TTC and CoC in the context of food components, employing a non-transparent dataset never placed in the public domain. Using a reconstructed all-carcinogen dataset from relevant publications, it is now clear that there are exceptions for all three CoC structural classes. N-Nitrosamines represent 62% of the N-nitroso class in the reconstructed dataset. Employing a contemporary dataset, 20% are negative in rodent carcinogenicity bioassays with less than 50% of N-nitrosamines estimated to fall into the highest risk category. It is recommended that CoC nitrosamines are identified by compound-specific data rather than structural alerts. Thus, it should be possible to distinguish CoC from non-CoC N-nitrosamines in the context of mutagenic impurities described in ICH M7 (R1).
Collapse
Affiliation(s)
- David J Snodin
- Xiphora Biopharma Consulting, 9 Richmond Apartments, Redland Court Road, Bristol, BS6 7BG, UK.
| |
Collapse
|
7
|
Lou C, Yang H, Deng H, Huang M, Li W, Liu G, Lee PW, Tang Y. Chemical rules for optimization of chemical mutagenicity via matched molecular pairs analysis and machine learning methods. J Cheminform 2023; 15:35. [PMID: 36941726 PMCID: PMC10029263 DOI: 10.1186/s13321-023-00707-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 03/06/2023] [Indexed: 03/23/2023] Open
Abstract
Chemical mutagenicity is a serious issue that needs to be addressed in early drug discovery. Over a long period of time, medicinal chemists have manually summarized a series of empirical rules for the optimization of chemical mutagenicity. However, given the rising amount of data, it is getting more difficult for medicinal chemists to identify more comprehensive chemical rules behind the biochemical data. Herein, we integrated a large Ames mutagenicity data set with 8576 compounds to derive mutagenicity transformation rules for reversing Ames mutagenicity via matched molecular pairs analysis. A well-trained consensus model with a reasonable applicability domain was constructed, which showed favorable performance in the external validation set with an accuracy of 0.815. The model was used to assess the generalizability and validity of these mutagenicity transformation rules. The results demonstrated that these rules were of great value and could provide inspiration for the structural modifications of compounds with potential mutagenic effects. We also found that the local chemical environment of the attachment points of rules was critical for successful transformation. To facilitate the use of these mutagenicity transformation rules, we integrated them into ADMETopt2 ( http://lmmd.ecust.edu.cn/admetsar2/admetopt2/ ), a free web server for optimization of chemical ADMET properties. The above-mentioned approach would be extended to the optimization of other toxicity endpoints.
Collapse
Affiliation(s)
- Chaofeng Lou
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China
| | - Hongbin Yang
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China
| | - Hua Deng
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China
| | - Mengting Huang
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China
| | - Weihua Li
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China
| | - Guixia Liu
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China
| | - Philip W Lee
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China
| | - Yun Tang
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China.
| |
Collapse
|
8
|
Marin-Kuan M, Pagnotti V, Patin A, Moulin J, Latado H, Varela J, Hammel YA, Gude T, Moor H, Billinton N, Tate M, Behnisch PA, Besselink H, Burleigh-Flayer H, Koster S, Szabo DT. Interlaboratory Study to Evaluate a Testing Protocol for the Safety of Food Packaging Coatings. TOXICS 2023; 11:156. [PMID: 36851031 PMCID: PMC9962921 DOI: 10.3390/toxics11020156] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 01/31/2023] [Accepted: 02/04/2023] [Indexed: 06/18/2023]
Abstract
According to European regulations, migration from food packaging must be safe. However, currently, there is no consensus on how to evaluate its safety, especially for non-intentionally added substances (NIAS). The intensive and laborious approach, involving identification and then quantification of all migrating substances followed by a toxicological evaluation, is not practical or feasible. In alignment with the International Life Sciences Institute (ILSI) and the European Union (EU) guidelines on packaging materials, efforts are focused on combining data from analytics, bioassays and in silico toxicology approaches for the risk assessment of packaging materials. Advancement of non-targeted screening approaches using both analytical methods and in vitro bioassays is key. A protocol was developed for the chemical and biological screening of migrants from coated metal packaging materials. This protocol includes guidance on sample preparation, migrant simulation, chemical analysis using liquid chromatography (LC-MS) and validated bioassays covering endocrine activity, genotoxicity and metabolism-related targets. An inter-laboratory study was set-up to evaluate the consistency in biological activity and analytical results generated between three independent laboratories applying the developed protocol and guidance. Coated packaging metal panels were used in this case study. In general, the inter-laboratory chemical analysis and bioassay results displayed acceptable consistency between laboratories, but technical differences led to different data interpretations (e.g., cytotoxicity, cell passages, chemical analysis). The study observations with the greatest impact on the quality of the data and ultimately resulting in discrepancies in the results are given and suggestions for improvement of the protocol are made (e.g., sample preparation, chemical analysis approaches). Finally, there was agreement on the need for an aligned protocol to be utilized by qualified laboratories for chemical and biological analyses, following best practices and guidance for packaging safety assessment of intentionally added substances (IAS) and NIAS to avoid inconsistency in data and the final interpretation.
Collapse
Affiliation(s)
- Maricel Marin-Kuan
- Société des Produits Nestlé SA-Nestlé Research, 1000 Lausanne, Switzerland
| | | | - Amaury Patin
- Société des Produits Nestlé SA-Nestlé Research, 1000 Lausanne, Switzerland
| | - Julie Moulin
- Société des Produits Nestlé SA-Nestlé Research, 1000 Lausanne, Switzerland
| | - Helia Latado
- Société des Produits Nestlé SA-Nestlé Research, 1000 Lausanne, Switzerland
| | - Jesús Varela
- Société des Produits Nestlé SA-Nestlé Research, 1000 Lausanne, Switzerland
| | - Yves-Alexis Hammel
- Société des Produits Nestlé SA-Nestlé Research, 1000 Lausanne, Switzerland
| | - Thomas Gude
- SQTS Swiss Quality Testing Services, 8953 Dietikon, Switzerland
| | - Heidi Moor
- SQTS Swiss Quality Testing Services, 8953 Dietikon, Switzerland
| | | | - Matthew Tate
- Gentronix Limited, Alderley Park, Cheshire SK10 4TG, UK
| | | | - Harrie Besselink
- BioDetection Systems B.V. (BDS), 1098 XH Amsterdam, The Netherlands
| | | | - Sander Koster
- Société des Produits Nestlé SA-Nestlé Research, 1000 Lausanne, Switzerland
| | | |
Collapse
|
9
|
Fowkes A, Foster R, Kane S, Thresher A, Werner AL, de Oliveira AAF. Enhancing global and local decision making for chemical safety assessments through increasing the availability of data. Toxicol Mech Methods 2023:1-12. [PMID: 36600456 DOI: 10.1080/15376516.2022.2156007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Toxicity safety assessments are a fundamental part of the lifecycle of products and aim to protect human health and the environment from harmful exposures to chemical substances. To make decisions regarding the suitability of testing strategies, the applicability of individual tests or concluding an assessment for an individual chemical requires data. This review outlines how different forms of data sharing, from enhancing publicly-available data to extracting knowledge from commercially-sensitive data, leads to increased quantity and quality of evidence being available for safety assessors to review. This can result in more confident decisions for different use cases in the context of chemical safety assessments. Although a number of challenges remain with progressing the evolution of toxicity safety assessments, data sharing should be considered as a key approach to accelerating the development and uptake of new best practices.
Collapse
|
10
|
Ponting DJ, Dobo KL, Kenyon MO, Kalgutkar AS. Strategies for Assessing Acceptable Intakes for Novel N-Nitrosamines Derived from Active Pharmaceutical Ingredients. J Med Chem 2022; 65:15584-15607. [PMID: 36441966 DOI: 10.1021/acs.jmedchem.2c01498] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The detection of N-nitrosamines, derived from solvents and reagents and, on occasion, the active pharmaceutical ingredient (API) at higher than acceptable levels in drug products, has led regulators to request a detailed review for their presence in all medicinal products. In the absence of rodent carcinogenicity data for novel N-nitrosamines derived from amine-containing APIs, a conservative class limit of 18 ng/day (based on the most carcinogenic N-nitrosamines) or the derivation of acceptable intakes (AIs) using structurally related surrogates with robust rodent carcinogenicity data is recommended. The guidance has implications for the pharmaceutical industry given the vast number of marketed amine-containing drugs. In this perspective, the rate-limiting step in N-nitrosamine carcinogenicity, involving cytochrome P450-mediated α-carbon hydroxylation to yield DNA-reactive diazonium or carbonium ion intermediates, is discussed with reference to the selection of read-across analogs to derive AIs. Risk-mitigation strategies for managing putative N-nitrosamines in the preclinical discovery setting are also presented.
