Effect of ethanol on the urinary excretion of cyclohexanol and cyclohexanediols, biomarkers of the exposure to cyclohexanone, cyclohexane and cyclohexanol in humans.

This study explored the acute effect of ethanol (EtOH) on the urinary excretion of cyclohexanol (CH-ol), 1,2- and 1,4-cyclohexanediol (CH-diol), biomarkers of exposure to important solvents, and chemical intermediates cyclohexanone (CH-one), cyclohexane (CH) and cyclohexanol. Volunteers (5-8 in each group) were exposed for 8 hours either to CH-one, CH or CH-ol vapor at concentrations of about 200, 1000, and 200 mg/m3, respectively, with concomitant ingestion of EtOH (4 14-g doses taken during the exposure). Urine was collected for 72 hours and analyzed for CH-ol and CH-diols using a procedure involving acidic hydrolysis and gas chromatographic determination. The metabolic yields of CH-ol, 1,2-, and 1,4-CH-diol, respectively, in the exposures with EtOH were as follows: 11.3%, 36%, 23% after the exposure to CH-one, 3.1%, 15%, 8% after the exposure to CH, and 6.6%, 24%, 18% after the exposure to CH-ol. [The corresponding values obtained previously in matching experiments without EtOH were as follows: 1.0%, 39%, 18% (CH-one); 0.5%, 23%, 11% (CH); and 1.1%, 19%, 8% (CH-ol).] The excretion curves of the metabolites in the exposures with EtOH were not delayed when compared with the corresponding curves of a comparison group. The urinary excretion of CH-diols is much less sensitive to EtOH than that of CH-ol. It is recommended to employ CH-diols as useful and more reliable biomarkers of exposure to CH-one, CH and CH-ol in field examinations.