A new multifunctional mPEG-b-PAA-grafted chitosan copolymer possessing amino and carboxyl groups,mPEG-b-PAA-g-CHI(compound 6) ,was designed for a potential application in gene/drug delivery and synthesized by the meth...A new multifunctional mPEG-b-PAA-grafted chitosan copolymer possessing amino and carboxyl groups,mPEG-b-PAA-g-CHI(compound 6) ,was designed for a potential application in gene/drug delivery and synthesized by the methods of reversible addition-fragmentation chain transfer(RAFT) polymerization of acrylic acid(AA) and grafting reaction of a biodegradable chitosan(CHI) derivative.Completion of the reactions and characterization of the resulting compounds were demonstrated by 1 H NMR,FTIR and gel permeation chtomatography(GPC) studies.The results show that the molar ratio of amino groups to carboxyl groups in the copolymer(compound 6) is 0.41-0.59.展开更多
A simple and efficient method for the preparation of a novel soluble chitosan derivative, diethoxy phosphoryl chitosan （PH-chitosan）, has been developed. Ph-chitosan was characterized by elemental analysis, FT-IR, N...A simple and efficient method for the preparation of a novel soluble chitosan derivative, diethoxy phosphoryl chitosan （PH-chitosan）, has been developed. Ph-chitosan was characterized by elemental analysis, FT-IR, NMR, ICP, XRD, TG and SEM, respectively. The chemical identity of PH-chitosan was determined by FT-IR and confirmed by NMR, and those results unequivocally demonstrated that diethoxy phosphoryl groups were grafted onto the amino and hydroxyl groups of chitosan. The results of XRD indicated that the crystalline structure of chitosan was destroyed due to the incorporation of diethoxy phosphoryl group resulting in loss of hydrogen bond. The analysis of TG demonstrated that PH-chitosan was less thermal stable than chitosan. This simple synthetic method provided a new and available approach to prepare a soluble high molecule weight chitosan derivative.展开更多
Oxymatrine （OM）/N-succinyl-chitosan （Suc-Chi, with a degree of substitution being 0. 32） was synthesized via the ring-opening reaction of succinic anhydride with chitosan in dimethyl sulfoxide. OM-loaded Suc-Chi n...Oxymatrine （OM）/N-succinyl-chitosan （Suc-Chi, with a degree of substitution being 0. 32） was synthesized via the ring-opening reaction of succinic anhydride with chitosan in dimethyl sulfoxide. OM-loaded Suc-Chi nanoparticles were prepared by an ionotropic gelation process and OM was quantified via the HPLC method： The influences of the initial OM concentration on the nanoparticle characteristics and OM release behavior were evaluated. The nanoparticles were found to have a mean diameter within a range of 267-392 nm, a positive surface charge, and a zeta potential in the range of 19-27 inV. The formulation with an initial OM concentration of 100μg/mL provided the highest loaded capacity（0. 77% ） and the highest extent of the released OM （68% at 24 h）, suggesting the possibility to achieve a therapeutic dose. According to the data obtained, this Suc-Chi-based nanotechnology will open up new and interesting prospects for the development of new anticancer drugs.展开更多
基金Project(20704011) supported by the National Natural Science Foundation of ChinaProject(09JJ3027) supported by the Natural Science Foundation of Hunan Province,ChinaProject(50725825) supported by the National Science Foundation for Distinguished Young Scholars
文摘A new multifunctional mPEG-b-PAA-grafted chitosan copolymer possessing amino and carboxyl groups,mPEG-b-PAA-g-CHI(compound 6) ,was designed for a potential application in gene/drug delivery and synthesized by the methods of reversible addition-fragmentation chain transfer(RAFT) polymerization of acrylic acid(AA) and grafting reaction of a biodegradable chitosan(CHI) derivative.Completion of the reactions and characterization of the resulting compounds were demonstrated by 1 H NMR,FTIR and gel permeation chtomatography(GPC) studies.The results show that the molar ratio of amino groups to carboxyl groups in the copolymer(compound 6) is 0.41-0.59.
基金This work was supported by the National Natural Science Foundation of China （No. 20872134）.
文摘A simple and efficient method for the preparation of a novel soluble chitosan derivative, diethoxy phosphoryl chitosan （PH-chitosan）, has been developed. Ph-chitosan was characterized by elemental analysis, FT-IR, NMR, ICP, XRD, TG and SEM, respectively. The chemical identity of PH-chitosan was determined by FT-IR and confirmed by NMR, and those results unequivocally demonstrated that diethoxy phosphoryl groups were grafted onto the amino and hydroxyl groups of chitosan. The results of XRD indicated that the crystalline structure of chitosan was destroyed due to the incorporation of diethoxy phosphoryl group resulting in loss of hydrogen bond. The analysis of TG demonstrated that PH-chitosan was less thermal stable than chitosan. This simple synthetic method provided a new and available approach to prepare a soluble high molecule weight chitosan derivative.
文摘Oxymatrine （OM）/N-succinyl-chitosan （Suc-Chi, with a degree of substitution being 0. 32） was synthesized via the ring-opening reaction of succinic anhydride with chitosan in dimethyl sulfoxide. OM-loaded Suc-Chi nanoparticles were prepared by an ionotropic gelation process and OM was quantified via the HPLC method： The influences of the initial OM concentration on the nanoparticle characteristics and OM release behavior were evaluated. The nanoparticles were found to have a mean diameter within a range of 267-392 nm, a positive surface charge, and a zeta potential in the range of 19-27 inV. The formulation with an initial OM concentration of 100μg/mL provided the highest loaded capacity（0. 77% ） and the highest extent of the released OM （68% at 24 h）, suggesting the possibility to achieve a therapeutic dose. According to the data obtained, this Suc-Chi-based nanotechnology will open up new and interesting prospects for the development of new anticancer drugs.
