ABSTRACT
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
ABSTRACT
Objective To prepare and characterize ursolic acid nanoparticles (UANs), and to investigate its improvement of equilibrium solubility and dissolution rate. Methods UANs were prepared by emulsion solvent evaporation method, and followed by freeze-drying. The organic phase was trichloromethane containing 30% ethanol, the aqueous phase is ultrapure water, poloxamer 188 was as surfactant and cryoprotectant. The optimal conditions for preparing nanoparticles were screened out using single-factor experiment. The particle size was used as the basis for optimization experiment. The following six main parameters had significant influences on particle size were picked out, including the concentration of poloxamer 188, volume ratio of organic to water phase, homogenate speed and homogenate time, as well as homogenization pressure and cycles. And then, dynamic light scattering equipment was used to analyze the mean particle size, the morphology of UANs powder obtained was presented by scan electronic micro-scope (SEM). The UANs weather and how changes in surface chemical character and physical structure was estimated by using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The equilibrium solubility study and dissolution test were carried on raw ursolic acid (UA) and UANs. Results The optimal conditions of preparation UANs: 0.05% of poloxamer 188, 1:4 of volume ratio of organic to water phase, 7 000 r/min of homogenate speed for 2 min and a homogenization pressure of 50.0 MPa for 6 times. Based on the optimal conditions, the mean particle size was (157.5 ± 28.0) nm and Zeta potential of (20.33 ± 1.67) mV. Particle distribution of UANs illustrated that UA had been nanoscale with uniform particle size distribution. SEM showed that UANs were nearly spherical. By the XRD and DSC, we could acquaint UA in UANs had the same chemical structure as the raw UA but had been amorphous state. The result of solubility test figured that the equilibrium solubility of UANs was 13.48 times in SGF, 11.79 times in SIF and 23.99 times in deionized water than raw UA. The dissolution rate of UANs prepared by ESE method has been up to 14.72 times in SGF and 74.35 times in SIF. Conclusion This study indicates that the emulsion solvent evaporation method has an array of valued on improving water solubility of UA, and it will have benefit on enhancing oral bioavailability.
ABSTRACT
Objective To develop a method for the synthesis of poly [lactic-co-(glycolic acid)] (PLGA) wrinkled microparticles,and to investigate their immobilization on model protein,i.e.bovine serum albumin (BSA),so as to provide a scientific basis for the preparation of artificial antigen-presenting cells (aAPCs).PLGA wrinkled microparticles were prepared by double emulsion-solvent evaporation method combined with porogen NH4HCO3.The effects of PLGA relative molecular mass,porogen mass concentration and double emulsion stirring speed on the morphology of PLGA micro particles were investigated.The PLGA wrinkled particles were incubated with different concentrations of FITC-conjugated BSA (FITC-BSA).The levels of BGA loaded with PLGA wrinkled particles were detected by laser scanning confocal microscopy,flow cytometry and diquinoline formic acid.The effect of the loading process on the BSA structure was analyzed by circular dichroism spectrometer.Results The molecular weight of 5 000 was the optimized parameters for PLGA wrinkled microparticles preparation.The morphology of PLGA wrinkled particles could be maintained when the mass concentration of porogen NH4HCO3 was less than 10 g/L.When the mixing speed of multiple emulsion increased from 400 r/min to 3 600 r/min,the average particle size of PLGA wrinkled particles decreased from 35 μm to 9 μm,which meets the size requirement of artificial aAPCs.The fluorescence intensity of PLGA wrinkled particles was directly proportional to the concentration of BSA,and the BSA structure was not affected by the adsorption of BSA by the PLGA wrinkled particles.Conclusion The relative molecular mass of PLGA has an important influence on the morphology of the particles.PLGA with a relative molecular mass of 5 000 can be used to prepare particles with a wrinkled topology,which can load proteinaceous macromolecules and maintain protein activity.This result has potential applications in artificial aAPCs.
