Trypanocidal activity and platinum plasma kinetics of cis-Pt pentamidine iodide in Trypanosoma brucei sheep model

The trypanocidal properties of cis-Pt pentamidine iodide have been studied on the T. b. brucei sheep model. The compound was evaluated on the lymphatic-plasma phase of the disease and appeared to be active on the circulating parasites. Cis-Pt pentamidine iodide was active at 5 mgl.kg-1 in one single dose both in mouse and sheep trypanosomiasis models. The chemotherapeutic index was about 200 in the mouse. As we observed previously with the chloride derivative, platinum plasma values for cis-Pt pentamidine iodide were rather constant between 24 and 48 hours. The nature of the salt associated to cis-Pt pentamidine had a direct effect on the compound kinetics. The iodide compound was distributed quickly and largely within deep compartments according to a monocompartmental model. The theoretical volume of distribution was 6.41.kg-1 for a 100% absorbed fraction. The two iodide ions of the complex probably played an important role in the compound kinetics mainly due to the extended release effect. The iodide salt of cis-Pt pentamidine could therefore be used in chemoprophylaxis of African trypanosomiasis.