Spectroscopic Investigation Of Rose Bengal/ Cyclodextrin Interactions In Aqueous Solution: The Case Of The Hydroxypropyl Cyclodextrins

The interaction of Rose Bengal (RB) with hydroxypropyl-alpha-cyclodextrin (HP-alpha-CD), hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and hydroxypropyl-gamma-cyclodextrin (HP-gamma-CD) has been studied in water and in acetate buffer at pH 4.5 by UV-Vis absorption, fluorescence spectroscopy and Induced Circular Dichroism at 298 K. Evidence of the complex formation between the RB and all HP-CDs have been obtained both in water and in buffer. Binding constants and stoichiometry of RB/HP-CD complexes in water have been determined by applying the modified Benesi-Hildebrand equation to the fluorescence measurements.