Sustained-release microsphere of nomegestrol acetate of analogs thereof and preparation method and application thereof

The invention discloses a sustained-release microsphere to achieve the aims of contraception and long-term treatment of endometriosis uterine, which comprises the following components: (1) nomegestrol acetate or analogs thereof, and (2) a biodegradable polymer, wherein the weight ratio of an ester-terminated polymer to a carboxyl-terminated polymer is between 1:0.01-1:1 the ester-terminated polymer is selected from polylactide-glycolide, polylactide, poly-beta-hydroxybutyrate, poly ortho ester, polycaprolactone, poly-phosphate, polyanhydride, or poly-cyanoacrylate the carboxyl-terminated polymer is selected from polyglycolic acid and polylactic acid-glycolic acid and the weight of the nomegestrol acetate or the analogs thereof accounts for 5 to 80 percent of the total weight of the microsphere. The invention also discloses a preparation method and application of the sustained-release microsphere.