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.

Microsponge: An Innovative Strategy For Drug Delivery System

Microsponge technology has been introduced in topical drug products to facilitatethe controlled release of active drug into the skin in order to reduce systemic exposure andminimize local cutaneous reactions to active drugs. Microsponge consists of macroporousbeads, typically 10-25µ in diameter, loaded with active agent. When applied to the skin, themicrosponge releases its active ingredients on a time mode and also in response to otherstimuli. Microsponge drug delivery technology holds a great promise for reaching the goal ofcontrolled and site-specific drug delivery and hence, has attracted wide attention ofresearchers. This article presents a broad review of Microsponges delivery system discussingthe principles and preparation methods. Appropriate analytical techniques for characterizationof Microsponges like Particle size and its distribution, surface morphology, porosity, densityare covered. These microsponges are used in the sunscreens, creams, ointments, over-thecounter skin care preparations, which are meant for topical application. Microsponge drugdelivery can provide increased efficacy for topically active agents with enhanced safety,extended product stability and improved aesthetic properties in an efficient and novel manner.They are mostly used for topical use and have recently been used for oral administration

Evaluation of polyelectrolyte and emulsion covalent crosslink of chitosan for producing mesalasine loaded submicron particles

This study evaluates various techniques for producing mesalamine (5ASA)-loaded particles employing chitosan as a biopolymer: (1) the polyelectrolyte complexation of chitosan with phthalate hypromelose (HP), (2) the chemical crosslinking of chitosan with genipin and (3) the water-in-oil emulsion method associated with chemical crosslinking with genipin. Systems were characterized by dynamic light scattering, zeta potential (ζ), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR) and a drug release profile. Method (1) was efficiently produced unloaded nanoparticles (491 nm, PdI=0.26 and ζ = 23.2), but the conditions for chitosan and HP cross-linking enhanced the precipitation of 5ASA. Method (2) caused the degradation of the drug. Method 3 produced sub-micron and microparticles, thereby varying the agitation method; 3 h magnetic agitation resulted in 2692 nm, Pdi = 0.6 and ζ = 46, while Ultra-Turrax, 5 min produced submicron particles (537 nm, PdI = 0.6). The percentage yield was approximately 50%, which is very satisfactory considering the impossibility of encapsulating 5ASA using other methods. FTIR showed the covalent interaction of chitosan and genipin. The drug release was rapid in acidic fluid, but in neutral pH a slower release was obtained in the initial stage, followed by rapid release, which may ensure the controlled release of 5ASA in the colon.

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.

Preparation,Characterization and Transdermal Ability Study in vitro of Ibuprofen Nano-powder / 中国药房

OBJECTIVE:To prepare and characterize Ibuprofen (IBU) nano-powder,and to investigate its transdermal ability in vitro. METHODS:Using chloroform-ethanol(7:3,V/V)as organic phase,deionized water as aqueous phase and polysorbate 80 as surfactant,the emulsification method was used to prepare IBU nano-powder. Laser granulometric analysis,Fourier transform in-frared spectroscopy(FT-IR),X-ray diffraction(XRD),differential scanning calorimetry(DSC)were used to characterize IBU na-no-powder. IBU nano-powder was compared with bulk drug in respects of saturation solubility,dissolution rate and transdermal rate in vitro. RESULTS:The optimum condition was as follows that the concentration of polysorbate 80 was 5 mg/mL;the volume ra-tio of water phase-organic phase was 40:1;the concentration of IBU was 250 mg/mL;homogenate speed was 5000 r/min;homog-enate time was 2 min. Prepared IBU nano-powder was polyporous crumbly coralliform,and its chemical structure kept stable;the nano-powder changed from crystal to amorphous state;the particle size was 179.6 nm,and drug-loading amount was 8.99%;satu-ration solubility,dissolution rate and transdermal rate of IBU nano-powder were 148,1.23 and 4.08 times of bulk drug. CONCLU-SIONS:The prepared IBU nano-powder shows good water-solubility and percutaneous permeability.

Analysis on the clinical value of methods used for the detection of treponema pallidum antibody / 中华流行病学杂志

