Application of inclusion chromatography to the determination of in vitro metabolites of estriol.

The application of inclusion chromatography with beta-cyclodextrin as a mobile phase additive in high-performance liquid chromatography to the determination of in vitro metabolites of estriol is reported. Compared to conventional methods, the inclusion chromatography gives much more satisfactory separation of isomeric estriol derivatives in a short time. Species difference (rat and guinea pig liver homogenates) is observed in the glucuronidation of estriol. The hydroxylation of estriol with rat liver homogenate occurs preferentially at the 2-position. Methylation of this product with catechol-O-methyl transferase in rat liver gives almost equal amounts of 2- and 3-methyl ethers. In contrast, 4-hydroxyestriol gives 4-methyl ether as a main product.