Ora in mostra 1 - 10 di 4358
  • Pubblicazione
    Chemical, biological and antitumor properties of ruthenium-dimethylsulfoxide complexes
    (Springer-Verlag, 1989)
    G. MESTRONI
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    M. CALLIGARIS
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    W. M. ATTIA
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    F. QUADRIFOGLIO
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    S. CAUCI
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    SAVA, GIANNI
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    ZORZET, SONIA
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    C. MONTI BRAGADIN
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    M. TAMARO
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    DOLZANI, LUCILLA
      1
  • Pubblicazione
    Synthesis of a new mPEG‑Dexamethasone Conjugate and preliminary bioavailability studies in rabbits
    ( 2008)
    ZACCHIGNA, MARINA
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    G. DI LUCA
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    ; ;
    S. DRIOLI
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    BONORA, GIAN MARIA
    Poly(ethylene glycol) esters have been proposed as a potential oral-controlled drug delivery system for dexamethasone (DXM). The drug was covalently attached to monomethoxypolyethylene glycol amine (mPEG-NH2) (Mw = 10,000 Da) using a succinate linker. A new PEG-based prodrug system was designed using ester derivatives. The drug-polymer conjugate (mPEG-DXM) was freely water soluble at room temperature. First of all, the adduct hydrolytic stability was assessed at physiological pH. Then, the bioavailability was evaluated by orally administering the mPEG-DXM conjugate in rabbits and comparing to that obtained by the intravenous route. The area under the concentration-time curve (AUC) of PEGylated drug was twice as large as that of the parent drug after oral administration. In conclusion, PEGylated DXM was useful for maintaining the DXM concentration in the blood after oral administration.
    WOS© Citazioni 6
  • Pubblicazione
    Influence of the microwave technology on the physical-chemical properties of solid dispersion with Nimesulide
    ( 2009) ; ;
    DE ZORDI, NICOLA
    This work describes a new approach to prepare solvent-free solid dispersions (SDs) for Nimesulide (NMS), involving the use of microwaves irradiation (MW). In particular, the microwave technology has been considered in order to prepare an enhanced release dosage form for the poorly soluble drug Nimesulide (NMS), employing Gelucire® 50/13 and Poloxamer 188 (Lutrol® F 68) as surfactant carriers. Their physicochemical characteristics and dissolution properties were compared to the corresponding physical mixtures and the drug alone. The results attested a correspondence of the solid state of the drug before and after the irradiation treatment and that an amorphisation form of the drug in SD systems was obtained. After six months this data was confirmed.
    Scopus© Citazioni 40WOS© Citazioni 36
  • Pubblicazione
    Synthesis, characterization and properties of water-soluble gold nanoparticles with tunable core size
    ( 2003) ;
    Polizzi S.
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    Battagliarin M.
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    Scrimin P.
    Robust, water-soluble gold clusters protected by monolayers of ligands containing a short alkyl chain (C7) close to the gold surface and a triethylene glycol monomethylether unit (TEG) to impart solubility in water and other polar solvents were prepared and characterized. Thiol 7 (N1-{2-[2-(2-methoxyethoxy)ethoxy]ethyl}-8- sulfanyloctanamide) constitutes a good and versatile capping agent for the preparation of these nanoparticles. By tuning the Au/thiol ratio and sodium borohydride addition rate, nanoparticles with different core diameters ranging from 1.5 to 4.2 nm, as determined by TEM analysis, could be obtained. The size distribution of the gold cores appears to become broader as the Au/thiol ratio used to prepare the nanoparticles increases. Characterization of these nanoclusters also by NMR, UV-Vis and FTIR spectroscopies is reported. Solubility properties have been studied in a large variety of solvents and different solubility behaviors were observed for nanoparticles of different sizes. Exchange reactions were carried out successfully with small (1.9 nm) and large nanoparticles (4.2 nm) using dodecanethiol as the entering thiol. This demonstrates that these materials can be used for the preparation of nanoclusters with different functional groups soluble in polar solvents including water. The synthetic procedure described represents a facile route to tailoring the size and solubility properties of Au nanoparticles.
    WOS© Citazioni 71
  • Pubblicazione
      3
  • Pubblicazione
    EPR Study of Dialkhyl Nitroxides as Probes to Investigate the Exchange of Solutes between the Ligand Shell of Monolayers Protected Gold Nanoparticles and Aqueous Solutions
    ( 2004)
    Lucarini M.
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    Franchi P.
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    Pedulli G. F.
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    Scrimin P.
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    EPR spectroscopy has been used to study the interaction of para-substituted benzyl hydroxyalkyl nitroxides with the monolayer of water-soluble protected gold cluster made by a short alkyl chain and a triethylene glycol monomethyl ether unit. The inclusion of nitroxide probes in the more hydrophobic environment of the monolayer gave rise to a reduction of the value of both nitrogen and beta-proton hyperfine splittings. The spectra also showed selective line broadening attributed to modulation of the spectroscopic parameters as the result of exchange between free and complexed nitroxide. The rate constants were obtained by analyzing the EPR line shape variations as functions of nanoparticle concentration and temperature. This represents, to the best of our knowledge, the first determination of rate constants for the solubilization of organic substrates in a monolayer-protected cluster.
