Pharmacokinetics and red cell utilization of iron(III) hydroxide-sucrose complex in anaemic patients: a study using positron emission tomography

The pharmacokinetics of a single intravenous injection of 100 mg iron hydro xide-sucrose complex labelled with a tracer in the form of Fe-52/Fe-59 was followed in six anaemic patients for a period ranging from 6 to 8.3 h using positron emission tomography (PET). Red cell utilization of the labelled i ron was followed for 4 weeks. PET data showed radioactive uptake by the liv er. spleen and bone marrow. The uptake by the macrophage-rich spleen demons trated the reticuloendothelial uptake of this iron preparation, with subseq uent effective release of that iron for marrow utilization. Red cell utiliz ation. followed for 4 weeks, ranged from 59% to 97%. The bone marrow influx rate constant was independent of blood iron concentration, indicating non- saturation of the transport system in bone marrow. This implied that higher doses of the iron complex can probably be used in the same setting, if hig her influx rate into the marrow compared with the liver seemed to be consis tent with higher red fell utilization, This would indicate that early distr ibution of the injected iron complex may predict the long-term utilization.