The Experts below are selected from a list of 17799 Experts worldwide ranked by ideXlab platform
Nicolas Tsapis - One of the best experts on this subject based on the ideXlab platform.
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Comb-Like Fluorophilic-Lipophilic-Hydrophilic Polymers for Nanocapsules as Ultrasound Contrast Agents
2018Co-Authors: Sophie Houvenagel, Laurence Moine, Guilherme Picheth, Annie Brûlet, Alexis Chennevière, Vincent Faugeras, Camille Dejean, Olivier Couture, Nicolas Huang, Nicolas TsapisAbstract:Imaging the enhanced permeation and retention effect by ultrasound is hindered by the large size of commercial ultrasound contrast agents (UCAs). To obtain nanosized UCAs, triblock coPolymers of poly(ethylene glycol)-polylactide-poly(1H,1H,2H,2H-heptadecafluorodecyl methacrylate) (PEG-PLA-PFMA) with distinct numbers of perfluorinated pendant chains (5, 10, or 20) are synthesized by a combination of ring-opening polymerization and atom transfer radical polymerization. Nanocapsules (NCs) containing perfluorooctyl bromide (PFOB) intended as UCAs are obtained with a 2-fold increase in PFOB encapsulation efficiency in fluorinated NCs as compared with plain PEG-PLA NCs thanks to fluorous interactions. NC morphology is strongly influenced by the number of perfluorinated chains and the amount of polymer used for formulation, leading to peculiar capsules with several PFOB cores at high PEG-PLA-PFMA 20 amount and single-cored NCs with a thinner shell at low fluorinated polymer amount, as confirmed by small-angle neutron scattering. Finally, fluorinated NCs yield higher in vitro ultrasound signal compared with PEG-PLA NCs, and no in vitro cytotoxicity is induced by fluorinated Polymers and their degradation products. Our results highlight the benefit of adding comb-like fluorinated blocks in PEG-PLA Polymers to modify the nanostructure and enhance the echogenicity of nanocapsules intended as UCAs.
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Comb-Like Fluorophilic-Lipophilic-Hydrophilic Polymers for Nanocapsules as Ultrasound Contrast Agents
2018Co-Authors: Sophie Houvenagel, Laurence Moine, Guilherme Picheth, Annie Brûlet, Alexis Chennevière, Vincent Faugeras, Camille Dejean, Olivier Couture, Nicolas Huang, Nicolas TsapisAbstract:© 2018 American Chemical Society. Imaging the enhanced permeation and retention effect by ultrasound is hindered by the large size of commercial ultrasound contrast agents (UCAs). To obtain nanosized UCAs, triblock coPolymers of poly(ethylene glycol)-polylactide-poly(1H,1H,2H,2H-heptadecafluorodecyl methacrylate) (PEG-PLA-PFMA) with distinct numbers of perfluorinated pendant chains (5, 10, or 20) are synthesized by a combination of ring-opening polymerization and atom transfer radical polymerization. Nanocapsules (NCs) containing perfluorooctyl bromide (PFOB) intended as UCAs are obtained with a 2-fold increase in PFOB encapsulation efficiency in fluorinated NCs as compared with plain PEG-PLA NCs thanks to fluorous interactions. NC morphology is strongly influenced by the number of perfluorinated chains and the amount of polymer used for formulation, leading to peculiar capsules with several PFOB cores at high PEG-PLA-PFMA20amount and single-cored NCs with a thinner shell at low fluorinated polymer amount, as confirmed by small-angle neutron scattering. Finally, fluorinated NCs yield higher in vitro ultrasound signal compared with PEG-PLA NCs, and no in vitro cytotoxicity is induced by fluorinated Polymers and their degradation products. Our results highlight the benefit of adding comb-like fluorinated blocks in PEG-PLA Polymers to modify the nanostructure and enhance the echogenicity of nanocapsules intended as UCAs.
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Comb-Like Fluorophilic-Lipophilic-Hydrophilic Polymers for Nanocapsules as Ultrasound Contrast Agents
2018Co-Authors: Sophie Houvenagel, Laurence Moine, Guilherme Picheth, Vincent Faugeras, Camille Dejean, Olivier Couture, Nicolas Huang, Annie Brûlet, Alexis Chennevière, Nicolas TsapisAbstract:Imaging the enhanced permeation and retention effect by ultrasound is hindered by the large size of commercial ultrasound contrast agents (UCAs). To obtain nanosized UCAs, triblock coPolymers of poly(ethylene glycol)-polylactide-poly(1H,1H,2H,2H-heptadecafluorodecyl methacrylate) (PEG-PLA-PFMA) with distinct numbers of perfluorinated pendant chains (5, 10, or 20) are synthesized by a combination of ring-opening polymerization and atom transfer radical polymerization. Nanocapsules (NCs) containing perfluorooctyl bromide (PFOB) intended as UCAs are obtained with a 2-fold increase in PFOB encapsulation efficiency in fluorinated NCs as compared with plain PEG-PLA NCs thanks to fluorous interactions. NC morphology is strongly influenced by the number of perfluorinated chains and the amount of polymer used for formulation, leading to peculiar capsules with several PFOB cores at high PEG-PLA-PFMA20 amount and single-cored NCs with a thinner shell at low fluorinated polymer amount, as confirmed by small-angle neutron scattering. Finally, fluorinated NCs yield higher in vitro ultrasound signal compared with PEG-PLA NCs, and no in vitro cytotoxicity is induced by fluorinated Polymers and their degradation products. Our results highlight the benefit of adding comb-like fluorinated blocks in PEG-PLA Polymers to modify the nanostructure and enhance the echogenicity of nanocapsules intended as UCAs
Marianne Paulsson - One of the best experts on this subject based on the ideXlab platform.