    Scopus© Citazioni 66WOS© Citazioni 60
  • Pubblicazione
    Effect of core size on the partition of organic solutes in the monolayer of water-soluble nanoparticles: an ESR investigation
    ( 2005)
    Lucarini M.
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    Franchi P.
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    Pedulli G. F.
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    GENTILINI, CRISTINA
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    Polizzi S.
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    Scrimin P.
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    ESR spectroscopy has been used to study the interaction of para-pentylbenzyl hydroxyalkyl nitroxide with the monolayer of water-soluble protected gold clusters having a core diameter ranging from 1.6 to 5.3 nm. The solubilization of the nitroxide probe in the more hydrophobic environment of the monolayer strongly depends on the size of the gold core. In particular, the partition equilibrium constant increases as the nanoparticle diameter decreases. These results have been attributed to the different packing of the chains in the monolayer resulting from the different radius of curvature of the investigated nanoparticles. This represents, to the best of our knowledge, the first report demonstrating that the core size of metallic nanoparticles affects the solvating properties of the protective organic monolayer.
    Scopus© Citazioni 75WOS© Citazioni 71
  • Pubblicazione
    Pharmaceutical and Nutraceutical Applications of Supercritical Carbon Dioxide
    (Nova Science Publisher, 2014)
    DE ZORDI, NICOLA
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    KIKIC, IRENEO
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    SOLINAS, DARIO
    The main objective of this chapter is to review and highlight the main applications of Supercritical Carbon Dioxide (SCO2) techniques in several fields such as food science, pharmaceuticals, chemical residues, biofuel, and polymers. In particular supercritical processes such as particle design, impregnation and extraction processes will be investigated. Supercritical Fluid Particle Design (SCFPD), through different processes, allows to increase the solubility and dissolution rate of poorly water-soluble drugs and to improve the molecular properties of Active Pharmaceutical Ingredients (API) and Drug Delivery System (DDS). The chapter will be focused on the most recent developments of these processes covering the fundamental concept of SCO2 and the principle of SCFPD processes that are typically used to control both particle size and polymorphic form of the treated substances. Extraction with supercritical fluids arises in the last three decades as a promising alternative to conventional analytical methods for lipid extraction, and currently has consolidated its application in extraction processes of raw materials of plant and animal origin. Its advantages, over conventional techniques, are many and well known, but this technology stands out mainly by environmental factors and products quality. The aspects related to the use of SCO2 for extraction and fractionation of lipids, with special emphasis in triglycerols and fatty acids (in particular Polyunsaturated Fatty Acids –PUFA) will be investigated. A brief overview on the separation procedures involving supercritical technology, as supercritical fluid chromatography, will be also presented.
  • Pubblicazione
    Microwave generated solid dispersions containing ibuprofen
    ( 2008) ;
    BELLICH, BARBARA
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    BAXA, PIETRO
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    The purpose of this study was to apply the attractive technique of the microwaves irradiation (MW) for the preparation of solvent-free solid dispersions (SD). In particular, the microwave technology has been considered in order to prepare an enhanced release dosage form for the poorly soluble drug Ibuprofen (IBU), employing PVP/VA 60/40 (PVP/VA 64) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) as hydrophilic carriers. Their physico-chemical characteristics and dissolution properties were compared to the corresponding physical mixtures and the drug alone. The results of physico-chemical characterization attested a correspondence of the solid state of the drug before and after irradiation treatment and that an amorphous form of the drug was obtained. This result, together with the presence of the hydrophilic polymers determined a remarkable enhancement of the in vitro dissolution rate of the drug suggesting that the microwave technique could be considered as a new and interesting method to prepare drug–polymer systems.
  • Pubblicazione
    Preparation of Theophylline-Hydroxypropylmethylcellulose matrices using Supercritical Antisolvent Precipitation : a preliminary study.
    Several controlled release systems of drugs have been elaborated using a supercritical fluid process. Indeed, recent techniques using a supercritical fluid as a solvent or as an antisolvent are considered to be useful alternatives to produce fine powders. In this preliminary study, the effect of Supercritical Anti Solvent process (SAS) on the release of theophylline from matrices manufactured with hydroxypropylmethylcellulose (HPMC) was investigated. Two grades of HPMC (HPMC E5 and K100) as carriers were considered in order to prepare a sustained delivery system for theophylline which was used as a model drug. The characterization of the drug before and after SAS treatment, and the coprecipitates with carriers, was performed by X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). The dissolution rate of theophylline, theophylline-coprecipitates, and matricial tablets prepared with coprecipitates were determined. The physical characterizations revealed a substantial correspondence of the drug solid state before and after supercritical fluid treatment while drug-polymer interactions in the SAS-coprecipitates were attested. The dissolution studies of the matrices prepared compressing the coprecipitated systems showed that the matrices based on HPMC K100 were able to promote a sustained release of the drug. Further, this advantageous dissolution performance was found to be substantially independent of the pH of the medium. The comparison with the matrices prepared with untreated substances demonstrated that matrices obtained with SAS technique can provide a slower theophylline release rate. A new mathematical model describing the in vitro dissolution kinetics was proposed and successfully tested on these systems.
    WOS© Citazioni 11