Optimization of preparation procedures for nano-sponges of flavonoids fromGlycyrrhizae Radix et Rhizoma by Box-Behnken response surface methodology based on CRITIC weighted evaluation / 中国中药杂志

In this paper, nano-sponges of flavonoids from Glycyrrhizae Radix et Rhizoma (LF-NSP) were prepared by agitation-freeze drying method. Box-benhnken design and response surface method based on the single factor experiment was used to optimize the preparation process, with the stirring temperature as well as stirring time and speed as the independent variables, while with drug loading, particle size and the generalized "normalized value" as the response values. In addition, the nano-sponges were characterized by scanning electron microscope (SEM), infraredspectroscopy (FT-IR) and differential scanning calorimetry (DSC), and its release in vitro was also investigated. The results showed that the optimum preparation conditions for glycyrrhizin nano-sponges were as follows：The proportion of main drug and auxiliary drug was 1:2; the proportion of crosslinking agent DPC and β-CD was 4:1; stirring temperature 45 °C for 4.8 h at 245 r·min⁻¹. The comprehensive score of LF-NSP prepared under these conditions was 94.78. FT-IR and DSC results indicated the formation of Glycyrrhiza flavonoids nano-sponges, and SEM showed that they were spherical particles in shape. In release experiment in vitro, the cumulative release of glycyrrhizin flavonoids nano-sponges for 240 min was 81.8%, while that of crude drug was only 31.5%. Nano-sponges can significantly improve the dissolution of flavonoids from Glycyrrhizae Radix et Rhizoma.

Preparation of nanosuspensions of flavonoids from Glycyrrhizae Radix et Rhizoma and the in vitro dissolution rate / 中成药

AIM To prepare nanosuspensions of flavonoids from Glycyrrhizae Radix et Rhizoma and to determine the in vitro dissolution rate.METHODS Precipitation-high pressure homogenization method was adopted in the preparation of nanosuspensions.With mean particle size and polydispersity index (PDI) as evaluation indices,concentrations of flavonoids,povidone K30 (PVP K30) and polyethylene glycol 400 (PEG 400) as influencing factors,central composite design-response surface method was applied to optimizing the preparation.For the freedried powder prepared by freeze-drying method,the optimal kind and ratio of lyoprotectant were screened.Then the in vitro dissolution rates of freeze-dried powder and physical mixture were compared.RESULTS The optimal conditions were determined to be 10.00 mg/mL for flavonoids' concentration,and 2.30 mg/mL for both PVP K30 and PEG 400 concentrations,the mean particle size and PDI were (172.3 ± 1.2) nm and 0.175 ± 0.004,respectively.The optimal lyoprotectant was 5％ mannitol-lactose (3 ∶ 2),the mean particle size and PDI after redissolution were (239.7 ±2.1) nm and 0.193 ±0.032,respectively.The in vitro dissolution rate of lyoprotectant reached 87.7％ within 60 min,which was much higher than that of physical mixture (less than 30％).CONCLUSION Nanosuspension can effectively improve the in vitro dissolution rate of flavonoids from Glycyrrhizae Radix et Rhizoma.