Chemical composition, particle size range, and biological activity of some low molecular weight heparin derivatives (original) (raw)
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Journal of Pharmaceutical Sciences, 1990
High-field (300 MHz) 'H NMR spectral analysis and particle size distribution analysis employing the quasielastic light scattering (QELS) technique were performed on samples of the 1st International Standard for low molecular weight (LMW) heparin derivatives recently selected by the World Health Organization (WHO). We propose that the results of these analyses, which showed that the material is highly homogeneous in particle size and retains spectral features characteristic of its porcine mucosal origin, form an appropriate basis for physicochemical comparison between the "Standard' and other LMW heparin preparations. Analogous to this information from the ' H data, the 13C
Journal of Chromatography A, 2017
Heparin, a highly sulfated glycosaminoglycan, has been used as a clinical anticoagulant over 80 years. Low molecular weight heparins (LMWHs), heparins partially depolymerized using different processes, are widely used as clinical anticoagulants. Qualitative molecular weight (MW) and quantitative mass content analysis are two important factors that contribute to LMWH quality control. Size exclusion chromatography (SEC), relying on multiple angle laser scattering (MALS)/refractive index (RI) detectors, has been developed for accurate analysis of heparin MW in the absence of standards. However, the cations, which ion-pair with the anionic polysaccharide chains of heparin and LMWHs, had not been considered in previous reports. In this study, SEC with MALS/RI and inductively coupled plasma/mass spectrometry detectors were used in a comprehensive analytical approach taking both anionic polysaccharide and ion-paired cations heparin products. This approach was also applied to quantitative analysis of heparin and LMWHs. Full profiles of MWs and mass recoveries for three commercial heparin/LMWH products, heparin sodium, enoxaparin sodium and nadroparin calcium, were obtained and all showed higher MWs than previously reported. This important improvement more precisely characterized the MW properties of heparin/LMWHs and potentially many other anionic polysaccharides.
“Supersulfated” heparin fragments, a new type of low-molecular weight heparin
Biochemical Pharmacology, 1987
A new type of low-molecular-weight heparin (ss-LMW-H) was prepared (by controlled depolymerization and concurrent sulfation of heparin with a mixture of sulfuric and chlorosulfonic acid), to test the influence of extra-sulfate groups on biological properties of heparin fragments. The fragments had an average molecular weight ranging from 5000 to 10,000, a sulfate-to-carboxyl molar ratio of 2.8-3.1, and electrophoretic mobilities and NMR spectra distinctly different from those of the parent heparins.
Seminars in Thrombosis and Hemostasis, 2007
Various branded low molecular weight heparins (LMWHs) have been used for the treatment and prevention of thrombotic for over 20 years. With the introduction of generic LMWHs and the recent events involving heparin contamination, a great deal of effort is being expended in investigating ways of monitoring and regulating this class of complex drugs. In this paper, we present the characterization of different forms of LMWHs, as well as the comparison of 5 enoxaparin copies from different manufactures. The data suggests that, while some of these drugs are structurally comparable, specific analytical methods as well as biological and pharmacological tests may be used to address their similarity, quality and potential interchangeability. The proposed approach may also be useful in comparing biosimilar and branded LMWHs.
Physicochemical Characterization of Low Molecular Weight Heparin
0 Nuclear magnetic resonance spectroscopy (NMR), Raman spectroscopy, dynamic light scattering (DLS), and high performance exclusion chromatography (HPEC) were used to characterize two different commercial preparations of low molecular weight (LMW) heparin, produced either by peroxide cleavage or deaminative cleavage using nitrous acid. Proton NMR showed 4% contamination by dermatan sulfate in the material produced by deaminative cleavage using nitrous acid and <4% for the material produced by peroxide cleavage. The Raman spectra of the nitrous acid produced material showed an equivalent amount of Osulfation to that in the material produced by peroxide, but about a 10% reduction in the content of N-sulfated glucosamine, as expected from the deamination reaction. DLS and HPEC indicated the presence of <0.2% of very high molecular weighvaggregate material for the peroxide preparation compared to 1% for the nitrous acid-prepared material. The weight average molecular weight (I%) determined from HPEC was 5900 Da for the nitrous acid-prepared material and 6850 Da for the peroxideproduced material. The number average molecular weight (M,,) calculated from this data was 5200 Da for the nitrous acid preparation and 5300 Da for the peroxide-produced material. In addition, the nitrous acidprepared material exhibited a much narrower size distribution of oligomeric species, as evidenced by the polydispersity (M,.,/M,,) of 1.1 for the nitrous acid-prepared material, as compared with a value of 1.3 for the peroxideprepared material. These studies demonstrate that significant differences between preparations of LMW heparin can be resolved using these techniques. This is of critical importance in the design of quality assurance methods.
