Abstract: Objective To prepare capsaicin-β-cyclodextrin inclusion complex (CAP-β-CD) and inspect their solubilities. Methods CAP-β-CD was prepared by the coprecipitation method and optimum formation conditions for preparation was selected by orthogonal design. The measurements of the apparent solubility and equilibrium constant were carried out by phase solubility diagram. Results The optimal conditions for forming CAP-β-CD complexes were 21:1 of capsaicin to cylcodextrin molar ratio, 70℃of temperature, 70 rpm of stirring strength, and 6 h of reaction duration at pH 11. The solubilities of capsaicin in inclusion complexes were the biggest at 25, 37, 45 ℃, which were 0.32, 0.60, 1.08 mg·mL-1, respectively. Conclusion By forming stable inclusion complex with β-CD, the solubility of capsaicin was increased.

Key words: capsaicin, β-cyclodextrin, inclusion complex, inclusion constants