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Development of New Approach Methodologies (NAMs) capable of providing a No Expected Sensitization Induction Level (NESIL) value remains a high priority for the fragrance industry for conducting a Quantitative Risk Assesment (QRA) to evaluate dermal sensitization. The in vitro GARDskin assay was recently adopted by the OECD (TG 442E) for the hazard identification of skin sensitizers. Continuous potency predictions are derived using a modified protocol that incorporates dose-response measurements. Linear regression models have been developed to predict human NESIL values. The aim of the study was to evaluate the precision and reproducibility of the continuous potency predictions from the GARDskin Dose-Response (DR) assay and its application in conducting QRA for fragrance materials using a Next Generation Risk Assessment (NGRA) framework. Results indicated that the GARDskin Dose-Response model predicted human NESIL values with a good degree of concordance with published NESIL values, which were also reproducible in 3 separate experiments. Using Isocyclocitral as an example, a QRA was conducted to determine its safe use levels in different consumer product types using a NGRA framework. This study represents a major step towards the establishment of the assay to derive NESIL values for conducting QRA evaluations for fragrance materials using a NGRA framework., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The use of threshold of toxicological concern (TTC) supports the safety assessment of exposure to low levels of chemicals when toxicity data are limited. The Research Institute for Fragrance Materials (RIFM) delivers safety assessments for fragrance materials that result in safe products for consumer use. A major goal for the RIFM safety assessment program is to invest in alternative methods to animal testing for use in assessment of fragrance materials. This includes use of TTC, which provides a pragmatic approach for safety evaluation of fragrance materials in the absence of chemical-specific toxicity data and reduces the need to generate new animal data. To bolster the TTC approach for support of fragrance materials and specifically to strengthen the Cramer class II threshold, the RIFM database was reviewed with a goal of identifying fragrance materials with data that can be added to the existing TTC databases. The RIFM database identified a total of 476 chemicals that were added to the existing TTC databases. The chemicals were then individually assigned a Cramer class and 238, 76 and 162 chemicals in Cramer class I, II and III respectively were identified. The RIFM-TTC dataset was then combined with the COSMOS-Federated TTC dataset for a total of 421, 111 and 795 chemicals in Cramer class I, II and III respectively. The combined dataset further expands the chemical space thereby providing more robust 5th percentile thresholds. Moreover, the combined dataset bolsters the threshold for Cramer class II to include a total of 111 chemicals which is an improvement over the original (Munro) TTC dataset which only included 28 chemicals in Cramer Class II and the COSMOS Federated dataset which had 40 chemicals. This allows for a more reliable and robust 5th percentile NOAEL value for Cramer class II chemicals of 1.27 mg/kg bw/day. The 5th percentile NOAELs for Cramer class I, II and III from the combined dataset are 4.91, 1.27 and 0.29 mg/kg bw/day, which supports the threshold values derived from the original Munro dataset. This work confirms the adequacy of the existing TTC values and provides further support for the use of TTC as a tool to conduct safety assessments for fragrance materials. It further opens the future possibility of updating the existing values with more robust TTC values for fragrance and cosmetic materials., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

