Preliminary Studies on the Distribution and Excretion of Tritiated Daunomycin in Men

³H-daunomycin was injected in 10 patients with widespread cancer (in 7 cases intravenously, in 1 case into the ascitic fluid and in 2 cases intraarterially) at the dose of 1 mg/kg. The radioactivity was determined in plasma, urine, stools, ascitic fluid and cerebrospinal fluid with the hyamine hydroxide method. The radioactivity was determined with a Tri-Carb apparatus, model 3003. From this study ³H-daunomycin seems to be rapidly fixed by body tissues regardless of the route of administration. Low plasma levels of radioactivity were detected even at early intervals after drug administration. ³H-daunomycin levels fall very rapidly when the drag is injected into the ascitic fluid; low urinary and fecal excretion were also observed during the first week. No radioactivity was detected in the cerebrospinal fluid, which indicates that daunomycin at the dose given does not cross the blood brain barrier. Since daunomycin appears to be taken up quickly by the cells, where it is retained for long periods of time, accumulation and toxic effects are more likely to occur with a daily dose rather than with intermittent dose schedule.