Publications (7)12.35 Total impact
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Article: PVA/STMP based hydrogels as potential substitutes of human vitreous.
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ABSTRACT: PVA based hydrogels were synthesised using, as crosslinking agent, trisodium trimetaphosphate (STMP) to obtain potential substitutes for the vitreous body of the eye. The hydrogels, obtained using different amounts of STMP, were characterised by Infrared Spectroscopy which confirmed the successful occurrence of crosslinking reaction. The mechanical spectra of the fully hydrated samples confirmed covalently crosslinked systems (i.e. G' > G''). The rheological analysis pointed out that only one of the hydrogels (PVA STMP 8:1) showed a behaviour similar to that of human vitreous. The hydrogel was also subjected to injection through a small needle, a procedure that is essential in the use of vitreous substitutes. Further analysis in terms of light transmittance, water content measurements, diffusion coefficient and cytotoxicity confirmed the applicability of such a hydrogel as vitreous substitute.Journal of Materials Science Materials in Medicine 05/2010; 21(8):2491-500. · 2.32 Impact Factor -
Article: Structure‐property relationships in densely grafted π‐stacked polymers
Journal of Polymer Science Part A Polymer Chemistry 04/2010; 48(11):2446 - 2461. · 3.92 Impact Factor -
Article: Synthesis and Spontaneous Polymerization of Oligo(ethylene glycol)-Conjugated Benzofulvene Macromonomers. A Polymer Brush Forming a Physical Hydrogel
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ABSTRACT: Two methyl end-capped oligo(ethylene glycol) esters (1a,b) of benzofulvene derivative BF1 were synthesized and induced to polymerize spontaneously by solvent removal to give poly-1a,b showing both NMR and absorption/emission spectra very similar to those of poly-BF1. Poly-1a,b showed relatively high molecular weight and the tendency to depolymerize to a different degree as a function of the temperature in the presence of solvents, while they exhibited appreciable stability in the absence of solvent. Poly-1b, bearing a longer oligo(ethylene glycol) side chain, featured an amphiphilic character and interacted with a number of organic solvents to produce transparent gel aggregates, and with water to give a quite compact physical gel. Rheological studies performed on the hydrogel suggested strong gel characteristics and the combination of rheology and NMR transverse relaxation measurements allowed the pore size distribution in the hydrogel to be defined. Finally, biological studies performed with poly-1b solutions showed neither cytotoxicity nor cell viability impairment suggesting potential biocompatibility features for this polymer. In conclusion, poly-1b can be considered a promising polymer for the preparation of hydrogels potentially useful in a range of biological and biotechnological applications such as drug delivery, molecular recognition, biosensing, protein and DNA separation, micro- and nanofluidics, as well as tissue engineering.04/2009; -
Article: Anionic Polymerization of a Benzofulvene Monomer Leading to a Thermoreversible π-Stacked Polymer. Studies in Macromolecular and Aggregate Structure
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ABSTRACT: The polymerization of trans-diene BF1 [ethyl 1-methylene-3-(4-methylphenyl)-1H-indene-2-carboxylate] has been studied in the presence of various amounts of an anionic initiator such as phenyllithium in order to obtain information on the properties of this diene monomer and on its polymers. The anionic polymerization of BF1 produced a mixture of oligomers and a polymer (poly-BF1-AP), the proportion of which is regulated by the amount of the initiator used. Poly-BF1 was separated from lower oligomers on the basis of the solubility in n-hexane, and the soluble material was further fractionated by chromatography to obtain activated monomers and dimers. The structure of dimers and poly-BF1-AP has been investigated by NMR spectroscopy, absorption and emission spectroscopy, and mass spectrometry. The whole set of results is consistent, confirming for poly-BF1 a vinyl (1,2) polymer chaining stabilized by means of aromatic stacking interactions. The thermoreversibility of poly-BF1-AP was characterized by 1H NMR and compared to its DSC features. Remarkably, SEC-MALS analysis showed that the molecular weight of poly-BF1-AP is relatively low (about 10 kg/mol), and SEM studies revealed that the polymer is liable to give nanospheres and microspheres showing favorable shapes and dimensions. These results suggest the potential tuning of the material properties of these π-stacked polymers by means of the regulation of the molecular weight.03/2008; -
