publicado na web em 07/06/2018 Natural naphthoquinones such as lapachol (Lp) have demonstrated promising biological activities. However, these quinones present low systemic biodisponibility due to its poor aqueous solubility. To overcome this problem, nanoemulsions (NE) formed by oily core are able to incorporate hydrophobic molecules thus enabling them to be dispersed into an aqueous phase. The present study reports the development, characterization, and physical stability of NE containing lapachol. NE formulations (F1, F2, F3, F4, and F2-Lp) were prepared using emulsion phase inversion (EPI) method and characterized in relation to droplet size, size distribution (PDI), zeta potential, and physical stability. The formulation chosen to incorporate lapachol (F2-Lp) showed droplet size in nanometric scale with homogeneous size distribution (PDI < 0.2) and negative zeta potential (about −30 mV). In addition, good physical stability of F2 and F2-Lp was demonstrated using analytical centrifugation with photometric detection where the light transmission profiles did not change throughout the dispersions. Nanoemulsion containing lapachol presented a strong reddish aspect; however, the incorporation of this naphthoquinone did not alter the main physicochemical parameters of NE formulation. The in vitro release study demonstrated a sustained release profile from NE with about 60% of lapachol released within 54 h.

Hesperetin is a flavanone with recognized biological activities. However, such activities are limited due to its restricted aqueous solubility and stability. In this regard, the main aim of this study was to develop and characterize lipid nanocarriers containing hesperetin.Nanostructured lipid carriers (NLC) were prepared using phase inversion temperature method and characterized by size, polydispersity index (PdI), zeta potential, physical stability, TEM analysis, encapsulation efficiency, in vitro release, and in vitro cytotoxic effect in cell line. Lipid nanocarriers presented diameter below 80 nm, narrow PdI (< 0.2), and negative zeta potential (-20 mV). Accelerated stability studies of NLC demonstrated good physical stability for a period of 12 months. According to TEM, NLC were almost spherical with particle size < 100 nm and homogeneous size distribution. DSC curves showed that formulations presented lipid core with a higher degree of crystalline disorder.Lipid nanocarriers were able to entrap hesperitin with efficiency 72.7 % (±0.92). In vitro release studies confirmed that NLC could modulate hesperetin release during 72 h. In vitro cytotoxicity assay of hesperitin-loaded NLC on T98G glioblastoma grade IV cells presented significant cytotoxic effect. Therefore, NLC were able to encapsulate successfully hesperetin and demonstrated excellent in vitro cytotoxicity on glioblastoma cells.