Effect of α-Cyclodextrin on Fluorouracil

Abstract

α-cyclodextrin (α-CD) contain six glucopyronose units with a hydrophilic hydroxyl group on their outer surface and a hydrophobic cavity in the center.  α-cyclodextrin combine with fluorouracil  to form an inclusion complex. Spectral characteristics of fluorouracil have been studied in   α-cyclodextrin. The inclusion complex of α-cyclodextrin with fluorouracil is investigated by UV-visible and fluorimetry spectroscopy. The absorption maxima of fluorouracil appear at 265.6 nm. Upon increasing the concentration of α-CD the absorption maxima is blue shifted from 265.6 nm to   246.4 nm. The absorption intensity increases with increasing the concentration of α-CD. In emission spectra it is red shifted from 385 nm to 413 nm.  The emission intensity is increased by the addition of  Î±-CD.  The association constant (K) of the Benesi-Hildebrand plot confirmed that 1:1 stoichiometric ratio was present in the inclusion complex. Phase solubility studies were carried out.