Blood substitutes Artificial oxygen carriers: perfluorocarbon emulsions

Artificial oxygen carriers aim at improving oxygen transport and oxygen unloading to the tissue. Artificial oxygen carriers may thus be used as an alternative to allogeneic blood transfusions or to improve tissue oxygenation and function of organs with marginal oxygen supply. The present article describes the currently evaluated perfluorocarbon emulsions, in order to summarize their efficacy, discuss potential side effects and illustrate potential future applications.Perfluorochemicals are chemically inert synthetic molecules that consist primarily of carbon and fluorine atoms, and are clear, colourless liquids. They have the ability to physically dissolve significant quantities of many gases including oxygen and carbon dioxide. Perfluorochemicals are hydrophobic, and are therefore not miscible with water. Perfluorochemicals thus have to be emulsified for intravenous use. With sophisticated technology, it is possible to generate a stable perfluorocarbon emulsion with exceptionally small particles (median diameter < 0.2 μm) [1].First-generation perfluorocarbon emulsions as well as Russian or Chinese products have been described in a previous review [1]. Western development of second-generation perfluorocarbon emulsions has focused on linear perfluorocarbon molecules such as perfluorooctyl bromide (C8F17Br, also referred to as perflubron), perfluorodecyl bromide (C10F21Br) and perfluorodichlorooctane (C8F16Cl2) [1]. Using solely 3.6%w/v egg yolk phospholipid, Alliance Pharmaceutical Corporation (San Diego, California, USA) developed a concentrated (60% w/v) and stable perfluorocarbon emulsion, Oxygent, which is composed of 58% w/v perfluorooctyl bromide and 2% w/v perfluorodecyl bromide, with an average particle size of 0.16-0.18 μm diameter. Hemagen/perfluorocarbon (St Louis, Missouri, USA) developed another concentrated (40% v/v) perfluorocarbon emulsion, Oxyfluor, using perfluorodichlorooctane, egg yolk phospholipid and triglycerid with an average particle size of