Current Strategies and Recent Advances in Nanostructured Delivery Systems for Managing Leishmaniasis-a Review

Abstract

Neglected tropical diseases (NTDs) comprise of a group of 17th infectious conditions endemic in many developing countries. Among these diseases, deadly, prevalent parasitic infection such as leishmaniasis, presents a significant global burden which is responsible for high morbidity/mortality rate especially in low-and middle-income/developed countries transmitted by phlebotomines sandflies. As per the WHO report, a total of 0.7-1.0 million new leishmaniasis cases, which are spread by 23 leishmania species in more than 98 countries are estimated with an alarming 26,000-65,000 death toll every year. The disease can be characterized by at least four syndromes: cutaneous leishmaniasis (CL), muco-cutaneous leishmaniasis (MCL), visceral leishmaniasis (VL) also known as kala-azar in the Indian sub-continent or black fever, which is the most firm form of the disease being lethal if untreated and post-kala-azar dermal leishmaniasis (PKDL). The lack of cheap, portable, easy to use diagnostic tools exhibiting high efficiency and specificity impede the early diagnosis of the disease. Its intracellular nature and disseminated locations of parasite, limited number of chemotherapeutic agents, increasing incidences of resistance to first line drugs, along with the cost, toxicities, low patient compliance and require long-term regimen and usually hospitalization, pose a great challenge to formulation scientists that have necessitated effective management of leishmaniasis infection by modulating the delivery of existing drugs. Over the past decade, research on development of alternative treatments such as nanotechnology-based drug delivery systems (nanoparticles, nanotubes, nanosuspensions, liposomes, nanovaccines, etc.), use of natural products as well as development of antileishmanial vaccine has been extensively investigated due to their unique properties, such as bioavailability, lowered toxicity, targeted drug delivery, high biocomatibilty and biodegradability. To identify all relevant literature, we searched Web of Sciences, Scopus, PubMed, NCBI, Scielo, Google Scholar, and profiled studies published between 1986 and 2020. The aim of this review is to summarize new advances and new strategies used on leishmaniasis therapy addressing alternative and innovative treatment paths such as combination or multi-drug uses, immunomodulation, drug repurposing and the nanotechnology-based drug delivery systems have been used to improve the therapeutic aspects of existing antileishmanial drugs, presenting a critical review and some suggestions for improving drug delivery.