Liposomes for the topical treatment of Cutaneous Leishmaniasis

OLIVERA, MARÍA EUGENIA; PÉREZ, ANA PAULA; CARRER, DOLORES CATALINA; ROMERO, EDER ILIA; GUZMÁN, MARÍA LAURA; BARROSO, PAOLA; APEZTEGUIA, GUATAVO; PERALTA, MARÍA FLORENCIA

Toledo

Congreso; WorldLeish; 2017

Background. Cutaneous Leishmaniasis is the most prevalent form of Leishmaniasis in Latin America. Topical treatment would minimize drugs side effects and enhance patient compliance. We have tested ultra-flexible liposomes carrying different candidate drugs for flexibility, skin penetration and effect on amastigotes viability in Leishmania (L.) amazonensis - infected macrophages. Methods. Four different drugs encapsulated in ultra-flexible liposomes were tested separately: AmphotericinB (AmB), Indole (Ind), Imiquimod (Imiq) and Miltefosine (Milt). Liposomes flexibility was studied by extrusion. Skin penetration was assayed with abdominal human skin in Franz cells in non-occlusive conditions and quantified by validated HPLC methods. Fluid liposomes were used as references. In vitro assays were performed in Raw 264.7 ? murine macrophages infected with L. amazonensis parasites in a ratio of 20 promastigotes per cell. Non adhered parasites were removed after five hours of incubation. Formulations were added in different quantities, and the leishmanicidal effect was measured after 48 hs by microscopy. Diff Quick coloration was used, and selectivity indexes were calculated (% infected macrophages X number of intracellular amastigotes) for comparative purposes. Results. The incorporation of Im did not produce significant changes in the flexibility of liposomes (ANOVA, p>0.05). An increase in flexibility was observed in Ind- containing liposomes. Formulations containing AmB could not be extruded at the working pressure, possibly due to a decrease in liposomes elasticity. From the liposomes applied on the skin surface, Ind penetrated the most, reaching even the receptor medium, followed by Im and AmB, which penetrated in smaller percentages into the epidermis and dermis. Drugs incorporated into ultra-flexible liposomes penetrated more than drugs in fluid liposomes.We found that each drug had its own most effective concentration in reducing amastigotes charge in vitro. AmB reduced 96% of amastigotes respect to control infected cells, while Im reduced 66%, Milt in 62% and Ind in 59%.Conclusions. There is a strong correlation between liposomes flexibility and drug skin penetration, regardless of the drug molecular weight. All drugs tested reached the dermis when incorporated in ultra-flexible liposomes, although in different amounts. Regarding leishmanicidal ability against infected macrophages, the AmB formulation was the most effective, followed by Im, Milt and Ind.