| 1. |
- Zhang, Tianji, et al.
(author)
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Characterization of epimerization and composition of heparin and dalteparin using a UHPLC-ESI-MS/MS method
- 2019
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In: Carbohydrate Polymers. - : ELSEVIER SCI LTD. - 0144-8617 .- 1879-1344. ; 203, s. 87-94
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Journal article (peer-reviewed)abstract
- Heparin is a significant anticoagulant that has been used in clinic over decades. Although numerous efforts have been made to characterize the molecular structure of heparin and its derivatives for safety of the medicine, technical barriers still exist because of their structural complexity. In this study, we have established a method capable to evaluate both the epimerization and composition of heparin and dalteparin by a UHPLC-HILIC/WAXMS/MS approach. Ten major disaccharide building blocks retaining the epimerization configuration of parental heparin chains were generated and well separated, 9 of which were unambiguously identified. Isomer identifications were achieved through high-resolution tandem mass spectrometry analysis with reference to elaborately prepared standards. The method was successfully applied for the sameness study of generic dalteparins in combination with an isotopic labelling procedure. We believe this robust method maybe adapted to quality control in pharmaceutical production of heparin and LMWHs.
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| 2. |
- Zhang, Tianji, et al.
(author)
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Oligosaccharides mapping of nitrous acid degraded heparin through UHPLC-HILIC/WAX-MS
- 2020
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In: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 231
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Journal article (peer-reviewed)abstract
- Building blocks characterization is a significant approach for understanding the molecular structure of heparin and its derivatives. Nitrous acid (HONO) depolymerization of heparin generates oligosaccharides that maintain the epimerization conformation on C5 of the uronic acids, reflecting the authentic structure of the parental chain. HONO treatment at pH 1.5 selectively cleaves the bond between N-sulfated glucosamine and hexuronic acid, resulting mainly disaccharides, as well as tetra-, tri-, and mono-saccharides. The tetrasaccharides are derived from the structure of N-acetylated domains while tri-, and mono-saccharides are derived from the reducing or the non-reducing end of the heparin chain. The resulted oligosaccharides were separated and analyzed using a UHPLC-HILIC/WAX-MS method. We succeeded in the identification of 19 tetrasaccharides, 19 trisaccharides and 4 monosaccharides species, majority of which is structurally characterized. By comparing the theoretical possibilities and actual occurrence of the well-characterized tetrasaccharides, we demonstrated that the biosynthesis of heparin is a systematic process.
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