Study on antitumor activity of paclitaxel-loaded polymeric micelles / 国际生物医学工程杂志

Objective To develop paclitaxel-loaded polymeric micelles from poly (ε-caprolactone)-poly (ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL),and to evaluate in vitro cytotoxicity as well as in vivo antitumor activity against EMT-6 tumor breast cell.Methods Paclitaxel-loaded polymeric micelles were prepared by thin-film hydration and ultrasonic method.The physical status of paclitaxel inside the polymeric micelles was investigated by differential scanning calorimetry (DSC).In vitro cytotoxicity of paclitaxel-loaded polymeric micelles against EMT-6 cell line was assessed by MTT assay.In vivo anticancer activity was evaluated against EMT-6 tumorbearing mice,with commercially available Taxol injection as control.Results Paclitaxel-loaded polymeric micelles exhibited homogeneous spherical shapes with apparent core-shell morphology.The average diameter of paclitaxelloaded polymeric micelles was 93 nm.DSC study indicated that paclitaxel was in solid amorphous state after being encapsulated in the polymeric micelles.In vitro cytotoxicity demonstrated that the cytotoxic effect of paclitaxelloaded polymeric micelles was lower than that of Taxol injection at the same paclitaxel content.Paclitaxel-loaded polymeric micelles showed greater tumor growth-inhibition effect in vivo on EMT-6 breast tumor in comparison with that of Taxol injection,with tumor growth inhibition of 85.79％ and 63.37％,respectively (P＜0.05).Conculsions The prepared paclitaxel-loaded polymeric micelles showed high anti-tumoral efficacy and low toxicity,and might have the potential to be developed as an effective anticancer drug-delivery system for cancer chemotherapy.

Research progress on polymersomes as drug delivery system / 国际生物医学工程杂志

Polymersomes have attracted tremendous attention as novel drug delivery systems because of their unique and superior structure,tunable membrane properties,colloidal stability,and ability in encapsulating a broad range of both water soluble and insoluble substances.In this paper,preparation method and criteria for the formation of polymersomes,their structure and characterization as well as amphiphilic block copolymers for vesicle formation are addressed.Moreover,research progress on polymersomes as drug delivery system in the field of therapeutic and diagnostic applications are reviewed in this paper.

Study on gene delivery system based on bisphosphonate-mediated gene-eluting stent / 国际生物医学工程杂志

ObjectiveThe aim of the present study was to investigate the incorporation of plasmid DNA (pDNA) onto a coronary stent by chemo-immuno-conjugation for achieving site-specific gene delivery.MethodsA gene eluting stent was fabricated by reacting with polyallylamine bisphosphonate (PAA-BP) to introduce amine reactive groups on the surface.Then an anti-DNA antibody was chemically coupled and pDNA was immunologically tethered on the stent surface.Radioactive-labeled antibody was used to evaluate binding capacity and stability.ResultsThe presence of amine groups on the modified stent surface was confirmed by XPS and AFM analysis.The isotope label assay indicated that the amount of antibody chemically linked on the stents was 15-fold higher than that of the control stent and its retention time was also significantly longer.ConclusionThe results suggested that a large amount of reactive amine groups were introduced on the PAA-BP modified 316L coronary stent surface.This study provide a potential metal surface modification method that could facilitate coupling and tethering of biological molecules such as anti-DNA antibody and plasmid DNA (pDNA) to achieve sustained and highly localized gene delivery for substrate-mediated gene transfection.

Preparation and biodistribution of paclitaxel-loaded nanoparticles after intravascular infusion / 国际生物医学工程杂志

ObjectiveTo prepare paclitaxel-loaded nanoparticles (NPs),and to observe drug biodistribution after intravascular infusion of the NPs using a DispatchTM catheter into New Zealand rabbit abdominal aorta models.Methods Paclitaxel-loaded NPs were prepared by ultrasonication/emulsificcation/solvent evaporation technique using biodegradable poly (lactic-co-glycolic acid)(PLGA) as drug carrier.NP size and morphology was assessed by submicro-laser defractometer and scanning electron microscopy.In vitro release of paclitaxel from the NPs was performed by shaking in PBS at 37℃.The NPs was delivered into New Zealand rabbit abdominal aorta using a DispatchTM catheter.ResultsThe diameter of paclitaxel NPs was around 246 nm with very narrow size distribution.The NPs showed good spherical shape with smooth uniform surface.Paclitaxel loading in the NPs was about 19.06％ with encapsulation efficiency about 93.25％.The NPs maintained a sustained in vitro drug release for 30 days in PBS.After in vivo NP infusion,paclitaxel was detected in the vascular tissue around the infusion site and it retained in the site for 21 days.ConclusionPLGA nanoparticles as local drug delivery carrier showed great potential to maintain a high local drug concentration and prolonged drug resident time in animal model in vivo.

