Nanocápsulas furtivas de óleo de copaíba contendo anfotericina B: um sistema promissor no tratamento de infecções fúngicas sistêmicas

Abstract

Infections caused by Candida spp. have a worldwide incidence and are considered a major challenge for public health due to its high morbidity and mortality. Although amphotericin B is used in the treatment of fungal infections, it has relevant associated toxicity. Based on that, several strategies have been developed to reduce the toxicity and risks caused by this molecule. Currently, nanosystems have assumed prominence especially when associated with natural products of therapeutic relevance among them nanocapsules provide a unique structure with polymeric shell and a core with a potential drug delivery. Thus, the aim of this work was to develop polymeric nanocapsules using ethyl-cyanoacrylate (ECA) as matrix with a stealth shell containing copaiba oil-resin and amphotericin B core as a promising system for the treatment of systemic fungal infections. Then, the copaiba oil-resin was characterized using GCMS and, copalic acid, β-bisabolene, β-caryophyllene and α-bergamothene were identified as major compounds. Subsequently, in silico molecular modeling was carried out to verify a possible antifungal activity from copaiba oil compounds and fungal proteins. A strong interaction between the compounds and the Δ-14-sterol protein site indicating antifungal activity through inhibition of ergosterol synthesis. Two systems were developed: one containing Pluronic® F-68 as a polymeric stabilizer (NF1) and the other containing low molecular weight chitosan (NF2). NF1 had a particle mean size of 255.1 ± 1.1 nm, polydispersity index (PdI) of 0.144 ± 0.020 and zeta potential of - 27.6 ± 0.15 mV. NF2 system had a particle mean size of 342.6 ± 4.5 nm, PdI of 0.162 ± 0.022 and zeta potential of + 20.2 ± 0.68 mV. To optimize the NF2 system, an experimental design approach was carried out using as variables, copaiba oil, ECA and chitosan, then it was possible to analyze the influence of the variables individually and relating them to each other, so the levels corresponding to particle mean size of 239.7 ± 4.4 nm, PdI of 0.160 ± 0.022 and zeta potential of + 43.1 ± 1.62 mV was selected (NFO). Thus, aiming the functionalization of the system, albumin (1 mg/mL) was bound on the surface of NFO system containing encapsulated amphotericin B (NFAMB 0.2) (%EE = 12.57 %) with particle mean size of 142.5 ± 5.0 nm, PdI of 0.198 ± 0.003 and zeta potential of + 23.6 ± 1.51 mV. ITC results confirm the interaction between albumin and the surface of the nanoparticles conducted by enthalpy due to the mechanism of electrostatic attraction and hydrogen bonds. Tests carried out allowed the development of polymeric nanocapsules containing amphotericin B and copaiba oil, which were functionalized with albumin presenting stealth properties as a potential system for the treatment of systemic fungal infections.