Repurposing butenafine as an oral nanomedicine for visceral leishmaniasis

Leishmaniasis is a neglected tropical disease affecting more than 12 million people worldwide, which in its visceral clinical form (VL) characterised by accumulation of parasites in the liver and spleen can lead to death if not treated. Available treatments are not well tolerated due to severe adverse effects, need for parenteral administration and patient hospitalisation, and long duration of expensive treatments. These treatment realities justify the search for new effective drugs, repurposing existing licensed drugs towards safer and non-invasive cost-effective medicines for VL. In this work, we provide proof of concept studies of butenafine and butenafine self-nanoemulsifying drug delivery systems (B-SNEDDS) against Leishmania infantum. Liquid B-SNEDDS were optimised using design of experiments and then were spray-dried onto porous colloidal silica carriers to produce solid-B-SNEDDS with enhanced flow properties and physicochemical characteristics. Optimal liquid B-SNEDDS consisted of Butenafine: Capryol 90: Peceol: Labrasol (3: 49.5: 24.2: 23.3, w/w) which were then sprayed-dryed with Aerosil 200 with a final 1:2 (Aerosil: liquid B-SNEDDS, w/w) ratio. Spray-dried particles exhibited near maximal drug loading, while maintaining excellent powder flow properties (angle of repose <10˚) and sustained release in acidic gastrointestinal media. Solid-B-SNEDDS demonstrated greater selectivity index against promastigotes and L. infantum infected amastigotes than butenafine alone. Developed oral solid nanomedicines enable the non-invasive and safe administration of butenafine as a cost-effective and readily scalable repurposed medicine for VL.