Abstract: Objective: The metabolic kinetics of two metabolites from tertiary butylhydroquinone, tertiary butylhydroquinone-sulfate and tertiary butylhydroquinone-glucuronide were investigated in rats. Methods: The concentrations of the metabolites in the serum of rats after oral exposure of tertiary butylhydroquinone were semi-quantitatively analyzed by liquid chromatography-mass spectrometry (LC-MS). Compartment model and metabolic kinetic parameters were evaluated by practical pharmacokinetic program. Results: The serum concentration-time profiles of two metabolites could be fitted with a two-compartment model and obeyed first-order kinetics. Conclusion: After oral administration of tertiary butylhydroquinone, the peak time of tertiary butylhydroquinone-sulfate and tertiary butylhydroquinone-glucuronide in the serum of rats were 0.17－0.61 h and 0.23－0.74 h, the distribution half-lives 0.32－1.11 h and 0.2－2.60 h, and the elimination half-lives 11.75－24.54 h and 24.42－55.78 h, respectively. The concentrations of two metabolites in the serum of male rats were higher than those in female rats. The exposure of two metabolites increased in a less-than-dose-proportional manner. Moreover, the metabolism of tertiary butylhydroquinone in rats reached saturation with increasing dose.

Key words: tertiary butylhydroquinone-sulfate, tertiary butylhydroquinone-glucuronide, metabolic kinetics, liquid chromatography-mass spectrometry