AIMTo investigate the formation mechanism, macromolecular drug loading capacity and release property of alginate-chitosan microcapsules (ACM).

METHODSACM was prepared by emulsification-gelation method and its formation mechanism was studied by DSC analysis. Using bovine serum albumin (BSA) as model drug, the drug loading and release properties of the microcapsules on macromolecular drug were investigated.

RESULTSThe results of DSC analysis showed that there is electrostatic interaction between materials encapsulated in the microcapsule. With the increase of BSA microcapsule ratio, the BSA loading percentage rose from 9.20% to 35.08%; and with the ascent of chitosan (CTS) concentration, the BSA loading percentage increased from 30.29% to 38.12%. The BSA microcapsules whowed a two-phase release in both 0.1 mol.L-1 HCl and phosphate buffer saline (pH 7.4). With the increase of CTS concentration, the BSA release more and more slowly in 0.1 mol.L-1 HCl.

CONCLUSIONSpheric and well-dispersed alginate-chitosan microcapsules were prepared. The microcapsule showed good loading capacity to BSA as well as sustained release to a certain degree.

Alginates ; chemistry ; Biopolymers ; Calorimetry, Differential Scanning ; Capsules ; Chitin ; analogs & derivatives ; chemistry ; Chitosan ; Delayed-Action Preparations ; Drug Carriers ; Drug Delivery Systems ; Serum Albumin, Bovine ; administration & dosage ; Technology, Pharmaceutical ; methods

AIMSome surfactants such as DSPE-PEG, Tween 80 and Brij 35 were used to modify the amphotericin B liposome, improve the stability, optimize the tissue distribution and decrease the toxicity of amphotericin B liposome.

METHODSThe amphotericin B liposome was prepared by the film-supersound method. The effects of cholesterol and amphotericin B on the encapsulation percentage were studied. The diameter, leakage percentage in phosphate buffer solution(PBS) and calf blood serum, and tissue distributions of amphotericin B liposome in the rat were determined.

RESULTSThe top encapsulation percentage of amphotericin B liposome is (91.2 +/- 1.6)%. After modification with DSPE-PEG, Tween 80 and Brij 35, the encapsulation percentages were improved, the average diameters were decreased and the stabilities were improved, the amphotericin B concentrations in the liver, spleen and kidney were decreased, and the amphotericin B concentrations in the brain were increased, especially in the AmB-L-Tween 80 group.

CONCLUSIONDSPE-PEG and Brij 35 could decrease the clearing of reticuroendothelial systems(RES) to the amphotericin B liposome and Tween 80 could facilitate the transporting of amphotericin B liposome into the brain.

Amphotericin B ; administration & dosage ; pharmacokinetics ; Animals ; Antifungal Agents ; administration & dosage ; pharmacokinetics ; Brain ; metabolism ; Drug Carriers ; Drug Delivery Systems ; Drug Interactions ; Liposomes ; chemistry ; Particle Size ; Phosphatidylethanolamines ; pharmacology ; Polyethylene Glycols ; pharmacology ; Polysorbates ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Surface-Active Agents ; pharmacology ; Tissue Distribution

AIMTo prepare thrombus-targeted urokinase liposomes and observe its improved thrombolytic efficacy on thrombus model rats.

METHODSThe ligand H-Arg-Gly-Asp-Ser-OH (RGDS) which has specific affinity to thrombus was synthesized by liquid phase method and anchored on the surface of liposomes by incorporating its conjugate with DSPE-PEG3,500-COOH into liposomal lipid bilayers, thus thrombus-targeted liposomes were produced. Urokinase (UK) liposomes were prepared at room temperature through method modification using hydrogenated soy phosphatidylcholine (HSPC); the in vivo thrombolysis of the obtained thrombus-targeted UK liposomes and its comparison with TBS (Tris-HCl buffered solution) control, free UK and UK liposomes were assessed on common carotid artery model rats.

RESULTSThe obtained liposomes were characteristic of high UK entrapment efficiency, small mean diameter and good storage stability. At the same dose (60,000 U.kg-1), compared to the wet thrombi weights of TBS control group, those of free UK group and UK liposome group showed no statistical difference, while those of targeted UK liposomes group were significantly decreased (P < 0.001); when evaluated in term of dry thrombi weights the result was slightly different. Compared to UK liposomes of the same dose, the targeted UK liposomes showed significantly improved thrombolytic efficacy (P < 0.01 in wet weights decrease and P < 0.05 in dry weights decrease respectively).

