- Synthesis and characterization of new malolactonate polymers and copolymers for biomedical applications
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A new class of malolactonate polymers and copolymers were synthesized, starting from the corresponding lactones, and then characterized. Different lateral groups were selected for these polyesters to achieve a wide range of materials characteristics and possible biological recognition. The monomers were prepared according to two established procedures, which gave rather good overall yields. The polymers were obtained by the anionic ring-opening polymerization of the corresponding four-member ring monomers in the presence of a quaternary ammonium salt as the initiator. Final macromolecular and thermal characteristics were in agreement with the designed monomer structures. Molecular weights in the range 4-20 kDa were obtained, as a result of chain transfer reactions. The prepared polyesters displayed stability up to 200°C, and, when tested in preliminary cell culture experiments, provided indications for future applications in the biomedical field.
- Bizzarri, Ranieri,Chiellini, Federica,Solaro, Roberto,Chiellini, Emo,Cammas-Marion, Sandrine,Guerin, Philippe
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- Nanoprecipitation of biocompatible poly(Malic acid) derivative, its ability to encapsulate a molecular photothermal agent and photothermal properties of the resulting nanoparticles
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Biocompatible nanoparticles (NPs) of hydrophobic poly(benzyl malate) (PMLABe) were prepared by nanoprecipitation. The influence of nanoprecipitation parameters (initial PMLABe, addition rate, organic solvent/water ratio and stirring speed) were studied to optimize the resulting formulations in terms of hydrodynamic diameter (Dh) and dispersity (PDI). PMLABe NPs with a Dh of 160 nm and a PDI of 0.11 were isolated using the optimized nanoprecipitation conditions. A hydrophobic near infra-red (NIR) photothermally active nickel-bis(dithiolene) complex (Ni8C12) was then encapsulated into PMLABe NPs using the optimized nanoprecipitation conditions. The size and encapsulation efficiency of the NPs were measured, revealing that up to 50 weight percent (wt%) of Ni8C12 complex can efficiently be encapsulated with a slight increase in Dh of the corresponding Ni8C12-loaded NPs. Moreover, we have shown that NP encapsulating Ni8C12 were stable under storage conditions (4?C) for at least 10 days. Finally, the photothermal properties of Ni8C12-loaded NPs were evaluated and a high photothermal efficiency (62.7 ± 6.0%) waswas measured with NPs incorporating 10 wt% of the Ni8C12 complex.
- Bellec, Nathalie,Camerel, Franck,Cammas-Marion, Sandrine,Pluta, Jean-Baptiste,Vargas Guerrero, Marian Gabriela
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- Tumor-targeting, pH-responsive, and stable unimolecular micelles as drug nanocarriers for targeted cancer therapy
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A new type of multifunctional unimolecular micelle drug nanocarrier based on amphiphilic hyperbranched block copolymer for targeted cancer therapy was developed. The core of the unimolecular micelle was a hyperbranched aliphatic polyester, Boltorn H40. The inner hydrophobic layer was composed of random copolymer of poly(εcaprolactone) and poly(malic acid) (PMA-co-PCL) segments, while the outer hydrophilic shell was composed of poly(ethylene glycol) (PEG) segments. Active tumor-targeting ligands, i.e., folate (FA), were selectively conjugated to the distal ends of the PEG segments. An anticancer drug, i.e., doxorubicin. (DOX) molecules, was conjugated onto the PMA segments with pH-sensitive drug binding linkers for pH-triggered drug release. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis showed that the unimolecular micelles were uniform with a mean hydrodynamic diameter around 25 nm. The drug loading content was determined to be 14.2%. The drug release profile, cell uptake and distribution, and cytotoxicity of the unimolecular micelles were evaluated in vitro. The folate-conjugated micelles can be internalized by the cancer cells via folate-receptormediated endocytosis; thus, they exhibited enhanced cell uptake and cytotoxicity. At pH 7.4, the physiological condition of bloodstream, DOX conjugated onto the unimolecular micelles exhibited excellent stability; however, once the micelles were internalized by the cancer cells, the pH-sensitive hydrazone linkages were cleavable by the intracellular acidic environment, which initially caused a rapid release of DOX. These findings indicate that these unique unimolecular micelles may offer a very promising approach, for targeted cancer therapy.
