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OBJECTIVE：To optimize the f ormulation of docetaxel （DTX）-mPEG-PLGA-mPEG （PELGE）-nanoparticles （NPs），and to characterize it and evaluate its in vitro drug release and antitumor activity. METHODS ：PELGE were synthesized by ring-opening polymerization. DTX-PELGE-NPs were prepared by using emulsion solvent evaporation method. The content of DTX in DTX-PELGE-NPs was determined by HPLC. Box-Behnken design-response surface methodology was applied to optimize the formulation of the nanoparticles using the amount of DTX ，PELGE and poloxamer 188 as independent variable ，using entrapped efficiency as dependent variable. The particle size and Zeta-potential of DTX-PELGE-NPs were characterized by laser particle size analyzer and transmission electron microscope. The in vitro release of the DTX-PELGE-NPs was investigated by ultra-filtered centrifugation，using DTX injection as reference. In vitro cytotoxicity of the DTX-PELGE-NPs was investigated by MTT assay ， using DTX and PELGE-NPs without DTX as reference . RESULTS ：The optimal formulation included 2.80 mg DTX ，20.60 mg PELGE and 6％ poloxamer 188. The entrapped efficiency of optimized DTX-PELGE-NPs was （86.79±1.32）％；drug-loading amount was （10.21±0.78）％，and average particle size was （78.4±2.9）nm；polydispersity coeffici ent was （0.187±0.018）and Zeta potential was （－20.6±1.5）mV. Furthermore ，DTX- PELGE-NPs showed a regular spherical and uniform distribution under scanning electron microscopy. Compared with DTXinjection（accumulative release rate of 92.3％ at 4 h），DTX- PELGE-NPs had a significant sustained-release effect （accumu-lative release rate of 78.6％ at 36 h）. 0.1-50 μg/mL PELGE-NPs had no obvious cytotoxicity to human breast cancer cells MCF-7（P＞0.05）. 0.5-10 μg/mL DTX-PELGE-NPs could significantly inhibit the growth of human breast cancer cells MCF-7， and its inhibitory effect （except for DTX-PELGE-NPs 10 μg/mL group）was significantly stronger than that of DTX injection （P＜ 0.05）. CONCLUSIONS ：The optimized formulation is stable and feasible. The obtained DTX-PELGE-NPs not only have uniform particle size ，high encapsulation rate obvious slow-release effect ，but also have stronger anti-tumor effect in vitro than DTX injection.
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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
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OBJECTIVE: To determine the effects of the amphiphilic block polymers, which have the same hydrophilic block with the different hydrophobic block, on the function of P-glycoprotein(P-gp). METHODS: The three different micelles were prepared by film dispersion method. The particle sizes and distributions were measured by dynamic light scattering. Critical micelle concentrations(CMC) were detected by fluorescence probe technique with the pyrene. Rhodamine 123, a specific probe substrate of P-gp, was applied to determine the effects of polymers on the function of P-gp using uptake and efflux method. RESULTS: The particle sizes of mPEG-PCL, mPEG-PDLLA, mPEG-PLGA were (55.9±0.2), (53.7±1.1) and (61.6±0.6)nm. The CMC values were 2.08, 5.42 and 26.4 μg·mL-1. R123 accumulation in Madin-Darby canine kidney/multidrug resistance 1(MDCK-MDR1)cell detected by uptake assay increased to a maximum in the presence of polymers at concentrations of 250 μg·mL-1 for mPEG-PCL, 1~25 μg·mL-1 for mPEG-PDLLA and mPEG-PLGA. In efflux assay, mPEG-PCL, mPEG-PDLLA, mPEG-PLGA decreased the percentage of efflux of R123 at concentrations above the CMC, below/at the CMC or below the CMC respectively, showed the similar RESULTS with uptake assay. CONCLUSION: The mPEG-PCL, mPEG-PDLLA, mPEG-PLGA polymers might have a potential to inhibit the efflux activity of P-gp, which was likely related to the structures of hydrophobic segments, concentrations and existing states of the polymers.
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Objective To investigate the uptake mechanism of HepG2.2.15 cells to the nanoparticles co-loaded with syringopicroside and hydroxytyrosol (SH-NPs). Methods The nanoparticles were prepared by using a nanoprecipitation method with mPEG-PLGA as nano-carrier co-loaded with syringopicroside and hydroxytyrosol. The uptake mechanism of HepG2.2.15 cells to SH-NPs was studied by fluorescence microscopy and flow cytometry using fluoresceineisothiocyanate (FITC) as a fluorescent marker. Results With colchicine as the inhibitor, the incubation time ranged from 0.5 to 24 h, the percentage of positive cells increased from 1.9% to 56.4%; When the drug concentration was 125, 250 μg/mL and 500 μg/mL, the positive cell percentages were 4.9%, 3.4% and 3.9%. With chloroquine as the inhibitor; the incubation time ranged from 0.5 to 24 h, the percentage of positive cells increased from 7.4% to 55.4%; When the drug concentration was 125, 250 and 500 μg/mL, the percentage of positive cells was 19.5%, 22.5% and 27.6%. Conclusion Colchicine and chloroquine have an inhibitory effect on HepG2.2.15 cells uptake, and the uptake of SH-NPs in HepG2.2.15 cells was positively correlated with drug concentration and incubation time. It can be concluded that the uptake mechanism of HepG2.2.15 cells to SH-NPs was nonspecific adsorption endocytosis.
