Preparation And Evaluation Of PH-sensitive CMCS-hyd-DNR Nano Drug Delivery System

Daunorubicin(DNR),an anthracycline antitumor antibiotic,was widely used for the therapy of tumor.Owing to its poor solubility and serious side effects,its clinical application is greatly limited.In this study,the amphiphilic polymer prodrug was prepared by linking DNR with the macromolecular carrier CMCS via an acid-sensitive hydrazone linkage.In aqueous media,the prodrug spontaneously formed pH responsive nano-sized particles.The main work and results of this paper were shown as follows:(1)The amphiphilic polymer prodrug CMCS-hyd-DNR was prepared through three-step synthesis,methyl glycinate(Me-G)was firstly conjugated to CMCS via an amidation reaction during the catalysis of EDC·HCl and NHS.Then,hydrazine hydrate was condensed with the carbomethoxy group to form hydrazide.Finally,the CMCS-hyd-DNR conjugates were obtained by attaching DNR to the hydrazide via a hydrazone bond.The conjugate was structurally characterized by Fourier transform infrared spectroscopy(FT-IR)and ~1H-NMR spectroscopy to prove its successful preparation;Ultraviolet spectrophotometer(UV)was employed to study the influence of molecular weight(MWs)of the carriers on the drug loading capacity by measuring the percentage of DNR.The drug loading capacity reduced from 12.45%to 5.89%when the MWs of CMCS increased from 7.0×10~4 to 7.4×10~5.(2)In aqueous media,the amphiphilic polymer prodrug CMCS-hyd-DNR can spontaneously form nanoparticles.The nanoparticle was spherical with good dispersity and negative charge in its surface.The mean size of nanoparticles increased from 104 to 216 nm when molecular weight increased from 7.0×10~4 to 7.4×10~5.A certain concentration of nanoparticle solution was incubated in simulated physiological environment to study the stability of the nanosystem.The mean size and PDI did not significantly differ during incubation,which indicate that the nanoparticles have excellent stability.(3)HPLC was employed to study the drug release in different pH medium,which indicated that the nanoparticle was highly pH-dependant.DNR was quickly released from the micelles at pH 5.0 i.e.,more than 65%DNR were released after 48h,while less than 23 and 18%of DNR were released,respectively.(4)CCK-8 was used to study the antitumor efficiency of the nanosystem,which implies that the antitumor efficiency between CMCS-hyd-DNR nanoparticles and free drug was strongly related to the incubation time and concentration of drug.As the concentration increased,the cell viability decreased;the incubation increased time increased,the cell viability decreased.Besides,the same method was used to study the cytotoxicity of polymer carriers,cell viability was still more than 90%even at concentrations of 10?g/mL,which indicates that the polymer carriers have excellent biocompatibility and can be safely used for drug delivery.The cellular uptake and intracellular distribution of free DNR and CMCS-hyd-DNR nanoparticles was investigated for 0,0.5,1,2,and 4 h by CLSM,indicating the faster released of free DNR inside the cells than CMCS-hyd-DNR nanoparticles.