This paper describes the evaluation of the lipophilicity of newly synthesized thiosemicarbazides and their cyclic analogues 1,2,4-triazol-3-thiones obtained using experimental and calculated methods. Previous studies have shown these compounds have antibacterial activity. The chromatographic behavior of analyzed compounds was studied by reversed phase high performance liquid chromatography (RP-HPLC) and reversed phase thin layer chromatography (RP-TLC). The aqueous mobile phases containing methanol were used in order to determine retention parameter (RM) and capacity factors (log k) of analyzed compounds. The lipophilicity parameters were obtained by linear extrapolation and they were compared with the calculated log P obtained using several software packages. The results indicate that both experimental chromatographic methods yielded similar results, and these methods are appropriate for determining the lipophilicity of analyzed compounds. High values of correlation coefficients between the log P values calculated using known algorithms (milogP, ALOGPs, AClogP, AlogP, MLOGP, KOWWIN, XLOGP2, XLOGP3) and the experimental data were obtained. Eight standard solutes with known log POW were analyzed under the same conditions as the tested substances in order to determine the log PHPLC and log PTLCparameters. A good correlation was obtained between log kw (or RMW) and the slope. All tested compounds were in agreement with the rule of five claims by Lipiński. The calculated log P values were experimentally confirmed (log PHPLC and log PTLC).
Keywords
lipophilicity; RP-HPLC; RP-TLC; log POW
