Integrated chromatographic and chemometric evaluation of lipophilicity in steroidal hydrazone derivatives across...

The retention behavior of structurally related steroidal semicarbazones, thiadiazolines, thiazolidin-4-ones, and monoethyl carbazate esters was investigated using thin-layer chromatography on octadecyl-silica (RP18) under reversed-phase (RP), micellar, microemulsion, and acetonitrile/phosphate-buffered saline (pH 7.4) mobile phase conditions. Classical binary methanol-water and acetone-water systems were used to determine R_M⁰, C⁰, and PC1, while R_M values obtained in micellar, microemulsion, and acetonitrile/phosphate-buffered saline (pH 7.4) systems were employed as lipophilicity-related descriptors. Micellar systems containing sodium dodecyl sulfate (SDS) and n-butanol enabled evaluation of pseudophase-mediated solubilization, whereas microemulsions, additionally incorporating n-octanol or n-heptane, introduced multiphase partitioning among aqueous, micellar, oil, and stationary phases. The buffered acetonitrile-based system provided a non-organized reference medium under physiologically relevant conditions. The relationships among chromatographic descriptors, chromatographic systems, and in silico lipophilicity estimates were assessed using the Sum of Ranking Differences (SRD) method and Hierarchical Cluster Analysis (HCA), with an average R_M-based reference ranking applied in SRD. Conventional RP and buffered systems showed the closest relationship with descriptors reflecting binary partitioning behavior, indicating dominant hydrophobic partitioning. In contrast, micellar and microemulsion systems formed distinct clusters, reflecting pseudophase and multiphase distribution effects. These findings demonstrate that organized mobile phases create mechanistically distinct retention environments, while the buffered system serves as a transitional, non-supramolecular reference medium bridging conventional reversed-phase and organized multiphase environments. This integrative chemometric framework enables statistically supported comparison of chromatographic systems and evaluation of their complementary contribution to lipophilicity.