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@#A thermosensitive hydrogel system consisting of PLGA-PEG-PLGA hydrogel and Pseudomonas aeruginosa DNA vaccine was constructed and the immune efficacy of the system was evaluated. The PLGA-PEG-PLGA thermosensitive hydrogel containing Pseudomonas aeruginosa DNA vaccine was prepared by a simple physical mixing method. The gelation temperature, cytotoxicity, and release curve in vitro were tested.The degradability of hydrogel in vivo was evaluated. The mice were divided into control group (PBS), hydrogel group (Hydrogel), in vivo-jetPEI/plasmid DNA group (in vivo-jetPEI/pDNA), and hydrogel + in vivo-jetPEI/plasmid group (Gel+in vivo-jetPEI/pDNA). Mice were immunized three times with a ten-day interval. Two weeks after the last immunization, the mice were sacrificed. The proliferation of splenic lymphocytes, serum specific IgG antibodies and IFN-γ in supernatant of splenic lymphocytes were detected. The gelation temperature of PLGA-PEG-PLGA hydrogel was (32 ± 0.5) ℃. There was no obvious toxicity to cells in vitro, and about 80% of plasmid DNA was released after 7 days in vitro. PLGA-PEG-PLGA hydrogel was biodegradable, and degraded almost completely after 15 days in vivo. The spleen lymphocytes proliferated; the levels of specific IgG antibodies and IFN-γ of in vivo-jetPEI/pDNA and Gel+in vivo-jetPEI/pDNA groups increased. The hydrogel could enhance the immune response induced by DNA vaccine.Results suggest that the thermosensitive hydrogel system consisting of PLGA-PEG-PLGA hydrogel and Pseudomonas aeruginosa DNA vaccine is a promising new strategy for the development of PA vaccine.
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PUE@PEG-PLGA micelles has excellent characteristics such as small particle size, high drug loading and slow drug release. The results of TEM electron microscopy showed that PUE@PEG-PLGA micelles had obvious core-shell structure. The critical micelle concentration(CMC) of PEG-PLGA micelles determined by pyrene assay was about 4.8 mg·L~(-1). Laser confocal experiments showed that PEG-PLGA micelles can enhance the cellular uptake of coumarin-6 and aggregate around the mitochondria; quantitative results of extracellular drug residues also indirectly confirmed that PEG-PLGA micelles can promote cellular uptake of the drug. Acute ischemic myocardial model rats were prepared by coronary artery ligation, and then the model rats were randomly divided into six groups: Sham operation group, model group, puerarin(PUE) group, as well as low-, mid-, and high-dose PUE@PEG-PLGA micelles groups. Drugs were given by iv administration 5 min after the ligation. The ST segment changes in the electrocardiogram were monitored; serum creatine kinase(CK), lactate dehydrogenase(LDH), aspartate aminotransferase(AST), and malondialdehyde(MDA) levels were detected and myocardial infarct size was also measured. Both PUE and PUE@PEG-PLGA micelles can reduce the elevated ST segment, reduce serum CK, LDH, AST and MDA levels, and reduce myocardial infarct size. The efficacy of PUE@PEG-PLGA medium and high dose groups was significantly better than that in the PUE group, and the efficacy in PUE@PEG-PLGA low dose group was basically equivalent to that in the PUE group. PUE@PEG-PLGA micelles can greatly improve the cardiomyocytes uptake of PUE, enhance the anti-acute myocardial ischemia effect of drugs, and reduce its dosage.
