Sensitivities of Leishmania species to hexadecylphosphocholine (miltefosine), ET-18-OCH3 (edelfosine) and amphotericin B

The sensitivities of both promastigote and amastigote stages of six species of Leishmania, L. donovani, L. major, L. tropica, L. aethiopica, L. mexicana and L. panamensis, were determined in vitro to the phospholipid drugs hexadecylphosphocholine (HPC, miltefosine) and ET-18-OCH3 (edelfosine). In all assays L. donovani was the most sensitive species, with ED50 values in the range of 0.12–1.32 μM against promastigotes and 1.2–4.6 μM against amastigotes. L. major was the least sensitive species in the majority of assays with ED50 values for HPC in the range of 4.8–13.1 μM against promastigotes and for HPC and ET-18-OCH3 in the range of 7.5–37.1 μM against amastigotes. Amphotericin B deoxycholate was used as the standard drug and gave submicromolar ED50 values in all assays; L. mexicana was the least sensitive species to this drug.