Method for preparing estradiol ultrafine particles with supercritical anti-solvent technology

The invention discloses a method for preparing estradiol ultrafine particles with a supercritical anti-solvent technology. The method comprises the steps as follows: step S1, estradiol is dissolved in an organic solvent, and an estradiol solution is prepared; step S2, CO2 is introduced into a crystallization kettle, and the temperature and pressure in the crystallization kettle are adjusted; step S3, CO2 is introduced continuously at a constant flow rate, and the estradiol solution prepared in step S1 is introduced into the crystallization kettle while the temperature and pressure in the crystallization kettle are kept unchanged; Step S4, CO2 is introduced continuously after the introduction of estradiol solution, the temperature and pressure in the crystallization kettle are kept unchanged, the pressure is relieved after a period of time, and after the pressure in the crystallization kettle is reduced to atmospheric pressure, the crystallization kettle is opened for collecting the estradiol ultrafine particl