Targeting Amphiphilic Peptides P23 Entrapped Doxorubicin And Its In Vitro Release Kinetics

In the 21st century,cancer has threatened human health seriously.Most anticancer drugs have poor solubility,short cycle time in the body,no target recognition ability,and cause serious damage to human organs.In order to reduce the side effects of anticancer drugs on humans,amphiphilic peptides which.have been used as drug transport carriers become a research hotspot.Amphiphilic peptides have good biological activity.They can be degraded in vivo and do not cause bioimmune reactions.The amphiphilic peptides can be self-assembled to nano microspheres nanofibers,and nanotubes in the aqueous solution or organic solvent.Therefore they can used to be anticancer drug transport carrier,which can improve the solubility of the drug,increase the utilization of the hydrophobic drug and reduce the toxic side effects of the human body.The peptides with targeting sequence can also enhance the targeting of the anticancer drug and increase the time for the drug to circulate in the body.Therefore,amphiphilic peptides are expected to be used as drug carriers for cancer treatment,and have broad prospects in the field of biomedicine.In this paper,the peptide DGRKKKKAAVALLPAVLLALLAP(P23)was designed and synthesized by myself.The P23@DOX were prepared by the forward dialysis method.The materials were characterized by LC-MS,Infrared Spectrometer,Transmission Electron Microscope and Nanoparticle Size Analyzer.The pH-release ability of the materials was investigated by acid-base titration experiments.Material toxicity to cells and the targeting of tumor cells were studied by in vitro cell experiments.The capacity of loading drug and release characteristics was studied by in vitro simulated drug release experiments.Determine the best fit model from five mathematical modles of drug release which were used to fit the vitro release of P23@DOX.The specific research results include the following three parts:(1)The results of LC-MS were consistent with the theoretical molecular weight of P23,and the results of Infrared Spectrometer were consistent with the characteristic functional groups of P23.The conditions for P23 form into micelles were optimized.The optimal conditions is that pH was 7.4 and the concentration was 0.1 mg mL-1.In the acid-base titration experiment,the buffering capacity was 18.96%from pH 5.3 to 7.4,indicating that P23 has a pH-releasing ability in acidic conditions and prolongs the residence time in the body.(2)The critical micelle concentration of P23 micelles was 1.018 mg·L-1,the average particle size of P23@DOX was 93 nm,and the drug loading and encapsulation efficiency were 22.65%and 35.1%.P23 showed low toxicity on HUVEC cells and 4T1 cells.When the concentration was 0～200 μg ·mL-1,the survival rate of HUVEC cells was always above 85%.At a concentration of 200 μg · mL-1,the inhibition rates of DOX and P23@DOX on 4T1 cells were 58.9%and 84.6%,indicating that P23@DOX has a stronger inhibitory effect on 4T1 cells than DOX.In the cell uptake experiment,P23@DOX was enriched around the tumor cells,indicating that P23@DOX can target the drugs to tumor cells.(3)In vitro drug release experiments showed that the release rate of P23@DOX was the highest at pH 1.2,which was 84.6%.The Weibull equation is the best fit for in vitro release simulation.The fitting equation was Q=78.47009(1-e-0 06166(t+10 56962)^3 28518)).The release rate at pH 4.6 was 55.10%and the release rate at pH 6.8 was 36.19%.The fitting equations respectively were Q=53.952(1-e-(0.10778(t+3.69179)^1.51503))and Q=29.83676(1-e-(0.14539(t+3 05137)^1.93247)).In summary,this paper prepared a drug transport carrier(P23@DOX),which could release drugs in acidic conditions,target 4T1 cells,inhibit 4T1 cell proliferation effectively and has little toxic side effects on normal cells.Therefore,it is expected to be applied to cancer treatment.