Subject(s)
Animals , Rats , Isoflavones , Pharmacology , Micelles , Myocardial Ischemia , Drug Therapy , Polyesters , Polyethylene Glycols , Random AllocationABSTRACT
Objective To prepare baicalin-polyethylene glycol-poly (lactic-co-glycolic acid) copolymer (PEG-PLGA)-loaded nanomicelles, and study its in vitro drug release properties and tissue distributed in rats with acute myocardial ischemia. Methods The preparation process of baicalin PEG-PLGA nanomicelles was optimized by orthogonal test. The optimized baicalin PEG-PLGA nanomicelles were characterized by particle size, Zeta potential, and TEM electron microscopy. The in vitro release assay and tissue distribution of the acute myocardial ischemia rat model were used to evaluate this drug delivery system. Results The preferred preparation conditions for baicalin PEG-PLGA nanomicelles were a mass ratio of baicalin to PEG-PLGA at 1:10 with a rotary evaporator rotation rate of 80 r/min and a hydration temperature of 40 ℃. The optimized baicalin PEG-PLGA nanomicelle particle size was (18.5 ± 0.5) nm, the zeta potential was (-10.9 ± 0.7) mV, the drug loading was (7.9 ± 0.3)%, and the encapsulation efficiency was (86.2 ± 2.5)%. The critical micelle concentration of PEG-PLGA nanomicelles was 3.8 μg/mL by oxime assay. TEM showed that baicalin PEG-PLGA nanomicelles presented a spherical shape with uniform particle size, In vitro release test showed that baicalin PEG-PLGA nanomicelles had obvious sustained release characteristics; Tissue distribution test showed that the order of distribution of baicalin PEG-PLGA nanomicelles in normal rat organs was liver > spleen > heart > kidney > lung > brain, while the distribution of baicalin PEG-PLGA nanomicelles in acute myocardial ischemia model was liver > heart > spleen > kidney > brain. Compared with normal rats, the drug concentration in the heart of rats with acute myocardial ischemia showed a significant increase trend in all time periods, and the highest drug concentration at 120 min could reach (2 897 ± 135) ng/mL, the highest drug concentration of the heart in the normal rats was (2 411 ± 89) ng/mL, which indicated that the baicalin PEG-PLGA nanomicelles had good targeting in the acute myocardial ischemia zone. Conclusion Baicalin PEG-PLGA nanomicelles have good drug-loading properties, slow release in vitro, and can accumulate drugs in the ischemic myocardium, which has good cardiac targeting.
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Objective To prepare gemcitabine hydrochloride thermosensitive gel injection and to stablish the determina‐tion methods of its contents .Methods Gemcitabine hydrochloride thermosensitive gel injection was prepared using PLGA‐PEG‐PLGA as thermosensitive viecle .The contents of gemcitabine hydrochloride were determined by HPLC .Results The formulation contained 40 mg/ml gemcitabine and 20% (wt) PLGA‐PEG‐PLGA with phase‐transition temperature of (37 ± 0 .15) ℃ ,showing the best viscosity around human body temperature .Gemcitabine hydrochloride presented a good linearity in the range of 5‐500 μg/ml(r=0 .999 8) ,which had good precision and reproducibility .The recovery rate of low ,middle and high concentrations of gemcitabine hydrochloride were (99 .5 ± 3 .2)% ,(100 .4 ± 2 .4)% ,(102 .1 ± 2 .4)% ,n=3 ,respectively . The average contents of gemcitabine hydrochloride in three batches of sample were (101 .87 ± 2 .95)% ,(99 .4 ± 2 .73)% , (98 .98 ± 0 .71)% ,n=3 ,respectively .Conclusion The quality of gemcitabine hydrochloride thermosensitive gel injection with PLGA‐PEG‐PLGA as matrix could be controlled .It is a promising new drug for pancreatic cancer .
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OBJECTIVE:To optimize the formulation of Methotrexate thermosensitive hydrogels,and to study the in vitro re-lease property of it. METHODS:Taking PLGA-PEG-PLGA as matrix and mannitol as viscosity modifiers,Methotrexate thermosen-sitive hydrogels were prepared. Using the absolute value of the deviation of gelation temperature between 35 ℃,its formulation was optimized by orthogonal test using the concentrations of PLGA-PEG-PLGA,methotrexate and mannitol as factors. The dialysis bag method was used to investigate accumulative release rate of Methotrexate thermosensitive hydrogels and methotrexate solution within 336 h in vitro. RESULTS:The optimal formulation was as PLGA-PEG-PLGA of 20%,methotrexate of 0.10% and mannitol of 0.10%;gelation temperature were 35.1,35.0,35.0℃. The average drug-loading rate was more than 90%. 12 d accumulative re-lease rate was more than 90%(r=3). Methotrexate solution has been substantially completely relased within 240 h. CONCLU-SIONS:Methotrexate thermosensitive hydrogels with sustained-release are prepared successfully,and the preparation technology is simple and practical.
