Physicochemical characteristics of OxyVita hemoglobin, a zero-linked polymer: liquid and powder preparations.

OxyVita-zero-link polymerized hemoglobin (OxyVita Hb) is a novel generation hemoglobin based oxygen carrier (HBOC). Our focus in this paper is to address the question of "Why is OxyVita Hemoglobin different than the previous generation of HBOCs?" Several critical related topics will be discussed: 1) OxyVita's unique chemistry; 2) the introduction of a viable powder form of OxyVita hemoglobin for dissolution in IV water or other IV fluids; 3) the physiochemical characteristics of OxyVita hemoglobin preparations; 4) the ability to formulate different products based upon specific applications; and 5) the important storage properties essential for use in a wide range of geographical locations.

Structural and redox behavior of OxyVita, a zero-linked polymeric hemoglobin: comparison with natural acellular polymeric hemoglobins.

A zero-linked polymeric hemoglobin (OxyVita Hb) has been developed for application as an acellular therapeutic hemoglobin-based-oxygen-carrier (HBOC). For effective and safe oxygen binding, transport and delivery, an HBOC must meet essential molecular requirements related to its structural integrity and redox stability. OxyVita is a super polymer possessing an average M.wt. of 17 x 10(6) Da. Structural integrity was determined by unfolding studies of OxyVita in the presence of increasing concentrations of urea. The unfolding midpoints (D(1/2)) of different preparations of OxyVita (solution and powder forms) were compared to Lumbricus Hb (LtHb) and Arenicola Hb (ArHb), natural acellular polymeric hemoglobins, which are serving as models for an effective and safe acellular HBOC. Reduction studies of OxyVita Hb using endogenous reducing agents were also investigated. Results from these studies indicate that: 1) OxyVita Hb exhibits greater resistance to conformational change than either LtHb or ArHb in the reduced (oxyHb) state; and 2) the reduction of met OxyVita Hb to oxyHb occurs slowly in the presence of either ascorbic acid (70% reduction in 560 min.) or beta-NADH (40% reduction in 90 min.). These studies provide consistent evidence that OxyVita Hb possesses physiochemical properties that exhibit structural integrity and redox behavior necessary for functioning as an effective and safe HBOC within clinical applications. These results are in agreement with observations made by other investigators as to the reduction in heme-loss of OxyVita Hb, essential for the reversible binding/release of molecular oxygen within the circulatory system.

OxyVita®C, a next-generation haemoglobin-based oxygen carrier, with coagulation capacity (OVCCC). Modified lyophilization/spray-drying process: proteins protection.

Uncontrolled haemorrhage is one of the leading causes of death. This issue is present in controlled environments, such as hospitals, as well as pre-hospital and remote locations. Treatment is more challenging in remote locations where there is a lack of effective products to deliver oxygen and control coagulation. Poorly treated haemorrhage can lead to rapidly deteriorating bodily conditions that can result in organ failure and tissue death. Thus, the availability of products to support oxygen delivery to tissues and coagulation processes within the body is essential for the effective treatment of severe haemorrhage, particularly in out-of-the-hospital settings. The presence of such products would fill the gap that is currently present in emergency treatment. Promising results of an ex-vivo study on a novel haemoglobin-based oxygen carrier OxyVita®C with coagulation capacity (OVCCC) are presented in this article. The proprietary protein protection technology allows for the powderization of protein components without changes in their characteristics and physiological activity. This technology was applied to the oxygen carrier OxyVita®C, to plasma and to platelets. The functionality of all tested components, as well as a mixture of OxyVita®C and platelets, was studied. The results suggest future clinical trials investigating the powderization of OVCCC, plasma and platelets are warranted. The development of this powderization method offers a huge advancement into a field in which no viable products exist.

Zero-link polymerized hemoglobin (OxyVita®Hb) stabilizes the heme environment: potential for lowering vascular oxidative stress.

A study was conducted to compare the resistance to heme exposure between myoglobin, bovine hemoglobin, and OxyVita®Hb (zero-link-hemoglobin-polymer). The rate of release of heme-iron is related to the tissue oxidative stress that can elicit deleterious effects in clinical uses of blood substitutes. Experimental work has focused on the unfolding of hemoglobin molecules, resulting in heme loss, by using urea as a denaturant and analyzing the Soret spectral region. These unfolding studies provide evidence for both the structural integrity and redox stability of OxyVita®Hb and demonstrate that OxyVita®Hb does not readily unfold and its heme exposure/release is greatly reduced.