356 research outputs found

    Combination of nanomicellar technology and in situ gelling polymer as ocular drug delivery system (Odds) for cyclosporine-a

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    A combination of in situ gelling systems and a loaded drug self-assembling nanomicellar carrier was chosen in this study as a new potential Ocular Drug Delivery System (ODDS) for Cy-closporine-A (CyA), a poorly water-soluble drug. Two non-ionic surfactants (d-α-tocopherol polyethylene glycol succinate, VitE-TPGS and polyoxyl 40 hydrogenated castor oil, RH-40) were used to produce the nanomicelles. The physical–chemical characterization of the nanomicelles in terms of CyA entrapment (EE%) and loading efficiency (LE%), cloud point (CP), regeneration time (RT), size and polydispersity index (PI) allowed us to select the best combination of surfactant mixture, which showed appropriate stability, high CyA-EE (99.07%), very small and homogeneous dimen-sions and favored the solubilization of an amount of CyA (0.144% w/w) comparable to that con-tained in marketed emulsion Ikervis®. The selected nanomicellar formulation incorporated into optimized ion-sensitive polymeric dispersions of gellan gum (GG-LA: 0.10, 0.15 and 0.20% w/w) able to trigger the sol–gel transition after instillation was characterized from technological (osmo-lality, pH, gelling capacity, rheological behavior, wettability, TEM and storage stability at 4 and 20 °C) and biopharmaceutical points of view. This new combined approach allowed us to obtain clear aqueous dispersions that were easy to instill and able to form a viscous gel when in contact with the tear fluid, improving CyA ocular bioavailability. Furthermore, this new ODDS prevented CyA transcorneal permeation, exhibited low cytotoxicity and prolonged the CyA resident time in the precorneal area compared to Ikervis®

    Influence of a Combination of Chemical Enhancers and Iontophoresis on In Vitro Transungual Permeation of Nystatin

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    To promote transungual permeation of nystatin (NYST), molecule with high molecular weight, no water-soluble, amphoteric by iontophoresis. The synergic effect of the combination of cetylpyridinium chloride, CPC, or polyoxyethylene (20) sorbitan monooleate, TW80, and iontophoresis was investigated. In vitro permeation experiments were carried out through bovine hoof slices using vertical diffusion cells. A low current density (0.2 mA/cm2) was applied by introducing Ag/AgCl electrodes in the donor (anode) and receptor (cathode) chambers. The donor phase consisted of a solution, a suspension, or gel-type vehicles containing NYST and surfactants in pH 5.6 HEPES buffer. The addition of CPC to NYST suspension (SOSP) produced a fivefold increase on the permeability of the bovine hoof membrane to the drug. The application of anodal iontophoresis further improved NYST flux. Conversely, NYST transungual permeation was not influenced by TW80 either in the passive diffusion or iontophoretic flux. Furthermore, the iontophoretic treatment does not appear to induce irreversible alterations to the hoof bovine membranes. The present work demonstrated the efficacy of iontophoresis as a treatment for different nail pathologies with large molecules very slightly soluble in water without irreversibly affecting the nail structure. A synergistic effect between CPC and iontophoresis was observed

    Assembling surfactants-mucoadhesive polymer nanomicelles (ASMP-nano) for ocular delivery of cyclosporine-A

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    The physiological protective mechanisms of the eye reduce the bioavailability of topically administered drugs above all for those with high molecular weight and /or lipophilic characteristics, such as Cyclosporine A (CyA). The combined strategy based on the association of nanomicelles and mucoadhesive polymer seems promising since a limited number of commercial products containing CyA have been recently approved. The scope of this investigation was the design of Assembling Surfactants-Mucoadhesive Polymer Nanomicelles (ASMP-Nano), based on a binary system of two surfactants in combination with hyaluronic acid, and their biopharmaceutical evaluation. The optimisation of the ASMP-Nano in term of the amount of surfactants, CyA-loading and size determined the selection of the clear and stable Nano1HAB-CyA formulation containing 0.105% w/w CyA loaded-nanomicelles with a size of 14.41 nm. The nanostructured system had a protective effect towards epithelial corneal cells with a cell viability of more than 80%. It interacted with cellular barriers favouring the uptake and the accumulation of CyA into the cells as evidenced by fluorescent probe distribution, by hindering CyA permeation through reconstituted corneal epithelial tissue. In pharmacokinetics study on rabbits, the nanomicellar carrier prolonged the CyA retention time in the precorneal area mainly in presence of hyaluronic acid (HA), a mucoadhesive polymer