Study on doxoru bicin-loaded star-shaped multi-arm PLGA-PEG-NH2 nanomicelles / 国际生物医学工程杂志

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.

Study on injectable paclitaxel loaded PCL/PEG/PCL thermosensitive hydrogels / 国际生物医学工程杂志

Objective To construct an injectable controlled delivery system of paclitaxel based on thermosensitive PCL1250-PEG1500-PCL1250 hydrogels. Methods A thermosensitive PCL1250-PEG1500-PCL1250 triblock copolymer was synthesized by ring-opening polymerization of e-CL using PEG (Mw=l 500) as the initiator and Sn(Oct)2 as the catalyst. The synthesized PCL1250-PEG1500-PCL1250 copolymers were characterized for their composition,structure, and molecular weight via 1H NMR and GPC techniques. A series of Paclitaxel loaded hydrogels with various predesigned hydrogel concentrations and initial drug loadings were prepared to investigate their gelation ability, in vitro drug release behavior and in vivo biodegradability. Results The results calculated from 1H NMR and GPC indicated that EG/CL ratio(1.55) was consistent with the initial feed ratio(1.6), which offered a strong proof to their composition and molecular structure. The thermosensitive PCL1250-PEG1500-PCL1250 hydrogels exhibited a desirable sol-gel transition ability within the concentration range of 15%-30%. The in vitro release rate of paclitaxel from the paclitaxel/PCL1250-PEG1500-PCL1250 hydrogels was controllable by altering the hydrogel concentrations and initial drug loadings. The PCL1250-PEG1500-PCL1250 hydrogels showed a good in situ gelation ability after subcutaneously injected into mouse back. The in situ formed hydrogels gradually degradated with time and almost disappeared after 45 days in vivo. Conclusion Both the controllable drug release behavior and promising biodegradability of this new thermosensitive PCL1250-PEG1500-PCL1250 hydrogels paved a way to develop a novel delivery system for paclitaxel.

Acceptability of Taxol-poly (alkyl-cyanoacrylates) micell material / 中国组织工程研究

BACKGROUND: Currently used poly (alkyl-cyanoacrylates) (PACA) produces aldehyde compound in its degradation, which is easily results in toxicity and stimulation to the body. Here, a novel TaxoI-PACA micell material was synthesized, which has broad application as a kind of liposolubility drug delivery carrier. OBJECTIVE: To verify the therapeutic efficacy of Paclitaxel-PECA micells for mouse breast cancer.METHODS: Paclitaxel drug delivery micells were prepared by a multi-emulsification technique and were characterized for size, drug loading capacity, and in vitro release. Bablc breast cancer model mice were randomly divided into the physiological saline, vacant control, paclitaxel positive control, and Paclitaxel-PECA micells with low-dose, medium-dose, and high-dose groups. Paclitaxel and PaclitaxeI-PECA micells were injected into the location of mouse breast cancer, and then the tumor inhibit rates were detected. RESULTS AND CONCLUSION: The mean diameter of Paclitaxel-PECA micells was 70 nm, with 19.89% loading amount of Paclitaxel. In vitro, micells maintained sustained release of Paclitaxel for 2 weeks. Compared with the physiological saline group, the PaclitaxeI-PECA micells group exhibited superior tumor inhibit effects with doses of 30, 60, and 90 mg/kg (P < 0.001 ), which was 68.49%, 77.03% and 81.87%, respectively. The results suggested that Paclitaxel-PECA micells material has excellent acceptability as sustained-release preparation for treating mouse breast cancer.

Chitosan chip and application to evaluate DNA loading on the surface of the metal.

The plasmid DNA (pDNA) loading by cationic polymers or/and cationic lipids is essential for gene therapy, especially for metal implants such as stents and artificial joints. Polycations can condense with pDNA by self-assembly, forming polyplexes spontaneously as a result of electrostatic interactions to carry and transfer pDNA in vivo. Cationic polymers, such as chitosan, can also protect pDNA from degradation by DNase. In this study, a chitosan chip was prepared and loaded with pDNA layer-by-layer with polycation/cationic lipids. By real-time surface plasmon resonance (SPR) sensorgram, pDNA loading ability, layer stability and protective effect on pDNA from DNase degradation have been detected. Chitosan can increase the pDNA loading amount of N-(1-(2,3-dioleoyloxy)propyl)-N, N, N-trimethylammonium methyl sulphate (DOTAP) and Lipofectmine 2000 (Lipo) on the chip surface. Different flow rates can affect the pDNA loading on the chitosan chip, and it is not significant at a lower flow rate. The pDNA protection by chitosan with different molecular weights from DNase degradation was also tested. Polycationic chitosan with higher molecular weight (> or =200 kDa) can fulfil the requirements for effective gene protection from DNase degradation. The results of this study present a platform for further optimization studies of polycation-based gene delivery systems.

