Metabolism and pharmacokinetics of 4-(p-chlorophenylthio)butanol (W-2719) in the rat and dog.

4-(p-Chlorophenylthio)butanol (W-2719) administered orally to rats and dogs is rapidly absorbed, metabolized and excreted. The only major biotransformation product found in blood was p-chlorophenylthioacetic acid (W-2683). No W-2719 or the intermediary p-chlorophenylthiobutyric acid (W-2718) could be found in plasma after oral administration of the drug. When W-2719 was given i.v. to dogs, both W-2719 and W-2718 appeared in plasma but each had a very short half-life of about 10 min. After an oral dose of W-2719 to dogs the plasma content of W-2683 peaked at 4-6 h, amounting to approximately 20% of the dose. More than 91% of the dose was excreted with 48 h, 83% in urine and 9% in feces. The predominant excretion product in urine was p-chlorothiophenol, most of which was excreted in a conjugated form. The other major urinary metabolite was W-2683, while smaller amounts of W-2718 and unchanged drug were also found. No significant effect of prolonged dosing of 14C-W-2719 to dogs was observed on plasma 14C levels, peak time, 14C half-life or excretion and composition patterns.