Preparation And Dissolution Of Solid Dispersions Of Daidzein

Daidzein is a kind of isoflavone, extracted from Pueraria. Daidzein has important physiological activity, but water-insoluble daidzein has low bio-availability. Solid dispersion technology is employed to increase solubility and dissolution. The bioavailability was improved by change of the existing form granularity and crystalline form.Daidzein solid dispersion was prepared with polyethylene glycol. The in vitro dissolution rates of different daidzein solid dispersions were measured by UV-VIS method to evaluate the effects of molecular weights, drug:polyethylene glycol ratios, and preparation methods on the dissolution rate of daidzein. The results showed that dissolution rates of daidzein were promoted with the increasing of polyethylene glycol molecular weights, and the polyethylene glycol:drug weight ratios. Preparation methods had little effect on the dissolution rates of DZ solid dispersion.The solid dispersions were also prepared by the solvent evaporation method with polyvinyl pyrrolidone (PVP K30). The influences of drug-carrier proportion, containing and not containing surfactants and different kinds of surface-active agents on the dissolution of daidzein were examined. In order to characterize the prepared solid dispersions, X-ray powder diffraction, Fourier transform infrared spectroscopy, as well as dissolution study were carried out. The results showed that the best drug-carrier proportion is 1:5 and surfactant can improve the dissolution rate of drug, especially the OP-emulsifier. Then the capsules were prepared with the solid dispersions of daidzein and the dissolution of capsules did not decrease obviously.