The objective of our study was to estimate metabolites of pseudocumene in the lung, liver, kidney and urine of rats after single and repeated inhalation exposure.
Male Wistar rats were exposed to pseudocumene vapors at nominal concentrations of 25, 100 or 250 ppm in the dynamic inhalation chambers for 6 h or 4 weeks (6h/day; 5 days/week). Following exposure, three metabolites were measured in biologic material after hydrolysis: 3,4-dimethylbenzoic acid (3,4- DMBA), 2,4-dimethylbenzoic acid (2,4-DMBA) and 2,5-dimethylbenzoic acid (2,5-DMBA). The metabolites were analyzed by gas chromatography with a flame ionization detector.
The study showed no significant increase in concentrations of the analyzed DMBA metabolites in the liver and lungs of rats exposed to repeated inhalation exposures to pseudocumene as compared to a single exposure. It was found that metabolic transformation of pseudocumene, leading to the production of 3,4- DMBA in the rats kidneys, are more pronounced after repeated inhalation exposure.