| Polyamino acid compounds as nanocarriers have the characteristics of biodegradability and good biocompatibility.They have been one of the most promising drug delivery systems in tumor-targeted nanopharmaceuticals.Polyamino acid materials have the characteristics of protein-like structure,easy-to-adjust hydrophile-hydrophobicity,in vivo enzymatic degradability,unique secondary structure,and contain multiple active groups.Recently,they have been increasingly used to prepare polymer nanocarriers.In this paper,poly-?-amino acid(?-PGA)materials were prepared by ring-opening polymerization with N-Boc-ethylenediamine as the initiator and glutamic acid anhydride as the polymerization element,which were applied as nanocarriers and investigation of drug-loaded nanopreparation Process,and then study its antitumor effect in vivo and in vitro.In the second chapter,BLG-NCA was prepared by chemical synthesis,and N-Bocethylenediamine was used to initiate the polymerization reaction.Poly-L-glutamic acid benzyl esters with different molecular weights were obtained through different polymerization reaction times,followed the benzyl protection was removed by 33% HBr to obtain two polyamino acid materials.The results of NMR and gel permeation chromatography proved that two ?-PGAs with weight average molecular weights of 13894 and 48590 were prepared successfully.In the third chapter,the preparation process of ?-PGA was determined by single factor experiment,with particle size and PDI,drug loading,entrapment efficiency and cumulative release in vitro as indexes,step by step screening for ?-PGA NPs molecular weight,preparation method,model drug screening,and preparation process optimization,and its quality was evaluated.The screening results were as follows: using ?-PGA(L)as the carrier,drug-loaded nanoparticles were prepared by precipitation method,and then DOX was selected as the model drug through the preparation of NPs,with 7 different functional groups.The three influencing factors of the drug-loading ratio,homogenization times,and ultrasonic power were investigated in the preparation process optimization.The results showed that the drug-loading ratio was 4:1 and the nanoparticles were homogenized for 5 times under high pressure at 1600 bar.Finally,the quality evaluation of the nanoparticles showed that the particle size of ?-PGA NPs had no obvious change after 30 days,and the stability in the medium was good.In the in vitro release test,the cumulative release of ?-PGA NPs reached 59.74 ±4.60% in pH=7.4 's PBS releases medium and 70.39 ±5.50% in pH=5.5 's PBS release medium,which showed obvious pH sensitivity.In the fourth chapter,the effects of molecular weight and preparation methods of ?-PGA on the anti-tumor effect of NPs in vitro were studied by CCK-8 method.The results showed that ?-PGA(L)and NPs prepared by precipitation method had a better anti-tumor effect in vitro.Then,the inhibitory effect of ?-PGA NPs on the proliferation of 4T1 cells and MCF-7 cells in vitro and the anti-tumor effect in vivo were investigated.At the same time,the contents of lactate dehydrogenase,glutamic oxaloacetic transaminase,creatine phosphokinase,and creatine phosphokinase isoenzyme in the serum of 4T1 tumor-bearing mice were detected,and the nucleolytic of tumor cells and cardiomyocytes were observed by H&E staining.The results showed that the tumor inhibition rate of DOX group was 45.43% ±17.53%,and a large number of cardiomyocyte apoptosises was found,while the tumor inhibition rate of ?-PGA/DOX NPs group was 67.40% ±11.45%.There was no lysis,fragmentation,and atrophy of the myocardial nucleus,and a small amount of inflammatory infiltration occurred and effectively inhibited the release of LDH,CK and CK-MB.In the fifth chapter,the analytical detection methods of CSL and DOX were constructed and methodological verification was carried out.The results showed that the constructed HPLC method met the requirements of methodological verification. |
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