Tracer studies of the distribution and trypanocidal action of stilbamidine in rats.

[(14)C]Stilbamidine was used to study the distribution of the drug in the organs and tissues of rats following intravenous injection. The prophylactic action of stilbamidine was shown to depend upon the unchanged drug retained in tissues, especially the liver. Only the parent drug was extracted from trypanosomes when an infection was treated during the acute phase, as shown by the use of the fluorescent properties of stilbamidine in conjunction with scanning and chromatographic techniques. The action of stilbamidine on trypanosomes is therefore a direct one. A method for the synthesis of [(14)C]stilbamidine in much improved yield is also described.