Identification of Related Substances in Erythromycin Drug by Liquid Chromatography/Mass Spectrometry

Abstract

A new LC-MS method has been developed for the determination of related substances in erythromycin. For method development, various solvent systems were used. An Ashaipak column was used at with a mobile phase consisting of 0.023 M ammonium formate (pH 10.3): water: acetonitrile (35:25:40) v/v/v. Using mass spectra as interpretative templates, seven known related substances in erythromycin samples were identified viz., erythromycin F, Ndemethylerythromycin A, erythro-mycin E, anhydroerythromycin A, erythromycin enol ether, erythromycin B and erythromycin C along with their fragmentation pattern.