Anti-leishmanial activity of a topical miltefosine gel in experimental models of New World cutaneous leishmaniasis

Objectives: Topical treatment for cutaneous leishmaniasis (CL) would be useful for treatment of some forms of the disease. The aim of this study was to develop and then evaluate a topical miltefosine gel for anti-leishmanial activity and toxicity in BALB/c mice infected with New World (NW)-CL species. Methods: A Carbopol-based gel of 0.5% miltefosine was prepared and physicochemical (colour, pH, consistency and antioxidant activity) and stability properties were determined using standard methodologies. Anti-leishmanial activities for Leishmania (Viannia) braziliensis and Leishmania (Viannia) panamensis were determined both in cultured parasites and in infected BALB/c mice after topical miltefosine gel treatment administered for 20 days. The gel was evaluated for its capacity to inhibit parasites at a 50% level after 3 days of treatment in vitro, and its capacity to reduce lesion size (mm(2)) and parasitic load after 20 days of treatment. Dermal irritation, contact hypersensitivity (CHS), clinical biochemical profile and the weight of the animals were determined after treatment. Results: The 0.5% miltefosine gel was transparent, homogeneous, colourless, of neutral pH, spreadable and stable at 4 degrees C for at least 3 months. It was active against parasites in vitro and in vivo, reducing CL lesion size by 84%-100% with no detected parasites. No signs of irritation, CHS or changes in weight, food intake, urea or transaminase serum levels were observed after treatment. Conclusions: The topical 0.5% miltefosine gel formulation was efficacious and non-toxic when administered topically in NW-CL murine models. This miltefosine formulation could be an appropriate candidate for further development.