Blood substitutes fluorochemical

Riess, J.G. Reassessment of criteria for the selection of per-fluorochemicals for second-generation blood substitutes analysis of structure/property relationships. Artif Organs 1984, 8, 44-56. 

Perfluorodecalin (FDC), used in the first generation of fluorochemical blood substitutes, has a half-retention time in organs of only 6 days, but the stability of its emulsions is insufficient [5]. Perfluorotripropylamine is added to perfluorodecalin in Fluosol-DA to increase emulsion stability. However, the retention time of perfluorotripropylamine in the body is longer than that of perfluorodecalin. Fluosol-DA is stored frozen and diluted with two aqueous solutions containing electrolytes and additives. 

The properties of a perfluorochemical emulsion depend critically on the surfactant used for emulsification. A surfactant used as an emulsifier in fluorochemical blood substitutes has to meet several criteria (1) provide a fine stable emulsion (2) be nontoxic, nonmutagenic, and nonhemolytic (3) be compatible with blood and endothelial cells (4) be pharmacologically, physiologically, or biochemically inactive and (5) either be excreted unchanged or in the form of harmless metabolites [41]. 

The surfactants used in the first-generation fluorochemical blood substitutes were ordinary soaps (potassium oleate), egg-yolk phospholipids (lecithin), or Pluronic F-68. These emulsifiers were used individually or as their mixtures. 

The history of fluorochemical blood substitutes started with the dramatic demonstration that a mouse can stay alive while submerged in a fluorochemical saturated with oxygen [163]. Since the early days of great optimism, the limitations of fluorochemical emulsions as blood substitutes have been recognized [5]. Difficulties with the preparation of stable emulsions, a low oxygen content at atmospheric pressures, and in vivo accumulation of fluorochemicals in tissues have restricted their intravascular use as blood substitutes [38]. The main emphasis is now on diagnostic applications and oxygen transport into ischemic tissues. 

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