title: Synthesis and characterization of a novel chitosan-N-acetyl-homocysteine thiolactone polymer using MES buffer.
abstract: We report a new "green" approach to synthesize a novel thiolated chitosan conjugate, chitosan-N-acetyl-homocysteine thiolactone (chitosan-AcHcys) using a "Good's buffers", 2-(N-morpholino)ethanesulfonic acid (MES). After that, the crosslinked Xr-chitosan-AcHcys was obtained only in the presence of air, without other reactants. The chitosan-AcHcys spectrum shows a partial incorporation of the thiolactone onto the polymer backbone. The derivative thermogravimetric analysis confirmed that chitosan-AcHcys is slightly less stable than starting chitosan; however, the peak profile is broadened which is indicative of deeper changes in the thermal degradation process. Also, aqueous dispersions with different concentrations of the crosslinked material (Xr-chitosan-AcHcys) were prepared and rheologically characterized. All aqueous dispersions are viscoelastic fluid with shear-thinning behavior. The viscosity of the dispersions (1-7% of chitosan-AcHcys) increases as a function of polymer concentration. So, we have achieved to disperse a high concentration of thiolated-chitosan derivative in water with different rheological characteristics, which could affect the drug release.
authors.affiliation: Dpto. Química Orgánica y Farmacéutica, Facultad de Farmacia, Universidad de Sevilla, Prof. García Gonzalez n(o) 2, 41012 Sevilla, Spain. Electronic address: cferris@us.es.
authors.forename: C
authors.initials: C
authors.lastname: Ferris
authors.affiliation: Dpto de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Sevilla, Prof. García Gonzalez n(o) 2, 41012 Sevilla, Spain. Electronic address: mcasas@us.es.
authors.forename: M
authors.initials: M
authors.lastname: Casas
authors.affiliation: Dpto de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Sevilla, Prof. García Gonzalez n(o) 2, 41012 Sevilla, Spain. Electronic address: mjlucero@us.es.
authors.forename: M J
authors.initials: MJ
authors.lastname: Lucero
authors.affiliation: Dpto. Química Orgánica y Farmacéutica, Facultad de Farmacia, Universidad de Sevilla, Prof. García Gonzalez n(o) 2, 41012 Sevilla, Spain. Electronic address: vdepaz@us.es.
authors.forename: M V
authors.initials: MV
authors.lastname: de Paz
authors.affiliation: Dpto de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Sevilla, Prof. García Gonzalez n(o) 2, 41012 Sevilla, Spain. Electronic address: mrosa@us.es.
authors.forename: M R
authors.initials: MR
authors.lastname: Jiménez-Castellanos
mesh_terms: D017738:Alkanesulfonic Acids / Q000737:chemistry*; D002021:Buffers; D048271:Chitosan / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D055772:Green Chemistry Technology; D006710:Homocysteine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D009025:Morpholines / Q000737:chemistry*; D055682:Viscoelastic Substances / Q000138:chemical synthesis / Q000737:chemistry*; D014783:Viscosity
chemical_list: D017738:Alkanesulfonic Acids; D002021:Buffers; D009025:Morpholines; D055682:Viscoelastic Substances; D006710:Homocysteine; C004550:2-(N-morpholino)ethanesulfonic acid; C025584:N-acetylhomocysteine; D048271:Chitosan; C007957:homocysteine thiolactone
keywords: 2-(N-Morpholino)ethanesulfonic acid (MES); Fourier transformed infrared spectroscopy (FT-IR); Green chemistry; Rheology; Thiolated-chitosan