Study On The Technology Of Evening Grass Oil Microcapsule

In this paper, evening primrose oil (EPO) was selected as core material and encapsulated by simple coacervation and spray drying methods. Antioxidant capacity and content of EPO were used as evaluation standard; the peroxide value (POV) of EPO was determined by titration analytical procedures and colorimetric method according to the national standard. The content of EPO microcapsules was determined by UV method. All the determinable methods were reliable and precise, which provided a basis for pharmaceutical process research.EPO was microencapsulated by simple coacervation method. Enteric polyacrylic resin Ⅱ and polyacrylic resin Ⅲ (1:1) were used as coating material,95%ethanol was used as solvent, polyoxyl40hydrogenated castor oil (RH40) was used as emulsifier, sodium dodecyl sulfate (SDS) was used as steric stabilizer, distilled water was used as nonsolvent. The oxidation rate of EPO was used as evaluation standard and single factor experiments and central composite design-response surface methodology were used to optimize the process condition, which the ratio of core materials to coating materials was41:59, the concentration of emulsifier was1.08%, homogenizing time was125s. The experimental results showed that the antioxidant capacity of EPO microcapsule was well. Microcosmic morphology of EPO microcapsule observed the whole morphology of the microcapsule was perfectly microsphere and better dispersity, but the surface microstructure of microcapsule was not smooth. The average particle size was7.30μm.EPO was microencapsulated by spray drying method. Gelatin and sucrose were used as wall material. The oxidation rate of EPO was used as evaluation standard. The optimum process conditions were found by single factor experiments and central composite design-response surface methodology the ratio of core to wall material was 9:16, the gelatin content of wall material was38.6%, inlet temperature was175℃, and the height of rotameter was28mm. The experimental results showed that the antioxidant capacity of EPO microcapsule was very well. Microcosmic morphology of EPO microcapsule observed the surface microstructure of microcapsule was smooth and the microcapsule was agglomerated. The microaggregate had narrower size distribution and the average particle size was13.16μm.The accelerated experiment showed that the oxidation rate of EPO, which was encapsulated in microcapsules by spray drying and simple coacervation methods were2.238meq/kg·d and5.900meq/kg-d respectively. The content of EPO microencapsulated by simple coacervation method was37.37%and the entrapment efficiency was93.12%; the content of EPO microencapsulated by spray drying method was39.36%and the entrapment efficiency was98.32%.By comparison, the antioxidant capacity of EPO microencapsulated by spray drying method was superior to simple coacervation method.