The Synthesis And Characterization Of MPEGylated Oligopepide Amphiphilic Block Copolymer

As the cross-development of polymer materials science, medical and biological science, so that drug delivery system has been rapid development, emerging a number of polymer materials. However, clinical applications are needed biodegradable polymer materials, so we design and synthesize temperature sensitive MPEGylated ligopeptide amphiphilic block copolymer as drug carrier material, and study some properties.The characteristic of polyethylene glycol is biocompatible, immunological inertia and non-toxic. It can be excreted when it's molecular weight is lesser than 30,000. Oligopeptide is one of essential nutrients, but also can be degraded endogenous substances which is absorbed and used. So the target compounds form hydrogel which is non-toxic and biocompatible. Hydrogel is insoluble and expansion but can absorb large numbers of water. The new functional polymer materials is the three-dimensional or interpenetrating network structure. It's main chain or side chain is included a large number of hydrophilic groups. The research of drug carrier Materials has become one of the hotspots.Oligopeptide was synthesized from amino acid, then amino and carboxyl groups are protected through liquid phase in the presence of HOBt/DIC condensation agent. The structure of products was characterized by using IR and 1H-NMR. Different amino acid sequences of MPEGylated oligopeptide amphiphilic block copolymer was synthesized from terminal carboxyl polyethylene glycol by ethyl bromide and oligopeptide. The chemical structure and molecular weight distribution were characterized by using infrared spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography. This paper designed and synthesized thermo-sensitive and biodegradable PEG-oligopeptide amphiphilic block copolymer, which provides foundation for a drug carrier material.The gel of target compounds are due to hydrogen bonding. It was preliminarily analysis of 1H-NMR spectra. We supposed that forming a micelle is due to hydrophobic stretching inward and wraping or dispersed in hydrophilic surface, and then formed hydrogel in heating conditions. We found that gel temperature was 37℃, dissolved in 65℃from the test of the mass ratio of 6% of the MPEGylated ligopeptide amphiphilic block copolymer solution. Therefor it can apply for drug carrier materials.