Seven commercial heparin active pharmaceutical ingredients and one commercial low molecular weight from different manufacturers were characterized with a view profiling their physico-chemical properties. All heparins had similar molecular weight properties as determined by polyacrylamide gel electrophoresis (MN 10–11 kDa, MW 13–14 kDa, polydispersity (PD) 1.3–1.4) and by size exclusion chromatography (MN 14–16 kDa, MW 21–25 kDa, PD 1.4–1.6). 1D 1H- and 13C-NMR evaluation of the heparin samples was performed and peaks were fully assigned using 2D NMR. The percentage of glucosamine residues with 3-O-sulfo groups and the percentage of N-sulfo groups and N-acetyl groups ranged from 5.8–7.9, 78–82 and 13–14 %, respectively. There was substantial variability observed in the disaccharide composition with, as determined by high performance liquid chromatography (HPLC)-mass spectral analysis of heparin lyase I–III digested heparins. Heparin oligosaccharide mapping was performed using HPLC following separate treatments with heparin lyase I, II and III. These maps were useful in qualitatively and quantitatively identifying structural differences between these heparins. The binding affinities of these heparins to antithrombin III and thrombin were evaluated by using a SPR competitive binding assay. This study provides the physico-chemical and activity characterization necessary for the appropriate design and synthesis of a generic bioengineered heparin.

Heparin is a widely used clinical anticoagulant that is prepared from pig intestine. A contamination of heparin in 2008 has led to a reexamination of animal-derived pharmaceuticals. A bioengineered heparin prepared by bacterial fermentation and chemical and enzymatic processing is currently under development. This study examines the challenges of reducing or removing endotoxins associated with this process that are necessary to proceed with preclinical in vivo evaluation of bioengineered heparin. The current process is assessed for endotoxin levels, and strategies are examined for endotoxin removal from polysaccharides and enzymes involved in this process.