José Orestes Del Ciampo

Quercetin in w/o microemulsion: In vitro and in vivo skin penetration and efficacy against UVB-induced skin damages evaluated in vivo

The present study evaluated the potential of a w/o microemulsion as a topical carrier system for delivery of the antioxidant quercetin. Topical and transdermal delivery of quercetin were evaluated in vitro using porcine ear skin mounted on a Franz diffusion cell and in vivo on hairless-skin mice. Skin irritation by topical application of the microemulsion containing quercetin, and the protective effect of the formulation on UVB-induced decrease of endogenous reduced glutathione levels and increase of cutaneous proteinase secretion/activity were also investigated. The w/o microemulsion increased the penetration of quercetin into the stratum corneum and epidermis plus dermis at 3, 6, 9 and 12h post-application in vitro and in vivo at 6h post-application. No transdermal delivery of quercetin occurred. By evaluating established endpoints of skin irritation (erythema formation, epidermis thickening and infiltration of inflammatory cells), the study demonstrated that the daily application of the w/o microemulsion for up to 2 days did not cause skin irritation. W/o microemulsion containing quercetin significantly prevented the UVB irradiation-induced GSH depletion and secretion/activity of metalloproteinases.

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.

Metronidazole-containing gel for the treatment of periodontitis: an in vivo evaluation

The aim of this investigation was to monitor metronidazole concentrations in the gingival crevicular fluid (GCF) collected from periodontal pockets of dogs after treatment with an experimental 15% metronidazole gel. Five dogs had periodontitis induced by cotton ligatures placed subgingivally and maintained for a 30-day period. After the induction period, only pockets with 4 mm or deeper received the gel. Each pocket was filled up to the gingival margin by means of a syringe with a blunt-end needle. GCF was collected in paper strips and quantified in an electronic device before and after 15 minutes, 1 h, 6 h, 24 h and 48 h of gel administration. The GCF samples were assayed for metronidazole content by means of a high performance liquid chromatography method. Concentrations of metronidazole in the GCF of the 5 dogs (mean +/- SD, in microg/mL) were 0 +/- 0 before gel application and 47,185.75 +/- 24,874.35 after 15 minutes, 26,457.34 +/- 25,516.91 after 1 h, 24.18 +/- 23.11 after 6 h, 3.78 +/- 3.45 after 24 h and 3.34 +/- 5.54 after 48 h. A single administration of the 15% metronidazole gel released the drug in the GCF of dogs in levels several-fold higher than the minimum inhibitory concentration for some periodontopathogens grown in subgingival biofilms for up to one hour, but metronidazole could be detected in the GCF at least 48 hours after the gel application.

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–H2O2–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 (IC50 = 0.6–0.9 µmol/L), followed by kaempferol (IC50 = 3.0–4.5 µmol/L) and galangin (IC50 = 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.

Optimization of protoporphyrin IX skin delivery for topical photodynamic therapy: Nanodispersions of liquid-crystalline phase as nanocarriers.

Nanodispersions of liquid-crystalline phases (NLPs) composed of monoolein and oleic acid were chosen as nanocarriers to improve the topical retention of the photosensitizer protoporphyrin IX (PpIX) and thereby optimize photodynamic therapy (PDT) using this photosensitizer. The nanodispersions were characterized by polarized light microscopy, small-angle X-ray diffraction and dynamic light scattering. The stability and encapsulation efficiency (EE%) of the nanodispersions were also evaluated. In vitro and in vivo skin penetration studies were performed to determine the potential of the nanodispersions for cutaneous application. In addition, skin penetration and skin irritancy (in an animal model) after in vivo application were visualized by fluorescence light microscopy. The nanodispersion obtained was characterized as a monodisperse system (~150.0 nm) of hexagonal liquid-crystalline phase, which provided a high encapsulation efficiency of PpIX (~88%) that remained stable over 90 days of investigation. Skin penetration studies demonstrated that the nanodispersion enhanced PpIX skin uptake 11.8- and 3.3-fold (in vitro) and 23.6- and 20.8-fold (in vivo) compared to the PpIX skin uptake of control formulations, respectively. In addition, the hexagonal phase nanodispersion did not cause skin irritation after application for two consecutive days. Overall, the results show that the nanocarrier developed is suitable for use in topical PDT with PpIX.

Evaluation of some biological aspects of the presence of abrasive silica and thickening silica in basic formulations of dentifrices

El objetivo del estudio fue evaluar algunas caracteristicas biologicas y de toxicidad provenientes de las formulaciones basicas de dentifricos que contienen silice en su composicion y compararlos con dos dentifricos disponibles comercialmente que tambien presentan silice. El analisis hematologico no mostro diferencias entre los grupos evaluados. Los niveles de trombocitos presentados por los grupos fueron tambien normales. La transaminasa gluamico pirubica se mostro un aspecto normal en 5 de los grupos estudiados, asi como en el grupo control. La transaminasa glutamico oxaloacetica en uno de los grupos tuvo un pequeno incremento. En relacion a la orina, 4 grupos presentaron leucocitosis urinaria significativamente mayor que el grupo de control. La evaluacion histologica del higado, estomago, rinones y glandulas submandibulares se presento con aspecto normal, sin presencia de infiltrado inflamatorio.

The Therapeutic Use of Propolis Extract in Alveolar Bone Contaminated with Bacterial Endotoxin

Propolis is a resinous substance obtained by bees, whose antibacterial, anti-inflammatory, antiviral, antifungal, immune stimulant, and local anesthetic wound healing properties have been considered for clinical practice. In particular, its anti-inflammatory and antibacterial characteristic seems to be a novel target for infectious process from dental origin. This work aimed to evaluate the propolis antibacterial potential against a bacterial endotoxin on dental alveoli. First, some properties of green propolis extract were analyzed (in vitro): 1) physicochemical profile 2) Minimum Inhibitory Concentration (MIC) against endotoxin from Gram negative Escherichia coli, and 3) its immunoregulatory activity on leukocytes from the spleen of rats. Then, an inflammatory process was induced in rats by a contamination with lipopolysaccharide (LPS) that is recognized as an endotoxin. For this purpose, rats were subjected to extractions of maxillary first molars, right and left, which immediately had the right dental socket contaminated with 0.1L of LPS (100 μg/kg). After 14 days from exodontia, these individuals were divided in groups treated with Pure Propolis Extract (EPP) and groups without therapy. The contaminated alveolar bone or the same area from animals without inflammation-induced were removed for histological and immunohistochemical processing. Our data reveal an important therapeutic action from green propolis. In vitro tests indicated low cytotoxicity for this compound. By a hematoxilin and eosin analysis, the group infected and treated with propolis presented the alveoli with more new bone tissue, characterized by bony trabeculae circling small cavities filled by a loose connective tissue containing blood vessels. Additionally, a histochemical marker of osteoclasts, tartrateresistant acid phosphatase (TRAP), was used to determine the new bone formation rate. The propolis induced more TRAP formation on alveolar bone infected by LPS. Our findings highlight the potential of propolis to be applied in dental material.