CONCLUSIONThe targeted UK liposomes displayed good targeted thrombolytic effect.

Animals ; Disease Models, Animal ; Drug Carriers ; Drug Delivery Systems ; Fibrinolytic Agents ; administration & dosage ; therapeutic use ; Liposomes ; Male ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Technology, Pharmaceutical ; Thrombosis ; drug therapy ; Treatment Outcome ; Urokinase-Type Plasminogen Activator ; administration & dosage ; therapeutic use

AIMTo target for hepatocytic cell, liposomes was modified by special ligand.

METHODSSterically stabilized liposomes (SSL) was conjugated with asialofeticin (AF), the ligand of asialoglycoprotein receptor (ASGP-R) of hepatocyte. ASGP-R-BLM is the ASGP-R reconstructed on bilayer lipid membrane (BLM). The recognition reaction between AF-SSL and ASGP-R-BLM can be monitored by the varieties of membrane electrical parameters. The targetability of AF-SSL mediated to hepatocyte was detected by radioisotopic labeled in vitro and in vivo. The therapeutic effect of antihepatocarcinoma was observed also.

RESULTSThe lifetime of ASGP-R-BLM decreased with the added amount of AF-SSL. It was demonstrated that there was recognition reaction between AF-SSL and ASGP-R-BLM. The combination of AF-SSL with hepatocyte was significantly higher than that of SSL without AF-modified in vitro and in vivo. The survival time of rat for AF-SSL carriered ADM (adriamycin) group was much longer and the toxicities on heart, kidney and lung were lower than those SSL carried ADM group.

CONCLUSIONIt is possible to actively target the cell with specific receptor by ligand modified liposomes. The result prvide scientific basis of hepatocyte targeted liposomes.

Animals ; Antineoplastic Agents ; administration & dosage ; therapeutic use ; Asialoglycoprotein Receptor ; Asialoglycoproteins ; chemistry ; Doxorubicin ; administration & dosage ; therapeutic use ; Drug Carriers ; Drug Delivery Systems ; Fetuins ; Hepatocytes ; metabolism ; Ligands ; Lipid Bilayers ; Liposomes ; chemistry ; metabolism ; Liver ; metabolism ; Liver Neoplasms, Experimental ; drug therapy ; Male ; Mice ; Random Allocation ; Rats ; alpha-Fetoproteins ; chemistry

AIMTo evaluate the effects of surfactants on the pharmacokinetics and distribution in rats after intravenous administration of SOD liposomes.

METHODSThe liposomes were prepared by reverse phase evaporation method. The activity of SOD was assayed by method of xanthine oxidase.

RESULTSThe T1/2 of SOD solution, common SOD liposome, SOD liposomes modified by DSPE-PEG2000 and Tween 80 were 0.25, 0.34, 0.66 and 0.41 h, respectively; AUC were 12.48, 24.66, 41.16 and 33.02 microg x h x mL(-1), respectively. Compared with the common liposome, the liposomes modified by DSPE-PEG and Tween 80 decreased the content of SOD in liver and spleen, but increased in brain.

CONCLUSIONThe three kinds of liposomes could increase T1/2 and AUC in some extent, especially in PEG-L group. Tween-L could increase the SOD content in brain, and PEG-L could decrease the SOD content in the liver and spleen compared with the common liposome.

Animals ; Area Under Curve ; Brain ; enzymology ; Injections, Intravenous ; Liposomes ; Liver ; enzymology ; Male ; Polysorbates ; pharmacology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Spleen ; enzymology ; Superoxide Dismutase ; administration & dosage ; pharmacokinetics ; Surface-Active Agents ; pharmacology ; Tissue Distribution

AIMTo study the action of RMP-7 and its derivative on transporting liposome across the blood brain barrier (BBB) into the brain.

