The work describes the preparation of a cobalt-heparin complex and the study of its properties, which included the analysis of elements, saccharide components, and biological and chemical assays. The bioactivity of this compound has been determined using both in. vivo and in vitro assays. In addition the effects of cations on the mobility of heparin were studied using microelectrophoresis. The cobaltic hexammine ion, Co(NH3)63+ seems to form a salt linkage with a disaccharide unit of heparin. Cobalt-heparin is insoluble in the usual solvents but is soluble in salt solutions of high ionic strength (0.6) and the cobalt ion can be removed from the heparin by dialysis in such salt solutions. The in vivo anticoagulant activity of cobalt-heparin complex is 93 to 95% that of heparin itself. On a weight for weight basis, the complex would be expected to have an activity of about 76% that of heparin. This may indicate that the complex causes the release of endogenous heparin. Different methods for the determination of the sacoharide components of heparin yield widely varying results and it is probable that the presence of cobalt interferes with some analytical methods of determining sulphur. Mieroelectrophoretic studies indicate that zinc combines with heparin sufficiently strongly that it is retained by the heparin in an electric field as the heparin migrates toward the anode.
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