Interaction of Clofazimine with Divalent Metal Ions: A Fluorescence Quenching Study

Abstract

The interaction of clofazimine (CFZ) with divalent metal cations was studied by measuring fluorescence quenching spectra, synchronous fluorescence spectra and ultraviolet spectra. The fluorescence quenching spectra of CFZ in the presence of metal ions showed that metal ions quenched the fluorescence of CFZ. The quenching constants were determined using the Stern–Volmer equation. The binding constants (log K) and binding site were obtained. The thermodynamic parameters obtained in this study revealed that the interaction between CFZ and metal ions was mainly driven by a hydrophobic force. The conformational changes of CFZ were investigated by synchronous spectrum studies.

Keywords:

• Clofazimine
• fluorescence quenching
• metal ions
• N,5-bis(4-chlorophenyl)-3-propan-2-yliminophenazin-2-amine