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Combined Use of Liquid Chromatography With Mass Spectrometry and Nuclear Magnetic Resonance for the Identification of Degradation Compounds in an Erythromycin Formulation

M Pendela, S Béni, E Haghedooren, L Van den Bossche, B Noszál, A Van Schepdael, J Hoogmartens, E Adams

Anal Bioanal Chem. 2012 Jan;402(2):781-90.

PMID: 22002558

Abstract:

A commercial erythromycin formulation containing erythromycin A (EA) as the major compound showed the presence of an unknown degradation compound that was co-eluted with erythromycin E (EE) in the European Pharmacopoeia (Ph. Eur.) liquid chromatographic (LC) method. The amount of the degradation compound increased with respect to time. To separate this unknown (UNK1), investigation was performed with different LC methods coupled to ultraviolet detection (LC-UV). With the present Ph. Eur. method, the degradation compound could not be well separated. However, with the most selective LC-UV method (XTerra method), two more degradation products (UNK2 and UNK3) were found in the formulation which could not be observed using other methods because of their poor separation. By combining the results obtained with LC-UV, LC/MS and LC/NMR, the degradation products were identified as pseudoerythromycin A hemiketal (PsEAHK), erythromycin A enol ether carboxylic acid and erythromycin C enol ether carboxylic acid. PsEAHK is known to be a base-catalysed degradation product of EA, whereas the other two degradation products were newly identified.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP105882697 Pseudoerythromycin A enol ether Pseudoerythromycin A enol ether 105882-69-7 Price
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