Collapse
Affiliation(s)
- David J Ponting
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds LS11 5PS, United Kingdom
| | - Krista L Dobo
- Drug Safety Research and Development, Global Portfolio and Regulatory Strategy, Pfizer Worldwide Research, Development, and Medical, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Michelle O Kenyon
- Drug Safety Research and Development, Global Portfolio and Regulatory Strategy, Pfizer Worldwide Research, Development, and Medical, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Amit S Kalgutkar
- Medicine Design, Pfizer Worldwide Research, Development, and Medical, 1 Portland Street, Cambridge, Massachusetts 02139, United States
| |
Collapse
|
11
|
Thomas R, Tennant RE, Oliveira AAF, Ponting DJ. What Makes a Potent Nitrosamine? Statistical Validation of Expert-Derived Structure-Activity Relationships. Chem Res Toxicol 2022; 35:1997-2013. [PMID: 36302501 PMCID: PMC9682520 DOI: 10.1021/acs.chemrestox.2c00199] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The discovery of carcinogenic nitrosamine impurities above the safe limits in pharmaceuticals has led to an urgent need to develop methods for extending structure-activity relationship (SAR) analyses from relatively limited datasets, while the level of confidence required in that SAR indicates that there is significant value in investigating the effect of individual substructural features in a statistically robust manner. This is a challenging exercise to perform on a small dataset, since in practice, compounds contain a mixture of different features, which may confound both expert SAR and statistical quantitative structure-activity relationship (QSAR) methods. Isolating the effects of a single structural feature is made difficult due to the confounding effects of other functionality as well as issues relating to determining statistical significance in cases of concurrent statistical tests of a large number of potential variables with a small dataset; a naïve QSAR model does not predict any features to be significant after correction for multiple testing. We propose a variation on Bayesian multiple linear regression to estimate the effects of each feature simultaneously yet independently, taking into account the combinations of features present in the dataset and reducing the impact of multiple testing, showing that some features have a statistically significant impact. This method can be used to provide statistically robust validation of expert SAR approaches to the differences in potency between different structural groupings of nitrosamines. Structural features that lead to the highest and lowest carcinogenic potency can be isolated using this method, and novel nitrosamine compounds can be assigned into potency categories with high accuracy.
Collapse
|
12
|
Fillon YA, Akhtar N, Andrews BI, Benstead D, Breitler S, Gronke RS, Olbrich M, Stolee JA, Vandermeersch T. Determination of Purge Factors for Use in Oligonucleotide Control Strategies. Org Process Res Dev 2022. [DOI: 10.1021/acs.oprd.1c00398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yannick A. Fillon
- Biogen Inc., 225 Binney Street, Cambridge, Massachusetts 02142, United States
| | | | - Benjamin I. Andrews
- GlaxoSmithKline Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
| | | | - Simon Breitler
- F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Robert S. Gronke
- Biogen Inc., 225 Binney Street, Cambridge, Massachusetts 02142, United States
| | - Martin Olbrich
- F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Jessica A. Stolee
- Biogen Inc., 225 Binney Street, Cambridge, Massachusetts 02142, United States
| | | |
Collapse
|
13
|
Dobo KL, Kenyon MO, Dirat O, Engel M, Fleetwood A, Martin M, Mattano S, Musso A, McWilliams JC, Papanikolaou A, Parris P, Whritenour J, Yu S, Kalgutkar AS. Practical and Science-Based Strategy for Establishing Acceptable Intakes for Drug Product N-Nitrosamine Impurities. Chem Res Toxicol 2022; 35:475-489. [PMID: 35212515 PMCID: PMC8941624 DOI: 10.1021/acs.chemrestox.1c00369] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
![]()
The potential for N-nitrosamine impurities in
pharmaceutical products presents a challenge for the quality management
of medicinal products. N-Nitrosamines are considered
cohort-of-concern compounds due to the potent carcinogenicity of many
of the structurally simple chemicals within this structural class.
In the past 2 years, a number of drug products containing certain
active pharmaceutical ingredients have been withdrawn or recalled
from the market due to the presence of carcinogenic low-molecular-weight N,N-dialkylnitrosamine impurities. Regulatory
authorities have issued guidance to market authorization holders to
review all commercial drug substances/products for the potential risk
of N-nitrosamine impurities, and in cases where a
significant risk of N-nitrosamine impurity is identified,
analytical confirmatory testing is required. A key factor to consider
prior to analytical testing is the estimation of the daily acceptable
intake (AI) of the N-nitrosamine impurity. A significant
proportion of N-nitrosamine drug product impurities
are unique/complex structures for which the development of low-level
analytical methods is challenging. Moreover, these unique/complex
impurities may be less potent carcinogens compared to simple nitrosamines.
In the present work, our objective was to derive AIs for a large number
of complex N-nitrosamines without carcinogenicity
data that were identified as potential low-level impurities. The impurities
were first cataloged and grouped according to common structural features,
with a total of 13 groups defined with distinct structural features.
Subsequently, carcinogenicity data were reviewed for structurally
related N-nitrosamines relevant to each of the 13
structural groups and group AIs were derived conservatively based
on the most potent N-nitrosamine within each group.
The 13 structural group AIs were used as the basis for assigning AIs
to each of the structurally related complex N-nitrosamine
impurities. The AIs of several N-nitrosamine groups
were found to be considerably higher than those for the simple N,N-dialkylnitrosamines, which translates
to commensurately higher analytical method detection limits.
Collapse
Affiliation(s)
- Krista L Dobo
- Drug Safety Research and Development, Global Portfolio and Regulatory Strategy, Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - Michelle O Kenyon
- Drug Safety Research and Development, Global Portfolio and Regulatory Strategy, Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - Olivier Dirat
- Global Product Development, Pfizer Worldwide Research, Development, and Medical, Sandwich CT13 9NJ, United Kingdom
| | - Maria Engel
- Drug Safety Research and Development, Global Portfolio and Regulatory Strategy, Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - Andrew Fleetwood
- East Kent Pharma Consulting Ltd., 10408413, England CT1 2TU, United Kingdom
| | - Matthew Martin
- Drug Safety Research and Development, Global Computational Safety Sciences, Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - Susan Mattano
- Sue Mattano Consulting, Mystic, Connecticut 06355, United States
| | - Alyssa Musso
- Drug Safety Research and Development, Genetic Toxicology, Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - James Christopher McWilliams
- Pharmaceutical Sciences Small Molecules, Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - Alexandros Papanikolaou
- Drug Safety Research and Development, Global Portfolio and Regulatory Strategy, Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - Patricia Parris
- Drug Safety Research and Development, Global Portfolio and Regulatory Strategy, Pfizer Worldwide Research, Development, and Medical, Sandwich CT13 9NJ, United Kingdom
| | - Jessica Whritenour
- Drug Safety Research and Development, Global Portfolio and Regulatory Strategy, Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - Shu Yu
- Pharmaceutical Sciences Small Molecules, Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - Amit S Kalgutkar
- Medicine Design, Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
| |
Collapse
|
14
|
Ponting DJ, Burns MJ, Foster RS, Hemingway R, Kocks G, MacMillan DS, Shannon-Little AL, Tennant RE, Tidmarsh JR, Yeo DJ. Use of Lhasa Limited Products for the In Silico Prediction of Drug Toxicity. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2425:435-478. [PMID: 35188642 DOI: 10.1007/978-1-0716-1960-5_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Lhasa Limited have had a role in the in silico prediction of drug and other chemical toxicity for over 30 years. This role has always been multifaceted, both as a provider of predictive software such as Derek Nexus, and as an honest broker for the sharing of proprietary chemical and toxicity data. A changing regulatory environment and the drive for the Replacement, Reduction and Refinement (the 3Rs) of animal testing have led both to increased acceptance of in silico predictions and a desire for the sharing of data to reduce duplicate testing. The combination of these factors has led to Lhasa Limited providing a suite of products and coordinating numerous data-sharing consortia that do indeed facilitate a significant reduction in the testing burden that companies would otherwise be laboring under. Many of these products and consortia can be organized into workflows for specific regulatory use cases, and it is these that will be used to frame the narrative in this chapter.
