Documents & Resources
New Approach Methodologies (NAMs) for the In Vitro Assessment of Cleaning Products for Respiratory Irritation: Workshop Report
August 22, 2025The use of in vitro new approach methodologies (NAMs) to assess respiratory irritation depends on several factors, including the speci cs of exposure methods and cell/tissue-based test systems. This topic was examined in the context of human health risk assessment for cleaning products at a 1-day public workshop held on 2 March 2023, organized by the American Cleaning Institute® (ACI). The goals of this workshop were to (1) review in vitro NAMs for evaluation of respiratory irritation, (2) examine different perspectives on current challenges and suggested solutions, and (3) publish a manuscript of the proceedings.
Evaluation of a Non-Animal Toolbox Informed by Adverse Outcome Pathways for Human Inhalation Safety
August 22, 2025This work evaluated a non-animal toolbox to be used within a next-generation risk assessment (NGRA) framework to assess chemical-induced lung effects using human upper and lower respiratory tract models, namely MucilAir -HF and EpiAlveolar systems, respectively.
Development of Preliminary Candidate Surface Guidelines for Air Force-Relevant Dermal Sensitizers Using New Approach Methodologies
August 22, 2025Allergic contact dermatitis (ACD) is an immunologic reaction to a dermal chemical ex-posure that, once triggered in an individual, will result in an allergic response following subsequent encounters with the allergen. Air Force epidemiological consultations have in-dicated that aircraft structural maintenance workers may experience ACD at elevated rates compared to other occupations. We aimed to better understand the utility of non-animal testing methods in characterizing the sensitization potential of chemicals used during Air Force operations by evaluating the skin sensitization hazard of Air Force-relevant chemicals using new approach methodologies (NAMs) in a case study.
Micronucleus Induction by 5-Methoxypsoralen in the Photo Reconstructed Skin Micronucleus Assay
March 28, 2025To address a lack of suitable non-animal tools to screen novel ingredients in personal care products for mutagenic/clastogenic activity after solar light exposure, we initiated a three-phase program to develop a new approach methodology (NAM) which integrates established UVA/UVB/visible light (UV/vis) photo-activation techniques to the reconstructed skin micronucleus (RSMN) assay. The first phase of the program established a repeat exposure photo- irradiation schedule in reconstructed human epidermal (RhE) tissues, and the second phase was conducted to identify a photo-genotoxic substance for use as a positive control in subsequent third phase studies focused upon test method evaluations. An ideal positive control should be non-mutagenic in the absence of photo-activation, but is recognized to have human-relevant photo-induced mutagenic or carcinogenic etiology or, at minimum, is known to induce micronuclei in replicating mammalian cells after photo-irradiation.
Addressing Key Factors in Cryopreservation Method Development Ensures Robust Performance for Human Precision-cut Lung Slices
March 28, 2025As new approach methodologies (NAMs) are increasingly explored to identify dependable and accurate non-animal alternatives to predict human toxicities, several 3-dimensional test systems have emerged as excellent models of the human respiratory tract. Among these, human precision-cut lung slices (hPCLS) are considered highly relevant, containing many cell types (including key immune cells), small airways, and respiratory parenchyma in a native architecture configuration. Despite their excellent representation of the deep lung, limited accessibility to fresh (non-transplantable) human donor lungs has hampered the hPCLS model as a mainstream test system for screening efforts and standardization toward regulatory applications. Hence, efforts for cold- and cryo-preservation of hPCLS have emerged as potential solutions that will enable hPCLS access in a flexible manner.
Genotoxicity Evaluation of Fragrances and Botanicals using ToxTracker Assay
March 28, 2025The ToxTracker® assay has gained attention as a second tier non-animal test method to the standard battery of in vitro genotoxicity assays by providing mechanistic insights into the modes of action including DNA damage, oxidative stress, cellular stress, protein damage, and the validated method is currently undergoing review at the OECD level for acceptance within international regulatory frameworks. As such, ToxTracker® is designed to identify both genotoxic and non-genotoxic carcinogens, thus providing industry and regulatory toxicologists with highly useful information for hazard and risk assessment purposes. Whereas ToxTracker® can be used as a confirmatory assay when chemicals show positive or equivocal results in Ames and/or micronucleus tests, the test method is also used for rapid and cost-effective screening of chemicals to identify potential DNA mutagens. The test method is reported to have a wide chemical applicability domain; accordingly, this study was focused on evaluating chemicals found to have genotoxic potential either from classic genetox test methods or have compelling evidence of in vivo carcinogenic activity.
Transfer and Refinement of the Reactive Oxygen Species (ROS) Assay to Evaluate Photoreactivity Potential
March 28, 2025Photoreactivity evaluation is one of the initial screenings in a photosafety assessment that can identify compounds which may have the potential to produce various types of adverse photo reactions, including photoirritation (or phototoxicity), photoallergy, and photogenotoxicity. The Reactive Oxygen Species (ROS) Photoreactivity Assay, adopted under OECD Test Guideline (TG) 495, is an in chemico test system that measures the amount of ROS generated by a test compound upon exposure to simulated sunlight. The generation of ROS is determined through measurement of singlet oxygen (SO) and superoxide anion (SA) produced through the bleaching of p-nitrosodimethylaniline (RNO) and the reduction of nitroblue tetrazolium (NBT) in respective reaction mixtures.
Optimizations of the Reconstructed Human Epidermis-Based Phototoxicity Testing to Evaluate the Safety of Long-Lasting Cosmetic Products
January 10, 2025The safety of cosmetic products coming in contact with consumers’ skin is often assessed using New Approach Methodologies, which include Reconstructed human Epidermis (RhE) tissue models that have demonstrated utility as reliable test systems. In our manuscript, we evaluated the phototoxicity potential of long-lasting cosmetic products, such as lipsticks and foundations containing UV-absorbing ingredients. given their design to persist on application areas of skin, technical challenges were encountered in the experiments using RhE tissues as the products could not be entirely removed at the end of the exposure period. (more…)
A Proof-of-Concept for Safety Evaluation of Inhalation Exposure to Known Respiratory Irritants Using In Vitro and In Silico Methods
January 8, 2025There is increased interest in developing non-animal test systems for inhalation exposure safety assessments. However, defined methodologies are absent for predicting local respiratory effects from inhalation exposure to irritants. The current study introduces a concept for applying in vitro and in silico methods for inhalation exposure safety assess- ment. (more…)
Building Confidence and Transparency Into a New Validation Paradigm
November 26, 2024For the last two decades, validation management organizations have evaluated new test methods according to the OECD’s Guidance Document 34: Guidance Document On The Validation And International Acceptance Of New Or Updated Test Methods For Hazard Assessment (“GD 34”, 2005, https://doi.org/10.1787/20777876; now under revision).