Chitosan functionalized poly (ε-caprolactone) nanoparticles for amphotericin B delivery

Amphotericin B (AmB) is a broad-spectrum antifungal drug used in the treatment of fungal invasive infections. However, its clinical use has been limited due to its side effects and toxicity, especially the nephrotoxicity. Furthermore, AmB presents low aqueous solubility, low permeability over the membranes and poor stability in the gastric environment, which makes it unavailable to be administered by the oral route. In this study, chitosan-coated poly (epsilon-caprolactone) nanoparticles were developed to provide the oral delivery of AmB and reduce its toxicity. Nanoparticles were obtained by nanoprecipitation and parameters as particle size, polydispersity index (PDI), zeta potential, morphology, in vitro AmB release (in physiological pH and simulated gastrointestinal fluids), state of molecular aggregation, cytotoxicity over erythrocytes and Vero cells line and in vitro antifungal activity were fully investigated. Nanoparticles presented mean size of 318 +/- 35 nm, PDI of 0.24 +/- 0.02, zeta potential of +36.2 +/- 1.8 mV due to chitosan-coating, and 69% of AmB encapsulation. The kinetic release profile of AmB from nanoparticles was of second order and diffusion-governed in pH 7.4. The release in the gastrointestinal simulated fluids showed that the chitosan-coated PCL nanoparticles presented good stability during the time evaluated. AmB was released from nanoparticles in a state of low molecular aggregation. Cytotoxicity over erythrocytes and Vero cells line revealed that nanoencapsulation significantly reduced the AmB-related cytotoxicity (p < 0.05) compared to the free drug. In the antifungal activity against Candida parapsilosis strain, the MIC of AmB-loaded nanoparticles was 5-fold higher than free AmB, but the strain was susceptible to nanostructured AmB. Chitosan-functionalized PCL are potential carriers for the oral AmB delivery, reducing its cytotoxicity and maintaining its activity.