On the basis of the safety assessment carried out using a conservative approach, the SCCS considers the use of Acetylated Vetiver Oil (AVO) with 1% alpha-tocopherol as a fragrance ingredient in cosmetic leave-on and rinse-off type products safe at the concentrations proposed by IFRA. Acetylated Vetiver Oil (AVO) contains some constituents that belong to the chemical group of aldehydes and ketones that are known to be reactive towards biological entities, such as DNA and proteins. However, the overall health risk of such components is likely to be negligible at the concentrations intended to be used in cosmetics products. The SCCS has noted that Acetylated Vetiver Oil (AVO) is a moderate skin sensitiser in test animals. Considering the results of the HRIPT study and the fact that AVO has been used for years in cosmetics without evidence of sensitising potential, it is unlikely that AVO would be causing contact allergy in humans. Inhalation toxicity of Acetylated Vetiver Oil (AVO) was not assessed in this Opinion because no data were provided. Assessment of the inhalation risk would be needed if Acetylated Vetiver Oil (AVO) was intended to be used in sprayable products., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Ingredient chemicals like fragrances may cause adverse health effects. Frequent health risk assessments and stringent management of consumer products are of paramount importance to reduce these serious occurrences. In this study, the respiratory and dermal health effects were assessed in relation to air fresheners. Twenty six fragrance ingredients, thirty four biocidal ingredients, and sixteen hazardous ingredients were analyzed and assessed according to their risk to human health on five groups by application type in eighty two air fresheners. For hazard characterization of ingredients, toxicological information on the intrinsic properties of the ingredients was collected, and reference values were determined as chronic NOAEL. Exposure assessment was performed in two steps. The 95th exposure factor values were used to estimate exposure to assume the worst-case scenario and the maximum concentration determined by the product purpose and application type was used type in tiered 1 assessment. The values input into the exposure algorithms were developed via the exposure route. In the tiered 2 assessment, the 75th exposure factor values were used to estimate the assumed reasonable exposure to ingredients. Six ingredients for the inhalation and twelve ingredients for the dermal route were conducted for tiered 2 assessment. This study showed that the assessed ingredients have no health risks at their maximum concentrations in air fresheners. The approach should be used to establish improved guidelines for specific ingredients that may pose inhalation and dermal hazard., (Copyright © 2018. Published by Elsevier Inc.)

The Threshold of Toxicological Concern (TTC) is a pragmatic approach in risk assessment. In the absence of data, it sets up levels of human exposure that are considered to have no appreciable risk to human health. The Cramer decision tree is used extensively to determine these exposure thresholds by categorizing non-carcinogenic chemicals into three different structural classes. Therefore, assigning an accurate Cramer class to a material is a crucial step to preserve the integrity of the risk assessment. In this study the Cramer class of over 1000 fragrance materials across diverse chemical classes were determined by using Toxtree (TT), the OECD QSAR Toolbox (TB), and expert judgment. Disconcordance was observed between TT and the TB. A total of 165 materials (16%) showed different results from the two programs. The overall concordance for Cramer classification between TT and expert judgment is 83%, while the concordance between the TB and expert judgment is 77%. Amines, lactones and heterocycles have the lowest percent agreement with expert judgment for TT and the TB. For amines, the expert judgment agreement is 45% for TT and 55% for the TB. For heterocycles, the expert judgment agreement is 55% for TT and the TB. For lactones, the expert judgment agreement is 56% for TT and 50% for the TB. Additional analyses were conducted to determine the concordance within various chemical classes. Critical checkpoints in the decision tree are identified. Strategies and guidance on determining the Cramer class for various chemical classes are discussed., (Copyright © 2014 Elsevier Inc. All rights reserved.)

α-Hexylcinnamaldehyde (HCA) and p-tert-butyl-alpha-methylhydrocinnamic aldehyde (BMHCA) are synthetic aldehydes, characterized by a typical floral scent, which makes them suitable to be used as fragrances in personal care (perfumes, creams, shampoos, etc.) and household products, and as flavouring additives in food and pharmaceutical industry. The aldehydic structure suggests the need for a safety assessment for these compounds. Here, HCA and BMHCA were evaluated for their potential genotoxic risk, both at gene level (frameshift or base-substitution mutations) by the bacterial reverse mutation assay (Ames test), and at chromosomal level (clastogenicity and aneuploidy) by the micronucleus test. In order to evaluate a primary and repairable DNA damage, the comet assay has been also included. In spite of their potential hazardous chemical structure, a lack of mutagenicity was observed for both compounds in all bacterial strains tested, also in presence of the exogenous metabolic activator, showing that no genotoxic derivatives were produced by CYP450-mediated biotransformations. Neither genotoxicity at chromosomal level (i.e. clastogenicity or aneuploidy) nor single-strand breaks were observed. These findings will be useful in further assessing the safety of HCA and BMHCA as either flavour or fragrance chemicals., (Copyright © 2013 Elsevier Inc. All rights reserved.)

