METHOD OF PRODUCING POROUS POLYMER MICROPARTICLES USING FREEZE DRYING Russian patent published in 2024 - IPC F26B5/06 C08J9/28 

FIELD: biotechnology; medicine.

SUBSTANCE: invention relates to biotechnology and medicine, namely to creation of highly porous polymer particles used in regenerative medicine, tissue engineering and surgery, as well as nasal or transdermal forms of drug delivery, or as haemostatic agents. Freeze drying is used to produce porous polymer microparticles. Method involves several steps: at the first, a polymer solution is prepared using water and diluted solutions of acids and alkalis, or buffer aqueous solutions or 1,4-dioxane, dimethylsulfoxide as solvents. To the weighed portion of polymer material with content of 0.5 to 2 wt.% of dry substance of the final amount of the solution, 98–99.5 wt.% of solvent is added; stirring on a magnetic mixer for at least 48 hours at room temperature and speed from 100 to 300 rpm. Then, an aerosol formation step is carried out, followed by shock freezing, which includes pouring a polymer solution or suspension into a pneumatic sprayer reservoir with subsequent spraying at pressure of 3 bar into a metal container filled with liquid nitrogen by 2/3 of its volume. After that, the main part of liquid nitrogen is evaporated at room temperature, particles are transferred to pre-cooled to -195 °C polypropylene cup and left in the freezing chamber at a temperature of -24 °C for 24 hours until complete evaporation of nitrogen. Last stage is drying of the frozen suspension, which includes removal of the solvent from the pores by means of sublimation drying with further additional drying in a drying cabinet at room temperature.

EFFECT: proposed invention enables to obtain porous polymer microparticles using freeze drying.

3 cl, 2 dwg, 9 ex