Antiaging effects of a skin care formulation containing nanoencapsulated antioxidants: A clinical, in vitro, and ex vivo study.

BACKGROUND: The development of effective cosmetic products for the reduction of the signs of skin aging is a complex process which requires an optimized combination of ingredients and specialized systems to deliver the actives to the skin layers. AIM: To evaluate the tolerance and antiaging clinical efficacy of a cosmetic formulation containing a blend of nanoencapsulated antioxidants: ascorbyl palmitate, resveratrol, tocopherol, caffeine, carnosine, and niacinamide. METHODS: Clinical efficacy was determined by subjective and instrumental analyses of collagen synthesis by fluorescence spectroscopy, by three-dimensional imaging analysis of suborbital edema, and by analysis of skin hydration and sebum content by biophysical techniques-Corneometer® and Sebumeter®. RESULTS: The studied formulation was safe and effective for the improvement of skin appearance by increasing collagen synthesis and skin moisturizing and by reducing facial blemishes, swelling, and oiliness. A preclinical exploratory approach using an experimental model of human cell and skin cultures agreed with the observed antiaging effects, identifying mechanisms related to the containment of oxidative stress, reduction of melanin production, increased synthesis of type I procollagen, and regulation of the epidermal cohesion protein filaggrin. CONCLUSIONS: The skin benefits obtained resulted from the combination of the ingredients in the formulation and the nanoencapsulation-based delivery system, which favors the solubility, safety, efficacy, and bioavailability of the preparation to the skin.

In vitro cytotoxicity of co-exposure to superparamagnetic iron oxide and solid lipid nanoparticles.

Increased production and use of different types of nanoparticles (NPs) in the last decades has led to increased environmental release of these NPs with potential detrimental effects on both the environment and public health. Information is scarce in the literature on the cytotoxic effect of co-exposure to many NPs as this concern is relatively recent. Thus, in this study, we hypothesized scenarios of cell's co-exposure to two kinds of NPs, solid lipid nanoparticles (SLNs) and superparamagnetic iron oxide nanoparticles (SPIONs), to assess the potential cytotoxicity of exposure to NPs combination. Cytotoxicity of SPIONs, SLNs, and their 1:1 mixture (MIX) in six tumor and six non-tumor cell lines was investigated. The mechanisms underlining the induced cytotoxicity were studied through cell cycle analysis, detection of reactive oxygen species (ROS), and alterations in mitochondrial membrane potential (ΔΨM). Double staining with acridine orange and ethidium bromide was also used to confirm cell morphology alterations. The results showed that SPIONs induced low cytotoxicity compared to SLNs. However, the mixture of SPIONs and SLNs showed synergistic, antagonistic, and additive effects based on distinct tests such as viability assay, ROS generation, ΔΨM, and DNA damage, depending on the cell line. Apoptosis triggered by ROS and disturbances in ΔΨM are the most probable related mechanisms of action. As was postulated, there is possible cytotoxic interaction between the two kinds of NPs.

In vitro and in vivo effects of free and chalcones-loaded nanoemulsions: insights and challenges in targeted cancer chemotherapies.

Several obstacles are encountered in conventional chemotherapy, such as drug toxicity and poor stability. Nanotechnology is envisioned as a strategy to overcome these effects and to improve anticancer therapy. Nanoemulsions comprise submicron emulsions composed of biocompatible lipids, and present a large surface area revealing interesting physical properties. Chalcones are flavonoid precursors, and have been studied as cytotoxic drugs for leukemia cells that induce cell death by different apoptosis pathways. In this study, we encapsulated chalcones in a nanoemulsion and compared their effect with the respective free compounds in leukemia and in non-tumoral cell lines, as well as in an in vivo model. Free and loaded-nanoemulsion chalcones induced a similar anti-leukemic effect. Free chalcones induced higher toxicity in VERO cells than chalcones-loaded nanoemulsions. Similar results were observed in vivo. Free chalcones induced a reduction in weight gain and liver injuries, evidenced by oxidative stress, as well as an inflammatory response. Considering the high toxicity and the side effects induced generally by all cancer chemotherapies, nanotechnology provides some options for improving patients' life quality and/or increasing survival rates.

Influence of surfactant and lipid type on the physicochemical properties and biocompatibility of solid lipid nanoparticles.

Nine types of solid lipid nanoparticle (SLN) formulations were produced using tripalmitin (TPM), glyceryl monostearate (GM) or stearic acid (SA), stabilized with lecithin S75 and polysorbate 80. Formulations were prepared presenting PI values within 0.25 to 0.30, and the physicochemical properties, stability upon storage and biocompatibility were evaluated. The average particle size ranged from 116 to 306 nm, with a negative surface charge around -11 mV. SLN presented good stability up to 60 days. The SLN manufactured using SA could not be measured by DLS due to the reflective feature of this formulation. However, TEM images revealed that SA nanoparticles presented square/rod shapes with an approximate size of 100 nm. Regarding biocompatibility aspects, SA nanoparticles showed toxicity in fibroblasts, causing cell death, and produced high hemolytic rates, indicating toxicity to red blood cells. This finding might be related to lipid type, as well as, the shape of the nanoparticles. No morphological alterations and hemolytic effects were observed in cells incubated with SLN containing TPM and GM. The SLN containing TPM and GM showed long-term stability, suggesting good shelf-life. The results indicate high toxicity of SLN prepared with SA, and strongly suggest that the components of the formulation should be analyzed in combination rather than separately to avoid misinterpretation of the results.

Hypericin encapsulated in solid lipid nanoparticles: phototoxicity and photodynamic efficiency.

The hydrophobicity of some photosensitizers can induce aggregation in biological systems, which consequently reduces photodynamic activity. The conjugation of photosensitizers with nanocarrier systems can potentially be used to overcome this problem. The objective of this study was to prepare and characterise hypericin-loaded solid lipid nanoparticles (Hy-SLN) for use in photodynamic therapy (PDT). SLN were prepared using the ultrasonication technique, and their physicochemical properties were characterised. The mean particle size was found to be 153 nm, with a low polydispersity index of 0.28. One of the major advantages of the SLN formulation is its high entrapment efficiency (EE%). Hy-SLN showed greater than 80% EE and a drug loading capacity of 5.22% (w/w). To determine the photodynamic efficiency of Hy before and after encapsulation in SLN, the rate constants for the photodecomposition of two (1)O2 trapping reagents, DPBF and AU, were determined. These rate constants exhibited an increase of 60% and 50% for each method, respectively, which is most likely due to an increase in the lifetime of the triplet state caused by the increase in solubility. Hy-SLN presented a 30% increase in cell uptake and a correlated improvement of 26% in cytotoxicity. Thus, all these advantages suggest that Hy-loaded SLN has potential for use in PDT.