Toxicological Assessment of ENDPs In Vivo

Abstract Assessment of inhaled gases, aerosols, mixtures, or novel compounds includes preclinical rodent inhalation studies. The Organisation for Economic Co-operation and Development (OECD) provides guidance for designing and conducting such studies. Studies conducted in accordance with these guidelines have been shown to be suitable for assessing aerosols from electronic nicotine delivery products (ENDPs) and those generated with ingredients used in e-vapor products (EVPs). Although several inhalation studies that followed OECD guidelines have evaluated heated tobacco products as well as the key ingredients used in e-liquids, the number of studies on EVPs is still limited. The available data show that, overall, exposure to ENDP aerosols leads to lower incidence and severity of findings in multiple organ systems than cigarette smoke. This has been largely manifested in the much lower pulmonary inflammation and pathological findings in the lungs. Systemic effects have been noted in ENDP-exposed animals, most of which are attributable to nicotine exposure or technical stress linked to nose-only exposure restraint and typically alleviated during the postexposure recovery period.