What is local respiratory toxicity, and why study it?
The human nose is a highly sensitive organ that can detect a wide variety of odors at very small concentrations. Thus, it is not surprising that 99% of all fragrance ingredients fall below the most conservative inhalation Threshold of Toxicological Concern (TTC). The TTC is the level of exposure to a substance beneath which there is no concern for adverse effects.
Local respiratory toxicity refers to the potential of an ingredient to cause adverse effects on respiratory system organs, such as the nose, larynx, trachea, bronchi, and lungs. Even though detailed aggregate exposure analysis shows that inhalation exposure to fragrance ingredients in consumer products is low, the Research Institute for Fragrance Materials (RIFM) evaluates all fragrance ingredients for their respiratory toxicity potential as part of its robust safety assessment program.
Due to limited in vivo (in the body) respiratory studies in the existing scientific literature, RIFM evaluates local respiratory toxicity for fragrance ingredients by using the available and relevant target data, read-across, or the TTC, in accordance with the guidelines of the RIFM Criteria Document. Using real-world exposure data collected using the Creme RIFM Aggregate Exposure Model, RIFM scientists can determine if exposure to a fragrance ingredient is at a safe level.
Nevertheless, as with the other human health endpoints, the local respiratory toxicity endpoint is also the focus of New Approach Methodologies (NAMs). RIFM is collaborating with various scientific organizations to develop new animal-alternative ways to evaluate respiratory toxicity that simulate conditions in the human body.
Senior Scientist Nikaeta Sadekar, PhD, DABT, leads RIFM’s Local Respiratory Toxicity safety assessment and research programs.