Abstract: 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 to 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 to drug weight ratios. Preparation methods had little effect on the dissolution rates of daidzein solid dispersion.

Key words: daidzein, polyethylene glycol, solid dispersion, dissolution rate