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Zhao W.,Northwestern Polytechnical University | Zhang H.,Northwestern Polytechnical University | Lu T.,Northwestern Polytechnical University | Liu W.,Northwestern Polytechnical University | And 3 more authors.
Applied Surface Science | Year: 2013

Electrostatic self-assembly was applied to fabricate novel-structured magnetic liposomes. According to the charge characteristics of the magnetic nanoparticles and the drug-loaded liposomes, magnetic liposomes were fabricated by alternately assembling the suitable polyelectrolytes and magnetic nanoparticles onto the drug-loaded liposomes. TEM photograph provided direct evidence for successful fabrication of the novel-structured magnetic liposomes. It was also found that electrostatic self-assembly is a universal approach to prepare novel-structured magnetic liposomes with tunable size. The reversed phase high performance liquid chromatography (RP-HPLC) method was established to determine the content of the drug in the magnetic liposomes. The content of the magnetic nanoparticles in the magnetic liposomes was determined by UV spectrophotometry, which proved that the content of magnetic nanoparticles in novel-structured magnetic liposomes was higher than in traditional-structured magnetic liposomes. In vitro drug release from the magnetic liposomes was carried out, and fitting of the release curve using Curve Expert software indicated that the in vitro drug release of the magnetic liposomes was in accordance with the First-order equation. © 2012 Elsevier B.V. All rights reserved.

Zhao W.,Northwestern Polytechnical University | Kong D.,Northwestern Polytechnical University | Lu T.,Northwestern Polytechnical University | Chen T.,Northwestern Polytechnical University | Chen T.,Shaanxi Liposome Research Center
2011 International Conference on Remote Sensing, Environment and Transportation Engineering, RSETE 2011 - Proceedings | Year: 2011

Nimodipine often dissolve out of the injecta for its poor water-solubility, which makes trouble in clinical application. Currently, polymeric micelle is popular drug delivery system for the poorly water soluble drugs, which can be solubilized within the hydrophobic inner core of a micelle. It is believed that compatibility between the micellar hydrophobic chain and the drug would have influence on solubilization. In this study, molecular simulation using Materials Studio simulation software was carried out to investigate the compatibility between several micellar hydrophobic chains and nimodipine, and structure optimization was completed to obtain suitable hydrophobic chain for nimodipine. It was shown that among the hydrophobic chains involved in this paper, poly(benzyl glutamate) has best compatibility with nimodipine, which was optimized hydrophobic chain for nimodipine-loaded micelle.© 2011 IEEE.

Ma Y.,Xian Jiaotong University | Lu T.,Northwestern Polytechnical University | Zhao W.,Northwestern Polytechnical University | Wang Y.,Northwestern Polytechnical University | And 3 more authors.
Antimicrobial Agents and Chemotherapy | Year: 2014

Artemether and lumefantrine (also known as benflumetol) are difficult to formulate for parenteral administration because of their low aqueous solubility. Cremophor EL as an emulsion excipient has been shown to cause serious side effects. This study reports a method of preparation and the therapeutic efficacies of novel lipid emulsion (LE) delivery systems with artemether, lumefantrine, or artemether in combination with lumefantrine, for parenteral administration. Their physical and chemical stabilities were also evaluated. Furthermore, the in vivo antimalarial activities of the lipid emulsions developed were tested in Plasmodium berghei-infected mice. Artemether, lumefantrine, or artemether in combination with lumefantrine was encapsulated in an oil phase, and the in vivo performance was assessed by comparison with artesunate for injection. It was found that the lumefantrine lipid emulsion (LUM-LE) and artemether-lumefantrine lipid emulsion (ARM-LUM-LE-3) (1:6) began to decrease the parasitemia levels after only 3 days, and the parasitemia inhibition was 90% at doses of 0.32 and 0.27 mg/kg, respectively, with immediate antimalarial effects greater than those of the positive-control group and constant antimalarial effects over 30 days. LUM-LE and ARM-LUM-LE-3 demonstrated the best performance in terms of chemical and physical stabilities and antiplasmodial efficacy, with a mean particle size of 150 nm, and they have many favorable properties for parenteral administration, such as biocompatibility, physical stability, and ease of preparation.Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Ma Y.F.,Northwestern Polytechnical University | Wang Z.,Northwestern Polytechnical University | Wang Z.,Shaanxi Liposome Research Center | Zhao W.,Northwestern Polytechnical University | And 6 more authors.
International Journal of Nanomedicine | Year: 2013

