Study On The Preparation Of Enzymatic Cleavable Peptide Nanopartides Modified With Tumor-specific And Its Pharmacodynamics

Tumor-targeted drug delivery system was a good drug delivery,in which drug was enriched by carrier in the tumor target.The ideal system needs not only drug concentration in tumor tissue,at the same time can also be specific identification of tumor cells,thus it maximized the therapy and reduced the side effect of drugs.The specifc peptide modified amphiphilic triblock copolymer is a good choice for carrier.Lipophilic drugs could be encapsulated into the core-shell to keep active.The peptide was cleaved only in tumor tissue,thus drug was deliveried into tumor cells.In this work,as the target by MMP-2 in tumor cells,the tumor-targeting amphiphilic triblock copolymers with the enzymatic-cleavable peptide,Me PEG-Pe Ptide-PCL,was designed and synthesized.Curcumin,the antitumor drug,was then used as a model to encapsulate into the core-shell type polymeric nanoparticles,aimed at improving the bioavailability and targeted therapy of curcumin.In addition,the characterization of nanoparticles and its antitumor efficiency were studied.The main contents bellows:1)The HPLC analysis method of the concentration of curcumin was established.This method’s characteristics of specificity,accurcy and recovery were investigated.The results demonstrated that HPLC method met the requirements of the analytic determination.2)Synthesis and characterization of hydrophilic segments Me PEG-COOH and Me PEG-NHS.Me PEG-COOH was effectively prepared with 4-dimethylaminopyridine as the catalyst and linear Me PEG polymer and succinic anhydride as raw material under nitrogen.Then,Me PEG-NHS was gained by the activation of Me PEG-COOH in the presence of N-hydroxysuccinimide and N,N-dicyclohexylcarbodiimide.The copolymers were characterized by ¹H-NMR,FT-IR analysis.The characterization results confirmed that the product had expected structure.The influence factors such as weight ratio,catalyst dosage and acid-binding agent etc.were investigated by orthogonal test.The optimum condition of preparetion was:n（MP）:n（SA）=1:2,n（MP）:n（TEA）=1:1,catalyst dosage was 5%.3)Synthesis and characterization of lipophilic segments PCL-NHt Boc and PCL-NH₂.PCL-NHt Boc was prepared by ring-opening polymerization ofε-caprolactone in the presence of diethyl zinc as an initiator.PCL-NH₂ was gained by deprotection.A GPC method was established to analysis the molecular weight of copolymers,the copolymers PCL-NH₂ was characterized by ¹H-NMR and GPC.The characterization results confirmed that expected result of the product PCL-NH₂.4)Preparation of curcumin-loaded nanoparticles.Three block amphiphilic polymers Me PEG-Pe Ptide-PCL as the carrier was synthesized.Curcumin-loaded nanoparticles was prepared by interfacial precipation method.The results demonstrated that drug entrapment efficiency 65.25%,drug loading capacity 1.07%,and showed an average size of nanoparticles 118.6 nm,zeta potential value of-4.30m V.The ellipsoid shape of Cur-NPs was observed by transmission electron microscopy（TEM）.The FT-IR evaluation showed that the curcumin had been entrapped in Me PEG-Pe Ptide-PCL.5)The antitumor efficiency of Cur-NPs in vitro.MTT assay was carried out using cervical cancer Hela cell as model cells and a series of concentration Cur-NPs/DMEM solutions.The results showed that the higher concentration of Cur-NPs was efficient for inhibitory of Hela cells.