Study of biologically relevant physical-chemical properties of bile salts by reverse-phase liquid chromatography

Summary The study of chromatographic behaviour of bile salts with reverse-phase HPLC columns (C18 and C8) and buffered water — methanol eluent systems indicated that the octanol-water partition coefficient and the micellar cholesterol-solubilizing capacity are linearly correlated with the chromatographic mobilities if eluents with pH>7 and 0.154 M saline concentration are used (correlation coefficients 0.98 and 0.86 respectively). The critical micellar concentration was poorly correlated with the chromatographic mobility under the various conditions tested. The pKa values of bile salts were determined by the changes of mobility with the pH of eluent. Values in the range 4.92–5.06 and 4.27–4.47 were found respectively for unconjugated and glycineconjugated bile salt, in agreement with previous estimates. Values in the range 0.74–1.02 represent the first direct evaluation for taurine-conjugates.