Chemical microdetermination of heparin in plasma

A new, simple, and highly sensitive method for the determination of heparin has been established. Heparin was first converted into unsaturated disaccharides through the action of heparin lyases I, II, and III. A major trisulfated unsaturated disaccharide product results, consistent with structural analysis of a number of pharmaceutical heparins using one- and two-dimensional 1H NMR spectroscopy. This disaccharide was analyzed by HPLC using fluorometric postcolumn derivatization. The correlation between the amount of this trisulfated unsaturated disaccharide and anticoagulant activity of heparin as measured by anti-IIa was determined. The analysis of these pharmaceutical heparins showed a linear correlation between both HPLC and bioassay. This HPLC method was then applied to a pharmacokinetic study of heparin intravenously administered to rabbits.