Sangart’s lead product candidate, Hemospan®, uses unique polyethylene glycol conjugation to create a human hemoglobin-based product that is intended to serve as an alternative to red blood cell transfusions. Hemospan® is specifically designed to the optimal molecular size, viscosity, oxygen affinity and diffusion potential to target oxygen delivery to tissues at risk of oxygen deprivation. Extensive research and testing demonstrates that this approach optimizes oxygen delivery without the side effects that plagued earlier generation products. Compared to red blood cells Hemospan® offers universal compatibility, decreased risk of infectious disease transmission, longer storage life and an extension of the supply of donated blood.

The starting material for Hemospan® is unmodified hemoglobin derived from human red cells. Pharmaceutical grade polyethylene glycol (PEG) polymers are then attached to the surface of hemoglobin using simple chemical reactions.

A unique property of PEG is its ability to interact with water. When attached to the surface of hemoglobin, or any other protein, a layer of water is created that surrounds the protein and:

• Protects the hemoglobin from the immune system.
• Increases the effective size of the hemoglobin molecule, prolonging circulation time.
• Provides a viscosity similar to blood.

The over-riding factor making Hemospan® successful is that its oxygen delivery mimics that of red blood cells. The properties necessary to maintain normal oxygen delivery are molecular size, viscosity, oxygen affinity, and diffusion. These factors interact in a very specific way to present the right amount of oxygen to the blood vessel wall. This prevents blood vessel constriction and maintains blood flow through capillary beds. Based on experiments with artificial capillaries and several different animal models, Sangart has identified the factors that govern oxygen delivery by cell-free hemoglobin, and optimized these into the Hemospan® formulation.