Development, Characterization, and In Vitro Biological Performance of Amphotericin B and Terbinafine Microemulsions Against Leishmania major

This study evaluated the effect of microemulsion (ME) containing Amphotericin B (AmB) alone and associated with Terbinafine (Tbf) on Leishmania major (L. major) using in vitro models. The ME formulations of these drugs were formulated and described. After evaluating their cytotoxicity on the J774A1 macrophage (MΦ), their potency against promastigotes and intracellular amastigotes models was evaluated using an in vitro MTT assay and Giemsa stain, respectively. Based on pseudo ternary phase diagrams, unloaded ME, Tbf-loaded ME (ME-Tbf), and, AmB-loaded ME (ME-AmB) with mean droplet sizes 3.4 ± 0.81, 10.05 ± 0.21, and 8.21 ± 0.46 were successfully prepared, respectively. Concerning toxicity, ME-AmB and ME-Tbf indicated lower toxicity on MΦs compared to the free drugs. The ME formulations showed considerably inhibitory effects compared to the free drug forms when the IC50 was examined. The IC50 values of AmB (59.19 ± 1.74 and 36.4 ± 3.2 μg/mL), ME-AmB (7.5 ± 0.9 and 0.8 ± 0.05 μg/mL), Tbf (234.5 ± 9 and 128.8 ± 0.28 μg/mL), ME-Tbf (26.27 ± 0.2 and 11.97 ± 0.6 μg/mL), AmB + Tbf (30.18 and 24.93 μg/mL), and ME-AmB + ME-Tbf (4.79 and 0.37 μg/mL) were estimated after 48 and 72 h, respectively.