Chelate compounds as components of acellular, oxygen-delivering, resuscitation fluids

The feasibility of various metal chelates as components of acellular resuscitation fluids is examined, with particular emphasis on the bonding mode and kinetics of the dioxygen adduct formed. End-on (Pauling type) or bridged peroxo-dimer structures using iron(II) or cobalt(II) as the active metal ion are currently the most promising candidates for investigation. Criteria which must be met in order to confer desirable O2-binding properties upon the coordinated metal ions are described and ligand systems (porphyrins, Schiff-bases, lacunar macrobicycles) which help fulfill these criteria are critiqued. An important aspect of acellular O2-delivering systems is the mode of dispersion, which in turn is a function of the properties of the metal chelate; this question is broached, for general application, in terms of true solutions, emulsions and colloidally suspended solids.