Disposition of 2-mercaptobenzothiazole and 2-mercaptobenzothiazole disulfide in rats dosed intravenously, orally, and topically and in guinea pigs dosed topically

To determine the metabolic disposition of [14C]‐2‐mercaptobenzothiazole (MBT) and [14C]‐2‐mercaptobenzothiazole disulfide (MBTS), male and female rats were dosed topically. Topical doses were 36.1 μg/animal for [14C]MBT and 33.6 μg/animal for [14C]MBTS. Although more MBT passed through the skin than MBTS and although, relative to rats, guinea pigs absorbed a greater percentage of the dose (33.4% compared to 16.1–17.5% of the MBT and 12.2% compared to 5.94–7.87% for MBTS), the disposition of radioactivity derived from the two compounds was similar. Washing of the skin removed more of the radioactivity from guinea pigs than from rats. For both sexes of rats dosed intravenously with [14C]MBT (0.602 mg/kg) or [14C]MBTS (0.571 mg/kg), disposition of the compounds was similar. In 72 h, 90.9–101% of the dose appeared in the urine and 3.79–15.1% in the feces. At this time, a small portion of the administered radioactivity (1.52–1.96% of the dose) remained associated with erythrocytes. Oral dosing of rats was for ...