Formulation and evaluation of the vascular endothelial growth factor loaded polycaprolactone nanoparticles

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.

Preparation and characterization of ginkgolide K-loaded PLGA-PEG nanoparticles and its neuroprotective activity in vitro / 中草药

Objective To prepare and characterize ginkgolide K-loaded mPEG-PLGA [poly (D,L-lactide-co-gly-colide)-block-poly (ethylene glycol)] polymer nanoparticles (GK-mPEG-PLGA-NPs) and to evaluate its neuroprotective effect on the H2O2-induced PC12 cells injury in vitro. Methods The PLGA-PEG-COOH polymer was selected as carrier and double emulsion solvent evaporation technique was employed to prepare the stealth nanoparticles. The encapsulation efficiency (EE) and drug load (DL) of GK-mPEG-PLGA-NPs were investigated by HPLC. The size distribution, zeta potential, and surface morphology of GK-mPEG-PLGA-NPs were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. The in vitro release of GK-mPEG-PLGA-NPs was examined using phosphate buffer solution (pH 7.4) as the releasing medium for 24 h. The H2O2-induced PC12 cells injury models was established for the investigation of the protective effect of GK-mPEG-PLGA-NPs on nerve cells in vitro. Results EE and DL of GK-mPEG-PLGA-NPs was (83.40 ± 2.85)% and (3.26 ± 0.24) mg/g, respectively. The average diameter of GK-mPEG-PLGA-NPs was (93.19 ± 2.77) nm and zeta potential was (-11.93 ± 1.71) mV. The cumulative rate of drug release was (90.5 ± 4.0)% after 60 h in phosphate buffer solution. GK-mPEG-PLGA-NPs significantly inhibited the apoptosis of PC12 cells and the release of lactic dehydrogenase induced by H2O2. However, the protective action of GK-mPEG-PLGA-NPs on the H2O2-iduced PC12 cells injury was significantly weaker than that of GK. Conclusion Our results proved that GK-mPEG-PLGA-NPs had a sustained release behavior in vitro and the neuroprotective effect of GK-mPEG-PLGA-NPs on H2O2-induced PC12 cells, which indicates that GK-mPEG-PLGA-NPs has the prospect of application and deserves further research. Key words: ginkgolide K; mPEG-PLGA; in vitro release; in vitro neuroprotection; d

Study on Formulation Optimization and in vitro Release Characteristics of Bevacizumab Multivesicular Liposomes / 中国药房

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.

Double emulsion and complex coacervation in stevia encapsulation / Doble emulsión y coacervacion compleja en la encapsulación de estevia

Background: Stevia leaves a residual flavor at moment of being consumed, and its sweet taste remains little time, whereby, encapsulation is an option to mitigate these problems. Objective: Evaluate the double emulsion system followed by complex coacervation in stevia encapsulation. Methods: The effect of the concentration of the sweetener was determined (3.5; 5; 7.5 and 10% p/p) as well as the concentration of the wall material (2.5 and 5% p/p), on the morphology, capsules size, and encapsulation capacity. The double emulsion was prepared, the coacervate was formed, and then capsules were lyophilized. The morphology and capsule size were measured before and after lyophilization by optical microscopy. From Fourier´s infrared transformed spectrometry, encapsulation capacity was analyzed. Water activity and solubility were measured in lyophilized capsules. Results: Micro and nanocapsules (minimum size of 19.39 ± 0.74µm and 62.33 ± 6.65µm maximum) were obtained. Micrographs showed that the encapsulation technique used, allows obtaining dispersed stevia capsules and those of round and homogeneous morphology. The encapsulation capacity was 84.37 ± 4.04%. The minimum value of water activity was 0.49 ± 0.01 and 17.65 ± 0.91% of solubility. Conclusions: An increased in encapsulation capacity was obtained when the highest concentration of the wall material was used. The capsule diameter increased as the sweetener concentrations increased. The formulation to 5% (p/p) of stevia and 5% (p/p) in wall material was associated with better controlled release of the sweetener, which allows establishing subsequent applications in which the sweet taste is prolonged and the stevia bitter taste concealed.