Objective To explore the clinical value of five methods commonly used for the detection of clinical syphilis antibody.Methods A total of 160 confirmed syphilis cases were chosen as the experimental group while 200 non-syphilis cases were set as the control group.Serum specimens were detected by methods as Treponema pallidum particle agglutination assay (TPPA),chemiluminescent microparticle immune assay (CMIA),enzyme linked immunosorbent assay (ELISA),emulsion method (TP-AD) and toluidine red unheated serum test (TRUST).Sensitivity and specificity were evaluated on five methods.Titers of syphilis antibody in different stages and pre/post on treament among syphilis patients were compared and analyzed under the five methods.Results The sensitivity vs.specificity of TPPA,CMIA,ELISA,TP-AD and TRUST appeared as 100.00％ vs.99.50％,99.38％ vs.99.00％,98.12％ vs.99.00％,94.38％ vs.94.50％ and 85.62％ vs.95.50％,respectively.Among the patients at primary or latent stages,the syphilis antibody positive rate detected by TRUST appeared lower than that detected by ELISA,TPPA,CMIA or TP-AD,and the differences were statistically significant (P＜0.01).There were no statistical differences in the syphilis antibody positive rate of syphilis patients in the secondary or tertiary stages detected by five methods (P＞0.05).In each stage of the syphilis patients,the syphilis antibody positive rate detected by ELISA or of CMIA combined with TRUST both reached 100.00％.Before and after treatment in 121 cases of confirmed syphilis,there was statistically significant difference in the syphilis antibody positive rate detected by TRUST method (P＜0.05).There was no statistical significance in the syphilis antibody positive rate detected by other four methods (P＞0.05).Conclusions The sensitivity and specificity of TPPA,CMIA and ELISA methods were better.Methods as ELISA or as CMIA combined with TRUST both appeared reliable for syphilis screening in every stage of the disease.TRUST was suitable for the determination of active stage syphilis and monitoring the effects after treatment.

Analysis on the clinical value of methods used for the detection of treponema pallidum antibody / 中华流行病学杂志

Objective To explore the clinical value of five methods commonly used for the detection of clinical syphilis antibody.Methods A total of 160 confirmed syphilis cases were chosen as the experimental group while 200 non-syphilis cases were set as the control group.Serum specimens were detected by methods as Treponema pallidum particle agglutination assay (TPPA),chemiluminescent microparticle immune assay (CMIA),enzyme linked immunosorbent assay (ELISA),emulsion method (TP-AD) and toluidine red unheated serum test (TRUST).Sensitivity and specificity were evaluated on five methods.Titers of syphilis antibody in different stages and pre/post on treament among syphilis patients were compared and analyzed under the five methods.Results The sensitivity vs.specificity of TPPA,CMIA,ELISA,TP-AD and TRUST appeared as 100.00％ vs.99.50％,99.38％ vs.99.00％,98.12％ vs.99.00％,94.38％ vs.94.50％ and 85.62％ vs.95.50％,respectively.Among the patients at primary or latent stages,the syphilis antibody positive rate detected by TRUST appeared lower than that detected by ELISA,TPPA,CMIA or TP-AD,and the differences were statistically significant (P＜0.01).There were no statistical differences in the syphilis antibody positive rate of syphilis patients in the secondary or tertiary stages detected by five methods (P＞0.05).In each stage of the syphilis patients,the syphilis antibody positive rate detected by ELISA or of CMIA combined with TRUST both reached 100.00％.Before and after treatment in 121 cases of confirmed syphilis,there was statistically significant difference in the syphilis antibody positive rate detected by TRUST method (P＜0.05).There was no statistical significance in the syphilis antibody positive rate detected by other four methods (P＞0.05).Conclusions The sensitivity and specificity of TPPA,CMIA and ELISA methods were better.Methods as ELISA or as CMIA combined with TRUST both appeared reliable for syphilis screening in every stage of the disease.TRUST was suitable for the determination of active stage syphilis and monitoring the effects after treatment.

Preparation and Formula Optimization of Silybin Liposomes Coated by N-trimethyl Chitosan / 中国药房

OBJECTIVE:To prepare silybin liposomes(SLBL)coated by N-trimethyl chitosan(TMC)(TMC60-SLBL),and to optimize the formula. METHODS:The effects of 3 kinds of preparation methods on encapsulation efficiency of SLBL were com-pared,including film dispersion method,multiple emulsion method and reverse evaporation method. The formula of TMC60-SLBL was optimized by orthogonal test using encapsulation efficiency as index with the concentration of phospholipid,ratio of phospholip-id to cholesterol,ratio of silybin to lipids,hydration temperature as factors. The stability of TMC60-SLBL by optimal formula at 4 and 25℃within 30 d,the particle size and Zeta potential of TMC60-SLBL and SLBL were all compared. RESULTS:The encapsu-lation efficiency of TMC60-SLBL prepared by the film dispersion method was the highest,without statistical significance in encap-sulation efficiency before and after cutting (P>0.05). The optimal formula was with the concentration of phospholipid 6 mg/ml;the ratio of phospholipid to cholesterol 40∶1;the ratio of silybin to lipids 1∶30;the temperature of hydration medium 45 ℃;the encapsulation efficiency were(82.08±2.6)%,RSD=3.17%(n=3). The preparation was stable at 4℃;the mean diameter of SL-BL and TMC60-SLBL were(131.9±1.9)nm and(161.2±2.0)nm,and Zeta potential respectively were(-23.18±1.14)mV and (36.73 ± 2.84) mV. CONCLUSIONS:TMC60-SLBL is prepared successfully,and its formula is simple and practicable with high encapsulation efficiency.

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.

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.