Non-Anticoagulant Low Molecular Weight Heparins for Pharmaceutical Applications
Journal of Medicinal Chemistry, 2019
Heparin is a polypharmacological agent with anticoagulant activity. Periodate oxidation of the nonsulfated glucuronic acid residue results in non-anticoagulant heparin derivative (NACH) of reduced molecular weight. Similar treatment of a low molecular weight heparin, dalteparin, also removes its anticoagulant activity, affording a second heparin derivative (D-NACH). A full structural characterization of these two derivatives reveals their structural differences. SPR studies display their ability to bind to several important heparin-binding proteins, suggesting potential new therapeutic applications.
Biochemical Pharmacology
A new type of low-molecular-weight heparin (ss-LMW-H) was prepared (by controlled depolymerization and concurrent sulfation of heparin with a mixture of sulfuric and chlorosulfonic acid), to test the influence of extra-sulfate groups on biological properties of heparin fragments. The fragments had an average molecular weight ranging from 5000 to 10,000, a sulfate-to-carboxyl molar ratio of 2.8-3.1, and electrophoretic mobilities and NMR spectra distinctly different from those of the parent heparins.
Journal of Analytical Chemistry, 2019
The composition and properties of heparin preparations are studied by NMR spectrometry. Approaches to the determination of the most important heparin quality indicators (biological origin and manufacturing company) based on multivariate modeling of the NMR profile of a sample are considered. Chemometric modeling of two-dimensional (2D) NMR spectra (DOSY, HSQC, HMBC) by the principal component and discriminant analysis is performed to increase the efficiency of analysis. Multivariate regression models (partial least squares) are built for the first time to determine the average molecular weight of heparin. Quantitative NMR spectrometry is applied to the determination of water, calcium and sodium cations, and also chloride and acetate anions in heparin preparations. The determination of all characteristics requires five consecutive measurements by NMR (1 H, 2 D, 35 Cl, 23 Na, and 2D DOSY) spectrometry and one sample preparation. The duration of analysis of one sample, including measurements and signal processing, takes no more than 20 min. The proposed approach is universal and can be used in the analysis of other medicinal preparations.
Carbohydrate Polymers, 2011
Various branded low molecular weight heparins (LMWHs) have been used for the treatment and prevention of thrombotic for over 20 years. With the introduction of generic LMWHs and the recent events involving heparin contamination, a great deal of effort is being expended in investigating ways of monitoring and regulating this class of complex drugs. In this paper, we present the characterization of different forms of LMWHs, as well as the comparison of 5 enoxaparin copies from different manufactures. The data suggests that, while some of these drugs are structurally comparable, specific analytical methods as well as biological and pharmacological tests may be used to address their similarity, quality and potential interchangeability. The proposed approach may also be useful in comparing biosimilar and branded LMWHs.
Analytical chemistry, 2016
Low molecular weight heparins (LMWHs) are widely used anticoagulant drugs. They inherit the heterogeneous backbone sequences of the parent heparin, while the chemical depolymerization process modifies the non-reducing end (NRE) and reducing end (RE) of their sugar chains. Some side reactions may also occur and increase the structural complexity of LMWHs. It is important to precisely characterize the structures of LMWHs, especially their chemical modifications, to ensure drug quality and safety. Compositional analysis provides a powerful approach to reveal the building blocks that make up the LMWHs, which are the mutual consequence of the heparin starting materials and the manufacturing process. Here, we introduce a comprehensive analytical method to recover the most basic building blocks of LMWHs. A strategy of combining both enzymatic digestion and oxidative degradation of LMWH was used to make the NRE, RE and backbone structures differentiable from one another. Satisfactory separa...