Ferric pyrophosphate citrate (FPC) is a novel complex iron salt, developed to replace iron losses in patients with anemia in an entirely new way. This unique and differentiated molecule consists of an iron atom complexed to one pyrophosphate and two citrate anions. This formulation has been shown to allow for rapid donation of iron to transferrin, the protein in the blood that binds to iron and transports it through the body, including to the bone marrow. This mechanism uses the body’s own means to transport iron safely to tissues that need iron (i.e. red blood cells and muscle).
[Crystal structure of FPC-bound transferrin]. (n.d.).
FPC is a form of protected iron in which citrate and pyrophosphate are tightly complexed to the iron. The molecule is water soluble, making the iron completely bioavailable. FPC has the ability to deliver iron directly and completely to transferrin. This transferrin-bound iron is immediately delivered to the bone marrow to be incorporated into hemoglobin.
The structure of FPC minimizes the potential for the iron to be taken up into the body’s storage cells, such as those present in the liver and other tissues. Iron release from body storage cells can be slowed or blocked when inflammation is present. Because of its Mechanism of Action, FPC increases bioavailable iron without excessively increasing body iron stores or causing inflammation, iron toxicity, or oxidative stress.
In addition, FPC iron is delivered regardless of other underlying conditions which might otherwise block the release of iron. Some of the challenges of managing iron in sick patients, including inflammation, hepcidin block, and functional iron deficiency, can be overcome with FPC due to its ability to provide bioavailable iron.
FPC is highly soluble in water and, therefore, can be formulated for parenteral administration either by the dialysis solution or intravenously. As a result, this novel approach to iron management has the potential for application in the treatment of anemia in many disease states.