[Correlation between the structures and physicochemical properties of chemotherapeutic fluoroquinolone agents].

The acid-base properties, the lipophilicity and the HPLC behaviour of nine antibacterial fluoroquinolone derivatives were studied to reveal relationship between these physico-chemical parameters and the chemical structure. Basicity of compounds with two proton-binding sites is depicted here in terms of protonation macro- and microconstants. The concentrations of microspecies (cation, zwitterion, neutral and anion) were calculated in the function of pH. The microspeciation of fluoroquinolones were used to derive relationship between the apparent and true octanol/water partition coefficients. An analysis of structure-chromatographic behaviour has been performed utilizing the retention values was determined in a chromatographic system methanol-aqueous phosphate buffer/ODS. Close correlation was found between the lipophilicity and chromatographic behaviour of the tested compounds when pH dependence and the influence of an ionpairing agent were investigated.