Construction And In Vitro Evaluation Of A Targeted Nano-drug Delivery System Based On Dendrimers

At present,the incidence and mortality of cardiovascular disease(CVD)are the highest in the world.It has become one of the most serious public health problem in the world,and has caused enormous economic burden.Atherosclerosis(AS)is considered to be the main cause of cardiovascular disease.In clinic,surgical treatment of atherosclerosis is easy to cause the risk of postoperative thrombosis and in stent restenosis.Drug intervention,using niacin,statin,α-lipoic acid and EDTA chelation,has been applied.However,non-targeted and toxic side effects lead to unsatisfactory clinical treatment effects.Therefore,it is necessary to explore new strategies for the treatment of atherosclerosis.The rapid development of nanomedicine has broadened the field of vision for the construction of a new targeted nano-drug delivery system to achieve atherosclerosis treatment.In this paper,the fourth generation of polyamide-amine dendrimers(G4),glycyrrhetinic acid(GA)and polyethylene glycol(PEG)were used as nanocarrier,targeting agent and connecting arm respectively to synthesize GA-PEG-G4 and GA-G4 targeting nanocarriers with different degrees of substitution through amidation reaction.The chemical structures of the products were characterized by differential scanning calorimetry(DSC),Fourier transform infrared(FT-IR)and hydrogen nuclear magnetic resonance(~1H-NMR),it was proved that GA-PEG-G4 and GA-G4 nanocarriers were successfully prepared.The number of substitutions of GA and PEG in GA-PEG-G4 nanocarriers and the number of substitutions of GA in GA-G4 nanocarriers were calculated by ~1H-NMR.The number of replacements increased with the increase of the feed ratio.The GA-PEG-G4 nanocarriers synthesized with the feed ratio of 10:1 had better particle size dispersion and more uniform particle size.Choose cholesterol ester hydrolase(CEH)as the model drug,and prepare drug-loaded cholesterol ester hydrolase nanoparticles(CEH/GA-PEG-G4 NPs)by electrostatic adsorption method.The encapsulation efficiency(EE%)and drug loading(LC%)were determined by coomassie blue staining.It was finally determined that when the mass ratio of carrier and drug was 1:1,drug-loaded nanoparticles with better EE%(81.18%)and LC%(13.86%)could be obtained.The in vitro release results showed that compared with the normal physiological environment,the drug-loaded nanoparticles had a faster release rate and a large amount in an acidic intracellular environment.In vitro hemolysis and cytotoxicity experiments preliminarily verified that the GA-PEG-G4 targeting nanocarriers had biological safety.It had also been verified that PEG modification can improve the biocompatibility of the materials better.