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Abstract In an attempt to increase molecular stability and provide controlled release, vascular endothelial growth factor (VEGF) was encapsulated into polycaprolactone (PCL) nanoparticles. Both VEGF-free and VEGF-loaded PCL nanoparticles were formulated by w/o/w double emulsion of the dichloromethane-water system in the presence of polyvinyl alcohol (PVA) and rat serum albumin. To achieve the optimal formulation concerning particle size and monodispersity, studies were carried out with different formulation parameters, including PVA concentration, homogenization time and rate. Scanning electron microscopy and dynamic light scattering analysis showed respectively that particles had a spherical shape with a smooth surface and particle size varying between 58.68-751.9 nm. All of the formulations were negatively charged according to zeta potential analysis. In vitro release study was performed in pH 7.4 phosphate-buffered saline at 37°C and released VEGF amount was measured by enzyme-linked immunosorbent assay (ELISA) method. At the end of the 35th day, 10% of total encapsulated VEGF was released with a sustained-release profile, which fitted the Korsmeyer-Peppas kinetic model. The bioactivation of the nanoparticles was evaluated using XTT and ELISA methods. As a result, the released VEGF was biologically active and also VEGF loaded PCL nanoparticles enhanced proliferation of the human umbilical vein endothelial cells in cell culture.
Subject(s)
Vascular Endothelial Growth Factor A , Nanoparticles/classification , In Vitro Techniques/methods , Enzyme-Linked Immunosorbent Assay/methods , Microscopy, Electron, Scanning/methods , Cell Culture Techniques/methods , Human Umbilical Vein Endothelial CellsABSTRACT
OBJECTIVE:To prepare Bevacizumab(BEV)multivesicular liposomes(BEV-MVLs)with sustained-effect,and to study their in vitro release characteristics. METHODS:BEV-MVLs were prepared by double emulsion method. Box-Behnken design-response surface methodology was used to optimize the prescription with the concentration of glycerol trioleate(TO)in organic phase,ratio of 1,2-dioleoyl-sn-glycero-3-phosphocholine(DOPC)-cholesterol(CH)(mol/mol),the concentration of L-lysine in external water phase as factors,using encapsulation rate as index. The morphology of BEV-MVLs was observed by inverted fluorescence microscope and SEM;particle size was determined by laser particle size analyzer;the BEV content was determined by HPLC and calculate the encapsulation rate and in vitro accumulative release rate.RESULTS:The optimized prescription was as follows as TO of 2.72 mmol/L in organic phase,DOPC-CH ratio of 0.67(mol/mol)and L-lysine of 40 mmol/L in external water phase. The encapsulation rate of BEV-MVLs was(80.65±4.42)%(n=3),and relative error of it to predicted value was 2.54%. The liposomes were spherical in appearance shape and uniform in size,and they were typical non-concentric vesicle structure with average particle size of 16.80 μm. 30 d in vitro accumulative release rate was about 92%. CONCLUSIONS:Prepared BEV-MVLs show sustained-effect,and their encapsulation rate reaches the expected effect.
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OBJECTIVE: To provide a review of the research progresses of the multivesicular liposomes as a carrier of the protein and peptide drugs. METHODS: To summarize and analyze the researches of the protein/peptide drugs encapsulated in multivesicular liposomes according to the related articles. RESULTS AND CONCLUSION: A major problem in the clinical usage of protein and peptide drugs is frequent injection, for they have poor stability, short half-life time and high clearance. This challenge has been successfully met by the multivesicular liposomes encapsulating the peptide and protein drugs. The new liposome uses depot foam technology to achieve high loading sufficient and encapsulation, and they are very competent carriers of the compounds, especially the water-soluble drugs.