Preparation of intramyocardial bilayered porous biodegradable drug delivery stents / 中国组织工程研究

OBJECTIVE:To prepare an intramyocardial bilayered porous biodegradable drug delivery stent and to evaluate its effects on myocardial channel after transmyocardial revascularization (TMR).METHODS:A biodegradable drug delivery stent was prepared by using poly (ε-caprolactone) (PCL),bovine serum albumin (BSA)and poly (D,L-lactide-co-glycolide) (PLGA).The levels of BSA in stent and released in vitro were determined by the Coomassie brilliant blue assay.The mechanical strength of stent was tested by universal material testing machines.Porcine models of chronic myocardial ischemia were created to evaluate the effects of this stent on myocardial channel after TMR,RESULTS:Each bilayered porous stent could carry 10 mg BSA and release about 80% of BSA after 30 days.The stent diminished 80% of initial scale under the stress of 1.2 MPa.It could keep myocardial channel patency after TMR.CONCLUSION:An intramyocardial bilayered porous biodegradable drug delivery stent was successfully prepared.It could sustain the pressure from the heart and maintain myocardial channel patency after TMR.

Paclitaxel loaded poly(ε-caprolactone)/poloxamer 188 blend microspheres and in vivo evaluation of its antitumor activity / 国际生物医学工程杂志

Objective To prepare paclitaxel-loaded poly(ε-caprolactone)(PCL)/pluronic F68(F68)blend microspheres as a controlled release system. Methods Paclitaxel-loaded PCL/F68 blend microspheres were prepared by the oil-in water(O/W)emulsion/solvent evaporation method. Characterization of the microspheres followed to examine the particle size, the drug encapsulation efficiency, the surface morphology, in vitro release behavior and DSC analysis. In vivo antitumor activity of paclitaxel-loaded PCL/F68 blend microspheres was evaluated in mice bearing with hepatoma H22 cells ascites tumor. Results The results showed that the porous structure can be formed in the surface of PCL/F68 blend microspheres. Faster and controlled release of paclitaxel from PCL/F68 blend microspheres was achieved in comparison with the PCL microspheres. In animal tests, paclitaxel-loaded PCL/F68 blend microspheres showed the potent antitumor activity against hepatoma H22 cells in ascites tumor model. Conclusion The paclitaxel loaded PCL/F68 blend microspheres were found to own a faster release rate and a remarkably controlled release behavior.

Application of control-release preparations of growth factor in treating neurodegeneration diseases / 国际生物医学工程杂志

Incorporation of growth factors in polymeric drug delivery systems serves to maintain its bioactivity and long-term sustained release. With the development of controlled release techniques from simple mixing growth factors with carrier materials to controlled release microspheres, this kind of delivery formulations gain their extensive application. The present review focused on the application of biodegradable delivery systems of growth factors in treating neurodegeneration diseases.

Perspective on the application of nanoparticules as drug delivery and control release systems / 基础医学与临床

Nanoparticule (NP) as a drug and gene carrier has shown great potential and has been widely studied. Due to its ultra-small size, NP can achieve intelligent delivery of drugs, such as deliver drug site-specifically to disease focus or targeted tissue, even into target cells. The carrier materials of NPs provide it with such advantages as shielding odor, long-term sustained releasing of drug, lowering uoxicity,extend biologic half life of drug and gene, etc. This review emphasizes the manufacturing techniques and application of nanoparticles as drug and gene delivery system.

Polymeric nanoparticles with therapeutic gene for gene therapy: I. Preparation and in vivo gene transfer study / 生物医学工程学杂志

VEGF nanoparticle (VEGF-NP) was prepared by a multi-emulsification technique using a biodegradable poly-dl-lactic-co-glycolic (PLGA) as matrix material. The nanoparticles were characterized for size, VEGF loading capacity, and in vitro release. VEGF-NP and naked VEGF plasmid were intramuscularly injected into the ischemia site of the rabbit chronic hindlimb ischemia model and the efficiency of VEGF-NP as gene delivery carrier for gene therapy in animal model was evaluated. Gene therapuetic effect was assessed evaluated by RT-PCR, immunohistochemistry and angiography assay. The average size of VEGF-NP was around 300 nm. The encapsulation efficiency of VEGF was above 96%. Loading amount of VEGF in the nanoparticles was about 4%. In vitro, nanoparticles maintained sustained-release of VEGF for two weeks. Two weeks post gene injection the capillary density in VEGF-NP group (81.22 per mm2) was significantly higher than that in control group (29.54 mm2). RT-PCR results showed greatly higher VEGF expression in VEGF-NP group (31.79au * mm) than that in naked VEGF group (9.15 au * mm). As a carrier system for gene therapy in animal model, VEGF-NP is much better than naked DNA plasmid. The results demonstrate great possibility of using NP carrier in human gene therapy.

