biostudies-literatureUnknown21(1)Thoma TFreie Universität BerlinInternational Zinc Association, Brussels, Belgium<h4>Background</h4>Significant variations exist in the forms of ZnO, making it impossible to test all forms in in vivo inhalation studies. Hence, grouping and read-across is a common approach under REACH to evaluate the toxicological profile of familiar substances. The objective of this paper is to investigate the potential role of dissolution, size, or coating in grouping ZnO (nano)forms for the purpose of hazard assessment. We performed a 90-day inhalation study (OECD test guideline no. (TG) 413) in rats combined with a reproduction/developmental (neuro)toxicity screening test (TG 421/424/426) with coated and uncoated ZnO nanoforms in comparison with microscale ZnO particles and soluble zinc sulfate. In addition, genotoxicity in the nasal cavity, lungs, liver, and bone marrow was examineParticle and fibre toxicology24https://www.ebi.ac.uk/biostudies/studies/S-EPMC11100124biostudies-literatureToxicological inhalation studies in rats to substantiate grouping of zinc oxide nanoforms.PMC11100124Groeters SDammann MWiench KVasquez MSchneider SWohlleben WDewhurst NLombaert NStrauss VThoma TMa-Hock LSpirlet CLandsiedel RTreumann SSeiffert SHonarvar NFunk-Weyer DMarxfeld HfalseToxicological inhalation studies in rats to substantiate grouping of zinc oxide nanoforms.<h4>Background</h4>Significant variations exist in the forms of ZnO, making it impossible to test all forms in in vivo inhalation studies. Hence, grouping and read-across is a common approach under REACH to evaluate the toxicological profile of familiar substances. The objective of this paper is to investigate the potential role of dissolution, size, or coating in grouping ZnO (nano)forms for the purpose of hazard assessment. We performed a 90-day inhalation study (OECD test guideline no. (TG) 413) in rats combined with a reproduction/developmental (neuro)toxicity screening test (TG 421/424/426) with coated and uncoated ZnO nanoforms in comparison with microscale ZnO particles and soluble zinc sulfate. In addition, genotoxicity in the nasal cavity, lungs, liver, and bone marrow was examine2024-01-01T00:00:00Z2024 May2026-04-12T15:33:44.916Z2026-04-07T13:17:57.499ZS-EPMC111001243876076110.1186/s12989-024-00572-y