Analysis of Heparin Samples by Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy in the Solid State

Abstract

Heparin is a polydisperse, heterogeneous polysaccharide of the glycosaminoglycan (GAG) class that has found widespread clinical use as a potent anticoagulant and is classified as an essential medicine by the World Health Organization. The importance of rigorous monitoring and quality control of pharmaceutical heparin was highlighted in 2008, when the existing regulatory procedures failed to identify a life-threatening adulteration of pharmaceutical heparin with oversulfated chondroitin sulfate (OSCS). The subsequent contamination crisis resulted in the exploration of alternative approaches for which the use of multidimensional nuclear magnetic resonance (NMR) spectroscopy techniques and multivariate analysis emerged as the gold standard. This procedure is, however, technically demanding and requires access to expensive equipment. An alternative approach, utilizing attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) combined with multivariate analysis, has been developed. The method described enables the differentiation of diverse GAG samples, the classification of samples of distinct species provenance, and the detection of both established heparin contaminants and alien polysaccharides. This methodology has sensitivity comparable to that of NMR and can facilitate the rapid, cost-effective monitoring and analysis of pharmaceutical heparin. It is therefore suitable for future deployment throughout the supply chain.

Approaches to Assure Similarity between Pharmaceutical Heparins from Two Different Manufacturers

“…Infrared spectroscopic was a pioneer method for the analysis of heparin and other glycosaminoglycans [30]. Although it is still a useful and reliable technique [31], infrared spectroscopy is rarely used nowadays and has been replaced by NMR methods, which are more sensitive and informative. The combination of 1D and 2D NMR experiments allows access to specific parameters at the atomic level, which enables the exact determination of the monosaccharide composition, sulfation, and N-acetylation patterns, linkage positions and anomeric configurations [32][33][34].…”

The Structure Determination of Organic Molecules by Co-crystallization of Anthracene-Based Crystallization Chaperone

“…Whether the organic compounds are natural products − or synthesized by chemists, it is extremely important to determine their structures and absolute conformations at the atomic level. Over the past few decades, numerous researchers have developed and refined many methods for the structural identification of organic molecules, such as nuclear magnetic resonance ( NMR ), − infrared spectroscopy ( IR ), − mass spectrometry ( MS ), − single crystal X-ray diffraction ( X-ray SCD ), − etc. Among them, X-ray SCD can provide direct and accurate structural information and is globally recognized as a fairly reliable method for the structural identification of organic compounds, including their stereochemical conformation.…”