Preparation And Properties Of Self-assembled Co-delivery Reduction-sensitive Paclitaxel Dimer And Tetrandrine Nanoparticles

Cancer is one of the most deadly diseases in the world.Chemotherapy is the main treatment for cancer,but chemotherapy drugs are often susceptible to systemic toxicity due to their poor biocompatibility.At present,the use of nano-carrier materials to deliver chemotherapeutic drugs has been extensively studied,but there are still many defects,such as low drug encapsulation rate,excessive or too small micelle size.At the same time,chemotherapy drugs easily cause multidrug resistance of tumor cells leading to chemotherapy failure.Multidrug resistance is mainly caused by overexpression of P-glycoprotein(P-gp)in tumor cells.Recent studies have found that tetrandrine(TET)can effectively inhibit the overexpression of P-gp,and the use of nanocarrier materials to co-deliver anti-tumor drugs and P-gp inhibitors has become a hot research topic.The sequential release of P-gp inhibitors and anticancer drugs is of great significance for reversing the multidrug resistance of tumor cells and improving the antitumor effect of chemotherapeutic drugs.Based on this,this paper designed and prepared co-coated paclitaxel dimerization.The prodrugs(PTX2)and TTE’s mPEG-PLGA/PTX2/TET nanoparticals,the main research contents and conclusions are summarized as follows:1.A disulfide-linked paclitaxel dimer prodrug(PTX2)was prepared by using the antitumor drug paclitaxel(PTX)as a raw material.The synthesis of PTX2 was confirmed by 1H-NMR and UHPLC-Orbitrap HRMS.2.Using PTX2,TET and amphiphilic block copolymer methoxyl poly(ethylene glycol)-lactic-co-glycolic acid as raw materials,mPEG-PLGA blank nanoparticals were prepared by solvent evaporation method.mPEG-PLGA/PTX2 drug-loaded nanoparticals and mPEG-PLGA/PTX2/TET nanoparticals co-coated with PTX2 and TET.The average particle size of mPEG-PLGA/PTX2/TET nanoparticals is 146nm.In the range of 100-200nm,the passive targeting effect(EPR effect)in vivo can be achieved.The polydispersity coefficient(PDI)is about 0.1,indicating that the nanoparticles’ distribution is uniform and monodispersed,while the TEM shows that the appearance is round and uniform,and there is no adhesion between the micelle particles.The stability test of micelles showed that mPEG-PLGA/PTX2/TET did not change the micelle size and dispersion within two weeks.3.The encapsulation efficiency and drug loading of PTX2 and TET in nanoparticals were measured by UHPLC-Orbitrap HRMS.The mass ratio of mPEG-PLGA,PTX2 and TET during the preparation process was changed,and the effect of carrier material and drug mass ratio on the drug loading in drug-loaded micelles was studied.The results showed that when the mass ratio of mPEG-PLGA to PTX2 was 10:1,the drug loading and encapsulation efficiency of PTX2 in mPEG-PLGA/PTX2 nanoparticals were 95.39%and 8.71%,respectively;when mPEG-PLGA,PTX2 and TET were respectively When the mass ratio was 10:1:1,the drug loading and encapsulation efficiency of PTX2 in mPEG-PLGA/PTX2/TET nanoparticals were 73.91%and 6.88%,respectively,and the drug loading of TET was 88.83%and 8.16%respectively.4.In vitro release experiments of mPEG-PLGA/PTX2/TET nanoparticals showed that in a reducing environment of 40 mL of phosphate buffer solution containing 10 mM DTT and 0.5%(w/v)Tween 80,at 24 h,30%of TET was released,70%of PTX2 was hydrolyzed to PTX,and 87%of PTX2 was hydrolyzed to PTX at 48h.5.MTT colorimetric assay showed that the inhibition rate of mPEG-PLGA/PTX2/TET nanoparticals on breast cancer MCF-7 cells was 45.64%and 54.06%at 24h and 48h(PTX2 concentration was 10ng/mL).The mPEG-PLGA/PTX2 nanoparticals are 23.79%and 36.33%,the former increased by 91.8%and 48.8%respectively compared with the latter;the inhibition rate of mPEG-PLGA/PTX2/TET nanoparticals on MCF-7 cells was basically the same as that of DMSO solution of the same concentration of PTX.However,mPEG-PLGA/PTX2/TET nanoparticals can achieve controlled release with better biocompatibility and targeting.At the same time,the inhibition rate of mPEG-PLGA blank nanoparticals on MCF-7 cells was very low,indicating that the drug-loaded materials had no obvious toxicity to cells.6.Cellular uptake experiments showed that the fluorescence of Rho123+TET group in MCF-7 cells was stronger than that of Rho123 group,and the fluorescence of mPEG-PLGA/(R+T)group was stronger than that of Rho123+TET group.It indicated that the addition of TET can inhibit P-gp pumping the drug out of the cell,thereby increasing the concentration of the drug in the cancer cells,and the use of the mPEG-PLGA vector also significantly increased the accumulation of the drug in the cell.The innovation of this thesis is that the first preparation of mPEG-PLGA/PTX2/TET nanoparticals can achieve the first release of TET to inhibit P-gp,and then PTX2 in the tumor cells with high concentration of glutathione(GSH).In the reducing environment,it is reduced to PTX,inhibiting the proliferation and division of tumor cells,and achieving the purpose of reversing the multidrug resistance of tumor cells.Secondly,in order to obtain the ideal encapsulation efficiency and drug loading,the drug-loading material-to-drug ratio in the preparation process was optimized,and a better drug-loading effect was achieved.