We have assayed a variety of CPP on these cells, quantified their uptake and defined their pathways. Definition of cargo molecules capable to be transported by CPPs and their application into reversal of resistance due to a faulty accumulation of drug, as miltefosine in Leishmania. We improved CPP specificity by incorporation of peptide sequences with higher Leishmania recognition, from biopanning of phage peptide expression libraries, and targeting intracellular organelles, either by modification of the physicochemical characteristics of CPPs on Leishmania or by incorporation into their sequence of organelle import sequences.