Zhang Xb
Peking University
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Publication
Featured researches published by Zhang Xb.
Journal of Controlled Release | 2002
Sha Li; Wang Xt; Zhang Xb; Ren-jie Yang; Hong-zhi Zhang; Lin-zhong Zhu; Hou Xp
Spherical and well-dispersed alginate-chitosan microcapsules, with a mean diameter of 77.28+/-0.93 microm (n=3), were prepared by the emulsification-gelation method. Adriamycin hydrochloride (ADM) was used as a model drug to investigate the drug loading capacity and release characteristics of the microcapsules. The drug/carrier ratio and chitosan concentration influenced the encapsulation efficiency of adriamycin. The adriamycin release from microcapsules was obviously different in 0.1 mol/l HCl from that in phosphate-buffered saline (PBS, pH 7.4). The drug was completely and rapidly released in 0.1 mol/l HCl, while it showed a sustained release after a burst release in PBS. The increase in chitosan concentration had no effect on adriamycin release in PBS. Using sulforhodamin B (SRB)-staining survival assay, the inhibition of adriamycin alginate-chitosan microcapsules (ADM-ACM) to different cancer cell lines (human BGC-823 cells, Bel-7402 cells and Hela cells) in vitro was determined. The inhibitory rate of ADM-ACM suspension to the three cell lines significantly outran that of ADM solution, no matter at high or low concentration. The effects of blank alginate-chitosan microcapsules (BACM) on renal arterial embolization were examined with transcatheter arterial embolization in rabbits. The angiogram and histopathological results indicated the blank microcapsules had excellent short- and long-term effects on renal arterial embolization.
Drug Delivery | 2004
Zhang Xb; Ying Xie; Yiguang Jin; Hou Xp; Liya Ye; Jinning Lou
To investigate the effect of RMP-7 and its derivative on drug transport across blood brain barrier (BBB), RMP-7 and DSPE-PEG-NHS [1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-n-[poly(ethyleneglycol)]-hydroxy succinamide, PEG M 3400] were conjugated under mild conditions and the reaction ratio was determined using MALDI–TOF-MS (matrix-assisted laser desorption-ionization time-of-flight mass spectrometry). An endothelial cell monolayer in vitro BBB model was established and used to determine the bioactivity of RMP-7 and its derivative “opening BBB.” Horse radish peroxide (HRP), liposome (HRP-L-PEG), and Evens blue (EB) liposome (EB-L-PEG) were prepared using the reverse-phase evaporation method. HRP-L-PEG-RMP-7 and EB-L-PEG-RMP-7 were obtained by inserting DSPE-PEG-RMP-7 into the surface of liposome. The bioactivity of RMP-7 and DSPE-PEG-RMP-7 opening BBB were evaluated to determine their effect on the permeation ratio of HRP and HRP liposome across the in vitro BBB model. To evaluate the in vivo bioactivity of RMP-7 and DSPE-PEG-RMP-7 on EB transport across BBB into the brain, the indicated compounds were administered to rats. Then, brain slices were analyzed using confocal laser scanning microcopy and the EB concentration in the brain, liver, spleen, lung, and kidney was determined using the formamide–extraction–ultraviolet-spectrophotometric method. The results demonstrated that RMP-7 was conjugated with DSPE-PEG-NHS at the molecular ratio of 1:1 and the product is DSPE-PEG-RMP-7. Compared with adding HRP alone, RMP-7 and DSPE-PEG-RMP-7 improved 2- to 3-fold the transport of HRP in the in vitro BBB model. The in vivo experiments showed that DSPE-PEG-RMP-7 was better at facilitating EB transport into brain than RMP-7. The reason may be that DSPE-PEG-RMP-7 can “open BBB” as soon as the EB-L-PEG-RMP-7 reaches BBB.
Journal of Neuroimmune Pharmacology | 2009
Zhang Xb; Daria Y. Alakhova; Elena V. Batrakova; Shu Li; Yili Li; Alexander V. Kabanov
A synthetic amphiphilic block copolymer Pluronic P85 (P85) was shown to be among the most potent inhibitors of Pgp efflux system in the blood–brain barrier (BBB) and capable of enhancing delivery of Pgp substrates to the brain. The purpose of this work is to evaluate the effects of P85 on amino acid transport in BBB. Primary bovine brain microvessel endothelial cells (BBMEC) grown on membrane inserts were used as an in vitro BBB model. Expression of amino acid transporters, like large neutral amino acid transporter 1, cationic amino acid transporter 1, and small neutral amino acid transporter 1, were confirmed by reverse transcriptase polymerase chain reaction. Effects of P85 on amino acid transporters were examined using their substrates: 3H-phenylalanine, 3H-lysine, and 3H-methylaminoisobutyric acid, respectively. BBMEC permeability studies were carried out in apical (AP) to basolateral (BL) and BL to AP directions. P85 added at the AP side had little, if any, effect on AP to BL (“blood to brain”) transport for all examined amino acids in BBMEC monolayers. However, 0.1% P85 added at the BL side significantly increased the BL to AP transport of these substrates. Furthermore, the effective concentrations of P85 were also shown to induce plasma membrane depolarization and increase intracellular sodium concentration in BBMEC, which can contribute to the effects of the copolymer on the energy-dependent transport systems. All together, despite profound effects on transport system(s) at the brain side of cell monolayers, P85 had no effect on AP to BL transport of amino acids in brain microvessel endothelial cell model.
Journal of Controlled Release | 2005
Ying Xie; Liya Ye; Zhang Xb; Wei Cui; Jinning Lou; Tsuneji Nagai; Hou Xp
Journal of Drug Targeting | 2003
Zhang Xb; Jieqiong Xie; Sha Li; Wang Xt; Hou Xp
Journal of Peking University. Health sciences | 2004
Ying Xie; Liya Ye; Zhang Xb; Hou Xp; Jinning Lou
Acta pharmaceutica Sinica | 2003
Wang Xt; Sha Li; Zhang Xb; Hou Xp
Acta pharmaceutica Sinica | 2004
Zhang Xb; Yuan S; Lei Pc; Hou Xp
Acta pharmaceutica Sinica | 2004
Xie Y; Ye Ly; Cui W; Xu K; Zhang Xb; Lou Jn; Hou Xp
Acta pharmaceutica Sinica | 2003
Zhang Xb; Jin Yg; Xie Y; Xu K; Hou Xp