Collapse
|
15
|
Recycling of Post-Consumer Packaging Materials into New Food Packaging Applications—Critical Review of the European Approach and Future Perspectives. SUSTAINABILITY 2022. [DOI: 10.3390/su14020824] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The European strategy for plastics, as part of the EU’s circular economy action plan, should support the reduction in plastic waste. One key element in this action plan is the improvement of the economics and quality of recycled plastics. In addition, an important goal is that by 2030, all plastics packaging placed on the EU market must either be reusable or can be recycled in a cost-effective manner. This means that, at the end, a closed-loop recycling of food packaging materials should be established. However, the use of recyclates must not result in less severe preventive consumer protection of food packaging materials. This may lead to a conservative evaluation of authorities on post-consumer recyclates in food packaging applications. On the other hand, over-conservatism might over-protect the consumer and generate insurmountable barriers to the application of post-consumer recyclates for food packaging and, hence, counteract the targets of circular economy. The objective of this review is to provide an insight into the evaluation of post-consumer recyclates applied in direct contact to food. Safety assessment criteria as developed by the European Food Safety Authority EFSA will be presented, explained, and critically discussed.
Collapse
|
16
|
Vichare AS, Kamath SU, Leist M, Hayes AW, Mahadevan B. Application of the 3Rs principles in the development of pharmaceutical generics. Regul Toxicol Pharmacol 2021; 125:105016. [PMID: 34302895 DOI: 10.1016/j.yrtph.2021.105016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 07/06/2021] [Accepted: 07/19/2021] [Indexed: 10/20/2022]
Abstract
Although the 3Rs are broadly applied in nonclinical testing, a better appreciation of the 3Rs is needed in the field of differentiated or value-added pharmaceutical generics because the minor changes in formulation, dosage form, indication, and application route often do not require additional safety testing. The US FDA and the EU EMA have comprehensive regulations for such drugs based on quality, therapeutic equivalence, and safety guidelines. However, no scientific publications on how the concept of replacement and reduction from 3Rs principles can be applied in the safety assessment of differentiated generics were found in the public domain. In this review, we discuss the application of 3Rs in nonclinical testing requirements for differentiated generics. Practical examples are provided in the form of case studies from regulated markets. We highlight the need for utilization of existing data to establish equivalence (differentiated generic vs innovator) in efficacy and safety. The case studies indicate that data requirements from animal experiments have been reduced to a large extent in some major markets without compromising quality and safety. In this context, we also highlight the problem that on a global scale, a true reduction of animal experiments will only be achieved when all countries adopt similar practices.
Collapse
Affiliation(s)
- Abhijit S Vichare
- Global Preclinical & Product Safety, Abbott Healthcare Pvt Ltd., Mumbai, India.
| | - Sushant U Kamath
- Global Preclinical & Product Safety, Abbott Healthcare Pvt Ltd., Mumbai, India
| | - Marcel Leist
- In vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
| | - A Wallace Hayes
- The University of South Florida, College of Public Health, Tampa, FL, USA
| | | |
Collapse
|
17
|
Assessing the impact of expert knowledge on ICH M7 (Q)SAR predictions. Is expert review still needed? Regul Toxicol Pharmacol 2021; 125:105006. [PMID: 34273441 DOI: 10.1016/j.yrtph.2021.105006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 07/08/2021] [Accepted: 07/10/2021] [Indexed: 11/21/2022]
Abstract
The ICH M7 (R1) guideline recommends the use of complementary (Q)SAR models to assess the mutagenic potential of drug impurities as a state-of-the-art, high-throughput alternative to empirical testing. Additionally, it includes a provision for the application of expert knowledge to increase prediction confidence and resolve conflicting calls. Expert knowledge, which considers structural analogs and mechanisms of activity, has been valuable when models return an indeterminate (equivocal) result or no prediction (out-of-domain). A retrospective analysis of 1002 impurities evaluated in drug regulatory applications between April 2017 and March 2019 assessed the impact of expert review on (Q)SAR predictions. Expert knowledge overturned the default predictions for 26% of the impurities and resolved 91% of equivocal predictions and 75% of out-of-domain calls. Of the 261 overturned default predictions, 15% were upgraded to equivocal or positive and 79% were downgraded to equivocal or negative. Chemical classes with the most overturns were primary aromatic amines (46%), aldehydes (45%), Michael-reactive acceptors (37%), and non-primary alkyl halides (33%). Additionally, low confidence predictions were the most often overturned. Collectively, the results suggest that expert knowledge continues to play an important role in an ICH M7 (Q)SAR prediction workflow and triaging predictions based on chemical class and probability can improve (Q)SAR review efficiency.
Collapse
|
18
|
Batke M, Afrapoli FM, Kellner R, Rathman JF, Yang C, Cronin MTD, Escher SE. Threshold of Toxicological Concern—An Update for Non-Genotoxic Carcinogens. FRONTIERS IN TOXICOLOGY 2021; 3:688321. [PMID: 35295144 PMCID: PMC8915827 DOI: 10.3389/ftox.2021.688321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 05/25/2021] [Indexed: 11/22/2022] Open
Abstract
The Threshold of Toxicological Concern (TTC) concept can be applied to organic compounds with the known chemical structure to derive a threshold for exposure, below which a toxic effect on human health by the compound is not expected. The TTC concept distinguishes between carcinogens that may act as genotoxic and non-genotoxic compounds. A positive prediction of a genotoxic mode of action, either by structural alerts or experimental data, leads to the application of the threshold value for genotoxic compounds. Non-genotoxic substances are assigned to the TTC value of their respective Cramer class, even though it is recognized that they could test positive in a rodent cancer bioassay. This study investigated the applicability of the Cramer classes specifically to provide adequate protection for non-genotoxic carcinogens. For this purpose, benchmark dose levels based on tumor incidence were compared with no observed effect levels (NOELs) derived from non-, pre- or neoplastic lesions. One key aspect was the categorization of compounds as non-genotoxic carcinogens. The recently finished CEFIC LRI project B18 classified the carcinogens of the Carcinogenicity Potency DataBase (CPDB) as either non-genotoxic or genotoxic compounds based on experimental or in silico data. A detailed consistency check resulted in a dataset of 137 non-genotoxic organic compounds. For these 137 compounds, NOEL values were derived from high quality animal studies with oral exposure and chronic duration using well-known repositories, such as RepDose, ToxRef, and COSMOS DB. Further, an effective tumor dose (ETD10) was calculated and compared with the lower confidence limit on benchmark dose levels (BMDL10) derived by model averaging. Comparative analysis of NOEL/EDT10/BMDL10 values showed that potentially bioaccumulative compounds in humans, as well as steroids, which both belong to the exclusion categories, occur predominantly in the region of the fifth percentiles of the distributions. Excluding these 25 compounds resulted in significantly higher but comparable fifth percentile chronic NOEL and BMDL10 values, while the fifth percentile EDT10 value was slightly higher but not statistically significant. The comparison of the obtained distributions of NOELs with the existing Cramer classes and their derived TTC values supports the application of Cramer class thresholds to all non-genotoxic compounds, such as non-genotoxic carcinogens.