- Yang, Xiaoqiang,Grailer, Jamison J.,Pilla, Srikanth,Steeber, Douglas A.,Gong, Shaoqin
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experimental part
p. 496 - 504
(2011/01/03)
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- Synthesis and study of the cancer cell growth inhibitory properties of α-, γ-tocopheryl and γ-tocotrienyl 2-phenylselenyl succinates
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Vitamin E succinate selenium-conjugated molecules were synthesized and their apoptogenic properties were evaluated. 4-Methyl-2-phenylselenyl succinate (4) was prepared by the reaction of sodium benzeneselenolate with 2-bromosuccinic anhydrite in methanol
- Vraka, Panayiota S.,Drouza, Chryssoula,Rikkou, Maria P.,Odysseos, Andreani D.,Keramidas, Anastasios D.
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p. 2684 - 2696
(2007/10/03)
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- Tocopherol ester compounds
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Disclosed are novel tocopherol ester compounds having the formula wherein X is a chain of 2 or 3 carbon atoms, e.g., ethylene and trimethylene, joining the 2 carbonyl groups to which they are bonded; and R1is a group having the formula —Y—Rsup
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Page column 4
(2010/02/06)
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- MONOCYCLIC BETA-LACTAMS AND PROCESS FOR THE PREPARATION THEREOF
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Monocyclic beta-lactam compounds represented by the formula STR1 wherein R 1 is H, NH 2, acylamino, C 1 -C 4 alkyl, etc.; R 2 is e.g. C 1 -C 4 alkyl, hydroxyalkyl, aminoalkyl, carboxy, esterified carboxy, esterified carboxyalkyl, or carboxyalkyl; and R 3 is hydrogen, benzyl, substituted benzyl, pivaloyl, --SO 3 M, or --P(C-O)(OM')2; are obtained by the cyclization of an O-substituted hydroxamate of a beta-substituted alkylcarboxylic acid. For example, alpha-ethylmalic acid monobenzyl ester is reacted with O-benzylhydroxylamine to form the O-benzylhydroxamate of the free carboxy group, and the hydroxamate is cyclized with diethyl diazodicarboxylate and triphenylphosphine to form the beta-lactam of the above formula wherein R 1 is ethyl, R 2 is benzyloxycarbonyl and R 3 is benzyl. The beta-lactam compounds are useful intermediates for preparing beta-lactamase inhibitors and monocyclic beta-lactam antibiotics and, when R 3 is --SO 3 M or -P(C-O)(OM')2 the compounds and salts thereof are antibacterial agents.
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- Antimicrobial composition and method containing N-(3,5-dihalophenyl)-imide compounds
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Novel N-(3,5-dihalophenyl)imide compounds, which exhibit a strong antimicrobial activity against microorganisms including phytopathogenic fungi, parasites of industrial products and pathogenic microorganisms, represented by the formula, STR1 wherein X and X' each represent halogens and A represents a substituted ethylene such as chloroethylene, C1 - C4 alkylthioethylene, C1 - C2 alkyl-ethylene or 1,2-di-C1 - C2 -alkyl-ethylene, a cyclopropylene such as 1,3-dimethylcyclopropylene, trimethylene, a cyclohexylene-1,2-, cyclohexenylene-1,2-, cyclohexadienylene-1,2- or o-phenylene. The N-(3,5-dihalophenyl)imide compounds can be obtained by any of methods which produce imide compounds or reaction of an N-(3,5-dihalophenyl)maleimide compound with a mercaptan, a hydrogen halide, phosphorus chloride or thionylchloride.
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