Hemoglobin tetramers stabilized with polyaspirins

Organic acids activated by esterification with 3,5-dibromosalicylate react preferentially either with the β82 lysines or the α99 lysines of hemoglobin. The versatility and site specificity of these polyaspirins and the usage of both human and bovine hemoglobins allowed the construction of a family of oxygen carriers with various P50, ranging from 10 to 60 mm Hg. These derivatives are obtained in pure homogeneous form by column chromatography. They show different properties regarding urine elimination, P50, oxygen binding cooperativity, transport of CO₂, and methemoglobin content. In the rat 30% exchange of blood volume with 7% solutions of the carriers initially produced an 'apparent' increase in GFR, ERPF and a sustained increase in urine flow. Then these parameters returned to the control values. Cronic experiments on rats using as much as 60 mg 100 g^-1 also indicate normal renal function after 48 h.