Molecular dynamics simulations of UC781-cyclodextrins inclusion complexes in aqueous solution

Area of Science:

• Computational Chemistry
• Drug Delivery Systems
• Supramolecular Chemistry

Background:

• The anti-HIV drug UC781 is highly potent but requires effective delivery systems.
• Cyclodextrins (CDs) are widely used to improve drug solubility and stability.
• Understanding drug-cyclodextrin interactions is crucial for developing new pharmaceutical formulations.

Purpose of the Study:

• To investigate the inclusion complex formation between UC781 and three different cyclodextrins (βCD, MβCD, HPβCD) in aqueous solution.
• To determine the structural basis for the varying stability of these complexes.
• To establish a reliable computational method for predicting drug-CD complex formation.

Main Methods:

• Molecular dynamics (MD) simulations were employed to model the interactions between UC781 and βCD, MβCD, and HPβCD.
• Analysis of binding energies, complex stability, and structural orientations within the CD cavities.
• Investigation of the influence of aqueous solution on the inclusion complexes.

Main Results:

• Simulations confirmed the entrapment of UC781's phenyl ring within the CD cavities.
• The NH group of UC781 formed interactions with the hydroxyl groups on the wider rim of the CDs.
• 2,6-dimethyl-β-cyclodextrin (MβCD) formed the most stable inclusion complex with UC781, attributed to its methoxy groups.
• Detailed structural analysis provided insights into UC781's orientation and the impact of the aqueous environment.

Conclusions:

• MβCD demonstrates superior complexation with UC781 compared to βCD and HPβCD, highlighting its potential for enhanced drug delivery.
• The study provides a validated computational approach for predicting the formation and stability of other drug-cyclodextrin inclusion complexes.
• Findings contribute to the rational design of novel drug delivery systems for anti-HIV agents and other pharmaceuticals.