PLGA nanoparticles as delivery systems for protoporphyrin IX in topical PDT: cutaneous penetration of photosensitizer observed by fluorescence microscopy.

Poly(D,L lactic-co-glycolic acid) (PLGA) based nanoparticles (NPs) are proposed for topical delivery of Protoporphyrin IX (PpIX) in Photodynamic Therapy of skin cancers. PpIX loaded into PLGA NPs showed nanometric average diameter (-280 nm), spherical forms and pH - 5.7, conditions suitable for topical application. In vitro release of PpIX from NPs was sustained up to 24 hr with a burst release effect of about 37.0% at 2 hr. Penetration and distribution of PpIX in hairless mice skin was determined by fluorescence microscopy 8 or 24 hrs after application of PpIX-NPs in the animals. At 24 hours, areas located in deeper regions of the skin were found to have greater fluorescence intensity. The finding indicates a localized effect of PpIX-NPs in the epidermis plus dermis--a site of action for topical PDT--and suggests a potential use of PpIX-NPs in PDT associated to skin cancer treatments.

In vitro evaluation of the antioxidant activity of liposomal flavonols by the HRP-H2O2-luminol system.

Considering that antioxidant flavonols have been reported to be beneficial to human health, but that their low water solubility and bioavailability limit their administration through systemic route, the development of suitable flavonol-carriers is of great importance for clinical therapeutics. The aim of this study was to prepare liposomes containing flavonols or not and evaluate their antioxidant activity. Vesicles were obtained by ethanol injection method and characterized in terms of entrapment efficiency, size and zeta potential. Inhibitory activity of liposomal flavonols on reactive oxygen species generation was assessed in vitro using luminol-H(2)O(2)-horseradish peroxidase technique. Antioxidant activity of liposomal flavonols is dependent on concentration and chemical structure of active compound. Quercetin and myricetin are the most active flavonols (IC(50) = 0.6-0.9 µmol/L), followed by kaempferol (IC(50) = 3.0-4.5 µmol/L) and galangin (IC(50) = 4.0-7.0 µmol/L). Our results suggest that antioxidant-loaded liposomes may be promising tools for therapy of diseases where oxidative stress is involved.

Nanostructured lipid carrier co-delivering tacrolimus and TNF-α siRNA as an innovate approach to psoriasis.

Since psoriasis is an immuno-mediated skin disease, long-term therapies are necessary for its treatment. In clinical investigations, tacrolimus (TAC), a macrolide immunosuppressive inhibitor of calcineurin, arises as an alternative for the treatment of psoriasis, acting in some cytokines involved in the pathogenesis of the disease. Here, we aim to study the psoriasis treatment with TAC and siRNA for one of most cytokines expressed in psoriasis, the TNF-α. A multifunctional nanostructure lipid carrier (NLC) was developed to co-delivery TAC and siRNA. Results showed that the particle size and zeta potential were around 230 nm and + 10 mV, respectively. The release study demonstrated a controlled release of TAC, and the permeation and retention profile in the skin tissue show to be promising for topical application. The cell viability and uptake in murine fibroblast presented low toxicity associated to uptake of NLC in 4 h, and finally, the in vivo animal model demonstrates the efficiency of the NLC multifunctional, exhibiting a reduction of the cytokine TNF-α expression about 7-fold and presenting a synergic effect between the TAC and TNF-α siRNA. The developed system was successfully to treat in vivo psoriatic animal model induced by imiquimod and the synergic combination was reported here for the first time. Graphical abstract.

Liquid crystalline phase nanodispersions enable skin delivery of siRNA.

The ability of small interfering RNAs (siRNAs) to potently but reversibly silence genes in vivo has made them particularly well suited as a new class of drugs that interfere with disease-causing or disease-promoting genes. However, the largest remaining hurdle for the widespread use of this technology in skin is the lack of an effective delivery system. The aim of the present study was to evaluate nanodispersed systems in liquid crystalline phases that deliver siRNA into the skin. The proposed systems present important properties for the delivery of macromolecules in a biological medium, as they are formed by substances that have absorption-enhancing and fusogenic effects; additionally, they facilitate entrapment by cellular membranes due to their nano-scale structure. The cationic polymer polyethylenimine (PEI) or the cationic lipid oleylamine (OAM) were added to monoolein (MO)-based systems in different concentrations, and after dispersion in aqueous medium, liquid crystalline phase nanodispersions were obtained and characterized by their physicochemical properties. Then, in vitro penetration studies using diffusion cell and pig ear skin were carried out to evaluate the effect of the nanodispersions on the skin penetration of siRNA; based on these results, the nanodispersions containing MO/OA/PEI/aqueous phase (8:2:5:85, w/w/w/w) and MO/OA/OAM/aqueous phase (8:2:2:88, w/w/w/w) were selected. These systems were investigated in vivo for skin penetration, skin irritation, and the ability to knockdown glyceraldehyde 3-phosphate dehydrogenase (GAPDH) protein levels in animal models. The results showed that the studied nanodispersions may represent a promising new non-viral vehicle and can be considered highly advantageous in the treatment of skin disorders; they were effective in optimizing the skin penetration of siRNA and reducing the levels of the model protein GAPDH without causing skin irritation.

Verificação da efetividade de esterilização de um equipamento a vapor químico insaturado: estudo-piloto / Verification of the sterilization efectivity of an insatured chemical steam equipment: pilot-study

Este estudo-piloto trata do emprego de um equipamento a vapor químico insaturado para ser usado como método de esterilização. O aparelho é de origem nacional e a solução à base de álcoois. Os resultados iniciais são positivos