| Aiming at solving the problem of low persistence,low stability,and easy to loss for the common formulation of the pectcide and protein drug,the improved solvent extraction method and the solvent evaporation of double emulsion were used to prepare the mixed formulation of the pyraclostrobin and the microcapsule of Bovine serum protein,respectively in this thesis research.Meanwhile,the solvent evaporation of emulsion was improved to control the morphology of the product polymer particle.The results of the research showed that,1.The "one-step" improved solvent extraction method could be used to prepare the mixed formulation of the aqueous microcapsule-suspension(CS)and suspension(SE)with pyraclostrobin as the core material,poly(ε-caprolactone)(PCL)as the wall material,acetone as the solvent,water as the anti-solvent,and poly vinyl alcohol(PVA)as the surfactant.The product was characterized with its stability,encapsulation efficiency(EE),drug loading efficiency(DLE),release kinetics,and size and morphology.The effects of ratio of core to wall,temperature,and surfactant concentration on the EE,DLE and releases kinetics were investigated.Good stability for more than 48 hours and release kinetics were observed for the mixed formulation.The duration of release of the pyraclostrobin was prolonged to longer than 12 days.2.The influence of homogenization stirring rate,evaporation temperature,and type of oil phase solvent on the morphology of polymer particles was investigated by single factor method for the solvent evaporation O/W emulsion.When a single hydrophobic solvent was used as oil phase,the particle morphology could be adjusted by changing the evaporation rate of the solvent and the mobility of the polymer chain to prepare smooth spherical solid particles,loose spherical particles,and bowl shaped particles.When a binary mixture solvent was used as oil phase,(Ⅰ)if two hydrophobic solvents were used,the situation was same as that of a single hydrophobic solvent;(Ⅱ)if a hydrophobic solvent and a hydrophilic solvent were used,(A)when the amount of hydrophilic solvent was small so that the polymer concentration in dispersed phase droplets after extraction could not reach the phase separation concentration,the situation was same as that of(I).(B)When the amount of hydrophilic solvent was large so that the liquid-liquid phase separation occurred and the concentration was close to the liquid-solid separation point after solvent extraction,the product was shorter micrometer fibers.(C)if the liquid-solid phase separation had occurred after solvent extraction,the formation of the bowl shaped particles would be promoted by the increase in the solvent evaporation temperature.3.The bovine serum protein(BSA)microcapsule was prepared by solvent evaporation method of W/O/W double emulsion with BSA as core material,and polylactic acid(PLA)as wall material.The effects of the mass ratio of W1/O,the mass ratio of O/W2,and the concentration of BSA on the encapsulation efficiency(EE),drug loading efficiency(DLE),and drug delivery rate were investigated.And in the scope of this study,the best condition for highest EE and DLE was:the mass ratio of W1/O was 1/5,the mass ratio of O/W2 was 1/6,the concentration of BSA was 1wt%,the concentration of PLA was 3wt%,and PVA concentration was 3wt%.Meanwhile,the BSA microcapule was prepared under these parameters,and the particle size distribution,product particle morphology,and in vitro release kinetics of the product were characterized.The results showed that in the PBS buffer solution,the release period of BSA microcapsule in vitro was more than 180h,and its release behavior agreed with the first-order in vitro release model. |
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