Heparin stability by determining unsubstituted amino groups using HILIC-MS

Abstract

The thermal instability of the anticoagulant heparin is associated, in part, with the solvolytic loss of N-sulfo groups. This study describes a new method to assess the increased content of unsubstituted amino groups present in thermally-stressed and autoclave-sterilized heparin formulations. N-acetylation of heparin samples with acetic anhydride-d6 is followed by exhaustive heparinase treatment, and disaccharide analysis by hydrophilic interaction chromatography mass spectrometry. The introduction of stable isotopic label provides a sensitive probe for the detection and localization of the lost N-sulfo groups potentially providing valuable insights into degradation mechanism and the reasons for anticoagulant potency loss.