Collapse
Affiliation(s)
- Monika Batke
- Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), Hannover, Germany
| | | | - Rupert Kellner
- Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), Hannover, Germany
| | - James F. Rathman
- Altamira, LLC, Columbus, OH, United States
- Molecular Networks GmbH, Nuremberg, Germany
| | - Chihae Yang
- Altamira, LLC, Columbus, OH, United States
- Molecular Networks GmbH, Nuremberg, Germany
| | - Mark T. D. Cronin
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Sylvia E. Escher
- Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), Hannover, Germany
- *Correspondence: Sylvia E. Escher
| |
Collapse
|
19
|
Yamada T, Kurimoto M, Hirose A, Yang C, Rathman JF. Development of a New Threshold of Toxicological Concern Database of Non-cancer Toxicity Endpoints for Industrial Chemicals. FRONTIERS IN TOXICOLOGY 2021; 3:626543. [PMID: 35295111 PMCID: PMC8915903 DOI: 10.3389/ftox.2021.626543] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 02/25/2021] [Indexed: 11/25/2022] Open
Abstract
In cases where chemical-specific toxicity data are absent or limited, the threshold of toxicological concern (TTC) offers an alternative to assess human exposure below which “there would be no appreciable risk to human health.” The application of TTC to non-cancer systemic endpoints has been pursued for decades using a chemical classification and Point of Departure (POD). This study presents a new POD dataset of oral subacute/subchronic toxicity studies in rats for 656 industrial chemicals retrieved from the Hazard Evaluation Support System (HESS) Integrated Platform, which contains hundreds of reliable repeated-dose toxicity test data of industrial chemicals under the Chemical Substances of Control Law in Japan. The HESS TTC dataset was found to have less duplication with substances in other reported TTC datasets. Each chemical was classified into a Cramer Class, with 68, 3, and 29% of these 656 chemicals distributed in Classes III, II, and I, respectively. For each Cramer Class, a provisional Tolerable Daily Intake (TDI) was derived from the 5th percentile of the lognormal distribution of PODs. The TDIs were 1.9 and 30 μg/kg bw/day for Classes III and I, respectively. The TDI for Cramer Class II could not be determined due to insufficient sample size. This work complements previous studies of the TTC approach and increases the confidence of the thresholds for non-cancer endpoints by including unique chemical structures. This new TTC dataset is publicly available and can be merged with existing databases to improve the TTC approach.
Collapse
Affiliation(s)
- Takashi Yamada
- Division of Risk Assessment, Center for Biological Safety Research, National Institute of Health Sciences, Kawasaki, Japan
- *Correspondence: Takashi Yamada
| | - Masayuki Kurimoto
- Division of Risk Assessment, Center for Biological Safety Research, National Institute of Health Sciences, Kawasaki, Japan
| | - Akihiko Hirose
- Division of Risk Assessment, Center for Biological Safety Research, National Institute of Health Sciences, Kawasaki, Japan
| | - Chihae Yang
- Molecular Networks GmbH, Nürnberg, Germany
- Department of Chemical and Biomolecular Engineering, College of Engineering, The Ohio State University, Columbus, OH, United States
| | - James F. Rathman
- Molecular Networks GmbH, Nürnberg, Germany
- Department of Chemical and Biomolecular Engineering, College of Engineering, The Ohio State University, Columbus, OH, United States
| |
Collapse
|
20
|
Thomas R, Thresher A, Ponting DJ. Utilisation of parametric methods to improve percentile-based estimates for the carcinogenic potency of nitrosamines. Regul Toxicol Pharmacol 2021; 121:104875. [PMID: 33556416 DOI: 10.1016/j.yrtph.2021.104875] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 12/09/2020] [Accepted: 01/23/2021] [Indexed: 10/22/2022]
Abstract
N-Nitrosamines have recently been the subject of intense regulatory scrutiny, including the setting of low exposure limits (18 ng/day) (European Medicines Agency (EMA), 2020). This paper evaluates different methodologies to determine statistically robust bounds on the carcinogenic potency of chemical classes, using historic TD50 data (Peto et al., 1984; Thresher et al., 2019) and exemplified for N-nitrosamines. Initially, the distribution of TD50 values (TD50s) for N-nitrosamines of known potency was characterised. From this, it is possible to compare parametric and non-parametric methods to obtain percentiles of interest from the distribution of TD50s, which are shown to be robust to uncertainty in the initial TD50 estimates. These methods may then be applied to different chemical subclasses. The values obtained may be of use in refining acceptable intakes for N-nitrosamines and their subclasses.
Collapse
|
21
|
Thresher A, Foster R, Ponting DJ, Stalford SA, Tennant RE, Thomas R. Are all nitrosamines concerning? A review of mutagenicity and carcinogenicity data. Regul Toxicol Pharmacol 2020; 116:104749. [DOI: 10.1016/j.yrtph.2020.104749] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/17/2020] [Accepted: 07/27/2020] [Indexed: 01/17/2023]
|
22
|
The TTC Data Mart: An interactive browser for threshold of toxicological concern calculations. ACTA ACUST UNITED AC 2020. [DOI: 10.1016/j.comtox.2020.100128] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
23
|
Pham LL, Borghoff SJ, Thompson CM. Comparison of threshold of toxicological concern (TTC) values to oral reference dose (RfD) values. Regul Toxicol Pharmacol 2020; 113:104651. [DOI: 10.1016/j.yrtph.2020.104651] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 03/23/2020] [Accepted: 03/24/2020] [Indexed: 10/24/2022]
|
24
|
Mahony C, Bowtell P, Huber M, Kosemund K, Pfuhler S, Zhu T, Barlow S, McMillan DA. Threshold of toxicological concern (TTC) for botanicals - Concentration data analysis of potentially genotoxic constituents to substantiate and extend the TTC approach to botanicals. Food Chem Toxicol 2020; 138:111182. [DOI: 10.1016/j.fct.2020.111182] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/03/2020] [Accepted: 02/05/2020] [Indexed: 12/21/2022]
|
25
|
Yang H, Lou C, Li W, Liu G, Tang Y. Computational Approaches to Identify Structural Alerts and Their Applications in Environmental Toxicology and Drug Discovery. Chem Res Toxicol 2020; 33:1312-1322. [DOI: 10.1021/acs.chemrestox.0c00006] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Hongbin Yang
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Chaofeng Lou
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Weihua Li
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Guixia Liu
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Yun Tang
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| |
Collapse
|
26
|
Nelms MD, Pradeep P, Patlewicz G. Evaluating potential refinements to existing Threshold of Toxicological Concern (TTC) values for environmentally-relevant compounds. Regul Toxicol Pharmacol 2019; 109:104505. [PMID: 31639428 DOI: 10.1016/j.yrtph.2019.104505] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/12/2019] [Accepted: 10/15/2019] [Indexed: 11/29/2022]
Abstract
The Toxic Substances Control Act (TSCA) mandates the US EPA perform risk-based prioritisation of chemicals in commerce and then, for high-priority substances, develop risk evaluations that integrate toxicity data with exposure information. One approach being considered for data poor chemicals is the Threshold of Toxicological Concern (TTC). Here, TTC values derived using oral (sub)chronic No Observable (Adverse) Effect Level (NO(A)EL) data from the EPA's Toxicity Values database (ToxValDB) were compared with published TTC values from Munro et al. (1996). A total of 4554 chemicals with structures present in ToxValDB were assigned into their respective TTC categories using the Toxtree software tool, of which toxicity data was available for 1304 substances. The TTC values derived from ToxValDB were similar, but not identical to the Munro TTC values: Cramer I ((ToxValDB) 37.3 c. f. (Munro) 30 μg/kg-day), Cramer II (34.6 c. f. 9.1 μg/kg-day) and Cramer III (3.9 c. f. 1.5 μg/kg-day). Cramer III 5th percentile values were found to be statistically different. Chemical features of the two Cramer III datasets were evaluated to account for the differences. TTC values derived from this expanded dataset substantiated the original TTC values, reaffirming the utility of TTC as a promising tool in a risk-based prioritisation approach.
