Branched polyethyleneimine (BPEI) is a cationic polymer widely utilized in household products (e.g., fragrances, antimicrobial sprays, and deodorants) due to its unique physicochemical properties, such as cationic nature, hydrophilicity, and strong adsorption capacity. Despite its broad utility, concerns regarding its biodistribution and potential toxicity remain unresolved. In this study, we employed positron emission tomography (PET) imaging with 64Cu-labeled-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetracetic acid (DOTA)-conjugated BPEI (64Cu-DOTA-BPEI) to evaluate the biodistribution and pulmonary toxicity of BPEI in rats following intratracheal instillation. Quantitative biodistribution analyses and PET imaging showed that 64Cu-DOTA-BPEI deposited in the lung at 37 MBq/rat exhibited high pulmonary retention, with about 65% initial dose at 72 h post-instillation. BPEI deposited in the lung showed limited clearance after systemic absorption, with the hepatobiliary system being the primary route, accounting for about 10-20% cumulative clearance up to 72 h. BPEI at 24 h post-instillation (15, 30, 60, and 90 µg/rat) produced a dose-dependent acute lung inflammation, characterized by neutrophilia and eosinophilia. Although inflammation reactions were resolved by 14 days after a single instillation, its long retention in the lung and high cytotoxic potential imply that repeated exposures can cause chronic lung diseases. These findings highlight the need for careful safety evaluation of household products containing BPEI, especially when inhaled as aerosols, due to its prolonged pulmonary retention and high cytotoxic potential.
Keywords: Household chemicals; Inhalation; Polyethyleneimine; Radiotracer; Toxicity.
© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.