Preparation and property screening of the solid inclusion complex of norfloxacin with p-sulfonated calix[4]arene.

The complexation of norfloxacin (NFLX) by p-sulfonated calix[4]arene (SC4A) in aqueous solution has been studied by fluorescence spectroscopy and 1H NMR spectroscopy. A 1:1 stoichiometry and a 8086 L mol(-1) stability constant of the NFLX-SC4A complex was obtained by spectrofluorometric titrations. The equimolar solid state inclusion complex of NFLX-SC4A was prepared by the co-precipitation method and then characterized by various techniques, including differential scanning calorimetry (DSC), X-ray powder diffractometry (XRD), Fourier-transform infrared analysis (FT-IR) and scanning electron microscopy (SEM). The experimental results of these chemical property screenings confirmed that NFLX and SC4A can form a stable host-guest complex in the solid state, and SC4A appears to function as a complexing and solubilizing agent for NFLX.