Collapse
Affiliation(s)
- Mark D Nelms
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, 37830, USA; Center for Computational Toxicology & Exposure (CCTE), U.S. Environmental Protection Agency, Research Triangle Park, Durham, NC, 27709, USA
| | - Prachi Pradeep
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, 37830, USA; Center for Computational Toxicology & Exposure (CCTE), U.S. Environmental Protection Agency, Research Triangle Park, Durham, NC, 27709, USA
| | - Grace Patlewicz
- Center for Computational Toxicology & Exposure (CCTE), U.S. Environmental Protection Agency, Research Triangle Park, Durham, NC, 27709, USA.
| |
Collapse
|
27
|
Thresher A, Gosling JP, Williams R. Generation of TD 50 values for carcinogenicity study data. Toxicol Res (Camb) 2019; 8:696-703. [PMID: 31588346 PMCID: PMC6762014 DOI: 10.1039/c9tx00118b] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 07/15/2019] [Indexed: 11/21/2022] Open
Abstract
Carcinogenic potency is a key factor in the understanding of chemical risk assessment. Measures of carcinogenic potency, for example TD50, are instrumental in the determination of metrics such as the threshold of toxicological concern (TTC), acceptable intake (AI) and permitted daily exposure (PDE), which in turn impact on human exposure. The Carcinogenic Potency Data Base (CPDB) has provided a source of study information, complete with calculated TD50 values. However, this is no longer actively updated. An understanding of carcinogenic potency, which can be derived from dose-response data, can be used as part of human risk assessments to generate safety thresholds under which cancer risk is judged to be minimal. The aim of this paper is to produce a transparent methodology for calculating TD50 values from experimental data in a manner consistent with the CPDB. This was then applied across the same data as used in the CPDB and analysis done on the correlation with the CPDB TD50 values. While the two sets of values showed a high level of correlation overall, there were some significant discrepancies. These were predominantly due to a lack of clarity in the CPDB methodology and inappropriate use of a linear model in TD50 calculation where the data was not suitable for such an approach.
Collapse
Affiliation(s)
- Andrew Thresher
- Lhasa Limited , Granary Wharf House , 2 Canal Wharf , Leeds , West Yorkshire LS11 5PS , UK .
| | | | - Richard Williams
- Lhasa Limited , Granary Wharf House , 2 Canal Wharf , Leeds , West Yorkshire LS11 5PS , UK .
| |
Collapse
|
28
|
Kawamoto T, Fuchs A, Fautz R, Morita O. Threshold of Toxicological Concern (TTC) for Botanical Extracts (Botanical-TTC) derived from a meta-analysis of repeated-dose toxicity studies. Toxicol Lett 2019; 316:1-9. [PMID: 31415786 DOI: 10.1016/j.toxlet.2019.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 07/31/2019] [Accepted: 08/08/2019] [Indexed: 12/31/2022]
Abstract
Threshold of Toxicological Concern (TTC) is a promising approach for evaluating the human health risk for systemic toxicity when there is a lack of toxicological information. The threshold for systemic toxicity is reportedly 1800, 540, and 90 μg/day for Cramer I-III chemical structures, according to Munro's structural decision tree, and 0.15 μg/day for genotoxic compounds. However, the concept of TTC has been developed for single substances; therefore, the applicability of TTC for mixtures remains unclear. To expand application of probability approach for mixtures, a validation study using the point of departures (PoDs) derived from mixtures is required. In the present study, we investigated novel TTC of botanical extracts (Botanical-TTC) for cosmetics from a meta-analysis based on the PoDs derived from repeated dose toxicity testing in botanical extracts. Accordingly, 213 PoDs were determined by repeated-dose toxicity studies and divided using a default uncertainty factor of 100 combined with the extrapolation factor of study duration to calculate the derived-no-effect-level (DNEL) and derived-minimal-effect-level (DMEL). The minimum DNEL/DMEL was 1.6-fold higher than the Cramer III TTC. In addition, because human health risk below the 1 st percentile value (663 μg/day) was considered as extremely limited, the exposure level can be proposed as Botanical-TTC.
Collapse
Affiliation(s)
- Taisuke Kawamoto
- Safety & Toxicology, Kao Germany GmbH, Pfungstädter Str. 98-100, D-64297, Darmstadt, Germany; Safety Science Research, Kao Corporation, 2-1-3, Bunka, Sumida-ku, Tokyo 131-8501, Japan.
| | - Anne Fuchs
- Safety & Toxicology, Kao Germany GmbH, Pfungstädter Str. 98-100, D-64297, Darmstadt, Germany
| | - Rolf Fautz
- Safety & Toxicology, Kao Germany GmbH, Pfungstädter Str. 98-100, D-64297, Darmstadt, Germany
| | - Osamu Morita
- Safety Science Research, Kao Corporation, 2-1-3, Bunka, Sumida-ku, Tokyo 131-8501, Japan
| |
Collapse
|
29
|
More SJ, Bampidis V, Benford D, Bragard C, Halldorsson TI, Hernández-Jerez AF, Hougaard Bennekou S, Koutsoumanis KP, Machera K, Naegeli H, Nielsen SS, Schlatter JR, Schrenk D, Silano V, Turck D, Younes M, Gundert-Remy U, Kass GEN, Kleiner J, Rossi AM, Serafimova R, Reilly L, Wallace HM. Guidance on the use of the Threshold of Toxicological Concern approach in food safety assessment. EFSA J 2019; 17:e05708. [PMID: 32626331 PMCID: PMC7009090 DOI: 10.2903/j.efsa.2019.5708] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The Scientific Committee confirms that the Threshold of Toxicological Concern (TTC) is a pragmatic screening and prioritisation tool for use in food safety assessment. This Guidance provides clear step-by-step instructions for use of the TTC approach. The inclusion and exclusion criteria are defined and the use of the TTC decision tree is explained. The approach can be used when the chemical structure of the substance is known, there are limited chemical-specific toxicity data and the exposure can be estimated. The TTC approach should not be used for substances for which EU food/feed legislation requires the submission of toxicity data or when sufficient data are available for a risk assessment or if the substance under consideration falls into one of the exclusion categories. For substances that have the potential to be DNA-reactive mutagens and/or carcinogens based on the weight of evidence, the relevant TTC value is 0.0025 μg/kg body weight (bw) per day. For organophosphates or carbamates, the relevant TTC value is 0.3 μg/kg bw per day. All other substances are grouped according to the Cramer classification. The TTC values for Cramer Classes I, II and III are 30 μg/kg bw per day, 9 μg/kg bw per day and 1.5 μg/kg bw per day, respectively. For substances with exposures below the TTC values, the probability that they would cause adverse health effects is low. If the estimated exposure to a substance is higher than the relevant TTC value, a non-TTC approach is required to reach a conclusion on potential adverse health effects.
Collapse
|
30
|
Short commentary on NDMA (N-nitrosodimethylamine) contamination of valsartan products. Regul Toxicol Pharmacol 2019; 103:325-329. [DOI: 10.1016/j.yrtph.2019.01.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 01/02/2019] [Indexed: 01/31/2023]
|
31
|
Wang Z, Dinh D, Scott WC, Williams ES, Ciarlo M, DeLeo P, Brooks BW. Critical review and probabilistic health hazard assessment of cleaning product ingredients in all-purpose cleaners, dish care products, and laundry care products. ENVIRONMENT INTERNATIONAL 2019; 125:399-417. [PMID: 30743146 DOI: 10.1016/j.envint.2019.01.079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 01/29/2019] [Accepted: 01/29/2019] [Indexed: 06/09/2023]
Abstract
Though numerous chemical ingredients are used in cleaning products, empirical mammalian toxicology information is often limited for many substances. Such limited data inherently presents challenges to environmental health practitioners performing hazard and risk assessments. Probabilistic hazard assessment using chemical toxicity distributions (CTDs) is an alternative approach for assessments of chemicals when toxicity information is lacking. The CTD concept allows for derivation of thresholds of toxicological concern (TTCs) to predict adverse effect thresholds for mammalian species. Unfortunately, comparative health hazard assessment of cleaning product ingredients in common use categories such as all-purpose cleaners (APC), dish care products (DCP) and laundry care products (LCP) has not been well studied. However, APC, DCP, and LCP are used routinely for household and industrial applications, resulting in residential and industrial occupational exposures. Therefore, we reviewed and then examined hazard information (median lethal dose (LD50), lowest-observed-adverse-effect level (LOAEL), and no-observed-adverse-effect level (NOAEL)) from different types of standard mammalian toxicity studies for oral toxicity in the rat model from the unique Cleaning Product Ingredient Safety Initiative mammalian toxicology database. Probabilistic distributions (CTDs) were subsequently constructed using LD50, NOAEL and LOAEL data from a specific toxicity study type for all available ingredients in these three use categories. Based on data availability, product type-specific and chemical category-specific CTDs were also generated and compared. For each CTD, threshold concentrations (TCs) and their 95% confidence intervals (95% CIs) at 1st, 5th, 10th, 50th, 90th, 95th and 99th percentiles were calculated using the log-normal model. To test whether the common default uncertainty factor (UF) approach (e.g., 3, 10) in mammalian health risk assessment provides sufficient protection, UFs were also derived for LOAEL-to-NOAEL and exposure duration (e.g., subchronic-to-chronic) extrapolations. Relationships between CTDs of acute LD50s and sublethal LOAELs/NOAELs were also examined for acute-to-chronic ratio calculations, which may be useful in extreme circumstances. Results from our critical review and meta-analysis appear particularly useful for hazard and risk practitioners when identifying TTCs for ingredients in product use categories, and other chemical classes. This approach can also support development of regulatory data dossiers through read across, chemical substitutions and screening-level health risk assessments when limited or no empirical toxicity information exists for industrial chemicals.