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Objective: To evaluate the in vitro release behavior of doxorubicin(Dox)-loaded microspheres and the stability of Dox during encapsulation process and in vitro release. Methods: Dox-loaded microspheres were prepared by double emulsion (W/O/ W) method with poly(lactic-co-glycolic acid) (PLGA) as the carrier material. The physical and chemical characteristics of microspheres, including the mean diameter, morphology, drug entrapment efficiency and loading rate, were evaluated. The in vitro release behavior and its influencing factors were determined by ultraviolet spectrophotometry. Dox stability was evaluated by HPLC method during the encapsulation process and in vitro release. Results: The prepared microspheres had a complete spheric shape and dispersive quality. The mean diameter of the microspheres was 85 μm; the drug entrapment efficiency was 95.1%; and the loading rate was 14.8%. Releasing rate of the microspheres slowed down with the increase of PLGA concentration and the decrease of W/O value. The encapsulation process had no obvious effect on the stability of Dox, while Dox degraded during in vitro release as the prolongation of time. On day 10, the peak area of degraded material accounted for 2.46%. Conclusion: Dox can be encapsulated in the microspheres by double emulsion method and different release rates of Dox can be achieved by adjusting PLGA concentration and W/O volume ratio.
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Objective: To prepare visualized iodized oil-5-fluorouracil loaded polylactic acid(PLA) micropheres for hepatic artery embolism treatment. Methods: Biocompatible and biodegradable material PLA was used as vector and iodized oil was used as positive contrast agent to prepare 5-fluorouracil loaded microspheres using double emulsion method. The preparation technology of the microspheres was developed through optimization of appearance, size distribution, drug loading, and encapsulation efficiency by orthogonal-designing method. Results: The prepared PLA microspheres were round in shape and had a homogenous diameter distribution. Scanning electron microscope (SEM) showed a pored surface, with an average diameter of 100 μm. The encapsulation efficiency and drug content of microspheres were (63.34%±0.54%) and (10.78%±0.14%), respectively. Conclusion: We have successfully prepared the visualized iodized oil-5-fluorouracil PLA microspheres, which can release 5-fluorouracil in a controlled manner.
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OBJECTIVE: To prepare Buserelin acetate nanoparticles(BA-NP) and to investigate its release property in vitro.METHODS: The BA-NP was prepared using double emulsion method.The content determination of BA-NP was performed using HPLC,and encapsulation efficiency and drug-loading rate of BA-NP were calculated.In vitro drug release property of nanoparticles was investigated by bag filter method.RESULTS: Prepared nanoparticles were even and regular in appearance.The linear range of buserelin acetate was 0.1～8.0 ?g?mL-1(r=0.999 9) with an average recovery of 105.38%.The RSD of intra-day and inter-day were lower than 1.78% and 0.93% respectively.The encapsulation efficiency of nanoparticles was(63.37?0.29)% and drug-loading rate of(1.03?0.09)%.The accumulative release rate of nanoparticles in phosphate buffer(pH=7.4) at 72 h was 62.35%.CONCLUSION: The preparation process of BA-NP is simple and particle with ideal release effect.
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At present PLA and its copolymer is a kind of most widely used biodegradable polymers to prepare microspheres because of its good biocompatibility. The double emulsion method is the most used technique for microspheres loade with water-soluble drugs, proteins and peptides. Microspheres with different particle size or release character could be used in different applications such as targeted drug delivery or long-acting drug delivery. The characters of microspheres are influenced by the preparative parameter. This article reviewed the preparative parameters that influence the character of microspheres.
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Objective:To evaluate the in vitro release behavior of doxorubicin(Dox)-loaded microspheres and the stability of Dox during encapsulation process and in vitro release.Methods: Dox-loaded microspheres were prepared by double emulsion(W/O/W) method with poly(lactic-co-glycolic acid)(PLGA) as the carrier material.The physical and chemical characteristics of microspheres,including the mean diameter,morphology,drug entrapment efficiency and loading rate,were evaluated.The in vitro release behavior and its influencing factors were determined by ultraviolet spectrophotometry.Dox stability was evaluated by HPLC method during the encapsulation process and in vitro release.Results: The prepared microspheres had a complete spheric shape and dispersive quality.The mean diameter of the microspheres was 85 ?m;the drug entrapment efficiency was 95.1%;and the loading rate was 14.8%.Releasing rate of the microspheres slowed down with the increase of PLGA concentration and the decrease of W/O value.The encapsulation process had no obvious effect on the stability of Dox,while Dox degraded during in vitro release as the prolongation of time.On day 10,the peak area of degraded material accounted for 2.46%.Conclusion: Dox can be encapsulated in the microspheres by double emulsion method and different release rates of Dox can be achieved by adjusting PLGA concentration and W/O volume ratio.