ABSTRACT
OBJECTIVE: To prepare capsaicin-solid lipid nanoparticles (CAP-SLNs) and study their physical and chemical properties. Then, the CAP-SLNs were modified with chitosan (CTS) and the pharmacokinetics across colon of rats was studied in vivo. METHODS: CAP-SLNs were prepared by emulsion-solvent evaporation method. The mean size, encapsulation efficiency and drug loading of the nanoparticles were investigated. RESULTS: The average diameter of CAP-SLNs was (118.89 ±25.0) nm, the encapsulation efficiency was (38.56 ±2.6)%, and the drug-loading was (6.17 ±0.21)%. After colon-specific delivery in rats, the AUC0.360 min(243. 63 ±61.46) mg · min · L-1 and ρmax(1.23 ±0.18) mg · L-1 of CTS-CAP-SLNs were 1.81-fold and 1.95-fold higher than CAP. CONCLUSION: It is simple and feasible to prepare CAP-SLNs by emulsion-solvent evaporation method. The pharmacokinetic parameters in rats are improved remarkably compared with CAP.
ABSTRACT
OBJECTIVE: To prepare lappaconitine (LA)-loaded polylactic acid (PLA) nanoparticles (LA/PLA NPs) and investigate its release properties in vitro. METHODS: LA/PLA NPs were prepared by optimized emulsion-solvent evaporation method with biodegradable PLA as carrier material and polyvinyl alcohol (PVA) as emulsifier. The entrapment efficiency and drug loading rate of LA were used as the main evaluation indexes to optimize the preparation process by orthogonal design method. The mean particle size was measured by laser particle size analyzer; the morphology of LA/PLA NPs was observed by atomic force microscope; the in vitro release behavior was studied by dynamic dialysis. RESULTS: The optimized LA/PLA NPs were spherical. The mean particle size was (429±9.19) nm, the entrapment efficiency and drug loading rate were (86.34±2.15)% and (45.85±1.34)%, respectively. The in vitro release study showed that the LA/PLA NPs could provide a continuous release of LA for 15 d. CONCLUSION: LA/PLA NPs with high entrapment efficiency and drug loading rate are prepared successfully, and show sustained release effect for LA in vitro.
ABSTRACT
OBJECTIVE: To prepare PLGA-PLL-PEG nanoparticles simultaneously loaded with daunorubicin (DNR) and tetrandrine (Tet).
ABSTRACT
Microspheres are multi-component system provide constant and prolonged drug release. Furthermore their floating abilities increase gastric residence time. These properties reduce the gastrointestinal toxic effects and dosing frequency and thereby improve the patient compliance. The present study aimed to formulate and evaluate telmisartan microspheres. Emulsion solvent evaporation (ESE) technique was employed for microsphere preparation using different ratios of ethyl cellulose polymer and drug. Prepared microspheres were evaluated for drug entrapment efficiency, micromeritic characters, floating behaviour and in vitro drug release. This revealed polymer drug ratio has influence on drug release.
ABSTRACT
The objective of present study is to develop oral colon specific pH dependant microcapsule of NSAID Drug Naproxen, to release drug in the colon and minimize or avoid local side effect by avoiding drug release in the upper git. Naproxen is encapsulated with Eudragit S 100 using O/W emulsion-solvent evaporation technique. Compatibility study was performed by I.R., D.S.C., X.R.D study. Microcapsules were evaluated for angle of repose, bulk density, tapped density, Carr’s index, particle size, drug loading, in-vitro drug release. The prepared microcapsules were white, free-flowing, and spherical in shape and particle size was in the range of 240.40-560.81μm. The drug-loaded microcapsules showed 69.88% to 98.73%. drug entrapment, angle of repose in the range of 28º.07” to 35 º.53”, bulk and tapped densities in the range of 0.4000 gm/cm3 to 0.4347 gm/cm3 and 0.4347gm/cm3 to 0.4787gm/cm3 respectively, Carr’s index ranges from 5.20 and 14.98. In vitro drug release studies were carried out up to 9th hr. in three different pH media, i.e., 0.1 N HCl (pH 1.2), phosphate buffer (pH 6.8 and 7.4). The drug-polymer concentration influences the particle size and drug release properties. All the formulations were following the Higuchi model of kinetic drug release.
ABSTRACT
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.