Collapse
Affiliation(s)
- Zhen Wang
- Department of Environmental Science, Baylor University, Waco, TX, USA; School of Environment, Jinan University, Guangzhou, China
| | - Dan Dinh
- Department of Environmental Science, Baylor University, Waco, TX, USA
| | - W Casan Scott
- Department of Environmental Science, Baylor University, Waco, TX, USA
| | | | - Michael Ciarlo
- EA Engineering, Science & Technology, Inc., Baltimore, MD, USA
| | - Paul DeLeo
- American Cleaning Institute, Washington, DC, USA
| | - Bryan W Brooks
- Department of Environmental Science, Baylor University, Waco, TX, USA; School of Environment, Jinan University, Guangzhou, China; Institute of Biomedical Studies, Baylor University, Waco, TX, USA.
| |
Collapse
|
32
|
Baken KA, Sjerps RMA, Schriks M, van Wezel AP. Toxicological risk assessment and prioritization of drinking water relevant contaminants of emerging concern. ENVIRONMENT INTERNATIONAL 2018; 118:293-303. [PMID: 29909348 DOI: 10.1016/j.envint.2018.05.006] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 05/01/2018] [Accepted: 05/02/2018] [Indexed: 05/19/2023]
Abstract
Toxicological risk assessment of contaminants of emerging concern (CEC) in (sources of) drinking water is required to identify potential health risks and prioritize chemicals for abatement or monitoring. In such assessments, concentrations of chemicals in drinking water or sources are compared to either (i) health-based (statutory) drinking water guideline values, (ii) provisional guideline values based on recent toxicity data in absence of drinking water guidelines, or (iii) generic drinking water target values in absence of toxicity data. Here, we performed a toxicological risk assessment for 163 CEC that were selected as relevant for drinking water. This relevance was based on their presence in drinking water and/or groundwater and surface water sources in downstream parts of the Rhine and Meuse, in combination with concentration levels and physicochemical properties. Statutory and provisional drinking water guideline values could be derived from publically available toxicological information for 142 of the CEC. Based on measured concentrations it was concluded that the majority of substances do not occur in concentrations which individually pose an appreciable human health risk. A health concern could however not be excluded for vinylchloride, trichloroethene, bromodichloromethane, aniline, phenol, 2-chlorobenzenamine, mevinphos, 1,4-dioxane, and nitrolotriacetic acid. For part of the selected substances, toxicological risk assessment for drinking water could not be performed since either toxicity data (hazard) or drinking water concentrations (exposure) were lacking. In absence of toxicity data, the Threshold of Toxicological Concern (TTC) approach can be applied for screening level risk assessment. The toxicological information on the selected substances was used to evaluate whether drinking water target values based on existing TTC levels are sufficiently protective for drinking water relevant CEC. Generic drinking water target levels of 37 μg/L for Cramer class I substances and 4 μg/L for Cramer class III substances in drinking water were derived based on these CEC. These levels are in line with previously reported generic drinking water target levels based on original TTC values and are shown to be protective for health effects of the majority of contaminants of emerging concern evaluated in the present study. Since the human health impact of many chemicals appearing in the water cycle has been studied insufficiently, generic drinking water target levels are useful for early warning and prioritization of CEC with unknown toxicity in drinking water and its sources for future monitoring.
Collapse
Affiliation(s)
- Kirsten A Baken
- KWR Watercycle Research Institute, Groningenhaven 7, 3433 PE Nieuwegein, The Netherlands.
| | - Rosa M A Sjerps
- KWR Watercycle Research Institute, Groningenhaven 7, 3433 PE Nieuwegein, The Netherlands
| | - Merijn Schriks
- KWR Watercycle Research Institute, Groningenhaven 7, 3433 PE Nieuwegein, The Netherlands
| | - Annemarie P van Wezel
- KWR Watercycle Research Institute, Groningenhaven 7, 3433 PE Nieuwegein, The Netherlands; Copernicus Institute of Sustainable Development, Utrecht University, Heidelberglaan 2, 3584 CS Utrecht, The Netherlands
| |
Collapse
|
33
|
Patlewicz G, Wambaugh JF, Felter SP, Simon TW, Becker RA. Utilizing Threshold of Toxicological Concern (TTC) with High Throughput Exposure Predictions (HTE) as a Risk-Based Prioritization Approach for thousands of chemicals. ACTA ACUST UNITED AC 2018; 7:58-67. [PMID: 31338483 DOI: 10.1016/j.comtox.2018.07.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Regulatory agencies across the world are facing the challenge of performing risk-based prioritization of thousands of chemicals in commerce. Here, we present an approach using the Threshold of Toxicological Concern (TTC) combined with heuristic high-throughput exposure (HTE) modelling to rank order chemicals for further evaluation. Accordingly, for risk-based prioritization, chemicals with exposures > TTC would be ranked as higher priority for further evaluation whereas substances with exposures < TTC would be ranked as lower priority. An initial proof of concept, using a dataset of 7986 substances with previously modeled median and upper 95% credible interval (UCI) total daily median exposure rates showed fewer than 5% of substances had UCI exposures > the Cramer Class III TTC (1.5 μg/kg-day). We extended the analysis by profiling the same dataset through the TTC workflow published by Kroes et al (2004) which accounts for known exclusions to the TTC as well as structural alerts. UCI exposures were then compared to the appropriate class-specific TTC. None of the substances categorized as Cramer Class I or Cramer Class II exceeded their respective TTC values and no more than 2% of substances categorized as Cramer Class III or acetylcholinesterase inhibitors exceeded their respective TTC values. The modeled UCI exposures for the majority of the 1853 chemicals with genotoxicity structural alerts did exceed the TTC of 0.0025 μg/kg-day, but only 79 substances exceeded this TTC if median exposure values were used. For substances for which UCI exposures exceeded relevant TTC values, we highlight possible approaches for consideration to refine the HTE : TTC approach. Overall, coupling TTC with HTE offers promise as a pragmatic first step in ranking substances as part of a risk-based prioritization approach.
Collapse
Affiliation(s)
- Grace Patlewicz
- National Center for Computational Toxicology (NCCT), Office of Research and Development, US Environmental Protection Agency, 109 TW Alexander Dr, Research Triangle Park, NC 27711, USA
| | - John F Wambaugh
- National Center for Computational Toxicology (NCCT), Office of Research and Development, US Environmental Protection Agency, 109 TW Alexander Dr, Research Triangle Park, NC 27711, USA
| | - Susan P Felter
- Procter & Gamble, Central Product Safety, Mason, OH 45040, USA
| | | | | |
Collapse
|
34
|
Yang H, Sun L, Li W, Liu G, Tang Y. Identification of Nontoxic Substructures: A New Strategy to Avoid Potential Toxicity Risk. Toxicol Sci 2018; 165:396-407. [DOI: 10.1093/toxsci/kfy146] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Hongbin Yang
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Lixia Sun
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Weihua Li
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Guixia Liu
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Yun Tang
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| |
Collapse
|
35
|
Hoersch J, Hoffmann-Doerr S, Keller D. Derivation of an inhalation TTC for the workplace based on DNEL values reported under REACH. Toxicol Lett 2018; 290:110-115. [PMID: 29596887 DOI: 10.1016/j.toxlet.2018.03.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/01/2018] [Accepted: 03/26/2018] [Indexed: 10/17/2022]
Abstract
The Threshold of Toxicological Concern (TTC) concept defines a generic tolerable exposure for chemicals of unknown toxicity below which the risk of adverse health effects is considered very small. The original concept was refined and extended over the years, based either on differentiated structural classes or on additional information on certain toxicological endpoints. Initially, the focus of the TTC application was only on systemic toxic effects after repeated oral intake and consisted of one value. However, under well-defined boundary conditions, a long-term systemic inhalation TTC could also serve as a cut-off criterion for occupational exposure in those cases where workers are exposed to very low levels of chemicals by inhalation contact and could therefore reduce the need to perform animal tests. Within the scope of the European REACH legislation, several thousand systemic long-term inhalation Derived No Effect Levels (DNELs) for workers have been published. By statistical evaluation of the DNEL distribution of 1876 chemicals and the resulting 99th percentiles, we propose an inhalation workplace TTC for systemic effects in the region of 50 μg/m3 (7 μg/kg body weight/day). Specific exclusion criteria apply for the discussed concept.
