Complexation between darunavir and β-Cyclodextrin. Experimental and theoretical studies

Abstract

Darunavir (DRV) is a protease inhibitor used in the treatment of HIVinfection, which constitutes a keystone in the therapy of patientsinfected with this virus. Unfortunately, DRV has low solubility inwater and poor bioavailability, therefore it requires administration inrelatively high doses in order to exhibit therapeutic efficacy. Acommonly applied approach to increase the solubility of drugs is theformation of complexes with macromolecules, of which molecularencapsulation with β-cyclodextrin (βCD) constitutes an alternative forthe development of new pharmaceutical dosage forms. Therefore, itwas to evaluate by theoretical (molecular modelling) and experimental(spectroscopic) approaches the possibility of obtaining an inclusioncomplex between DRV and βCD. From the results obtained by thedocking procedures, we found three clusters of conformations for the DRV:β-CD complex, corresponding to conformations in which the ligand moieties were buried into the β-CD hydrophobic cavities. Molecular modelling results were compared with spectroscopic studies, with 1H NMR studies evidencing that DRV and βCD proton resonances were modified upon complexation, thus confirming the formation of the inclusion complex. The combination of theoretical and experimental techniques confirmed the formation of the inclusion complex between DRV and βCD.