Soluble dextran-hemoglobin complex as a potential blood substitute.

A complex between soluble dextran and human hemoglobin has been synthesized by two different methods. In the alkylation method, hemoglobin was allowed to react with bromoacetyl groups incorporated into the dextran; the yield of the complex was about 80% in terms of the hemoglobin used. In the dialdehyde method, hemoglobin was allowed to react with dialdehyde groups on the dextran generated by periodate oxidation; the yield of the complex was about 60%. Both soluble dextran-hemoglobin complexes could bind and release oxygen reversibly, but the oxygen-binding curves were shifted to the left relative to that of free hemoglobin. In the rabbit, the complex obtained by the alkylation method was excreted by the kidneys and cleared from the circulation much more slowly than free hemoglobin.