Collapse
Affiliation(s)
- Johanna Hoersch
- Henkel AG & Co. KGaA, Henkelstr. 67, 40589 Düsseldorf, Germany.
| | | | - Detlef Keller
- Henkel AG & Co. KGaA, Henkelstr. 67, 40589 Düsseldorf, Germany
| |
Collapse
|
36
|
Snodin DJ. The cancer threshold of toxicological concern (TTC) in relation to foodstuffs and pharmaceuticals: A potentially useful concept compromised by a dubious derivation. Hum Exp Toxicol 2017; 37:789-802. [DOI: 10.1177/0960327117735571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The cancer threshold of toxicological concern (TTC) as determined by Kroes et al. in 2004 (0.15 µg/day and 1.5 µg/day at risk levels of 1 in 106 or 105, respectively) has been uncritically employed as a key metric in multiple regulatory guidance documents. There are numerous concerns regarding transparency and the highly conservative methodology in relation to its derivation; moreover, no formal confirmation has been undertaken by any regulatory body prior to its adoption. A recent joint report from the European Food Safety Authority and World Health Organization follows this trend, largely replicating previous conclusions and downplaying the need for a re-assessment. This view is challenged by Boobis et al. who confirm concerns regarding lack of transparency and stress that several of the assumptions and approaches used previously have been superseded by advances in knowledge; they recommend as a first step construction of a new dataset derived from the Carcinogenic Potency Database focusing on mutagenic DNA-reactive rodent carcinogens and a critical assessment of the relevance and reliability of carcinogenicity data. This type of approach is supported with two key exceptions: inclusion of data from the ToxTracker assay which provides a direct readout of DNA reactivity, and use of appropriate epidemiological data on acrylamide (AA) to determine a benchmark for human exposure to a typical DNA-reactive rodent carcinogen. It is concluded that a robust re-evaluation using an appropriate dataset and methodology is urgently needed to ensure the integrity of the cancer TTC before it is employed in its present form even more widely.
Collapse
Affiliation(s)
- DJ Snodin
- Xiphora Biopharma Consulting, Bristol, UK
| |
Collapse
|
37
|
Cartus A, Schrenk D. Current methods in risk assessment of genotoxic chemicals. Food Chem Toxicol 2017; 106:574-582. [DOI: 10.1016/j.fct.2016.09.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 09/06/2016] [Accepted: 09/08/2016] [Indexed: 12/15/2022]
|
38
|
Galloway SM. International regulatory requirements for genotoxicity testing for pharmaceuticals used in human medicine, and their impurities and metabolites. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2017; 58:296-324. [PMID: 28299826 DOI: 10.1002/em.22077] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 02/05/2017] [Indexed: 06/06/2023]
Abstract
The process of developing international (ICH) guidelines is described, and the main guidelines reviewed are the ICH S2(R1) guideline that includes the genotoxicity test battery for human pharmaceuticals, and the ICH M7 guideline for assessing and limiting potentially mutagenic impurities and degradation products in drugs. Key aspects of the guidelines are reviewed in the context of drug development, for example the incorporation of genotoxicity assessment into non-clinical toxicity studies, and ways to develop and assess weight of evidence. In both guidelines, the existence of "thresholds" or non-linear dose responses for genotoxicity plays a part in the strategies. Differences in ICH S2(R1) protocol recommendations from OECD guidelines are highlighted and rationales explained. The use of genotoxicity data during clinical development and in assessment of carcinogenic potential is also described. There are no international guidelines on assessment of potentially genotoxic metabolites, but some approaches to safety assessment are discussed for these. Environ. Mol. Mutagen. 58:296-324, 2017. © 2017 Wiley Periodicals, Inc.
Collapse
|
39
|
Boobis A, Brown P, Cronin MTD, Edwards J, Galli CL, Goodman J, Jacobs A, Kirkland D, Luijten M, Marsaux C, Martin M, Yang C, Hollnagel HM. Origin of the TTC values for compounds that are genotoxic and/or carcinogenic and an approach for their re-evaluation. Crit Rev Toxicol 2017; 47:705-727. [PMID: 28510487 DOI: 10.1080/10408444.2017.1318822] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The threshold of toxicological concern (TTC) approach is a resource-effective de minimis method for the safety assessment of chemicals, based on distributional analysis of the results of a large number of toxicological studies. It is being increasingly used to screen and prioritize substances with low exposure for which there is little or no toxicological information. The first step in the approach is the identification of substances that may be DNA-reactive mutagens, to which the lowest TTC value is applied. This TTC value was based on the analysis of the cancer potency database and involved a number of assumptions that no longer reflect the state-of-the-science and some of which were not as transparent as they could have been. Hence, review and updating of the database is proposed, using inclusion and exclusion criteria reflecting current knowledge. A strategy for the selection of appropriate substances for TTC determination, based on consideration of weight of evidence for genotoxicity and carcinogenicity is outlined. Identification of substances that are carcinogenic by a DNA-reactive mutagenic mode of action and those that clearly act by a non-genotoxic mode of action will enable the protectiveness to be determined of both the TTC for DNA-reactive mutagenicity and that applied by default to substances that may be carcinogenic but are unlikely to be DNA-reactive mutagens (i.e. for Cramer class I-III compounds). Critical to the application of the TTC approach to substances that are likely to be DNA-reactive mutagens is the reliability of the software tools used to identify such compounds. Current methods for this task are reviewed and recommendations made for their application.
Collapse
Affiliation(s)
- Alan Boobis
- a Department of Medicine , Imperial College London , London , UK
| | - Paul Brown
- b US Food and Drug Administration , Silver Spring , MD , USA
| | | | - James Edwards
- d DSM Nutritional Products Ltd , Kaiseraugst , Switzerland
| | - Corrado Lodovico Galli
- e Department of Pharmacological and Biomolecular Sciences , University of Milan , Milan , Italy
| | - Jay Goodman
- f Department of Pharmacology and Toxicology , Michigan State University , East Lansing , MI , USA
| | - Abigail Jacobs
- b US Food and Drug Administration , Silver Spring , MD , USA
| | | | - Mirjam Luijten
- h Centre for Health Protection , National Institute for Public Health and the Environment (RIVM) , Bilthoven , The Netherlands
| | | | - Matthew Martin
- j Environmental Protection Agency , Washington , DC , USA
| | - Chihae Yang
- k Chemical and Biomolecular Engineering , The Ohio State University , Columbus , OH , USA.,l Molecular Networks GmbH , Nürnberg , Germany.,m Altamira LLC , Columbus , OH , USA
| | | |
Collapse
|
40
|
Assessing safety of extractables from materials and leachables in pharmaceuticals and biologics – Current challenges and approaches. Regul Toxicol Pharmacol 2016; 81:201-211. [DOI: 10.1016/j.yrtph.2016.08.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 08/22/2016] [Indexed: 10/21/2022]
|
41
|
Examining the differences in current regulatory processes for sunscreens and proposed safety assessment paradigm. Regul Toxicol Pharmacol 2016; 79:125-141. [DOI: 10.1016/j.yrtph.2016.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 03/09/2016] [Accepted: 03/12/2016] [Indexed: 12/27/2022]
|
42
|
Tluczkiewicz I, Kühne R, Ebert RU, Batke M, Schüürmann G, Mangelsdorf I, Escher S. Inhalation TTC values: A new integrative grouping approach considering structural, toxicological and mechanistic features. Regul Toxicol Pharmacol 2016; 78:8-23. [DOI: 10.1016/j.yrtph.2016.03.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 03/24/2016] [Accepted: 03/29/2016] [Indexed: 11/29/2022]
|
43
|
Development and validation of a selective, sensitive and stability indicating UPLC-MS/MS method for rapid, simultaneous determination of six process related impurities in darunavir drug substance. J Pharm Biomed Anal 2016; 128:141-148. [PMID: 27262107 DOI: 10.1016/j.jpba.2016.05.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Revised: 05/13/2016] [Accepted: 05/16/2016] [Indexed: 11/20/2022]
Abstract
In this study a sensitive and selective gradient reverse phase UPLC-MS/MS method was developed for the simultaneous determination of six process related impurities viz., Imp-I, Imp-II, Imp-III, Imp-IV, Imp-V and Imp-VI in darunavir. The chromatographic separation was performed on Acquity UPLC BEH C18 (50 mm×2.1mm, 1.7μm) column using gradient elution of acetonitrile-methanol (80:20, v/v) and 5.0mM ammonium acetate containing 0.01% formic acid at a flow rate of 0.4mL/min. Both negative and positive electrospray ionization (ESI) modes were operated simultaneously using multiple reaction monitoring (MRM) for the quantification of all six impurities in darunavir. The developed method was fully validated following ICH guidelines with respect to specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision, robustness and sample solution stability. The method was able to quantitate Imp-I, Imp-IV, Imp-V at 0.3ppm and Imp-II, Imp-III, and Imp-VI at 0.2ppm with respect to 5.0mg/mL of darunavir. The calibration curves showed good linearity over the concentration range of LOQ to 250% for all six impurities. The correlation coefficient obtained was >0.9989 in all the cases. The accuracy of the method lies between 89.90% and 104.60% for all six impurities. Finally, the method has been successfully applied for three formulation batches of darunavir to determine the above mentioned impurities, however no impurity was found beyond the LOQ. This method is a good quality control tool for the trace level quantification of six process related impurities in darunavir during its synthesis.
