Relationships Between LC Retention, Octanol–Water Partition Coefficient, and Fungistatic Properties of 2-(2,4-Dihydroxyphenyl)benzothiazoles

The retention behavior of newly synthesized compounds with antimycotic activity from the 2-(2,4-dihydroxyphenyl)benzothiazole group by high-performance liquid chromatography has been investigated. RP-18 stationary phase and methanol-acetate buffer aqueous mobile phases at pH 4 and 7.4 have been used. In the case of the mobile phase at pH 7.4, higher concentrations of water can be applied than at pH 4. The studied compounds showed regular retention behavior, their log k values decreasing linearly with an increasing concentration of methanol in the mobile phase. On the basis of these relationships, the lipophilicity (log kw), specific hydrophobic surface area (S), and isocratic chromatographic hydrophobicity index (psi0) were determined. Similar log kw values and sensitivity to changes in the structure of compounds studied for both mobile phases have been found. Moderate correlations between the chromatographic parameters and the calculated octanol-water log P values were found. Finally, the lipophilicity parameters were compared with the fungistatic properties of compounds expressed by log MIC (minimum inhibitory concentration) values to find quantitative structure activity relationship equations.