Inhalation Toxicology of Azadirachtin and Neem Oil Pyrolysis Products: Derivation of a Health-Based Maximum Residue Limit (MRLInhalation) for Inhalable Crops

The widespread use of neem oil on crops intended for human inhalation (e.g., cannabis, hemp) poses an unquantified public health risk. Current regulatory safety standards are based on ingestion data, which fails to account for the chemical transformation (pyrolysis) that occurs during smoking or vaping. This pre-experimental proposal outlines a comprehensive, nine-phase investigation to analytically characterize the degradation products of neem oil residue (Azadirachtin and fatty acids), biologically verify their pulmonary toxicity, and derive a robust, health-protective Maximum Residue Limit (MRLInhalation). The study integrates analytical chemistry (Py-GC/MS), computational toxicology (PBPK modeling), and in vitro/in vivo lung toxicology to establish the No-Observed-Adverse-Effect-Level (NOAEL) necessary for regulatory action.