Heparin is one of the most widely used polysaccharide drugs in the world. It has gained great attention from researchers focusing on its structure, activity, and more recently, purity. Through pharmacopeia regulated analysis, the polydispersity, disaccharide sequence and statistical sulfation pattern of heparin have been well defined. However, the impact of processing conditions on physico-chemical properties of heparin have for the most part been neglected.
The aim of this research is to refocus attention on the chemical stability of heparin. The analysis is directed toward the understanding of mechanisms and kinetics of the structural changes in heparin under acidic conditions (pH 1 - 6).
Herein, the changes in the molecular structure as a function of time, pH and temperature are discussed. With the use of mono- and two-dimensional NMR spectroscopy the degradation processes were followed in real time. Using High Performance Anion Exchange Chromatography (HPAEC) the sugar composition of heparin was profiled at various stages of degradation whilst desulfation was also followed. Finally, changes in molecular weight were determined and the kinetics of these processes were analysed.
After connecting all the pieces from this complex analytical puzzle, we have elucidated a more complete understanding of the mechanism of heparin degradation in acidic environments.