METHODSRMP-7 and DSPE-PEG-NHS [[1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-n-[poly (ethylene-glycol)]-hydroxy succinamide]] were conjugated together in mild condition and MALDI-TOF-MS (Matrix-Assisted Laser Desorption-Ionization Time-of-Flight Mass Spectrometry) was used to determine their molecular ratio. An in vitro BBB model was established and used to determine in vitro bioactivity of RMP-7 and its derivative. The fluorescence of brain slices and the Evens Blue (EB) concentration in the brain, liver, spleen, lung and kidney of each group were used to evaluate the in vivo bioactivity of RMP-7 and its derivative on transporting liposome across the BBB.

RESULTSThe average molecular weight (MW) of the reaction product was 4,900, while those of DSPE-PEG-NHS and RMP-7 were 3,224 and 1,098. The results demonstrated that RMP-7 was conjugated to DSPE-PEG-NHS at the molecular ratio of 1:1, so the product was DSPE-PEG-RMP-7. RMP-7 and DSPE-PEG-RMP-7 was shown to improve the transporting of peralcohol enzyme across the in vitro BBB model 2-3 times higher than the peralcohol enzyme only. DSPE-PEG-RMP-7 could facilitate the transporting of EB into brain more easily than RMP-7.

CONCLUSIONBoth RMP-7 and DSPE-PEG-RMP-7 could facilitate the transporting of liposome across the BBB, especially DSPE-PEG-RMP-7.

Animals ; Biological Transport ; Blood-Brain Barrier ; drug effects ; Bradykinin ; analogs & derivatives ; pharmacology ; Brain ; metabolism ; Drug Carriers ; Drug Delivery Systems ; Evans Blue ; pharmacokinetics ; Liposomes ; pharmacokinetics ; Phosphatidylethanolamines ; Polyethylene Glycols ; Rats ; Rats, Sprague-Dawley ; Tissue Distribution

AIMTo study the therapeutic efficiency of amphotericin B liposome (AmB-L) targeting to the brain in mice with meningitis.

METHODSAmphotericin B liposome targeting to the brain were prepared by film-sonication method. Their concentration and encapsulation percentage were determined. The Candida albicans was injected into the brain of BALB/c mice and the meningitis model was set up. Then the therapeutic efficiency of amphotericin B liposome targeting to the brain was studied.

RESULTSThe encapsulation percentage of amphotericin B liposome was 93.3%. The meningitis model was set up after the Candida albicans was injected into the brain of BALB/c mice for 2 h. The therapeutic efficiency was increased after conjugating RMP-7 (the commercial nama is Cereport) to the surface of amphotericin B liposome.

CONCLUSIONThe therapeutic efficiency of Amphotericin B liposome targeting to the brain in the mice with meningitis was better than that of the common amphotericin B liposome and the life of the mice in AmB-L-PEG-RMP-7 group was longer than that of the mice in AmB-L-PEG group and AmB-L-PEG + RMP-7 group.

Amphotericin B ; administration & dosage ; pharmacokinetics ; therapeutic use ; Animals ; Antifungal Agents ; administration & dosage ; pharmacokinetics ; therapeutic use ; Biological Transport ; Blood-Brain Barrier ; drug effects ; Bradykinin ; analogs & derivatives ; pharmacology ; Brain ; metabolism ; Candida albicans ; Drug Delivery Systems ; Female ; Liposomes ; Male ; Meningitis, Fungal ; drug therapy ; microbiology ; Mice ; Mice, Inbred BALB C ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the protective effect of recombinant adenovirus-mediated human cytosolic glutathione peroxidase (hCGPx) gene transfection on vascular endothelial cells ECV304 from oxidative damage.

METHODSpGEM-T Easy Vector containing hCGPx cDNA and recombinant adenovirus shuttle plasmid pACCMV-pLpA were used to construct the shuttle plasmid pACCMV-hCGPx for cotransfection of 293 cells with pJM17, thereby to obtain the recombinant adenovirus AdCMV-hCGPx. Cultured ECV304 cells were transfected with AdCMV-hCGPx for 24, 48 and 72 h, respectively, with the cells transfected with the empty vector serving as control, and hCGPx gene expression was then examined in the transfected cells. The transfected cell viability and apoptotic cell ratio were evaluated after treatment of the cells with H(2)O(2).