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Objective To optimize the formulation and preparation technology of docetaxel (DTX)-loaded nanobubbles, and evaluate their properties. Methods The best ratio of methoxypoly(ethylene glycol)-poly(.DL-lactide-co-glycolide) (mPEG-PLGA) and different membrane stabilizers were optimized with Langmuir membrane balance. DTX-Loaded nano-micelles were encapsulated by mPEG-PLGA with an injection method. Nanoemulsions was formed after being added with perfluoropentane (PFP, the boiling point of 29.5 °C) as the organic phase. The formulations and preparation techniques of nanoemulsions were optimized and the conditions of nanobubbles formulaion was also evaluated. Cytotoxicity of DTX-loaded nanobubbles on MCF-7 cells was evaluated with the MTT method. Results The best ratio of mPEG-PLGA and Span 20 was 10: 1 (mol/mol). The membrane elasticity of the prepared nanobubbles with optimized formulations and the preparation techniques was good. In addition, they were obviously temperature-sensitive and ultrasonic-sensitive. The particle size of nanobubbles increased with higher temperature and decreased with lower temperature. The size of nanobubbles increased upon ultrasound application and then decreased a little. The cytotoxicity of DTX-loaded nanobubbles on MCF-7 cells was obvious and dose-dependent. Conclusion DTX-Loaded nanobubbles are a novel formulation with tumor-targeted and ultrasound-sensitive drug release.
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Objective To optimize the formulation and preparation technology of docetaxel(DTX)-loaded nanobubbles,and evaluate their properties. Methods The best ratio of methoxypoly(ethylene glycol)-poly(DL-lactide-co-glycolide)(mPEG-PLGA) and different membrane stabilizers were optimized with Langmuir membrane balance. DTX-Loaded nano-micelles were encapsulated by mPEG-PLGA with an injection method. Nanoemulsions was formed after being added with perfluoropentane(PFP,the boiling point of 29.5℃)as the organic phase. The formulations and preparation techniques of nanoemulsions were optimized and the conditions of nanobubbles formulaion was also evaluated. Cytotoxicity of DTX-loaded nanobubbles on MCF-7 cells was evaluated with the MTT meth?od. Results The best ratio of mPEG-PLGA and Span 20 was 10∶1(mol/mol). The membrane elasticity of the prepared nanobubbles with optimized formulations and the preparation techniques was good. In addition,they were obviously temperature-sensitive and ultra?sonic-sensitive. The particle size of nanobubbles increased with higher temperature and decreased with lower temperature. The size of nanobubbles increased upon ultrasound application and then decreased a little. The cytotoxicity of DTX-loaded nanobubbles on MCF-7 cells was obvious and dose-dependent. Conclusion DTX-Loaded nanobubbles are a novel formulation with tumor-targeted and ultra?sound-sensitive drug release.
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OBJECTIVE: To prepare Panax notoginseng saponins-loaded complex nano vesicles (PNS-CNV) with MPEG-PLGA nanoparticles as the core and investigate the physicochemical property of PNS-CNV and protective action on acute myocardial ischemia in rats. METHODS: Double emulsification-solvent evaporation method was used to prepare Panax notoginseng saponins-loaded nanoparticles using different molecular weight MPEG-PLGA (PNS-NP). Thin-film hydration method was applied to entrap PNS-NP as the core to form PNS-CNV. Ultrafiltration, transmission electron microscope, dynamic light scattering and electrophoretic light scattering were employed to study the entrapment efficiency of each index component in PNS and physicochemical parameters of PNS-CNV. Acute myocardial ischemia model in rats was established to investigate the protective effect of PNS-CNV. RESULTS: The molecular weight of MPEG-PLGA did not affect the entrapment efficiency, particle size and Zeta potential of PNS-CNV. The pharmacodynamic experiment indicated that comparing with PNS solution group, the SOD activity of rat myocardium in PNS-CNV group was elevated with markedly decreased H2O2, MDA and serum LDH activity (P<0.05). The protective effect of PNS-CNV with MPEG5000-PLGA was the most significant. CONCLUSION: CNV may be used as potential new oral drug delivery carriers.