Development, characterization, and in vitro biological performance of fluconazole-loaded microemulsions for the topical treatment of cutaneous leishmaniasis

Abstract

Cutaneous leishmaniasis (CL) is a resistant form of leishmaniasis that is caused by a parasite belonging to the genus Leishmania. FLU-loaded microemulsions (MEs) were developed by phase diagram for topical administration of fluconazole (FLU) as prominent alternative to combat CL. Three MEs called F1, F2, and F3 (F1-60% 50 M phosphate buffer at pH 7.4 (PB) as aqueous phase, 10% cholesterol (CHO) as oil phase, and 30% soy phosphatidylcholine/oil polyoxyl-60 hydrogenated castor oil/sodium oleate (3/8/6) (S) as surfactant; F2-50% PB, 10% CHO, and 40% S; F3-40% PB, 10% CHO, and 50 % S) were characterized by droplet size analysis, zeta potential analysis, X-ray diffraction, continuous flow, texture profile analysis, and in vitro bioadhesion. MEs presented pseudoplastic flow and thixotropy was dependent on surfactant concentration. Droplet size was not affected by FLU. FLU-loaded MEs improved the FLU safety profile that was evaluated using red cell haemolysis and in vitro cytotoxicity assays with J-774 mouse macrophages. FLU-unloaded MEs did not exhibit leishmanicidal activity that was performed using MTT colourimetric assays; however, FLU-loaded MEs exhibited activity. Therefore, these MEs have potential to modulate FLU action, being a promising platform for drug delivery systems to treat CL.

Figure 1

Ternary phase diagram. The marked areas represent the following. PS: phase separation; VOS: viscous opaque system; TVS: transparent viscous system; and LTS: liquid transparent system. The points designated F1, F2, and F3 are the studied MEs.

Figure 2

X-ray diffraction spectra for microemulsion components: (a) sodium oleate, (b) cholesterol, (c) polyoxyl-60 hydrogenated castor oil, (d) fluconazole, and (e) soy phosphatidylcholine.

Figure 3

X-ray diffraction spectra of FLU-unloaded MEs (F1, F2, and F3) and FLU-loaded MEs (F1D, F2D, and F3D): (a) F1 and F1D, (b) F2 and F2D, and (c) F3 and F3D.

Figure 4

Peak of bioadhesion (N) of FLU-unloaded MEs (F1, F2, and F3) and FLU-loaded MEs (F1D, F2D, and F3D). Each value represents the mean (± standard deviation) of at least seven replicates. Data were collected at 32 ± 0.5°C. No statistically significant difference was detected.

Figure 5

(a) Flow rheograms of FLU-unloaded MEs F1 (■), F2 (▲), and F3 (◆). (b) Flow rheograms of FLU-loaded MEs F1D (■), F2D (▲), and F3D (◆). Closed symbol represents up curve and open symbol represents down curve. Standard deviations have been omitted for clarity; however, in all cases, the coefficient of variation of triplicate analyses was less than 10%. Data were collected at 32 ± 0.5°C.

Figure 6

% cellular viability for FLU-free samples, FLU-unloaded MEs (F1, F2, and F3), and FLU-loaded MEs (F1D, F2D, and F3D). No statistically significant difference was detected.