| Gd-DTPA was developed firstly as the water-soluble paramagnetic contrast agent for MRI, and had been widely used in clinical magnetic resonance imaging so far. Liposomes as drug carrier could take control of drug release, improve drug efficacy, target to special organizations or cells actively through modified by special targeting molecules,so that drug could be delivered to specific organizations or cells actively. Glucose transporter protein 1(GLUT1), as the carrier of glucose, had been proved to express in many tumor cells excessively. The thesis presented here focuses mainly on the preparation of the Glycosylated PEG Liposomes encapsulating Gd-DTPA and its ability to target to tumor cells in vitro, which may be divided into the following five parts.Part one: ReviewsThis reviews could be divided into three parts:in the first part, the mechanism and classification of MRI contrast agent and character of Gd-DTPA were described. In the second part, we introduced the preparation methods of liposomes, its stability and quality control. In the third part we mainly introduced liposomes to target to organizations.Part two: Synthesis of N-palmitoyl glucosamineUsing palmitic acid N- hydroxysuccinimide and Glucosamine as reagents, synthesize N-palmitoyl glucosamine and optimize the reaction conditions. According to gas chromatogram, infrared absorption spectrum, mass spectrometry, H-NMR and C-NMR, infer the reaction product was N-palmitoyl glucosamine.And detect the physicochemical property of N-palmitoyl glucosamine.Part three: Preparation of Gd-DTPA liposomesPrepare four liposomes by retro-evaporation method, which is common liposome, PEGylated liposome, Glycosylated liposome, Glycosylated PEG Liposomes. The technics and influential factors of the prescription of four liposomes was studied. Optimize the preparation technics and prescription of liposomes. The results showed that four liposomes all had higher encapsulation efficiency and stability. Part four: Quality Evaluation of liposomesIn this part, the detemination method of Gd-DTPA with HPLC and encapsulation efficiency of liposomes was established. The size, shape, entrapment efficiency and stability of liposomes were studied. The results showed that, the detemination method of Gd-DTPA with HPLC, whose standard curve was y=135057x + 4153.8(r= 0.9998), had a good linear, precision, entrapment efficiency, recovery rate and low LLD. Determining the encapsulation efficiency of liposome by dialysis, was simple, convenient and reliable. The four liposomes were round, high encapsulation efficiency and high stability.Part five: Liposomes targeting to Tumor cellPrepare common liposome, PEGylated liposome, Glycosylated liposome, Glycosylated PEG Liposomes by retro-evaporation method. Then the four types of liposomes were trained with prostate cancer cells respectively. MRI and HPLC detected Gd-DTPA concentrations of prostate cancer after training. The results showed that, prostate cancer cells have on the uptake of four liposomes. SE-T1W signal values of each liposome MRI detection were:common Gd-DTPA liposomes362, PEGylated Gd-DTPA liposomes299, Glycosylated Gd-DTPA liposomes 397, Glycosylated PEG Gd-DTPA liposomes377. Gd-DTPA concentration of each liposome HPLC detection were: common Gd-DTPA liposomes 4.74×10-5mol, PEGylated Gd-DTPA liposomes 1.20×10-5mol, Glycosylated Gd-DTPA liposomes7.60×10-5mol, Glycosylated PEG Gd-DTPA liposomes2.05×10-5mol. Comparing the detection value of each group, we concluded that liposome as an drug carrier can carry drug to target tumor cell, phagocytosis of tumor cell to liposomes, which was modified by glucose, increase significantly.
|
PDF Full Text Request