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ObjectiveTo develop doxorubicine-loaded nanomicelles based on a type of novel starshaped 4-arm PLGA-PEG-NH2 amphiphilic block copolymers.Methods 4s-(PLGA-PEG-NH2) synthesized by 4s-PLGA and (H2N-PEG-NH2) according to N,N'-dicyclohexylcarbodiimide(DCC) condensation reaction was demonstrated by 1H NMR spectroscopy and gel permeation chromatography(GPC); DOX-loaded 4s-(PLGA-PEG-NH2) nanomicelles were self-assembled by doxorubicin(DOX) and 4s-(PLGA-PEG-NH2) via emulsion-solvent evaporation method and characterized in terms of morphology,particle size and size distribution,drug loading,encapsulation efficacy,cell uptake and cytotoxicity studies.Results4s-(PLGA-PEG-NH2) were capable of selfassembling intocore-shell nanomicelles structure and encapsulating DOX into their hydrophobic cores.The mean size of DOX-loaded 4s-(PLGA-PEG-NH2) was nanometer size; drug loading and encapsulation efficacy were around 7.5％ and 75.2％,respectively.Mean surface charge of the micelles was around -17.6 mV.In vitro cell uptake and cytotoxicity studies indicated that comparing to the DOX-loaded linear-(PLGA-PEG-PLGA)nanomicelles,DOX-loaded 4s-(PLGA-PEG-NH2) nanomicelles showed better performance in uptaking by HeLa cells and higher cytotoxicity to cancer cells.Conclusion4s-(PLGA-PEG-NH2) amphiphilic block copolymers can be successfully used in encapsulating DOX,self-assemblingcore-shell nanomicelles in aqueous solvent.Therefore,4s-(PLGA-PEG-NH2) copolymers can be considered as a promising drug carrier in effectively carrying hydrophobic drug,improving the efficacy while reducing the side effect.
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Using a micro-column packed with polyethylenimine aminated glycidyl methacrylatE-grafted-polytetrafluoroethylene fiber made by ourselves as the adsorption material, the adsorption behaviors of Pb and Cd under different conditions were studied by inductively coupled plasma optical emission spectrometry. The conditions for the preconcentration of Pb and Cd such as pH, flow-rate, time and eluent acidity were optimized. The results show that the PTFE-g-GMA-PEI Fiber has excellent adsorption property and high adsorption capacity for Pb2+ and Cd2+. The Enrichment factors for Pb2+ and Cd2+ were 30 and 80, respectively and the detection limits were 3.5 μg/L and 0.15 μg/L, respectively, the relative standard derivations were 1.5% and 0.6%(n=9)respectively. When the single ion concentration was 50 μg/L, the sampling frequency was 9 and 18 times/h, respectively. The method was applied to the simultaneous determination of trace lead and cadmium of several Chinese traditional medicine samples, the standard recovery of samples was 90%-108%.
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BACKGROUND: The effective therapy of artificial liver for severe hepatitis needs an absorbing material which possesses strong adsorptive property, high adsorption rate and good blood compatibility.OBJECTIVE: To study the adsorptive property of eight novel adsorbents for plasma bilirubin and cytokines in severe hepatitis patients. DESIGN: A controlled observation.SETTINGS: Graduate School of Tianjin Medical University, Tianjin Haihe Hospital, Tianjin Third Central Hospital and the Institute of Polymer Chemistry in Nankai University.PARTICIPANTS: All plasma was collected from 30 severe hepatitis patients hospitalized in Tianjin Third Central Hospital from November 2004 to November 2005. Informed consent was obtained from each patients. This experiment was approved by the hospital ethical committee. All the patients were divided into two groups at random: group 1 (n=10) and group 2 (n=20). The level of total bilirubin (TBiL) before therapy in two groups was (377.3±147.5) μmol/L and (327.6±140.1) μmol/L, respectively.METHODS: ①Adsorbents: Chitosan (Qingdao Lizhong Chitosan Factory, Shandong) with relative molecular weight 97 000 and de-acetyl grade 85%; Adsorbents No.1-3 were prepared by using 1%, 3%, 5% polyethyleneglycol (relative molecular weight 600) as porogenic agent. Adsorbent No.4 was aminated crosslinked chitosan microspheres; Adsorbent No.5 was divinyl-benzene crosslinked macroporous polystyrene microspheres; Adsorbent No.6 was post-crosslinked macroporous divinyl-benzene styrene copolymer microspheres; Adsorbents No.7 and 8 were chitosan wrapped adsorbent No.5 and 6.②Detection: Step 1: 3 mL plasma collected from each severe hepatitis patient in group 1 was absorbed with 1 mL of 8 kinds of adsorbents. Levels of plasma TBiL, direct bilirubin (DBiL) and indirect bilirubin (IBiL) before and after adsorption were determined by using the vanadate oxidation method to analyze the average adsorption capacity so as to screen the adsorbents with the better adsorptive properties. Step 2: 3 mL plasma collected from each severe hepatitis patient in group 2 was absorbed with 1 mL of two adsorbents selected from the step 1. The levels of bilirubin, interleukin-6 and tumor necrosis factor-α before and after the adsorption were analyzed by ELISA method.MAIN OUTCOME MEASURES: The levels of bilirubin and cytokines before and after the adsorption were determined.RESULTS: ①The data in the first step experiment showed that after No.4 and No.5 adsorbents were used, the level of plasma TBiL, DBiL and IBiL were significantly decreased (P < 0.01); no differences were found for other six kinds of adsorbents (P > 0.05).②The data in the second step experiment showed that the average levels of plasma TBiL, DBiL, IBiL, interleukin-6 and tumor necrosis factor-α were remarkably reduced after using adsorbents No.4 and No.5 (P < 0.01). Compared with adsorbent No.5, there were significant decrements for adsorbents No.4 (P < 0.01).CONCLUSION: Aminated chitosan microsphere has significant effects on adsorbing bilirubin and cytokines in plasma of severe hepatitis patients in vitro.