title: Interaction between PEO-PPO-PEO copolymers and a hexapeptide in aqueous solutions.
abstract: Interaction between PEO-PPO-PEO copolymers and a hexapeptide, growth hormone releasing peptide-6 (GHRP-6), was investigated by NMR to study the potential use of the copolymers in peptide drug delivery. (1)H NMR and nuclear Overhauser effect spectroscopy (NOESY) measurements determined that PO methyl protons interacted with methyl protons of the Ala moiety, aromatic protons of the Trp moiety, and some of the Phe aromatic protons. The Lys moiety and part of the Phe moiety entered the hydrophilic EO environment via hydrogen bonding. PEO-PPO-PEO copolymers and the peptide formed a complex in 1:1 stoichiometry. Binding constants between copolymers and GHRP-6 were determined, and it was indicated that the copolymers containing more EO and PO units will lead to greater affinity with the peptide. Isothermal titration calorimetry (ITC) measurements confirmed the results of NMR experiments. This study indicates that PEO-PPO-PEO copolymers have great potential in delivering peptide drugs.
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors.forename: Lianwei
authors.initials: L
authors.lastname: Jia
authors.forename: Chen
authors.initials: C
authors.lastname: Guo
authors.forename: Junfeng
authors.initials: J
authors.lastname: Xiang
authors.forename: Ning
authors.initials: N
authors.lastname: Wang
authors.forename: Liangrong
authors.initials: L
authors.lastname: Yang
authors.forename: Yalin
authors.initials: Y
authors.lastname: Tang
authors.forename: Huizhou
authors.initials: H
authors.lastname: Liu
mesh_terms: D009682:Magnetic Resonance Spectroscopy; D009842:Oligopeptides / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011409:Propylene Glycols / Q000737:chemistry*; D011522:Protons; D012996:Solutions / Q000737:chemistry
chemical_list: D009842:Oligopeptides; C116176:PEO-PPO-PEO; D011409:Propylene Glycols; D011522:Protons; D012996:Solutions; D011092:Polyethylene Glycols; C041048:growth hormone releasing hexapeptide