Objective:To prepare licorice total flavonoids nanosuspension lyophilized powder

and rsearch for its characterization and stability. Method:Licorice total flavonoids nanosuspension lyophilized powder was prepared by freeze-drying method

its powdery properties(angle of repose and bulk density) were determined

and it was characterized by the laser particle size analyzer

ultraviolet spectroscopy(UV)

Fourier transform infrared spectroscopy(FT-IR) and X-ray diffraction(XRD)

then its stability was investigated. Result:Mean particle size of licorice total flavonoids nanosuspension lyophilized powder was (239.7±2.1) nm and the polydispersity index(PDI) was 0.193±0.032

the rangle of repose was 41.45 degree and the bulk density was 0.267 g·cm-3.UV and FT-IR showed that the chemical structure of licorice total flavonoids did not change

XRD analysis showed that the drug was always in the amorphous state

and no crystal transformation occurred during the freeze-drying process.The stability test showed that appearance

redispersibility

angle of repose

bulk density

total flavonoid content and dissolution in 1 h of the lyophilized powder were not significantly affected at high temperature of 60℃

relative humidity of 75% and light intensity of (4 500±500) Lx. Conclusion:The lyophilized powder can significantly improve the dissolution of licorice total flavonoids

and the physical and chemical properties of drug do not change

the stability of lyophilized powder is good

and it can be further prepared as licorice total flavonoids solid preparation.