RESULTSThe expression ratio of hCGPx gene was significantly higher in the AdCMV-hCGPx-transfected cells than in those with empty vector transfection (P<0.01). The hCGPx gene-transfected cells showed significantly higher viability and significantly lower apoptotic ratio than the control cells following challenge with H(2)O(2)-induced oxidative damage.

CONCLUSIONhCGPx gene transfer mediated by recombinant adenovirus protects the vascular endothelial cells from oxidative damage in vitro, possibly due to the antioxidative and apoptosis-inhibiting effect of hCGPx.

Adenoviridae ; genetics ; Apoptosis ; drug effects ; Cell Line ; Cell Survival ; drug effects ; Cytosol ; enzymology ; Endothelial Cells ; cytology ; drug effects ; metabolism ; Flow Cytometry ; Genetic Vectors ; Glutathione Peroxidase ; biosynthesis ; genetics ; Humans ; Hydrogen Peroxide ; pharmacology ; Oxidative Stress ; Plasmids ; genetics ; Time Factors ; Transfection

AIMTo study the permeability of nerve growth factor (NGF) liposomes (NGF-L, NGF-SSL, NGF-SSL-T) on the blood-brain barrier (BBB) model and the distribution in vivo, and analyze the correlation between the results in vitro and in vivo.

METHODSThe BBB model in vitro was established by using mouse brain microvascullar endothelial cell, and the model was applied to study the permeability of NGF liposomes. The distribution of NGF of each group was studied by 125I labeled and SDS-PAGE method.

RESULTSThe highest encapsulation proportion was 34%, and the mean size of NGF liposomes was below 100 nm. The permeability of NGF liposomes on in vitro BBB model showed that the liposome could promote NGF to transport across the BBB, the permeability of NGF-SSL-T was the highest. The distribution in the brain showed in an order of NGF concentration NGF-SSL-T > NGF-SSL + RMP-7 > NGF-SSL > NGF-L. There was a close relationship between P(e) (permeability coefficient on in vitro BBB model) and BUI (brain uptake constant in vivo).

CONCLUSIONLiposomes can promote NGF to transport across the BBB, and the transporting ability BBB of NGF-SSL-T which RMP-7 incorporated into the surface of NGF liposomes is the best.

Animals ; Biological Transport ; drug effects ; Blood-Brain Barrier ; Bradykinin ; analogs & derivatives ; pharmacology ; Brain ; metabolism ; Cell Membrane Permeability ; Drug Delivery Systems ; Endothelial Cells ; cytology ; Liposomes ; Male ; Mice ; Nerve Growth Factor ; administration & dosage ; pharmacokinetics ; Particle Size ; Rats ; Tissue Distribution

OBJECTIVETo construct a replication-incompetent recombinant adenovirus mediating short hairpin RNA (shRNA)-induced tissue factor gene silencing in the islet.

METHODSFour pairs of complementary oligonucleotides were designed and synthesized to create double-stranded oligonucleotides (ds oligo). The ds oligos were cloned into Pentr/U6 vector to construct the shuttle plasmid pENTR/U6-shRNA, which was transduced into human islets via liposome after sequence verification. The plasmid with the best silencing effect was identified by real-time RT-PCR, followed by homologous recombination with the adenovirus backbone plasmid. The functional clone was transfected into 293A cells to amplify the adenovirus, whose silencing effect against TF expression was tested using real-time RT-PCR and Western blotting.

RESULTSThe pENTR/U6-shRNA shuttle plasmid was constructed and verified by sequencing. The recombinant adenovirus-mediated shRNA against TF was constructed, and real-time RT-PCR and Western blotting demonstrated that the strongest silencing effect of the adenovirus against TF occurred on the 4th day following islet transfection.

CONCLUSIONReplication-incompetent recombinant adenovirus-mediated shRNA against TF has been successfully constructed, which has good silencing effect against TF expression in human islet in vitro.

Adenoviridae ; genetics ; physiology ; Base Sequence ; Cell Line ; DNA, Recombinant ; genetics ; Gene Expression ; Genetic Engineering ; methods ; Humans ; Inverted Repeat Sequences ; Islets of Langerhans ; metabolism ; Plasmids ; genetics ; RNA Interference ; RNA, Small Interfering ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Thromboplastin ; deficiency ; genetics ; Viral Load ; Virus Replication