New delivery strategies for the old pentavalent antimonial drugs

Importance of the field: Pentavalent antimonials are the first-line drugs for treatment of the major tropical disease leishmaniasis. However, their use is limited by the need for daily parenteral administration, their severe side effects and treatment failures. As leishmaniasis belongs to the group of neglected diseases, the improvement of old drugs through new delivery approaches has more support than the development of new chemical entities. Areas covered in this review: The review covers, from 1977 to the present, the progress achieved towards pharmaceutically acceptable liposome-based formulations of antimonials, identification of specific ligands for improved targeting of infected macrophages and new approaches for oral and topical delivery of antimonial drugs. What the reader will gain: Insights into the most promising delivery strategies to improve antimonial therapy and the chemical basis and future directions for achieving innovative orally and topically effective formulations. Take home message: The development of drug delivery strategies for the old pentavalent antimonials is a still growing and promising field, with expected innovations in the near future from improved knowledge of antimony chemistry.