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121.
Marco Cespi Luca Casettari Giulia Bonacucina Gianfabio Giorgioni Diego R Perinelli Giovanni Filippo Palmieri 《先进技术聚合物》2013,24(11):1018-1024
This paper deals with a new application of diblock methoxy polyethylene glycol‐polylactide block copolymers, a class of synthetic biomaterials largely studied in the pharmaceutical and biomedical fields owing to their favorable properties such as biocompatibility, biodegradability, low immunogenicity, and good mechanical properties. In this work, these materials were evaluated as additives for gastro‐soluble pharmaceutical coating aimed to reduce film stiffness and water permeability. Two copolymers with different polylactide chain lengths were synthesized and characterized in term of molecular weight and solid‐state properties. A series of free films with different hypromellose/copolymers ratio were prepared and characterized in terms of appearance, components miscibility, plasticity, and water vapor permeability. The obtained results demonstrate that copolymers effectively influence hypromellose film properties according to their concentration and molecular weight. Specifically, the addition of the copolymer with a molecular weight of 6.5 kDa in a ratio hypromellose:polymer 5:1, allowed to obtain films with good appearance, improved plasticization, and water permeability properties. For higher molecular weight, copolymer or different ratios was not possible to observe the improvement of all the properties at the same time. The results also make possible to define the critical features to improve in order to use block copolymers as additive in hypromellose film coating. The availability of new water‐soluble additives able to work as plasticizer and moisture sealer in polymeric films represents an important progress not only in the field of pharmaceutical coating but also in that of food coatings, as for example in the formulation of edible films. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
122.
The amination reactions of chloromethylated polystyrene with N,N-dimethyldodecylamine, N,N-dimethyltetradecylamine, and N,N-dimethylhexadecylamine were studied. The physical properties, particularly the solubility properties of the resulting polymers, are influenced by the hydrophobic properties of the long alkyl chain on the N+ atoms. The main factor that influences the kinetics of the reactions is the polymersolvent interaction parameter. 相似文献
123.
It was established that linear polymers with quaternary ammonium groups are obtained by the reaction of chloromethylated polystyrene (CMPS) with hydroxyalkylic tertiary amines when the amines contain one or two hydroxyl groups, and that crosslinked polymers are obtained with aminoether groups when the amines have three hydroxyl groups, i.e., tris(2-hydroxyethy1)amine. The aminoether units appear by intramolecular rearrangement of quaternary ammonium structural units. Kinetic studies on the synthesis of polymers with quaternary ammonium groups from CMPS, poly(N,N-dimethylamino-ethylmethacrylate), and poly(N,N-dimethylaminopropylacrylamide), were performed. The main factors which influence the kinetics of reactions are steric hindrance of near neighboring groups, hydrophilic effect for hydroxyalkylamines and polymer-solvent interaction. 相似文献
124.
Mauro Formica Luca Giorgi Eleonora Macedi Giovanni Piersanti Maria Antonietta Varrese 《Supramolecular chemistry》2013,25(6):365-379
The synthesis and anion binding studies of the new neutral receptor 1,1′-(2,2′-(4,10-dimethyl-1,4,7,10-tetraazacyclododecane-1,7-diyl)bis(2-oxoethane-2,1-diyl))bis(3-(3,5-bis(trifluoromethyl)phenyl)urea) (L1) are reported. L1 is a macrocyclic ligand containing the 3,5-trifluoromethylphenylureido-binding fragment attached as a side arm on the tetraazacyclododecane. L1 is soluble in numerous organic solvents; the binding properties of L1 towards several simple anions (G) were investigated by NMR, UV–vis and fluorescence techniques in DMSO and CH3CN solutions. L1 is able to bind F? , Cl? and AcO? in both solvents; in addition, it binds Br? in CH3CN. Fluoride shows the highest constant values in the halide series (F? > Cl? > Br? ) and AcO? is the most strongly bound among all the anions investigated. L1 is able to signal the presence of the anions in solution by fluorescence change; in the case of acetate, this occurs in the visible range. 相似文献
125.
126.
Salvatore Sotgia Angelo Zinellu Gianfranco Pintus Gerard Aime Pinna Luca Deiana Ciriaco Carru 《Journal of separation science》2013,36(6):1002-1006
A new hydrophilic interaction ultra‐performance LC method was established for the whole blood measurement of L‐ergothioneine. Chromatographic separation was achieved in a fairly short time, less than 4 min, on a 100 × 2.1 mm Acquity UPLC BEH HILIC 1.7 μm column with a mobile phase consisting of a mixture of 100 mmol/L ammonium acetate/ACN/water (5:85:10, v/v/v) that flowed isocratically at 0.250 mL/min. The LOD and the limit of quantification were 3.85 and 11.67 μmol/L, respectively. The method exhibited linearity in a concentration range of 15.63–1000 μmol/L (R2 > 0.999). Mean recovery was 96.34% whereas intraassay and interassay precision were 1.52 and 1.82% RSD, respectively. On the whole, the developed method is simple, fast, precise, accurate, and sensitive and may be useful for routine analyses. 相似文献
127.
