| Ivermectin, as one of the abamectin derivatives, is currently the most widely used animalinsect repellent. The development of ivermectin formulation has become a current researchhot spot, especially in the case of long-acting agents. Ivermectin is effective in expelling andkilling both internal and external parasites in animals, so the development of long-termpreparation of ivermectin is necessary and can relieve stress in the animals.With polyanhydride as carrying material, this study selected the emulsion solventevaporation method for two kinds of ivermectin polyanhydride microspheres. Basicproperties of microspheres were investigated, the drug release of microspheres was studied,and the results are as follows：The study was conducted to prepare ivermectin (IVM) polyester anhydride microsphere.Microspheres loading IVM were prepared by emulsion method (O/W) based on solventevaporation. Two kinds of P (SA：RA) with SA/RA ratios of20：80and30：70were selectedas microsphere matrix. Polyinyl acetate （PVA） was used as emulsion stabilizing agent. Thesurface morphology and particle size of microspheres were examined by optical microscopy,encapsulation and drug loading were determined by UV spectrophotometry. The averagevolumn size of IVM/P (SA：RA30：70) microspheres is72.24±24.74μm, drug loading is19.59%and the encapsulation efficiency is88.44%. The average volumn size of IVM/P(SA：RA20：80) microspheres is64.18±26.14μm, drug loading is17.91%and theencapsulation efficiency is87.79%.(IVM) Polyanhydride microspheres were prepared byemulsified solvent evaporation. These two kinds of microspheres are both released by theDiffusion–Erosion model in vitro release test. IVM/P (SA：RA20：80) microspheressustained released better than IVM/P (SA：RA30：70). |
