Metabolism of Sodium Pentosan Polysulphate in Man Measured by a New Competitive Binding Assay for Sulphated Polysaccharides – Comparison with Effects Upon Anticoagulant Activity, Lipolysis and Platelet α-Granule Proteins

SummaryThree human volunteers were injected with a range of doses of pentosan polysulphate, SP54, i.v. or s.c. A competitive binding assay (CBA) for sulphated polysaccharides was used to detect circulating SP54 after doses as low as 1 mg i.v. and a linear relationship was observed between the peak plasma concentration of SP54 measured by CBA and the administered dose. A comparison was made between the clearance of SP54 measured by CBA and its anticoagulant and lipolytic activities. SP54 was detectable by CBA after doses which caused no alteration in activated partial thromboplastin time (APTT) or anti-factor Xa activity but after which a small increase of lipase activity was measurable. After SP54 at 10 mg i.v. or 100 mg s.c. anti-factor Xa activity was 4-6 times greater than would be expected from the in vitro activity of the concentrations of SP54 measured by CBA. Like heparin and other heparin analogues, SP54 caused an increase in plasma concentrations of platelet factor 4 (PF4) without a concomitant rise in p-thromboglobulin (β-TG).It is concluded that the newly developed CBA will provide a more sensitive means than conventional bioassays for the determination of plasma concentrations of SP54.

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A Sensitive Heparin-Protamine Competitive Binding Assay

10.1055/s-0038-1652629 ◽

1981 ◽

Author(s):

J Dawes ◽

D S Pepper

Keyword(s):

Binding Assay ◽

Antithrombin Iii ◽

Solid Phase ◽

Biological Fluids ◽

Heparan Sulphate ◽

Competitive Binding ◽

Platelet Factor ◽

Competitive Binding Assay ◽

Agarose Beads ◽

Potential Binding

Using protamine-agarose beads, with 125I- heparin as a tracer, we have developed a sensitive competitive binding assay with very wide applications. We are able to measure the concentrations of heparin and heparan sulphate in protease-treated biological fluids down to 40 ng. ml-1. Chondroitin and dermatan sulphates do not interfere with the assay, which can also be used to:(1) measure other acidic polysaccharides e.g. dextran sulphate, semisynthetic heparin analogues, and carrageenans.(2) assay proteins which bind to heparin, such as platelet factor 4, antithrombin III and protamine.(3) screen polymers and solid phases as potential binding materials for these molecules.(4) compare a series of polymers e.g. assess the degree of sulphation of heparins, or the affinity of basic polymers for heparin.Solid phase polyelectrolytes such as Dowex are potentially more robust substitutes for protamine- agarose, being resistant to proteases.

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Comparative Plasma Heparin Levels after Subcutaneous Sodium and Calcium Heparin

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648673 ◽

1978 ◽

Vol 40 (02) ◽

pp. 397-406 ◽

Cited By ~ 8

Author(s):

Joyce Low ◽

J C Biggs

Keyword(s):

Peak Plasma ◽

Plasma Concentrations ◽

Factor Xa ◽

Normal Subjects ◽

Sodium Salts ◽

Sodium Heparin ◽

Significant Difference ◽

Heparin Plasma ◽

Calcium Heparin ◽

Plasma Heparin

SummaryComparative plasma heparin levels were measured in normal subjects injected subcutaneously with 5,000 units of the sodium and calcium salts of heparin. Plasma heparin levels were measured up to 7 hr post-injection by an anti-factor Xa assay (Denson and Bonnar 1973). Preliminary studies indicated that heparin levels were reproducible in subjects who received two injections of the same heparin. Peak plasma concentrations (Cmax) and the time at which peak concentration was reached (Tmax) varied greatly from subject to subject. In one group of subjects (15) two commonly used heparins, a sodium heparin (Evans) and a calcium heparin (Choay) were compared. Peak heparin concentrations were not significantly different. However the Tmax for the sodium heparin (1.5 hr) was significantly earlier than the Tmax for the calcium heparin (3 hr) and this was not due to a difference in the volume of the two heparin injections. No significant difference could be detected in the plasma clearance rate and the molecular weight distribution of the two heparins.In two other groups of subjects, sodium and calcium preparations from two manufacturers were compared. In general, the sodium salts gave rise to significantly higher plasma concentrations, which could be interpreted as a greater bioavailability of sodium salts. These results indicate that the salt of the heparin can influence the plasma concentration achieved after subcutaneous injection.

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The Measurement of Heparin and Other Therapeutic Sufphated Polysaccharides in Plasma, Serum and Urine

Thrombosis and Haemostasis ◽

10.1055/s-0038-1660086 ◽

1985 ◽

Vol 54 (03) ◽

pp. 630-634 ◽

Cited By ~ 19

Author(s):

J Dawes ◽

C V Prowse ◽

D D Pepper

Keyword(s):

Biological Fluids ◽

Anticoagulant Activity ◽

Dose Range ◽

Plasma Concentrations ◽

Heparin Therapy ◽

Competitive Binding Assay ◽

First Order Kinetics ◽

Activity Measurements ◽

Heparin Activity ◽

Dose Dependent

SummaryThe competitive binding assay described will specifically and accurately measure concentrations of administered heparin in biological fluids with a sensitivity of 60 ng ml-1. Neither endogenous glycosaminoglycans, nor plasma proteins such as ATIII and PF4 interfere in the assay. Semi-synthetic highly sulphated heparinoids and LMW heparin can also be measured. Using this assay heparin clearance followed simple first-order kinetics over the dose range 100-5,000 units, but the half-life was strongly dose-dependent. There was good correlation with heparin activity measurements by APTT and anti-Xa clotting assays. Plasma concentrations were measurable for at least 5 h following subcutaneous injection of 10,000 units of heparin. Excretion in the urine could be followed after all but the lowest intravenous dose. This assay, used in conjunction with measurements of heparin anticoagulant activity, will be valuable in the elucidation of mechanisms of action of heparin and the heparinoids, and in the assessment and management of problems related to heparin therapy.

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