Nanoparticle as a new gene transferring vector in specific expression gene.

OBJECTIVE: To evaluate the possibility and efficiency of nanoparticle as a new vector in specific gene transference. METHODS: Nanoparticle-DNA complex was prepared with Poly-dl-lactic-co-glycolic acid (PLGA) bearing anti-sense monocyte chemotactic protein-1 (A-MCP-1), a specific expression gene, and the package efficiency, release progress in vitro, and the size of the complex were determined. The possibility of the new vector was evaluated with genomic DNA PCR by transferring gene into cultured smooth muscle cells (SMC), cationic lipids as a control. For study in vivo, jugular vein-to-artery bypass grafting procedures were performed on 20 New Zealand white rabbits, of which 6 grafts were transferred with nanoparticle-A-MCP-1 (200 microg), 6 with A-MCP-1 (200 microg) by cationic liposome, 4 with LNCX plasmid, and 4 as control. Fourteen days after the grafts were harvested, the expression of A-MCP-1 and its effect on MCP-1 in vein grafts were detected by dot blot, and the morphologic evaluation of grafts was performed. RESULTS: The package efficiency of the nanoparticle-DNA complex was 0.9%, release progress in vitro lasted 2 weeks, and the size ranged from 150 to 300 nm. SMC genomic DNA PCR showed that A-MCP-1 gene could be successfully transfected into cells by nanoparticle. The study in vivo indicated that A-MCP-1 mRNA was expressed in both local gene delivery groups, nanoparticle and liposome, meanwhile, MCP-1 expression in vein grafts was significantly inhibited and neointimal hyperplasia was notably reduced. CONCLUSION: Nanoparticle can act as a vector to transfect specific gene.

The effect of p27~(kip1) gene transfection mediated by PLGA nanoparticles on neointimal proliferation and apoptosis in rats vein grafts / 中国普通外科杂志

Objective To investigate whether human p27kip1 gene transfection mediated by nanoparticles( NP) can express p27kip1 protein and inhibit the neointimal formation in rat vein grafting models. Method Autogenous vein graft model was established in 120 Wistar rats by transplanting internal branch of jugular vein to carotid artery. Rats were divided into three groups: (1) p27 group; p27kip1 gene mediated by NP were transfected into the veins before anastomosis; (2) control group; the veins were transfected by simple NP; (3) grafting group;the veins were grafted without transfection. The grafted veins were harvested at 3 d, 7 d, 14 d and 28 d respectively after the operation. The exogenous p27 kip1 protein expression in veins was determined by Western blot. Intimal hyperplasia (IH) and PCNA were observed by pathology and analyzed by computer digitizing system. The presence of apoptotic VSMC was demonstrated by TUNEL method. Result p27kip1 gene transfection mediated by NP complex increased protein expression of p27kip1 gene and there was a significant decrease in the intimal average thickness at 7 d, 14 d and 28 d in p27 group (P

Inhibitory Effect of Mifepristone-releasing Implants on Endometriosis in Rats / 中国药房

OBJECTIVE:To observe the efficacy of mifepristone-releasing implants for endometriosis in rats.METHODS:Mifepristone-releasing implants(one tube at 0.75,1.5,and 3.0 cm in length,or 2,3,4 tubes at 3 cm in length) were embedded subcutaneously in model rats with endometriosis.The inhibition ratio on the endometriosis was measured 3 months later and compared with the placebo control group.RESULTS:In vitro mean drug release rate of about 9 ?g?d-1 was achieved for the one-tube implant at 3 cm in length for the first 15 days,but reduced to 5 ?g?d-1 after 30 days and which was maintained for over 6 months.Inhibition ratios of(18.6?17.3)%,(31.5?12.7)% and(72.2?12.3)% on the growth of endometrial explants were achieved after subcutaneous implantation of mifepristone-releasing implants(1 tube at 1.5 cm or 3 cm in length or 2 tubes at 3.0 cm in length),showing significance differences as compared with control group(P