Structural studies of coenzyme Q10 inclusion complex with g-cyclodextrin using chemical analyses and molecular modeling

Abstract

The stability, dispersibility and oral bioavailability of coenzyme Q10 (CoQ10) are known to be improved upon complexing CoQ10 with g-cyclodextrin (γ-CD). However, the details of the three-dimensional structure of the γ-CD/CoQ10 complex are not well understood. Therefore, the molecular composition and three-dimensional structure of the complex were investigated using chemical analyses and molecular modeling. The molecular ratio of γ-CD and CoQ10 in the complex was investigated by NMR as well as by HPLC to determine the γ-CD/CoQ10 ratio of 2.5. DSC analysis of the γ-CD/CoQ10 complex indicated formation of the inclusion complex. Three different complex models (γ-CDx2+CoQ10; γ-CDx3+CoQ10; γ-CDx5+CoQ10x2) that correspond to the derived γ-CD/CoQ10 ratio were also constructed and then molecular mechanics and dynamics calculations were carried out to provide several possible complex structures. Based on the complex structures thus obtained, structural and energetic features of the complexes were examined