Distribution and metabolism of 1,2,4-trimethylbenzene (pseudocumene) in the rat

1. Single doses of 1,2,4-trimethylbenzene (124TMB) or ¹⁴C-124TMB were administered orally to rats for metabolism and distribution studies.

2. ¹⁴C-124TMB was rapidly and widely distributed throughout the body with the highest levels in adipose tissue. No other preferential uptake of ¹⁴C-124TMB by any of the organs or tissues examined was evident.

3. Tissue levels declined rapidly within 24 h after dosage, with more than 99% of the administered radioactivity recovered in the urine during this period.

4. A complex mixture of isomeric trimethylphenols, dimethylbenzyl alcohols, dimethylbenzoic acids and dimethylhippuric acids excreted in the urine accounted for more than 81% of the administered dose. The major metabolites were 3,4-dimethyl-hippuric acid (30.2% dose), 2,4-dimethylbenzylalcohol (12.7% dose, primarily as sulphate and glucuronide conjugates) and 2,5-dimethylbenzyl alcohol (11.7% dose, primarily as sulphate and glucuronide conjugates).