Mariangela Potenza Giuseppina Sabatino Francesca Giambi Luca Rosi Anna Maria Papini Luigi Dei 《Analytical and bioanalytical chemistry》2013,405(2-3):691-701
The chemical analysis of egg-based wall paintings—the mezzo fresco technique—is an interesting topic in the characterisation of organic binders. A revised procedure for a dot-enzyme-linked immunosorbent assay (dot-ELISA) able to detect protein components of egg-based wall paintings is reported. In the new dot-ELISA procedure we succeeded in maximizing the staining colour by adjusting the temperature during the staining reaction. Quantification of the colour intensity by visible reflectance spectroscopy resulted in a straight line plot of protein concentration against reflectance in the wavelength range 380–780 nm. The modified dot-ELISA procedure is proposed as a semi-quantitative analytical method for characterisation of protein binders in egg-based paintings. To evaluate its performance, the method was first applied to standard samples (ovalbumin, whole egg, egg white), then to model specimens, and finally to real samples (Giotto’s wall paintings). Moreover, amino acid analysis performed by innovative ultra-performance liquid chromatography was applied both to standards and to model samples and the results were compared with those from the dot-ELISA tests. In particular, after protein hydrolysis (24 h, 114 °C, 6 mol L?1 HCl) of the samples, amino acid derivatization by use of 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate enabled reproducible analysis of amino acids. This UPLC amino acid analysis was rapid and reproducible and was applied for the first time to egg-based paintings. Because the painting technique involved the use of egg-based tempera on fresh lime-based mortar, the study enabled investigation of the effect of the alkaline environment on egg-protein detection by both methods. Figure
Model wall paintings specimens and typical dot-ELISA stains for egg proteins. 相似文献
128.
Vincenzo Mirabello Maria Caporali Luca Gonsalvi Gabriele Manca Andrea Ienco Maurizio Peruzzini 《化学:亚洲杂志》2013,8(12):3177-3184
The selective functionalization of the polyphosphorus moiety Ph2PCH2PPh2PPPP present as a tetrahapto‐ligand in complex [Ir(dppm)(Ph2PCH2PPh2PPPP)]+ ( 1 , dppm=Ph2PCH2PPh2) was obtained by reaction of 1 with water under basic conditions at room temperature. The formation of the new triphosphaallyl moiety η3‐P3{P(O)H} was determined in solution by NMR spectroscopy, and confirmed in the solid state by a single‐crystal X‐ray structure of the stable product [Ir(κ2‐dppm)(κ1‐dppm)(η3‐P3{P(O)H})] ( 2 ). In solution, 2 has a fluxional behavior attributable to the four P atoms belonging to the tetraphosphorus moiety in 1 and exhibits a chemical exchange process involving the two PPh2 moieties of the same bidentate ligand, as determined by 1D and 2D NMR spectroscopy experiments carried out at variable temperature. The mechanism of the reaction was investigated at the DFT level, which suggested a selective attack of an in‐situ generated OH? anion on one of the non‐coordinated phosphorus atoms of the P4 moiety. The reaction then evolves through an acid‐assisted tautomerization, which leads to the final compound 2 . Bonding analysis pointed out that the new unsubstituted P3‐unit in the η3‐P3{P(O)H} moiety behaves as a triphosphallyl ligand. 相似文献
129.
Luca Nicolotti Chiara CorderoCecilia Cagliero Erica LibertoBarbara Sgorbini Patrizia RubioloCarlo Bicchi 《Analytica chimica acta》2013
The study proposes an investigation strategy that simultaneously provides detailed profiling and quantitative fingerprinting of food volatiles, through a “comprehensive” analytical platform that includes sample preparation by Headspace Solid Phase Microextraction (HS-SPME), separation by two-dimensional comprehensive gas chromatography coupled with mass spectrometry detection (GC × GC–MS) and data processing using advanced fingerprinting approaches. 相似文献
130.
Sabina Strano-Rossi Erika Castrignanò Luca Anzillotti Sara Odoardi Fabio De-Giorgio Ana Bermejo Vincenzo L. Pascali 《Analytica chimica acta》2013
A method for the screening of various anabolic steroids and their esters in human hair, based on liquid-chromatography–high resolution mass spectrometry using an Exactive benchtop Orbitrap mass spectrometer, has been set up and validated. This method involved methanolic incubation of 30 mg of hair and analysis of the relevant extract in HPLC using a C18 column. The mass detector, with nominal resolving power of 100,000, operated in full scan mode in APCI under positive ionization mode. Analytes were identified by exact mass, correspondence of isotopic cluster and retention times. 相似文献