Study On The Properties Of Folic Acid Targeted Stimuli-responsive Polymer Micelles

In order to solve the problems of poor selectivity,low drug utilization,large toxic and side effects of chemotherapeutic drugs,researchers have developed a series of nano drug delivery systems,which still have some defects,such as low stability,poor biocompatibility and biodegradability,etc.Therefore,developing an ideal drug delivery system with good biocompatibility,high drug loading and stability has already become current research hotspots.In this paper,the stimuli-responsive polymer?-CD-?PCL-SS-PEG?₂₁and folic acid targeted polymer?-CD-?PCL-SS-PEG?₂₁-FA have been designed and successfully synthesized,using good biocompatibility and cavity structure?-cyclodextrin??-CD?as the core,biodegradable polycaprolactone?PCL?as the hydrophobic end,and highly stable polyethylene glycol?PEG?as the hydrophilic end.The structures of the synthesized polymers were characterized through nuclear magnetic resonance?¹H NMR?,fourier transform infrared?FT-IR?and gel permeation chromatography?GPC?,et al.The critical micelle concentration?CMC?of the polymer micelles was measured by fluorescence spectroscopy,the obtained CMC results were in the range of 0.0012-0.0034 mg/m L,which indicats that the polymer micelles have better stability.Investigation on the particle size and morphology of polymer micelles by dynamic light scattering?DLS?and transmission electron microscopy?TEM?shows that the micelles are regularly spherical with uniform particle size distribution,which satisfied the basic requirements of drug carriers.Drug-loaded micelles were prepared in aqueous solution by using oxaliplatin?OXA?as model drug.The performance of drug-loaded micelles measured by ultraviolet spectrophotometer demonstrated that folic acid can improve the drug loading and encapsulation efficiency,the maximum values were 22.82%and 68.48%.In vitro drug release experiments illustrated that the cumulative release of the drug-loaded micelles is about 5%in normal environment,which can effectively avoid the sudden release of oxaliplatin.Obviously,the cumulative release and rate of the drug-loaded micelles have enhanced in the reducing environment,indicating that the polymers have good redox-responsive properties.In conclusion,the stimuli-responsive polymer?-CD-?PCL-SS-PEG?₂₁and folic acid targeted polymer?-CD-?PCL-SS-PEG?₂₁-FA with high stability and drug loading have potential to targetedly deliver insoluble anti-cancer drugs,and significant value in the field of cancer treatment.