Biodistribution and excretion of a mixed fluorocarbon-hydrocarbon "dowel" emulsion as determined by 19F NMR

To investigate the biodistribution, possible metabolism and excretion of mixed fluorocarbon-hydrocarbon "dowel" molecules used as stabilizers of fluorocarbon emulsions, we have prepared a 25% w/v emulsion of such a molecule, and quantitatively evaluated, by means of 19F NMR, its behavior in the blood and reticuloendothelial system (RES) of rats. C6F13CH = CHC10H21 (F6H10E) was emulsified using egg yolk phospholipids (EYP). The emulsion (F6H10E/EYP: 25/6% w/v) was injected intravenously into 33 Sprague Dawley female rats at a 3.6 g/kg body weight dose of F6H10E. The animals were sacrificed at regular intervals of time. 24 hours after the injection, 70% of the injected dose was located in the liver, 17% in the spleen, 4% in the lungs, 2% in the kidneys and 2% in the blood. The half-time retention of the dowel molecule in the liver was estimated to be 25 +/- 5 days. None of the 33 treated animals died prior to the planned sacrifice date. The dowel molecule F6H10E proved to be well tolerated, and excreted reasonably fast, without metabolism. This appears to warrant the use of such molecules as stabilizers in injectable fluorocarbon emulsions destined to serve as oxygen carriers, contrast agents or drug delivery systems.