Preparation Of Gelatin Microspheres Of Opuntia Dillenii Haw. Polysaccharides

The gelatin microspheres of Opuntia dillenii Haw. polysaccharide(ODP-GMS) were prepared through crosslinking-emulsion method in this study. Content of glutaraldehyde, W/O ratio, accession amount of emulsifier, concentration of gelatin and polysaccharide Opuntia dillenii Haw. were optimized by single factor experiment. The results showed that the optimum concentration of glutaraldehyde and gelatin was1%and10%. The factors of influence on ODP-GMS preparation were investigated by orthogonal experiment. Contribution to the quality of ODP-GMS, in order of importance, are the parameters that set the concentration of ODP, accession amounts of emulsifier, and then W/O ratio. The results indicated the best W/O ratio was1:3, concentration of emulsifier and ODP were1%and10mg/mL. Drug-loading and drug embedding of ODP-GMS were respectively7.47%and91.38%. The experiments were stable and representational. The best preparation conditions of ODP-GMS were found:the W/O ratio of1to3.671.06%of emulsifier content,11.47mg/mL of the ODP concentration, through response surface analysis. The model of response surface experiment predicted the drug-loading could reach7.756%. The drug-loading was improved and the process conditions were optimized.The size of ODP-GMS with spheroidal shape was relatively homogeneous. It was without adhesion between sphere to sphere and easy to decentralize. The structure of ODP-GMS was observed by optical microscope. The results showed ODP mainly existed in centre of ODP-GMS and a few scattered throughout the sphere. Surface of ODP-GMS was smooth and most of them were spheroidal shape under scanning electron microscope. The diameter of ODP-GMS was about7.24μm. And conform to the normal distribution curve.The swelling of ODP-GMS was inspected. It was found that the diameter and of microsphere increased22.81±0.45%and its quality was up to403%after dissolving in water2h. The ODP-GMS slowly released drug85%in the PBS for24h. Drug release of ODP-GMS in the PBS was in agreement with Higuchi equation. ODP-GMS in the HC1slow-release was less effective for12h and the accumulative release rate reached90%. The drug release curve of ODP-GMS was suitable for the first order kinetics equation and release mechanism of Higuchi equation mathematical modeling. The ODP-GMS had a good stability and their drug-loading were affected less by temperature and humidity. There were no obvious differences in parameters of ODP-GMS stored at different temperature for3months. The results proved that ODP-GMS can be stored at normal temperature.The free radical scavenging activity of ODP-GMS was determined. The results showed that ODP-GMS had strong scavenging effects on three kinds of free-radical (OH, DPPH· and O2). Releasing for12h, the DPPH free radical scavenging potential of ODP-GMS reached50%. The antioxidant capacity of ODP-GMS releasing for24h had no obvious difference with an equal amount of fresh ODP. In conclusion, it was viable to prepare ODP-GMS through crosslinking-emulsion method.