syn-anti Isomerization in testosterone 17-enanthate 3-benzilic acid hydrazone

UV spectrophotometry, high-pressure liquid chromatography, and NMR were used to investigate syn-anti isomerization in testosterone 17-enanthate 3-benzilic acid hydrazone. In the crystalline state, the isomeric ratio is dependent on the crystallization solvent. In solutions, including injectable pharmaceutical formulations, an equilibrium isomer mixture (2:1) is formed.