Analysis of steroids XXXIX. Estimation of the impurity profile of 5α-androst-2-ene-17-one

Chemical and analytical characterization of related organic impurities in drugs

“…In the course of the early period of research aiming to optimize this reaction a 3β-phenyl derivative 25 was identified as an impurity of 26. The formation of this was due to the reaction of 24 with benzene, which was a component of the solvent mixture of the reaction [49].…”

“…More typically, at least one more step is necessary and this is usually mass spectrometry [15,35,36,37,40,43,44,46,47,48,49,52,55,56,57,58,65,66]. Due to its high sensitivity, small samples obtained from the TLC plate or analytical HPLC fraction are suitable to take good quality spectra in the off-line mode.…”

“…If NMR spectroscopy [16,30,33,35,36,37,41,43,44,46,47,48,49,52,55,56,63] is also necessary for the structure elucidation, somewhat larger sample size is necessary. These samples are usually obtained by semi-preparative HPLC [21].…”

“…If TLC is used, reflection UV spectra are similarly easily available [9]. Although UV spectroscopy is the least effective among the spectroscopic techniques, often very important information is obtainable for the structure elucidation [17,34,36,37,41,43,44,45,46,47,49,58,65,66,69,70].…”