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protein adsorption of poly ether urethane surfaces modified by amphiphilic and Hydrophilic Polymers
1994Co-Authors: Bengt Wesslen, Maria Kober, Christina Freijlarsson, Asa Ljungh, Marianne PaulssonAbstract:A commercial biomedical poly(ether urethane), Pellethane 2363-80AE, was surface modified through the use of amphiphilic polymeric additives, and through surface grafting with poly(ethylene glycol), PEG. Two different amphiphilic Polymers, Polymer C and Pluronic PE9400, were used as additives. Polymer C, a segmented polyurethane, was prepared from PEG1500, 4,4'-diphenylmethane diisocyanate and a C-16-C18 monoglyceride chain extender. Pluronic PE9400 is a propylene oxide-ethylene oxide tri-block co-polymer obtained from BASF. Adsorption of human albumin and fibrinogen to the modified surfaces was studied by means of radiolabelled proteins. By contact angle measurements and X-ray photoelectron spectra the amphiphilic Polymers were shown to accumulate at the polyurethane surfaces. Adsorption of fibrinogen, in particular, was significantly reduced by the amphiphilic additives to levels similar to those obtained for Pellethane surfaces grafted with PEG 20000. In vitro clotting times for citrate-buffered blood in contact with the amphiphilic surfaces increased as compared with the unmodified ones. (Less)
Sophie Houvenagel - One of the best experts on this subject based on the ideXlab platform.
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Comb-Like Fluorophilic-Lipophilic-Hydrophilic Polymers for Nanocapsules as Ultrasound Contrast Agents
2018Co-Authors: Sophie Houvenagel, Laurence Moine, Guilherme Picheth, Annie Brûlet, Alexis Chennevière, Vincent Faugeras, Camille Dejean, Olivier Couture, Nicolas Huang, Nicolas TsapisAbstract:Imaging the enhanced permeation and retention effect by ultrasound is hindered by the large size of commercial ultrasound contrast agents (UCAs). To obtain nanosized UCAs, triblock coPolymers of poly(ethylene glycol)-polylactide-poly(1H,1H,2H,2H-heptadecafluorodecyl methacrylate) (PEG-PLA-PFMA) with distinct numbers of perfluorinated pendant chains (5, 10, or 20) are synthesized by a combination of ring-opening polymerization and atom transfer radical polymerization. Nanocapsules (NCs) containing perfluorooctyl bromide (PFOB) intended as UCAs are obtained with a 2-fold increase in PFOB encapsulation efficiency in fluorinated NCs as compared with plain PEG-PLA NCs thanks to fluorous interactions. NC morphology is strongly influenced by the number of perfluorinated chains and the amount of polymer used for formulation, leading to peculiar capsules with several PFOB cores at high PEG-PLA-PFMA 20 amount and single-cored NCs with a thinner shell at low fluorinated polymer amount, as confirmed by small-angle neutron scattering. Finally, fluorinated NCs yield higher in vitro ultrasound signal compared with PEG-PLA NCs, and no in vitro cytotoxicity is induced by fluorinated Polymers and their degradation products. Our results highlight the benefit of adding comb-like fluorinated blocks in PEG-PLA Polymers to modify the nanostructure and enhance the echogenicity of nanocapsules intended as UCAs.
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Comb-Like Fluorophilic-Lipophilic-Hydrophilic Polymers for Nanocapsules as Ultrasound Contrast Agents
2018Co-Authors: Sophie Houvenagel, Laurence Moine, Guilherme Picheth, Annie Brûlet, Alexis Chennevière, Vincent Faugeras, Camille Dejean, Olivier Couture, Nicolas Huang, Nicolas TsapisAbstract:© 2018 American Chemical Society. Imaging the enhanced permeation and retention effect by ultrasound is hindered by the large size of commercial ultrasound contrast agents (UCAs). To obtain nanosized UCAs, triblock coPolymers of poly(ethylene glycol)-polylactide-poly(1H,1H,2H,2H-heptadecafluorodecyl methacrylate) (PEG-PLA-PFMA) with distinct numbers of perfluorinated pendant chains (5, 10, or 20) are synthesized by a combination of ring-opening polymerization and atom transfer radical polymerization. Nanocapsules (NCs) containing perfluorooctyl bromide (PFOB) intended as UCAs are obtained with a 2-fold increase in PFOB encapsulation efficiency in fluorinated NCs as compared with plain PEG-PLA NCs thanks to fluorous interactions. NC morphology is strongly influenced by the number of perfluorinated chains and the amount of polymer used for formulation, leading to peculiar capsules with several PFOB cores at high PEG-PLA-PFMA20amount and single-cored NCs with a thinner shell at low fluorinated polymer amount, as confirmed by small-angle neutron scattering. Finally, fluorinated NCs yield higher in vitro ultrasound signal compared with PEG-PLA NCs, and no in vitro cytotoxicity is induced by fluorinated Polymers and their degradation products. Our results highlight the benefit of adding comb-like fluorinated blocks in PEG-PLA Polymers to modify the nanostructure and enhance the echogenicity of nanocapsules intended as UCAs.