Background: Pseudomonas aeruginosa represents a good model of antibiotic resistance. These organisms have an outer membrane with a low level of permeability to drugs that is often combined with multidrug efflux pumps, enzymatic inactivation of the drug, or alteration of its molecular target. The acute and growing problem of antibiotic resistance of Pseudomonas to conventional antibiotics made it imperative to develop new liposome formulations to overcome these mechanisms, and investigate the fusion between liposome and bacterium. Methods: The rigidity, stability and charge properties of phospholipid vesicles were modified by varying the cholesterol, 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE), and negatively charged lipids 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol sodium salt (DMPG), 1,2-dimyristoyl-sn-glycero-3-phopho-L-serine sodium salt (DMPS), 1,2-dimyristoyl-sn-glycero-3-phosphate monosodium salt (DMPA), nature phosphatidylserine sodium salt from brain and nature phosphatidylinositol sodium salt from soybean concentrations in liposomes. Liposomal fusion with intact bacteria was monitored using a lipid-mixing assay. Results: It was discovered that the fluid liposomes-bacterium fusion is not dependent on liposomal size and lamellarity. A similar degree of fusion was observed for liposomes with a particle size from 100 to 800 nm. The fluidity of liposomes is an essential pre-request for liposomes fusion with bacteria. Fusion was almost completely inhibited by incorporation of cholesterol into fluid liposomes. The increase in the amount of negative charges in fluid liposomes reduces fluid liposomes-bacteria fusion when tested without calcium cations due to electric repulsion, but addition of calcium cations brings the fusion level of fluid liposomes to similar or higher levels. Among the negative phospholipids examined, DMPA gave the highest degree of fusion, DMPS and DMPG had intermediate fusion levels, and PI resulted in the lowest degree of fusion. Furthermore, the fluid liposomal encapsulated tobramycin was prepared, and the bactericidal effect occurred more quickly when bacteria were cultured with liposomal encapsulated tobramycin. Conclusion: The bactericidal potency of fluid liposomes is dramatically enhanced with respect to fusion ability when the fusogenic lipid, DOPE, is included. Regardless of changes in liposome composition, fluid liposomes-bacterium fusion is universally enhanced by calcium ions. The information obtained in this study will increase our understanding of fluid liposomal action mechanisms, and help in optimizing the new generation of fluid liposomal formulations for the treatment of pulmonary bacterial infections. © 2013 Ma et al, publisher and licensee Dove Medical Press Ltd.

Chen T.,Northwestern Polytechnical University | Chen T.,Shaanxi Liposome Research Center | Chen T.,Xian Libang Pharmaceuticals Ltd. | Wang R.-T.,Northwestern Polytechnical University | And 8 more authors.
Yaoxue Xuebao | Year: 2010

A new class of dendrimer polylysine poly(ethylene glycol)-lipid was designed and synthesized. The cationic polymer liposomes were prepared by the lipid film-extrusion and post-insertion two methods with these dendrimer polylysine poly(ethylene glycol)-lipid and other lipids. The structural properties of obtained cationic polymer liposomes were studied by laser light scattering and fluorescence spectrometer. It was demonstrated that the nano sized liposomes with different density of surface cationic charges can be prepared by either lipid film-extrusion or post-insertion methods, but post-insertion process did not affect drug loading, did not influence drug loading capacity and did not induce liposomal morphology and particle size. The density of positive charge does not affect the size and distribution of different liposomes size and distribution. It was the better choice for manufacture because post-insertion method did not cause early release of drug and size changes. Cell binding experiments show that cationic polymer liposomes, especially dendrimer polymer liposomes had higher local charge density, and therefore have dramatic non specific cell targeting ability.

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