Spectrofluorimetric study of host-guest complexation of ibuprofen with β-cyclodextrin and its analytical application

The characteristics of host-guest complexation between beta-cyclodextrin (beta-CD) and two forms of ibuprofen (protonated and deprotonated) were investigated by fluorescence spectrometry. 1:1 stoichiometries for both complexes were established and their association constants at different temperatures were calculated by applying a non-linear regression method to the change in the fluorescence of ibuprofen that brought about by the presence of beta-CD. The thermodynamic parameters (DeltaH, DeltaS and DeltaG) associated with the inclusion process were also determined. Based on the obtained results, a sensitive spectrofluorimetric method for the determination of ibuprofen was developed with a linear range of 0.1-2 mug ml(-1) and a detection limit of 0.03 mug ml(-1). The method was applied satisfactorily to the determination of ibuprofen in pharmaceutical preparations. (C) 2002 Elsevier Science B.V. All rights reserved.