A novel spectrofluorimetric method for determination of lomefloxacin based on supramolecular inclusion complex between it and p-sulfonated calyx[4]arene

The characteristics of host-guest complexation between p-sulfonated calix[4]arene (SC4A) and lomefloxacin (LFLX) were investigated by fluorescence spectrometry. 1:1 stoichiometry for the complexation was established and their association constant at 25 degrees C was calculated by applying a deduced equation. The interaction mechanism of the inclusion complex was discussed. It was found that an appropriate amount of cationic surfactant cetyltrimethylammonium bromide (CTAB) could remarkably enhance the fluorescence intensity of the supramolecular complex system. Based on the obtained results, a novel sensitive spectrofluorimetric method for the determination of lomefloxacin was developed with a linear range of 0.01-3.0 mu g ml(-1) and a detection limit of 0.008 mu g ml(-1). The proposed method was applied satisfactorily to determine lomefloxacin in pharmaceutical preparations. (c) 2005 Elsevier B.V. All rights reserved.