The toxicokinetics of 2-methylnaphtalene in rats

Background: The aim of the study was to evaluate the toxicokinetics of 2-methylnaphtalene (2-MN) during and after inhalation exposure. Material and Methods: Male Wistar rats were exposed to 2-MN vapours at nominal concentrations of 200 or 400 mg/m3 in the dynamic inhalation chamber for 6 hours or 5 days (6 h/day). Blood samples were collected during and after exposure. Blood concentrations of 2-MN were estimated by gas chromatography using the headspace technique. Results: During a 6-hour exposure to 200 or 400 mg/m3, blood 2-MN concentration increased rapidly within the first or second hour of exposure, respectively, after reaching a plateau. The elimination of 2-MN from blood followed an open two-compartment model. Conclusion: 2-MN was rapidly eliminated from blood of the animals exposed by inhalation to 2-MN. During exposure, lung retention of the chemical was found to decrease. Under conditions of repeated 2-MN exposure, no significant systemic 2-MN accumulation could be observed.