The invention belongs to the field of
drug sustained release preparations, and provides an
ovulation inducing preparation for improving
fertility and a preparation method thereof. The core-shell structure
microsphere design is adopted,
leuprorelin acetate is entrapped in the core of the
polylactic acid microsphere, and covalently anchored amido bond connection is formed through an
end group activated
polylactic acid NHS ester intermediate and a
chitosan-
sodium tripolyphosphate
ion network shell layer, so that the high stability of the shell layer is realized; by optimizing the compounding use of the
internal phase stabilizer and the freeze-
drying protective agent, the
particle size distribution D50 of the microspheres is controlled to be 10-60 microns, the thickness of the shell layer is controlled to be 0.05-5 microns, and high encapsulation efficiency, good
drug slow release performance and excellent storage stability are realized. The technical problems that in an existing
peptide medicine core-shell
microsphere system, a shell layer is prone to falling off, the
medicine is suddenly released, and the stability is poor after freeze-
drying are solved, and the
peptide medicine core-shell microsphere has the advantages of being high in encapsulation efficiency, controllable in release and good in
biocompatibility and has wide application value in the technical field of assisted
reproduction.