Abstract: The norfloxacin is an effective and safe anti-infective with broadspctrum, and can be taken orally. The interaction of norfloxacin with β-CD has been studied by several analytical techniques, including ¹H NMR, ¹³C NMR and fluorescence spectra. In this paper, inclusion complex of HP-β-CD with no rfloxacin were prepared based on the coprecipitation method. The characterization of the inclusion complex has been done by flu-orimetry, Irspectroscopy, differ ential scanning calorimetry, and 1D,2D NMR. H-5 of located in the interior of HP-β-CD cavity was observed considerably shifted upfeld, which provide some evidences for the interaction of norfloxacin and HP-β-CD. The experimental results confirmed the existence of a 1:1 inclusion complex of norfloxacin and HP-β-CD. The formation constant of the complex was determined by Fluorescence method, a modified Benesi Hildbrand procedure was employed to calculate the formation constant. A spacial configuration of the complex has been proposed based on these data.

Key words: Norfloxacin, HP-β-Cyclodextrin, 1D, 2D NMR, Fluorescence spectrum