    Design of epidermal growth factor immobilization on 3D biocompatible scaffolds to promote tissue repair and regeneration

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    Exogenous application of human epidermal growth factor (hEGF) stimulates epidermal wound healing. The aim of this study was to develop bioconjugates based on hEGF mimicking the protein in its native state and thus suitable for tissue engineering applications, in particular for treating skin-related disorders as burns. Ribonuclease A (RNase A) was used to investigate a number of different activated-agarose carriers: cyanogen bromide (CNBr)-activated-agarose and glyoxyl-agarose showed to preserve the appropriate orientation of the protein for receptor binding. EGF was immobilized on these carriers and immobilization yield was evaluated (100% and 12%, respectively). A peptide mapping of unbound protein regions was carried out by LC–MS to take evidence of the residues involved in the immobilization and, consequently, the flexibility and surface accessibility of immobilized EGF. To assess cell proliferative activities, 10, 25, 50, and 100 ng/mL of each immobilized EGF sample were seeded on fibroblast cells and incubated for 24, 48 and 72 h. The immobilized growth factor showed significantly high cell proliferative activity at 50 and 100 ng/mL compared to control and soluble EGF. Although both of the immobilized samples show dose-dependency when seeded with high number of fibroblast cells, CNBr-agarose-EGF showed a significantly high activity at 100 ng/mL and 72 h incubation, compared to glyoxyl-agarose-EGF

    Palate perforation differentiates cocaine-induced midline destructive lesions from granulomatosis with polyangiitis

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    L abuso di cocaina può talvolta causare lesioni destruenti della struttura osteocartilaginea del naso, dei seni paranasali, del palato, con caratteristiche cliniche che ricordano altre patologie sistemiche associate a lesioni necrotizzanti centrofacciali. La diagnosi differenziale tra lesioni destruenti della linea mediana indotte da cocaina (CIMDL) e granulomatosi associata a poliangioite (GPA) può essere complessa, in particolare se il paziente non ammette labuso di sostanze. 10 pazienti con CIMDL e perforazione palatale sono stati trattati presso la nostra Unità Operativa tra il 2002 ed il 2015. Tutti i casi sono stati sottoposti ad endoscopia nasale, TC o RMN del massiccio facciale ed Anca test. In 8 casi è stata effettuata anche la biopsia nasale. Contestualmente è stata eseguita una revisione della letteratura presente su PubMed riguardante i casi di perforazione palatale in pazienti affetti da CIMDL e GPA. Tutti i 10 pazienti oggetto dello studio presentavano perforazione palatale e distruzione dei turbinati inferiori; inoltre 7 pazienti presentavano perforazione del palato duro , 2 pazienti perforazione del palato molle ed 1 paziente perforazione di entrambi. Gli Anca test erano negativi in 8 pazienti e positivi in 2, sia per C-Anca sia per P-Anca. La revisione della letteratura edita in lingua inglese ha evidenziato perforazioni palatali in 5 pazienti affetti da GPA e in 73 pazienti affetti da CIMDL. La presenza di perforazione palatale in pazienti con lesioni destruenti della linea mediana può rappresentare un nuovo marker clinico a favore delle CIMDL nella diagnosi differenziale con GPA

    An enzymatic flow-based preparative route to vidarabine

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    The bi-enzymatic synthesis of the antiviral drug vidarabine (arabinosyladenine, ara-A), catalyzed by uridine phosphorylase from Clostridium perfringens (CpUP) and a purine nucleoside phosphorylase fromAeromonas hydrophila (AhPNP), was re-designed under continuous-flow conditions. Glyoxyl-agarose and EziGTM1 (Opal) were used as immobilization carriers for carrying out this preparative biotransformation. Upon setting-up reaction parameters (substrate concentration and molar ratio, temperature, pressure, residence time), 1 g of vidarabine was obtained in 55% isolated yield and >99% purity by simply running the flow reactor for 1 week and then collecting (by filtration) the nucleoside precipitated out of the exiting flow. Taking into account the substrate specificity of CpUP and AhPNP, the results obtained pave the way to the use of the CpUP/AhPNP-based bioreactor for the preparation of other purine nucleosides
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