Evaluation of mixtures of flavor chemicals in a 90-day nose-only exposures in sprague-dawley rats.

Background: One of the challenges to using some flavor chemicals in aerosol products is the lack of route of administration specific toxicology data.

Methods: Flavor chemicals (88) were divided into four different flavor mixtures based upon chemical compatibility and evaluated in 2-week dose-range-finding and subsequent 90-day nose-only rodent inhalation studies (OECD 413 and GLP compliant). Sprague-Dawley rats were exposed to vehicle control or one of three increasing concentrations of each flavor mixture.

Results: In the dose-range-range-finding studies, exposure to flavor mixture four resulted in adverse nasal histopathology in female rats at the high dose, resulting in this flavor mixture not being evaluated in a 90-day study. In the 90-day studies daily exposures to the three flavor mixtures did not induce biologically meaningful adverse effects (food consumption, body weights, respiratory physiology, serum chemistry, hematology, coagulation, urinalysis, bronchoalveolar lavage fluid analysis and terminal organ weights). All histopathology findings were observed in both vehicle control and flavor mixture exposed animals, with similar incidences and/or severities, and therefore were not considered flavor mixture related.

Conclusion: Based on the absence of adverse effects, the no-observed-adverse-effect concentration for each 90-day inhalation study was the highest dose tested, 2.5 mg/L of the aerosolized high dose of the three flavor mixtures.