Influence of the chromatographic capacity factor (log k') as an index of lipophilicity in the antibacterial activity of a series of 6-fluoroquinolones. Relationship between physico-chemical and structural properties and their hydrophobicity.

The aim of this study was to establish the influence of lipophilicity on the antibacterial activity (log 1/MIC50) of 22 fluoroquinolones and to assess the influence of their electronic, steric and topological properties on their hydrophobicity. The lipophilicity of the compounds, expressed as the chromatographic capacity factor (log k'), was determined by ion-pair reversed-phase HPLC. On the basis of the mathematical models developed, an attempt was made to confirm the mechanism of interaction of the quinolones with DNA-gyrase proposed previously.