PLGA nanoparticles loaded with the antileishmanial saponin β-aescin: factor influence study and in vitro efficacy evaluation.

Abstract Colloidal carriers are known to improve the therapeutic index of the conventional drugs in the treatment of visceral leishmaniasis (VL) by decreasing their toxicity whilst maintaining or increasing therapeutic efficacy. This paper describes the development of poly( d , l -lactide-co-glycolide) (PLGA) nanoparticles (NPs) for the antileishmanial saponin β-aescin. NPs were prepared by the W/O/W emulsification solvent evaporation technique and the influence of five preparation parameters on the NPs’ size ( Z ave ), zeta potential and entrapment efficiency (EE%) was investigated using a 2 5−2 fractional factorial design. Cytotoxicity of aescin, aescin-loaded and blank PLGA NPs was evaluated in J774 macrophages and non-phagocytic MRC-5 cells, whereas antileishmanial activity was determined in the Leishmania infantum ex vivo model. The developed PLGA NPs were monodispersed with Z ave ® 80 to the inner aqueous phase rendered the primary emulsion more stable, which in its turn led to better saponin entrapment. The selectivity index (SI) towards the supporting host macrophages increased from 4 to 18 by treating the cells with aescin-loaded NPs instead of free β-aescin. In conclusion, the in vitro results confirmed our hypothesis.