Collapse
|
44
|
Review of the Threshold of Toxicological Concern (TTC) approach and development of new TTC decision tree. ACTA ACUST UNITED AC 2016. [DOI: 10.2903/sp.efsa.2016.en-1006] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
45
|
Sorell TL. Approaches to the Development of Human Health Toxicity Values for Active Pharmaceutical Ingredients in the Environment. AAPS J 2016; 18:92-101. [PMID: 26338232 PMCID: PMC4706294 DOI: 10.1208/s12248-015-9818-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 08/14/2015] [Indexed: 01/30/2023] Open
Abstract
Management of active pharmaceutical ingredients (API) in the environment is challenging because these substances represent a large and diverse group of compounds. Advanced wastewater treatment technologies that can remove API tend to be costly. Because of the potential resources required to address API in the environment, there is a need to establish environmental benchmarks that can serve as targets for treatment and release. To date, there are several different approaches that have been taken to derive human health toxicity values for API. These methods include traditional risk assessment approaches that calculate "safe" doses using experimental data and uncertainty (safety) factors; point of departure (POD), which starts from a therapeutic human dose and applies uncertainty factors; and threshold of toxicological concern (TTC), a generic approach that establishes threshold values across broad classes of chemicals based on chemical structure. To evaluate the use of these approaches, each of these methods was applied to three API commonly encountered in the environment: acetaminophen, caffeine, and chlorpromazine. The results indicate that the various methods of estimating toxicity values produce highly varying doses. Associated doses are well below typical intakes, or toxicity thresholds cannot be derived due to a lack of information. No uniform approach can be applied to establishing thresholds for multiple substances. Rather, an individualized approach will need to be applied to each target API.
Collapse
Affiliation(s)
- Tamara L Sorell
- Brown and Caldwell, One Tech Drive, Suite 310, Andover, Massachusetts, 01810, USA.
| |
Collapse
|
46
|
Leeman W, Krul L. Non-intentionally added substances in food contact materials: how to ensure consumer safety. Curr Opin Food Sci 2015. [DOI: 10.1016/j.cofs.2015.11.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
47
|
Abstract
A critical evaluation of several recent regulatory risk assessments has been undertaken. These relate to propyl paraben (as a food additive, cosmetic ingredient or pharmaceutical excipient), cobalt (in terms of a safety-based limit for pharmaceuticals) and the cancer Threshold of Toxicological Concern as applied to food contaminants and pharmaceutical impurities. In all cases, a number of concerns can be raised regarding the reliability of the current assessments, some examples being absence of data audits, use of single-dose and/or non-good laboratory practice studies to determine safety metrics, use of a biased data set and questionable methodology and lack of consistency with precedents and regulatory guidance. Drawing on these findings, a set of recommendations is provided to reduce uncertainty and improve the quality and robustness of future regulatory risk assessments.
Collapse
Affiliation(s)
- DJ Snodin
- Xiphora Biopharma Consulting, Bristol, UK
| |
Collapse
|
48
|
Wang G, Zhu R, Yang L, Wang K, Zhang Q, Su X, Yang B, Zhang J, Fang J. Non-thermal plasma for inactivated-vaccine preparation. Vaccine 2015; 34:1126-32. [PMID: 26529075 DOI: 10.1016/j.vaccine.2015.10.099] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Revised: 10/08/2015] [Accepted: 10/24/2015] [Indexed: 11/15/2022]
Abstract
Vaccines are of great importance in controlling the spread of infectious diseases in poultry farming. The safety and efficacy of vaccines are also essential. To explore the feasibility of a novel technology (non-thermal plasma) in inactivated vaccine preparation, an alternating current atmospheric pressure non-thermal plasma (NTP) jet with Ar/O2/N2 as the operating gas was used to inactivate a Newcastle disease virus (NDV, LaSota) strain and H9N2 avian influenza virus (AIV, A/Chicken/Hebei/WD/98) for vaccine preparation. The results showed that complete inactivation could be achieved with 2 min of NTP treatment for both NDV and AIV. Moreover, a proper NTP treatment time is needed for inactivation of a virus without destruction of the antigenic determinants. Compared to traditional formaldehyde-inactivated vaccine, the vaccine made from NDV treated by NTP for 2 min (NTP-2 min-NDV-vaccine) could induce a higher NDV-specific antibody titer in specific pathogen-free (SPF) chickens, and the results of a chicken challenge experiment showed that NTP-2 min-NDV-vaccine could protect SPF chickens from a lethal NDV challenge. Vaccines made from AIV treated by NTP for 2 min (NTP-2 min-AIV-vaccine) also showed a similar AIV-specific antibody titer compared with traditional AIV vaccines prepared using formaldehyde inactivation. Studies of the morphological changes of the virus, chemical analysis of NDV allantoic fluid and optical emission spectrum analysis of NTP suggested that reactive oxygen species and reactive nitrogen species produced by NTP played an important role in the virus inactivation process. All of these results demonstrated that it could be feasible to use non-thermal NTP as an alternative strategy to prepare inactivated vaccines for Newcastle disease and avian influenza.
Collapse
Affiliation(s)
- Guomin Wang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, People's Republic of China
| | - Ruihao Zhu
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, People's Republic of China
| | - Licong Yang
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, People's Republic of China
| | - Kaile Wang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, People's Republic of China
| | - Qian Zhang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, People's Republic of China
| | - Xia Su
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, People's Republic of China
| | - Bing Yang
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, People's Republic of China.
| | - Jue Zhang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, People's Republic of China; College of Engineering, Peking University, Beijing 100871, People's Republic of China.
| | - Jing Fang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, People's Republic of China; College of Engineering, Peking University, Beijing 100871, People's Republic of China
| |
Collapse
|
49
|
Criteria for the Research Institute for Fragrance Materials, Inc. (RIFM) safety evaluation process for fragrance ingredients. Food Chem Toxicol 2015; 82 Suppl:S1-S19. [DOI: 10.1016/j.fct.2014.11.014] [Citation(s) in RCA: 1123] [Impact Index Per Article: 124.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 11/13/2014] [Accepted: 11/17/2014] [Indexed: 11/24/2022]
|
50
|
Costigan S, Meredith C. An approach to ingredient screening and toxicological risk assessment of flavours in e-liquids. Regul Toxicol Pharmacol 2015; 72:361-9. [DOI: 10.1016/j.yrtph.2015.05.018] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 05/14/2015] [Accepted: 05/16/2015] [Indexed: 11/16/2022]
|