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Preparation and in vitro characteristics of polymerized pyridoxylated hemoglobin
Author(s) -
Sehgai L. R.,
Rosen A. L.,
Gould S. A.,
Sehgal H. L.,
Moss G. S.
Publication year - 1983
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1046/j.1537-2995.1983.23283172857.x
Subject(s) - oncotic pressure , hemoglobin , polymerization , chemistry , methemoglobin , osmotic pressure , blood substitute , glutaraldehyde , oxygen , chromatography , biochemistry , polymer chemistry , organic chemistry , polymer , albumin
Stroma‐free hemoglobin solutions have been the subject of extensive studies as potential acellular oxygen carriers. Oncotic pressure considerations limit the hemoglobin concentration of the solutions (6–8 g/dl) to one‐half the normal whole blood values. Furthermore, the free hemoglobin has a short plasma half‐life (2–4 hours). In principle, polymerization offers a means of normalizing the oxygen‐carrying capacity as well as extending the plasma half‐life. Pyridoxylation of hemoglobin prior to polymerization provides an acceptable P 50 . Pyridoxylated hemoglobin (14–16 g/dl) was polymerized with a 12.5 percent glutaraldehyde solution. Since the goal was to obtain a 15 g per dl solution iso‐oncotic with plasma, the polymerization reaction was monitored by the drop in colloid osmotic pressure. The reaction was quenched with 1.3 M lysine when the colloid osmotic pressure reached normal values (20–25 torr). The polymerization yield was 80 percent, with molecular weights ranging from 120,000 to 600,000 Dalton. The polymerized hemoglobin had a binding coefficient of 1.32, a Pso of 16 torr, a Bohr coefficient of –0.12, and a Hill coefficient of 1.7. The viscosity of the solution was 4.5 centipoise. The methemoglobin levels were comparable to that of unpolymerized stroma‐free hemoglobin. Polymerized hemoglobin solutions provide a normal oxygen‐carrying capacity with a P 50 comparable to that of unpolymerized stroma‐free hemoglobin solutions.