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Production of the major anticoagulant drug, heparin, is a complex process that begins with the collection of crude material from a dispersed network of suppliers with poor traceability, an issue that was made apparent in 2007-2008, when batches of heparin were contaminated deliberately in the supply chain, resulting in over 100 deaths in the US alone. Several analytical techniques are used currently for the characterisation of pharmaceutical grade heparin, but few have been applied to its crude counterpart. One exception is NMR spectroscopy which was used to study crude heparin (2017), however, owing to the high set-up and running costs, as well as the need for skilled technical operators, the use of NMR at crude heparin production plants is unviable. An alternative, practical, spectroscopic method is attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) that is user-friendly, economical and, importantly, requires little specialised training or sample preparation. Using a top-down chemometric approach employing principal component analysis, ATR-FTIR spectroscopy was able to distinguish crude heparins based on their similarity to pharmaceutical heparin, as well as on their compositional and structural features, which included levels of sulphation, the extent of related conformational changes, as well as the quantities of chondroitin and dermatan sulphate present. This approach lends itself to automation and will enable users and regulators to undertake quality control of crude heparin during manufacture. The method requires only economical, portable equipment and little specialised training, bringing the high-quality analysis of crude heparin within reach of both manufacturers and regulators for the first time.

The widely used anticoagulant pharmaceutical, heparin, is a polydisperse, heterogeneous polysaccharide. Heparin is one of the essential medicines defined by the World Health Organisation but, during 2007-2008, was the subject of adulteration. The intrinsic heterogeneity and variability of heparin makes it a challenge to monitor its purity by conventional means. This has led to the adoption of alternative approaches for its analysis and quality control, some of which are based on multivariate analysis of 1H NMR spectra, or exploit correlation techniques. Such NMR spectroscopy-based analyses, however, require costly and technically demanding NMR instrumentation. Here, an alternative approach based on the use of attenuated total reflectance Fourier transform infrared spectroscopy (FTIR-ATR) combined with multivariate analysis is proposed. FTIR-ATR employs more affordable and easy-to-use technology and, when combined with multivariate analysis of the resultant spectra, readily differentiates between glycosaminoglycans of different types, between heparin samples of distinct animal origins and enables the detection of both known heparin contaminants, such as over-sulphated chondroitin sulfate (OSCS), as well as other alien sulphated polysaccharides in heparin samples to a degree of sensitivity comparable to that achievable by NMR. The approach will permit the rapid and cost-effective monitoring of pharmaceutical heparin at any stage of the production process and indeed, in principle, the quality control of any heterogeneous or variable material.