Artificial Oxygen Carriers as Red Blood Cell Substitutes: A Selected Review and Current Status

Two distinct approaches are being explored in red blood cell substitute (RCS) development: hemoglobin-based oxygen carriers (HBOCs) and perfluorocarbon-based oxygen carriers (PFBOCs). HBOCs are based on intra- and/or intermolecularly "engineered" human or animal hemoglobins (Hbs), optimized for O 2 delivery and longer intravascular circulation. Some are currently being evaluated in Phase II/III clinical studies. PFBOCs are aqueous emulsions of perfluorocarbon derivatives that dissolve relatively large amounts of O 2 . A PFBOC based on a 60% (wt/vol) emulsion of perfluorooctyl bromide has been evaluated in Phase II/III clinical trials. Although current PFBOC products generally require patients to breathe O 2 enriched air, they render certain advantages since they are totally synthetic. This article provides a short review of the basic principles, approaches, and current status of RCS development. Results of preclinical and clinical studies including recent Phase II/III clinical studies are discussed.