Effect of Organic Solvents on the Inclusion of Sparfloxacin and Norfloxacin with b-Cyclodextrin

Abstract

The complexation of sparfloxacin (SPR) and norfloxacin (NOR) by b-cyclodextrin (b-CD) in water and in mixed organic/aqueous media has been studied by absorption spectroscopy. Three organic solvents [dimethyl-sulphoxide, ethanol and 2-methyl-1-propanol have been adopted which differ in polarity and hydrophobicity. It has been shown that the presence of organic solvent causes the degradation of the 1 : 1 SPR : b-CD and NOR : b-CD complexes. The binding constants of the inclusion complexes of SPR and NOR with b-CD in water are greater than those with mixed organic-water media. The higher the hydrophobicity of the co-solvent, the weaker the complexation of SPR and NOR by b-CD.