Drug delivery systems in the treatment of African trypanosomiasis infections.

INTRODUCTION: Animal African trypanosomiasis (AT) is treated and controlled with homidium, isometamidium and diminazene, whereas human AT is treated with suramin, pentamidine, melarsoprol and eflornithine (DFMO), or a combination of DFMO and Nifurtimox. Monotherapy can present serious side effects, for example, melarsoprol, the more frequently used drug that is effective for both hemolymphatic and meningoencephalic stages of the disease, is so toxic that it kills 5% of treated patients. These treatments are poorly efficient, have a narrow safety index and drug resistance is a growing concern. No new drug has been developed since the discovery of DFMO in the 1970s. There is a pressing need for an effective, safe drug for both stages of the disease, and recent research is focused on the development of new formulations in order to improve their therapeutic index. AREAS COVERED: This review shows the potential interest of using nanoparticulate formulations of trypanocidal drug to improve parasite targeting, efficacy and, potentially, safety while being cost-effective. EXPERT OPINION: The design of drug formulations relevant to the treatment of AT must include a combination of very specific properties. In summary, the drug delivery system must be compatible with the physicochemical properties of the drug (charge, lipophilicity and molecular mass) in order to allow high drug payloads while being biocompatible for the patient.