An essential step in ensuring the toxicological safety of ingredients in consumer products is the evaluation of their skin sensitising potential. Where skin exposure is low, it is possible to conduct a risk assessment using the Dermal Sensitisation Threshold (DST), a process similar to that of the Threshold of Toxicological Concern. This paper describes work building on that previously published, whose aim was to produce a more robust tool for assessing the safety of consumer products. This consisted of expanding the Local Lymph Node Assay dataset used to define the original DST and classifying chemicals in the dataset according to their mechanistic chemistry domains. A DST of 900μg/cm(2) was derived for chemicals classified as non-reactive and non-proreactive. This value was benchmarked against human potency data for 58 fragrance allergens and was lower than the measured No Expected Sensitisation Levels for those classified as non-reactive. Use of this DST will help to eliminate the need for animal testing of non-reactive and non-proreactive chemicals where skin exposure is sufficiently low. For chemicals where a Quantitative Risk Assessment based on the DST does not give an adequate margin of safety, and those classified as reactive, a case-by-case risk assessment will be required., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Safety evaluation of the large number of diverse chemicals used as fragrance ingredients follows a systematic prioritization of data generation and analysis, consideration of exposure and critical analysis of the quality of the available information. In prior publications the research priorities used by the Research Institute for Fragrance Materials (RIFM), and the methods of exposure estimation used by industry have been summarized. This paper provides details of the approach used by the RIFM Expert Panel (REXPAN), to examine the dermal effects, systemic toxicity and environmental consequences of the use of and exposure to fragrance materials, which allow a reliable determination of safe use under intended conditions. The key to the usefulness of this analysis is the grouping of more than 2600 discrete ingredients into classes, based on chemical structures. Research sponsored by RIFM, data supplied by member companies, and relevant published reports from many sources are all considered during hazard characterization. A discussion is provided of REXPAN's decision tree approach to assessing the dermal, systemic and environmental endpoints and the types and quality of data included. This overall process results in well-documented conclusions which are provided to the International Fragrance Association (IFRA) as the basis for consideration of a new or existing Fragrance Material Standard and to industry for appropriate product risk management actions.

The National Academy of Science (NAS) risk assessment paradigm has been widely accepted as a framework for estimating risk from exposure to environmental chemicals (NAS, 1983). Within this framework, quantitative risk assessments (QRAs) serve as the cornerstone of health-based exposure limits, and have been used routinely for both cancer and noncancer endpoints. These methods have focused primarily on the extrapolation of data from laboratory animals to establish acceptable levels of exposure for humans. For health effects associated with a threshold, uncertainty and variability inherent in the extrapolation process is generally dealt with by the application of "uncertainty factors (UFs)." The adaptation of QRA methods to address skin sensitization is a natural and desirable extension of current practices. Based on our chemical, cellular and molecular understanding of the induction of allergic contact dermatitis, one can conduct a QRA using established methods of identifying a NOAEL (No Observed Adverse Effect Level) or other point of departure, and applying appropriate UFs. This paper describes the application of the NAS paradigm to characterize risks from human exposure to skin sensitizers; consequently, this method can also be used to establish an exposure level for skin allergens that does not present an appreciable risk of sensitization., (Copyright 2003 Elsevier Science (USA))

Over 2000 different ingredients are used in the manufacture of fragrances. The majority of these ingredients have been used for many decades. Despite this long history of use, all of these ingredients need continued monitoring to ensure that each ingredient meets acceptable safety standards. As with other large databases of existing chemicals, fulfilling this need requires an organized approach to identify the most important potential hazards. One such approach, specifically considering the dermal route of exposure as the most relevant one for fragrance ingredients, has been developed. This approach provides a rational selection of materials for review and gives guidance for determining the test data that would normally be considered necessary for the elevation of safety under intended conditions of use. As a first step, the process takes into account the following criteria: quantity of use, consumer exposure, and chemical structure. These are then used for the orderly selection of materials for review with higher quantity, higher exposure, and the presence of defined structural alerts all contributing to a higher priority for review. These structural alerts along with certain exposure and volume limits are then used to develop guidelines for determining the quality and quantity of data considered necessary to support an adequate safety evaluation of the chosen materials, taking into account existing data on the substance itself as well as on closely related analogs. This approach can be considered an alternative to testing; therefore, it is designed to be conservative but not so much so as to require excessive effort when not justified.