Antecedentes: La estevia deja sabor residual al ser consumida, y su sabor dulce permanece poco tiempo, por lo cual, la encapsulación es una opción para mitigar estos problemas. Objetivo: Se evaluó el sistema doble emulsión seguido por coacervación compleja en la encapsulación de estevia. Métodos: Se determinó el efecto de la concentración del edulcorante (3.5; 5; 7.5 y 10% p/p) y de la concentración del material de pared (2.5 y 5% p/p), en la morfología, tamaño de cápsulas, y capacidad de encapsulación. Se elaboró la doble emulsión, se formó el coacervado, y posteriormente, las cápsulas se liofilizaron. La morfología y el tamaño de las cápsulas, se midieron antes y después de la liofilización mediante microscopia óptica. A partir de espectrometría infrarroja de transformada de Fourier se analizó capacidad de encapsulación. En las cápsulas liofilizadas se midió actividad de agua y solubilidad. Resultados: Se obtuvieron micro y nanocápsulas (tamaño mínimo de 19.39±0.74µm y máximo 62.33±6.65µm). Las micrografías indicaron que la técnica de encapsulación usada, permite obtener cápsulas de estevia dispersas y de morfología redonda y homogénea. La capacidad de encapsulación fue 84.37±4.04%. El valor mínimo de actividad de agua fue 0.49±0.01, y solubilidad de 17.65±0.91%. Conclusiones: Se obtuvo incremento en la capacidad de encapsulación cuando se utilizó la mayor concentración del material de pared. El diámetro de las cápsulas aumentó a medida que se incrementaron las concentraciones del edulcorante. Se concluyó que la formulación a 5% (p/p) de edulcorante y de 5% (p/p) en material de pared fue el tratamiento que mejor se asocia a una liberación controlada de estevia, lo cual permite establecer posteriores aplicaciones en las que se prolongue el sabor dulce y enmascare el sabor amargo de la estevia.

Preparation and in vitro evaluation of antibacterial peptides from Plutella xylostella poly(lactic-co-glycolic acid) nanoparticles / 中草药

Objective: To prepare the antibacterial peptides from Plutella xylostella-loaded nanoparticles based on poly(lactic-co- glycolic acid) (CA-PLGA-NPs) and evaluate its physicochemical property and in vitro release. Methods: CA-PLGA-NPs were prepared by S/W/O/W double emulsion method combined with high-pressure homogenization. The morphology, particle size, polydispersion index (PDI), drug loading, encapsulation efficiency (EE), and in vitro release of the nanoparticles were studied. Results: CA-PLGA-NPs were spherical or similarly spherical, and the average particle size, PDI, drug loading, and EE were (358.76 ± 22.51) nm, 0.168 1 ± 0.012 2, (10.50 ± 0.28)%, and (60.92 ± 1.58)%, respectively. And burst phenomenon was not significant. The drug delivery stable phase was 2-10 d. Conclusion: S/W/O/W double emulsion method combined with high pressure homogenization method is suitable for the preparation of CA-PLGA-NPs, and provides a pharmaceutical basis for CA administration.

Prepraration of PLGA-PLL-PEG Nanoparticles Simultaneously Loaded with Daunorubicin and Tetrandrine / 中国药学杂志

OBJECTIVE: To prepare PLGA-PLL-PEG nanoparticles simultaneously loaded with daunorubicin (DNR) and tetrandrine (Tet).

Research progresses of multivesicular liposomes in delivery of protein and peptide drugs / 中国药学杂志

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.

In vitro release behavior of doxorubicin-loaded injectable microspheres / 第二军医大学学报

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.

Preparation of visualized iodized oil-5-fluorouraciI loaded polylactic acid microspheres / 第二军医大学学报

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.

Study on the Preparation of Buserelin Acetate Nanoparticles and Its Release Property in Vitro / 中国药房

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.

Preparation,optimization and characterization of NC-1900 loaded MePEG-PLA nanoparticles / 复旦学报（医学版）

Purpose To optimize the preparation of NC-1900 loaded MePEG-PLA nanoparticles (NPs). Methods MePEG-PLA copolymers of different molecular weight synthesized by solvent poly-merization method were used to prepare NC-1900 loaded MePEG-PLA NPs by double emulsion/solvent evaporation method.Orthogonal experimental design and multiple regressions were used to optimize the preparation method with nanoparticle size and NC-1900 encapsulation efficiency (EE) as res-ponse variables.NPs were characterized by particle size and Zeta potential detector and transmission electron microscope.The leakage of NC-1900 from NPs was evaluated by high-performance liquid chromatography (HPLC) detection. Results MePEG3000-PLA44800 NPs prepared according to the optimized conditions had a mean diameter of (77 ± 11) nm and EE of (21.4 ± 0.1) %.Only 5% and 15% of NC-1900 were leaked in pH 7.4 PBS and blank plasma at the end of 48 h,respectively. Conc-lusions The optimized MePEG3000-PLA44800 NPs is a favorable carrier for NC-1900.

Research progress on preparative parameters that influnce the characteristics of PLA/PLGA/PELA microspheres prepared by double emulsion method / 国际生物医学工程杂志

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.

In vitro release behavior of doxorubicin-loaded injectable microspheres / 第二军医大学学报

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.