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Comb-Like Fluorophilic-Lipophilic-Hydrophilic Polymers for Nanocapsules as Ultrasound Contrast Agents
2018Co-Authors: Sophie Houvenagel, Laurence Moine, Guilherme Picheth, Vincent Faugeras, Camille Dejean, Olivier Couture, Nicolas Huang, Annie Brûlet, Alexis Chennevière, Nicolas TsapisAbstract:Imaging the enhanced permeation and retention effect by ultrasound is hindered by the large size of commercial ultrasound contrast agents (UCAs). To obtain nanosized UCAs, triblock coPolymers of poly(ethylene glycol)-polylactide-poly(1H,1H,2H,2H-heptadecafluorodecyl methacrylate) (PEG-PLA-PFMA) with distinct numbers of perfluorinated pendant chains (5, 10, or 20) are synthesized by a combination of ring-opening polymerization and atom transfer radical polymerization. Nanocapsules (NCs) containing perfluorooctyl bromide (PFOB) intended as UCAs are obtained with a 2-fold increase in PFOB encapsulation efficiency in fluorinated NCs as compared with plain PEG-PLA NCs thanks to fluorous interactions. NC morphology is strongly influenced by the number of perfluorinated chains and the amount of polymer used for formulation, leading to peculiar capsules with several PFOB cores at high PEG-PLA-PFMA20 amount and single-cored NCs with a thinner shell at low fluorinated polymer amount, as confirmed by small-angle neutron scattering. Finally, fluorinated NCs yield higher in vitro ultrasound signal compared with PEG-PLA NCs, and no in vitro cytotoxicity is induced by fluorinated Polymers and their degradation products. Our results highlight the benefit of adding comb-like fluorinated blocks in PEG-PLA Polymers to modify the nanostructure and enhance the echogenicity of nanocapsules intended as UCAs
Bengt Wesslen - One of the best experts on this subject based on the ideXlab platform.
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protein adsorption of poly ether urethane surfaces modified by amphiphilic and Hydrophilic Polymers
1994Co-Authors: Bengt Wesslen, Maria Kober, Christina Freijlarsson, Asa Ljungh, Marianne PaulssonAbstract:A commercial biomedical poly(ether urethane), Pellethane 2363-80AE, was surface modified through the use of amphiphilic polymeric additives, and through surface grafting with poly(ethylene glycol), PEG. Two different amphiphilic Polymers, Polymer C and Pluronic PE9400, were used as additives. Polymer C, a segmented polyurethane, was prepared from PEG1500, 4,4'-diphenylmethane diisocyanate and a C-16-C18 monoglyceride chain extender. Pluronic PE9400 is a propylene oxide-ethylene oxide tri-block co-polymer obtained from BASF. Adsorption of human albumin and fibrinogen to the modified surfaces was studied by means of radiolabelled proteins. By contact angle measurements and X-ray photoelectron spectra the amphiphilic Polymers were shown to accumulate at the polyurethane surfaces. Adsorption of fibrinogen, in particular, was significantly reduced by the amphiphilic additives to levels similar to those obtained for Pellethane surfaces grafted with PEG 20000. In vitro clotting times for citrate-buffered blood in contact with the amphiphilic surfaces increased as compared with the unmodified ones. (Less)
Dennis Douroumis - One of the best experts on this subject based on the ideXlab platform.
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dissolution enhancement of poorly water soluble apis processed by hot melt extrusion using Hydrophilic Polymers
2013Co-Authors: Mohammed Maniruzzaman, M M Rana, Joshua S Boateng, John C Mitchell, Dennis DouroumisAbstract:The aim of this study was to investigate the efficiency of Hydrophilic Polymers to enhance the dissolution rate of poorly water-soluble active pharmaceutical ingredients (APIs) processed by hot-melt extrusion (HME). Indomethacin (INM) and famotidine (FMT) were selected as model active substances while polyvinyl caprolactam graft copolymer, soluplus (SOL) and vinylpyrrolidone-vinyl acetate copolymer grades, Kollidon VA64 (VA64) and Plasdone S630 (S630) were used as Hydrophilic polymeric carriers. For the purpose of the study, drug–polymer binary blends at various ratios were processed by a Randcastle single screw extruder. The physicochemical properties and the morphology of the extrudates were evaluated through X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Increased drug loadings of up to 40% were achieved in the extruded formulations for both drugs. INM and FMT exhibited strong plasticization effects with increasing concentrations and were found to be molecularly dispersed within the polymer blends. The in vitro dissolution studies showed increased INM/FMT release rates for all formulations compared to that of pure APIs alone.