Article: Structural Manipulation of Benzofulvene Derivatives Showing Spontaneous Thermoreversible Polymerization. Role of the Substituents in the Modulation of Polymer Properties
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ABSTRACT: The synthesis of a series of benzofulvene derivatives 3 related to the recently studied ethyl 1-methylene-3-(4-methylphenyl)-1H-indene-2-carboxylate (BF1) is described. The properties of these trans-diene derivatives were characterized with regard to their capability of polymerizing spontaneously to give new polymers based on functionalized indene monomeric units. The series of polymers has been investigated by NMR spectroscopy, multiangle light scattering online to size exclusion chromatography, UV−vis spectroscopy, mass spectrometry, differential scanning calorimetry, and scanning electron microscopy. The new polymers show very interesting properties such as a thermoreversible polymerization/depolymerization, a variable degree of π-stacking, a tendency to give nanostructured macromolecular aggregates, and a high solubility in the most common organic solvents. Remarkably, this study demonstrated that most of the polymer properties (e.g. formation, molecular weight, structure, thermoreversibility, and aggregation in nanostructured entities) may be modulated by the stereoelectronic characteristics of the substituents present on the indene moiety.03/2007; -
Article: Physicochemical and biopharmaceutical characterization of endo-2-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-2,3-dihydro-1H-benz[e]isoindol-1-one (CR3124) a novel potent 5-HT3 receptor antagonist.
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ABSTRACT: The physicochemical and biopharmaceutical properties, such as pK(a), crystal habit, water solubility, logD, molecular structure and dynamics, and membrane permeability of CR3124 (endo-2-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-2,3-dihydro-1H-benz[e]isoindol-1-one, a novel potent 5-HT(3) receptor antagonist) have been studied in order to obtain preformulation information. The study showed that CR3124 is a very rigid molecule in which conformational freedom due to the presence of a rotatable bond is restricted by the interaction between an activated hydrogen and the amide oxygen and the conformation of the tropane piperidine ring is regulated by the environment in such a manner as to optimize the intermolecular interactions with the solvent. This chameleon behavior appears to be capable of explaining the biopharmaceutical properties showed by CR3124, such as low wettability, relatively good solubility, and very high membrane permeability.Journal of Pharmaceutical Sciences 01/2007; 95(12):2706-21. · 3.06 Impact Factor -
Article: Physicochemical and biopharmaceutical characterization of endo‐2‐(8‐methyl‐8‐azabicyclo[3.2.1]oct‐3‐yl)‐2,3‐dihydro‐1H‐benz[e]isoindol‐1‐one (CR3124) a novel potent 5‐HT3 receptor antagonist
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ABSTRACT: The physicochemical and biopharmaceutical properties, such as pKa, crystal habit, water solubility, logD, molecular structure and dynamics, and membrane permeability of CR3124 (endo-2-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-2,3-dihydro-1H-benz[e]isoindol-1-one, a novel potent 5-HT3 receptor antagonist) have been studied in order to obtain preformulation information. The study showed that CR3124 is a very rigid molecule in which conformational freedom due to the presence of a rotatable bond is restricted by the interaction between an activated hydrogen and the amide oxygen and the conformation of the tropane piperidine ring is regulated by the environment in such a manner as to optimize the intermolecular interactions with the solvent. This chameleon behavior appears to be capable of explaining the biopharmaceutical properties showed by CR3124, such as low wettability, relatively good solubility, and very high membrane permeability. Copyright © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 95:2706–2721, 2006Journal of Pharmaceutical Sciences 08/2006; 95(12):2706 - 2721. · 3.06 Impact Factor
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Institutions
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2006–2007
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Università degli Studi di Siena
Siena, Tuscany, Italy
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