RESUMO
Viscum album L., popularly known as mistletoe, is well known for its anti-cancer properties, and the pharmaceutical application of hydroalcoholic dry extracts is still limited due to its low solubility in aqueous media, and physicochemical instability. The Pluronic® F127 is an amphiphilic polymer, which permits the solubilization of lipophilic and hydrophilic compounds. In this investigation, physicochemical features of hydrogel containing V. album dry extract (VADE-loaded-hydrogel) were performed by: dynamic light scattering (DLS), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM). VADE-loaded-hydrogel presented nanometer-size micelles with volume distribution ranging from 10.58 nm to 246.7 nm, and a polydispersity index of 0.441. The sample thermal analyses (TG and DSC) showed similar decomposition curves; however, the thermal events indicated an increase in thermal stability in relation to the presence of the extract. In addition to these interesting pharmaceutical features, IC50 values of 333.40 µg/mL and >1000 µg/mL were obtained when tumor (SCC-25) and non-tumor (L929) cells were incubated with VADE-loaded-hydrogel, respectively. The optical and ultrastructural cellular analysis confirmed the tumor selectivity since the following alterations were detected only in SCC-25 cells: disorganization of plasmatic membrane; an increase of cytoplasmatic vacuole size; alteration in the cristae mitochondrial shape; and generation of amorphous cellular material. These results emphasize the promising antitumoral potential of VADE-loaded-hydrogel as an herbal drug delivery system via in vitro assays.
RESUMO
Consumer demand for cosmetics is growing, causing a need to develop new systems to release active ingredients. Among these, nanostructured lipid carriers (NLCs) have certain advantages regarding penetration of active compounds in the skin. The study reported here aimed to develop an NLC system for controlled release of vitamin E, a substance that has antioxidant and photoprotective properties. The NLCs containing vitamin E (NLC-VE) were prepared by the melting-emulsionsolidification method, using beeswax as the solid lipid, medium-chain triglycerides (MCTs), coconut oil or avocado oil as liquid lipids and three different nonionic surfactants. The composition of the system was defined by studying the effect of various experimental factors on the size distribution, average diameter and physical stability of the nanoparticles. The optimization of these characteristics, achieved by a Box-Behnken statistical design, showed that 8% w/w of the nonionic surfactant Tween 80, 24% ultrasound amplitude and processing time of 2 minutes and 16 seconds generated nanoparticles with homogeneous size (PDI = 0.11±0.02), average diameter of 180±20 nm and physical stability of 12 weeks. The NLC-VE systems prepared under the optimal conditions, containing Tween 80, beeswax and MCTs, were formulated as viscous suspensions by adding Pluronic F-127, a poly(ethylene oxide)-poly(propylene oxide) block copolymer, at a concentration of 10% w/w. The colloidal nanosuspension obtained had a viscosity of 222 mPa·s and released 70% of the active substance in 6 hours, indicating it is a promising candidate for controlled release of vitamin E.