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OBJECTIVE:To prepare the scutellarin-PEG-PLGA drug-laded nanoparticles,optimize the formulation with ratio of colostrum and external aqueous phase,mass concentration of scutellarin and PEG-PLGA as factors and conduct quality evalua-tion. METHODS:A double emulsion-solvent evaporation method was adopted to prepare the scutellarin-PEG-PLGA nanoparticles. With the evaluation index of encapsulation efficiency,single factor and orthogonal test were used to determine the apparent shape, particle size,Zeta potential,drug loading amount,encapsulation efficiency and stability of prepared nanoparticles by optimized for-mulation with ratio of colostrum and external aqueous phase,mass concentration of scutellarin and PEG-PLGA as factors. RE-SULTS:The ratio of colostrum and external aqueous phase was 1∶15 and the mass concentrations of scutellarin and PEG-PLGA were respectively 10 mg/ml and 15 mg/ml in optimized formulation;the prepared nanoparticles were round or oval with the average particle size of(78.54±2.21)nm,Zeta potential of(-23.07±1.39)mV,drug loading amount of(1.67±0.12)%,and encapsula-tion efficiency of(45.32±1.29)%. There was no obvious changes in the particle size and encapsulation efficiency within 3 months at 4 ℃ preservation. CONCLUSIONS:The scutellarin-PEG-PLGA nanoparticles with better physical and chemical properties and stability are successfully prepared.
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OBJECTIVE: To prepare H102 loaded PEG-PLGA nanoparticles (H102-NP) and investigate its properties in vitro and in vivo. METHODS: Orthogonal design was used to optimize the formulation. The nanoparticles were characterized in terms of morphology, size, Zeta potential, drug encapsulation efficiency, in vitro release and stability. H102 concentrations in plasma and brain following tail vein injection of H102-NP in mice were measured by LC-MS. RESULTS: H102-NP were spherical and of regular size. The average size, Zeta potential and encapsulation efficiency of H102-NP were found to be around 137 nm, -38 mV and 64%. The cumulative release of H102-NP in pH 7.4 PBS and plasma at 12 d is 93% and 95%, respectively. Incubated in plasma and brain homogenate at 37°C for 12 h, the degradation of H102 encapsulated in nanoparticles was only 5%. Compared with H102 solution which was eliminated rapidly in blood with low concentration in brain, H102-NP was eliminated slowly in blood with higher concentration and longer duration in brain after intravenous administered in mice. The AUC of H102-NP was 245 times and 11 times higher in plasma and brain than that of H102 solution. CONCLUSION: H102-loaded nanoparticles are successfully prepared with good properties in vitro and in vivo, which showed a prospect for the treatment of Alzheimer's disease.
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OBJECTIVE: To synthesize magnetic thermosensitive hydrogel and study its heat effect under alternating magnetic field in vitro. METHODS: PLGA-PEG-PLGA triblock copolymer was synthesized by ring-opening polymerization of D, L-lactide and glycolide with PEG1500 in the presence of stannous iso caprylate. Magnetic thermosensitive hydrogel of different concentrations were prepared using different currents. The influences of the concentration of magnetic fluid and current of magnetic field on the heat effect were separately observed. RESULTS: The synthetized PLGA-PEG-PLGA triblock copolymer was excellently temperature sensitive. It retained the thermo-sensitivity of original hydrogel when the magnetic fluid was loaded. The 5, 10 and 20 min heating ability of magnetic fluid was positively linearly correlated with its concentration (r=0.9985, 0.9893 and 0.9711, respectively, n=3) and current of magnetic field (r=0.9948, 0.9977 and 0.9994, respectively, n=4). CONCLUSION: The magnetic thermosensitive hydrogel has excellent temperature sensitivity. When alternating magnetic field is applied, the temperature of the system can rise and reach above LCST of hydrogel. The temperature can be controlled by changing the concentration of magnetic fluid and the current of magnetic field. Copyright 2012 by the Chinese Pharmaceutical Association.