Heparin determinations

Miklautz, H., Riemann, J., and Vidic, H. J., The molecular weight distribution of heparin determined with a HPLC-LALLS technique, /. Liq. Chromatogr., 9, 2073, 1986. 

Galvanostatically pulsed sensors can be employed for heparin determination via titration with protamine using protocol described earlier [42, 43] and initial experiments showed that heparin detection in whole blood samples can be accomplished with this technology. 

Hattori, T., Kimura, K., Seyrek, E., Dubin, P.L. (2001). Binding of bovine serum albumin to heparin determined by turbidimetric titration and frontal analysis continuous capillary electrophoresis. Analytical Biochemistry, 295, 158-167. 

Heparin determined on each test portion by planchet count. Relatively uniform GBH areas from long-time adsorption sacks, selected ... 

U mL and a linear detection range of 0.2—2 U mL. Although heparin adsorption onto PEI in buffer solution had indicated superior sensitivity to that on protamine, in blood plasma it was not specific for heparin and adsorbed plasma species to a steady-state equilibrium. By reducing the incubation time and diluting the plasma samples with buffer to 50%, the nonspecific adsorption of plasma could be controlled and a PEI pretreated with blood plasma could be used successfully for heparin determination. Heparin adsorption in 50% plasma was Hnear between 0.05 and 1 U mL so that heparin plasma levels of 0.1—2 U mL could be determined with a relative error of 11% and an accuracy of 0.05 U mL. ... 

Figure 2.36 Tg of heparin determined by FHyperDSC. As the scan rate is increased moisture loss is delayed to higher temperatures revealing the glass transition, plasticised by the moisture.

A nurse is to give an SC injection of heparin to a patient. Determine what information the nurse needs to know about the patient before preparing the injection. Discuss how this information would affect the preparation of the injection and the technique used to give the SC injection. 

Blood coagulation tests for those receiving heparin by continuous IV infusion are taken at periodic intervals (usually every 4 hours) determined by the primary health care provider. If the patient is receiving long-term heparin therapy, blood coagulation tests may be performed at less frequent intervals... 

Our method for NMOR determination. The following procedure (carried out in a single day) was developed for blood, stomach contents, the homogenized whole mouse, and diet [(a standard semisynthetic diet prepared as in (9)]. After the rats were killed with C0 , we collected the blood (with a heparinized syringe from the heart) and the entire stomach contents. The whole mouse was frozen in liquid N2 and homogenized as in (2) ... 

The final yield and purity of a heparin preparation depend largely on the use of appropriate, analytical methods at different stages of extraction and purification. Heparin in tissue extracts is still most commonly determined biologically, by such assays as the U.S.P. assay for anticoagulant activity. It is now recognized10 that the anticoagulant activity does not measure the actual concentration of heparin (see also Sections XII and XIII). 

Although widely used, colorimetric methods for determining total ur-onic acid and hexosamine are now regarded as providing, at best, only semi-quantitative estimates of heparin.42 Colorimetric reactions in a strong acid, such as the carbazole reaction for the uronic acids48 and the Morgan-Elson reaction for the hexosamines,49 are not specific for hepa-... 

More-specific methods are available for identifying and quantitating the typical, amino sugar component of heparin (and some heparan sulfate species), namely, 2-deoxy-2-sulfoamino-D-glucose. Most of these methods are based on conversion of these residues into 2,5-anhydro-D-mannose by deamination with nitrous acid (see Section VIII,2). The 2,5-anhydro-D-mannose residues may be determined either colorimetrically,52-54 or fluorimetrically.55... 

Although liquid chromatography (l.c.) under elevated pressure is now used essentially for determining the molecular weight of heparin,74,75 as an alternative to methods using soft gels,76 it can undoubtedly be used as well for rapid analysis of mixtures of glycosaminoglycans. 

As another criterion of purity, the amino acid content of heparins should be determined. This is usually performed by ion-exchange88 or liquid89 chromatographic analysis of hydrolyzates. Reasonably pure heparin preparations contain < 1% of total amino acids, mostly L-serine and glycine. Heparin preparations should also be analyzed for residual solvents, and analytical (as well as biological) data be expressed on a dry basis. (Heparins equilibrated with atmospheric humidity contain up to 15%, or even more, of water.) Unless volatile materials are completely removed or accounted for, elemental analyses of heparin are meaningless. 

Polydispersity of molecular weights of heparin was recognized in early studies (reviewed in Refs. 9 and 183). However, the polyelectrolyte nature and heterogeneity of charge distribution have hampered accurate determinations of molecular-weight distribution. 

Complexation of antithrombin with thrombin (and probably also with other proteinases) occurs by formation of a covalent bond which, by subsequent splitting, produces unaltered proteinase and irreversibly modified antithrombin.405,406 The strength of heparin-antithrombin complexes, as determined by u.v.-difference,405 fluorescence,406,407 af-... 

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