Supramolecular interaction of Moxifloxacin and β-cyclodextrin spectroscopic characterization and analytical...

The supramolecular interaction of Moxifloxacin (Moxi) and β-cyclodextrin (β-CD) has been examined by UV-VIS, FTIR, H(1)NMR, SEM and fluorescence spectroscopy. The formation of inclusion complex has been confirmed on the base of changes of spectroscopy properties. The results showed that β-CD reacted with Moxi to form an inclusion complex. The Moxi and β-CD complex formed a host-guest complex in 1:1 stoichiometry and inclusion constant (K=3.95×10(2) L mol(-1)) was ascertained by the typical double reciprocal plots. Furthermore, the thermodynamic parameters (ΔH°, ΔS° and ΔG°) associated with the inclusion process were also determined. Based on the significant enhancement of the fluorescence intensity of Moxi produced through complex formation, a simple, accurate, rapid and highly sensitive spectrofluorometric method for the determination of Moxi in pharmaceutical formulation was developed. The measurement of relative fluorescence intensity was carried out at 464 nm with excitation at 289 nm. The factors affecting the inclusion complex formation were studied and optimized. Under the optimum reaction conditions, linear relationships with good correlation coefficients (0.99973) were in the concentration range of 10-60 ng/mL for spectrofluorimetry. The limit of detection (LOD) was found to be 1.6 ng/mL. The proposed method was successfully applied to the analysis of Moxi in pharmaceutical preparation.