The distribution and excretion of 14C- and 3H-labelled 4-prenyl-1,2-diphenyl-3,5-pyrazolidinedione (DA 2370) in the rat.

The distribution and excretion of radioactivity following a single or multiple oral administration of 3H-and/or 14C-4-prenyl-1,2-diphenyl-3,5-pyrazolidinedione (DA 2370) has been determined in rats. The daily excretion of radioactivity following a single administration (3H and 14C) or multiple doses (3H) fell to less than 1% of the dose in 4 days. A similar fall was observed at the end of 10 days continuous administration. The radioactivity in plasma reached a maximum between 2 and 4 h after administration of the drug (14C). Tissue levels were found to be effectively zero 24 h after administration of the drug for up to 10 days. The very large amounts of radioactivity lost in bile were found to correlate with blood, tissue and faecal levels.