RIFM fragrance ingredient safety assessment, 2-isobutylquinoline, CAS registry number 93-19-6

2-Isobutylquinoline was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, photoirritation/photoallergenicity, skin sensitization, and environmental safety. Target data show that 2-isobutylquinoline is not genotoxic. The repeated dose, reproductive, and local respiratory toxicity endpoints were evaluated using the Threshold of Toxicological Concern (TTC) for a Cramer Class III material, and the exposure to 2-isobutylquinoline is below the TTC (0.0015 mg/kg/day, 0.0015 mg/kg/day, and 0.47 mg/day, respectively). Data from read-across analog quinoline (CAS # 91-22-5) show that there are no safety concerns for 2-isobutylquinoline for skin sensitization under the current declared levels of use. The photoirritation endpoint was evaluated based on data and ultraviolet/visible (UV/Vis) spectra; 2-isobutylquinoline is not photoirritating. The photoallergenicity endpoint was evaluated based on UV/Vis spectra; 2-isobutylquinoline is not photoallergenic. The environmental endpoints were evaluated; 2-isobutylquinoline was found not to be Persistent, Bioaccumulative, and Toxic (PBT) as per the International Fragrance Association (IFRA) Environmental Standards, and its risk quotients (RQs), based on its current volume of use (VoU) in Europe and North America (i.e., Predicted Environmental Concentration/Predicted No Effect Concentration [PEC/PNEC]), are <1.