Obeticholic acid Impurity 2

Obeticholic acid Impurity 2 is a stereoisomeric variant of Obeticholic acid, characterized by its cholane steroidal nucleus and the C-24 carboxylic acid functionality. This compound specifically deviates from the parent active pharmaceutical ingredient through a distinct stereochemical arrangement at one or more chiral centers, likely involving an epimerization at the C-3 or C-7 hydroxyl groups, or the 6-ethyl substituent. Its structural framework comprises a perhydro-1H-cyclopenta[a]phenanthrene core, substituted with two hydroxyl functionalities, an ethyl group, and a carboxylic acid at position 24. This impurity is instrumental as a high-purity reference standard for the chromatographic quantification and quality control of Obeticholic acid.