Estimation of impurity profiles of drugs and related materials: part XXI. HPLC/UV/MS study of the impurity profile of ethynodiol diacetate

Abstract

The impurity profile of ethynodiol diacetate was investigated using the HPLC/UV/MS method. Using the slightly modified HPLC method of USP 24 two impurities, earlier isolated by preparative HPLC and investigated by NMR spectroscopy were separated and characterised. The mass spectra amended by the diode-array UV spectra supported the earlier found structures (E and Z isomers of 17alpha-ethinyl-estr-4-ene-3beta,17-diol-3-acetate-17-(3'-acetoxy-2'-butenoate). Another, hitherto not described impurity, 17alpha-ethinyl-estr-4-ene-3beta,17-diol-3-acetate-17-(3-oxo-butanoate) has also been separated and characterised by means of its mass spectrum, NMR and UV spectra.