Construction and in vivo evaluation of a thermosensitive hydrogel system loading with Pseudomonas aeruginosa DNA vaccine / 中国药科大学学报

@#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.

Formulation Optimization and in vitro Release Property Study of Methotrexate Thermosensitive Hydrogels / 中国药房

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.

Gemcitabine hydrochloride thermosensitive gel injection preparation and contents determination / 药学实践杂志

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 .

Systhesis of magnetic thermosensitive hydrogel and its heat effect under alternating magnetic field / 中国药学杂志

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.