Lipophilicity of Selected Steroid Compounds. I. Investigations on RP18W Stationary Phase by RP‐HPTLC

The selected steroid compounds (androsterone, epi‐androsterone, dehydro‐epi‐androsterone, testosterone, stigmasterol, β‐sitosterol, estradiol, hydrocortisone, and cholesterol) were investigated with the use reversed‐phase high performance thin layer chromatography on RP18W plates (#1.14296, E. Merck), using methanol‐water, acetonitrile‐water in different volume compositions as a mobile phase. The chromatographic parameters of lipophilicity (RMW and ϕ0) of the studied steroids were determined. Lipophilic parameters (RMW and ϕ0) were compared both, with measured (logPexp), and calculated partition coefficients (AlogPS, IAlogP, logPKOWIN, xlogP, ClogP, miLogP). Comparing all calculation procedures, generally ClogP and IAlogP are more appropriate for chromatographic parameters of lipophilicity and experimental n‐octanol‐water partition coefficients of studied steroid compounds. The results indicate that chromatographic parameters of lipophilicity may be used as a measure of lipophilicity of the investigated steroid compounds.