Optimization of the inclusion process of flemingia flavonoids with β-cyclodextrin by central composite design and response surface methodology

The aim of the experiment was to optimize the inclusion process of Flemingia flavonoids-β-cyclodextrin(TFF-β-CD) inclusion compound and identify its solubilization effect. On the basis of the pre-experiment,the formation of the inclusion compound was confirmed by infrared spectrophotometry. Using saturated aqueous solution method and the single factor test, response surface experiment was carried out to optimize the preparation process of TFF-β-CD inclusion compound with overall desirability of inclusion rate and yield as appraisement criteria. The result of pre- experiment showed that the TFF- β- CD inclusion compound had formed while the result of response surface methodology experiment showed that the optimum preparation process of TFF-β-CD inclusion compound was as follows:the feed ratio of β-cyclodextrin and TFF(mass ratio)5.5∶1,inclusion temperature 43 ℃,inclusion time 3.8 h and under the optimum conditions,the inclusion rate and the yield of the inclusion compound was 44.68% and 73.12% respectively. The solubility test showed that the solubility of TFF increased from(22.86±0.62) mg to(106.58±0.95) mg in water because of the preparation of TFF-β-CD inclusion compound. The TFF and β-CD could form stable inclusion complexes,the formation of which could increase the solubility of TFF in water significantly. Moreover the results of experiment provided a theoretical basis for the development of the oral preparation of TFF.