Poly(ε-caprolacton) nanospheres as an alternative way to reduce amphotericin B toxicity

A new stable amphotericin B nanosphere-based delivery system was obtained by a solvent displacement process. A reproducible and monodisperse size distribution centered on 220 nm was obtained, when AmB and poly(ε-caprolacton) were dissolved in an appropriate solvent mixture. UV-Visible and circular dichroism spectroscopy suggested that nanoparticles modified the aggregation state of AmB, probably due to a weak interaction between the drug and the polymer of the nanospheres. Zeta potential measurements indicated that amphiphilic amphotericin B could be adsorbed onto the nanospheres. Fourier transformed infrared spectroscopy (FT-IR) seemed to confirm the absence of drug incorporation into the core of these carriers and that no chemical interaction between the drug and the polymer occurred. The reduction of the acute toxicity of AmB in healthy mice by association of the antibiotic with nanospheres warrants further investigation of the antifungal activity of these systems.