A single oral fixed-dose praziquantel-miltefosine nanocombination for effective control of experimental schistosomiasis mansoni
Abstract Background: The control of schistosomiasis has been centered to date on a single drug, praziquantel (PZQ), with shortcomings including treatment failure, reinfection, and emergence of drug resistance. Drug repurposing, combination therapy or nanotechnology were explored to improve antischistosomal treatment. The aim of the present study was to utilize a novel combination of the three strategies to improve the therapeutic profile of PZQ. This was based on a fixed dose nanocombination of PZQ and miltefosine (MFS), an antischistosomal repurposing candidate, co-loaded at reduced doses into lipid nanocapsules (LNCs), for single dose oral therapy. Methods: Two nanocombinations were prepared to provide 250 mg PZQ-20 mg MFS/kg (higher fixed dose) or 125 mg PZQ-10 mg MFS/kg (lower fixed dose) respectively. Their antischistosomal efficacy in comparison with nontreated control and their PZQ or MFS singly loaded counterparts was assessed in murine schistosomiasis mansoni. A single oral dose of either formulation was administered on the initial day of infection, the 21 st and 42 nd days post infection. Scanning electron microscopic (SEM), parasitological and histopathological studies were used for assessment. Preclinical data were subjected to analysis of variance and Tukey post hoc test for pairwise comparisons. Results: Compared to singly loaded PZQ-LNCs, the higher dose nanocombination showed a significant increase in antischistosomal efficacy in terms of % reduction in worm burden, particularly against invasive and juvenile worms, and amelioration of hepatic granulomas. The efficacy of the higher dose nanocombination was significantly greater than that of its lower dose counterpart. SEM showed extensive dorsal tegumental damage with noticeable deposition of nanostructures. Conclusions: The therapeutic profile of PZQ could be improved by a novel multiple approach integrating drug repurposing, combination therapy and nanotechnology. Multistage activity and amelioration of liver pathology could be achieved by a new PZQ-MFS fixed dose nanocombination providing 250 mg PZQ-20 mg MFS/kg. To the best of our knowledge, this is the first report of a fixed dose nano-based combinatorial therapy for schistosomiasis mansoni. Further studies are needed to document the nanocombination safety and explore its prophylactic activity and potential to hinder the onset of resistance to the drug components. Key words: Praziquantel, miltefosine, lipid nanocapsules, Schistosoma mansoni, nanocombination, multistage activity, tegumental targeting, scanning electron microscopy