Molecular simulation and experimental study on the inclusion of rutin with β-cyclodextrin and its derivative

Rutin is a natural flavonoid compound with various biological activities, but its low water solubility limits its applications in the food and pharmaceutical fields. Complexation with cyclodextrins (CDs) is a powerful method to improve the poorly solubility of rutin, whereas the mechanism for the inclusion still needs to be explored. This study investigated the characteristic and mechanism for inclusion of rutin with β-cyclodextrin (β-CD) and 2,6 dimethyl-β-cyclodextrin (DM-β-CD). The molecular simulation provided the possible inclusion structure and revealed that the combination of rutin and CDs is a thermodynamically good process. It also indicated that the complex formed with DM-β-CD had better stability and water solubility compared with β-CD. Then the complexes of rutin with β-CD and DM-β-CD were prepared and characterized by FT-IR, XRD, and DSC analysis. Phase solubility studies demonstrated that the solubility of rutin was significantly enhanced by forming 1:1 stoichiometric inclusion complexes. The effect of DM-β-CD in improving the water solubility of rutin is 146% higher than that of β-CD, which was in accordance with the simulation predictions.