title: Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)/poly(epsilon-caprolactone) (PCL) amphiphilic block copolymeric nanospheres. II. Thermo-responsive drug release behaviors.
abstract: Amphiphilic block copolymers composed of relatively hydrophilic PEO-PPO-PEO block copolymer (Pluronic) and poly (epsilon-caprolactone) with hydrophobic character were synthesized by ring-opening polymerization of epsilon-caprolactone in the presence of PEO-PPO-PEO block copolymer using stannous octoate as a catalyst. Pluronic/PCL block copolymeric nanospheres with core-shell structure were prepared by dialysis method. They showed the average diameter of 116-196 nm depending on the type of copolymer. All the nanosphere samples exhibited a narrow size distribution. The critical micelle concentrations of Pluronic/PCL amphiphilic block copolymers determined by fluorescence spectroscopy were lower than that of the common low molecular weight surfactant. Their core-shell structure was confirmed by 1H NMR spectroscopy. Pluronic/PCL block copolymeric nanospheres exhibited the reversible change of size depending on the temperature. Release behaviors of indomethacin from Pluronic/PCL block copolymeric nanospheres also showed temperature dependence and a sustained release pattern. In addition, cytotoxicity test using an MTT assay method revealed that these indomethacin-loaded Pluronic/PCL nanospheres could remarkably reduce the cell damage compared with the unloaded free indomethacin.
authors.affiliation: Department of Industrial Chemistry, College of Engineering, Hanyang University, Seoul, South Korea.
authors.forename: S Y
authors.initials: SY
authors.lastname: Kim
authors.forename: J C
authors.initials: JC
authors.lastname: Ha
authors.forename: Y M
authors.initials: YM
authors.lastname: Lee
mesh_terms: D000465:Algorithms; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000737:chemistry; D002470:Cell Survival / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects; D006358:Hot Temperature; D006801:Humans; D007213:Indomethacin / Q000008:administration & dosage / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D008970:Molecular Weight; D010316:Particle Size; D011095:Polyethylenes / Q000737:chemistry* / Q000633:toxicity; D011126:Polypropylenes / Q000737:chemistry* / Q000633:toxicity; D013050:Spectrometry, Fluorescence
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D011095:Polyethylenes; D011126:Polypropylenes; C409526:pluronic-PCL block copolymer; D007213:Indomethacin