A Preliminary Study On The Amphiphilic Triblock Copolymers Micelles Of MPEG-PCL-PTyr

The aim of this study was to synthesize an in vivo biodegradable three block copolymer.Synthetic three block copolymer MPEG-PCLPTyr as a carrier.The antitumor active agent 10-Hydroxycamptothecin(HCPT)contained in the hydrophilic shell.So as to prepare a long acting and targeted nanoparticle drug delivery system.The quality of the micelles was detected,including its particle size,encapsulation efficiency,drug loading,in vitro release behavior,stability and so on.Further study the characteristic parameters such as hemolytic,critical relative concentration and so on.Finally,through in vitro study target the HCPT micelle into the hepatocytes.1.Synthesis and characterization of MPEG-PCL-PTyrTwo block copolymer MPEG-PCL was synthesized by ring opening polymerization.Secondly,through Gabriel reaction of hydroxyl terminated amino MPEG-PCL,and L-Tyr-NCA grafting synthesis of three block copolymer MPEG-PCL-PTyr.After the preparation,the structure,molecular weight and distribution of the block copolymers were characterized by IR,1H-NMR and GPC technology.Characterization of the test results showed that the successful synthesis of MPEG-PCL-PTyr three block copolymer.2.Preparation technology and quality evaluation of MPEG-PCLPTyr micellesScreening index for investigation of the best micelle preparation method for emulsion solvent evaporation method with the particle size,Zeta potential,PDI value and 10,selection of hydroxycamptothecin for target drugs,determination of micelle loading and encapsulation rate of HPLC method was established to prove its precision and accuracy of good methodology.at the same time to grain the size and encapsulation efficiency(EE%),drug loading(DL%)were investigated by single factor method to study preliminary formulation of the drug loaded micelles prescription and preparation process,and further optimized by orthogonal method,to determine the best process after the process of micelle stability,results showed that the micelle samples within 30 days of comparison stability,encapsulation rate had no significant change and no particles and precipitation.3.Study on the properties and in vitro release of MPEG-PCL-PTyr micellesUsing pyrene fluorescence analysis method to detect micellar CMC values between 1.0×10-4～1.0×10-3 mg·mL-1,inspected MPEG-PCL-PTyrHC--PT micelles of hemolysis showed that the micelles of various concentration of hemolysis rates were all less than 5%.Optimum application of drug loaded micelles in vitro release preliminary study data indicated that the drug without burst release phenomenon and is completely slow release that the nano micelles has certain characteristics of sustained-release.4.Effect of MPEG-PCL-PTyr micelle on human hepatocellular carcinoma HepG2 cellsThe MTT assay was used to investigate micellar MPEG-PCL-PTyrHCPT on HepG2 tumor cells in vitro inhibition,inhibition of activity data show that the experimental group on HepG2 cell proliferation inhibition rate was more than 0.5,with drug concentration increases,the inhibitory rate increased,at the same concentration,the inhibition of each drug rate with time prolonging and rise.The uptake of HepG2 cells was analyzed by fluorescence microscopy,and quantitative analysis was performed by flow cytometry.Cell uptake assay results showed that the percentage of the positive cells was 56.9±3.47%,and MPEG-PCL-PTyr-HCPT could be uptake by HepG2 tumor cells.