Dados do Trabalho

Título

Antileishmanial and antifungal potential of amphotericin B encapsulated in PLGA nano and microparticles for the treatment of cutaneous leishmaniasis and sporotrichosis

Introdução

Leishmaniasis and sporotrichosis are negleted diseases that presents problems related to chemotherapy, such as systemic and long treatments, even for the cutaneous form. Our group demonstrated that implants of polymeric microparticles have been shown to promote local sustained release of amphotericin B (AmB) and to be effective with a single dose, no systemic effect for treatment of cutaneous leishmaniasis.

Objetivo (s)

The aim of this study was to maximize the effect of AmB-loaded PLGA particles evaluating the differents sizes. Nano-sized particles are expected to be more easily phagocytosed by infected macrophages with leishmaniasis. Furthermore, due to the similar skin infection and sensitivity of Sporothrix to AmB, we proposed to further evaluate a potential use of PLGA/AmB microparticle implants in sporotrichosis.

Material e Métodos

For that, particles of different size ranges like NP, MicP and MacP were synthesized and characterised. First, NP, MicP and MacP containing 8.8% of AmB drug/formulation ratio were prepared by varying protocols of emulsion and solvent evaporation. For biology assays, Leishmania amazonensis promastigotes (2x10^5/mL) were incubated with different concentrations (0.01-100 µg/mL) of nano-microparticles and AmB free for 72 h and cell viability was assayed by resazurin. In vitro tests against Sporothrix brasiliensis yeast (1 x 10^5 CFU/mL) for 48 h by XTT. When tested for cytotoxicity to bone marrow-derived macrophages (BMDM) –1x10^5/well and 3T3 fibroblasts - 1x10^4/well were treated with different concentrations for 48 h and evaluated by resazurin.  

Resultados e Conclusão

Their sizes measured by DLS (NP - 294 ± 36 nm, PDI 0.2) and laser diffraction (MicP - 3.0 ± 0.5 µm, Span 0.7 and MacP = 49 ± 12 µm, Span 0.8). The AmB loading decreased with size: NP= 7.4% and MicP/MacP around 6.5%. . Nano-microparticles (0.02-0.04 µg/mL) showed activity similar to free AmB (0.01 µg/mL) against promastigotes.The initial release of AmB already manages to control the effect. High activity (IC50) of differents sizes (NP= 0.10; MicP=0.08 and MacP = 0.20 µg/mL), all more active than free AmB (IC50 = 0.70 µg/mL) in fungus. According to CC50, all particles were less than 4 and 6 fold cytotoxic than free AmB in BMDM and 3T3 fibroblasts, respectively. In conclusion, PLGA particles of three sizes with AmB were successfully synthesized, showing low cytotoxicity and antileishmanial and antifungal activity. In vivo studies are underway to evaluate potential application of sporothricosis and cutaneous leishmaniasis.

Palavras Chave

polymeric nanoparticles and microparticles; amphotericin B; Leishmaniasis; sporotrichosis