title: Synthesis and characterization of poly-alpha,beta-[N-(2-hydroxyethyl)-L-aspartamide]-g-poly(L-lactide) biodegradable copolymers as drug carriers.
abstract: A series of biodegradable amphiphilic graft polymers were successfully synthesized by grafting poly(L-lactide) (PLLA) sequences onto a water-soluble polymer poly-alpha,beta-[N-(2-hydroxyethyl)-L-aspartamide] (PHEA) backbone. We established the feasibility of preparing these novel graft polymers by the ring-opening polymerization initiated by the macroinitiator PHEA bearing hydroxyl groups without adding any catalyst. The successful grafting of PLLA sequences onto the PHEA backbone was verified by combined size exclusion chromatography (SEC) and multiangle laser light scattering (MALLS) analysis. The chemical structures of graft polymers were characterized by FTIR and (1)H NMR. The critical micelle concentration (CMC) of the graft polymer was determined by fluorescence probe technique using pyrene. By controlling the feed ratio of the macroinitiator to the monomer, graft polymers with different branch lengths can be obtained. Using the 3-(4,5 dimethylthiozol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay, the graft copolymer has been proved to have low cytotoxicity. Based on the amphiphilicity of the graft copolymers, nanoparticular drug delivery systems were prepared by the direct dissolution method and the dialysis method. The anticancer drug Tegafur was encapsulated into polymeric nanoparticles, and in vitro drug release behavior was investigated. Transmission electron microscopy (TEM) images demonstrate that these nanoparticles are regularly spherical in shape. The particle size and distribution of the nanoparticles were measured.
authors.affiliation: Key Laboratory of Biomedical Polymers of Ministry of Education, Department of Chemistry, Wuhan University, Wuhan 430072, People's Republic of China.
authors.forename: Tao
authors.initials: T
authors.lastname: Peng
authors.forename: Si-Xue
authors.initials: SX
authors.lastname: Cheng
authors.forename: Ren-Xi
authors.initials: RX
authors.lastname: Zhuo
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry / Q000633:toxicity; D001673:Biodegradation, Environmental; D002470:Cell Survival / Q000187:drug effects; D004337:Drug Carriers / Q000138:chemical synthesis / Q000737:chemistry / Q000633:toxicity; D016503:Drug Delivery Systems; D009682:Magnetic Resonance Spectroscopy; D008422:Materials Testing; D051379:Mice; D008854:Microscopy, Electron; D041681:NIH 3T3 Cells; D049329:Nanostructures; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000633:toxicity; D011091:Polyesters / Q000138:chemical synthesis / Q000737:chemistry / Q000633:toxicity; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D001672:Biocompatible Materials; D004337:Drug Carriers; D010455:Peptides; D011091:Polyesters; C008965:alpha,beta-poly((2-hydroxyethyl)-aspartamide); C033616:poly(lactide)