Ultrasmall superparamagnetic particles of iron oxide (USPIOs) of median diameter no less than 50 nm have been studied as blood-pool agents. They are given intravenously to enhance liver imaging in cirrhosis patients and visualize lymph nodes. They consist of non-stoichiometric microcrystalline iron oxide cores coated with dextrans (in peroxides) or siloxanes (in ferumoxsils). The most common form of iron oxide used is magnetite, a mixture of Fe2O3 and FeO; a mixture of Fe2O3 and Fe3O4 can be used instead. After injection, the particles accumulate in the reticuloendothelial system. Liver tumors have few or no reticuloendothelial cells, so there is a contrast between normal liver and tumor. These contrast agents are well tolerated, with no serious adverse effects.
The reported adverse effects include low back pain, vomiting and diarrhea, urticaria, flushing, dizziness, and muscle spasm [1]. Adverse reactions are higher with these particulate iron oxide agents than with gadolinium chelates. However, that is not a great cause for concern since few reactions are severe, and all are self-limiting. The USPIO contrast agent ferrite (Abdoscan, Amersham) is used in delineating the gastrointestinal tract after oral ingestion. Different rectal formulations of ferrite with different viscosities and iron concentrations have been evaluated in a phase II clinical study, in which ferrite enemas (200–500 ml) and intravenous gadodiamide (0.1 mmol/kg) were used in the evaluation and staging of rectal cancer in 113 patients [2]. Five patients had ten adverse events, including rectal pain, diarrhea, edema, a phobic reaction, nausea, and a rash; all recovered without further therapy. The high-viscosity formulation (70 g of granules/l) was better than the low-viscosity formulation in tumor staging, but the iron concentration (30 or 59 micrograms/ml) of the contrast agent was less important. If you are looking for high quality, high purity and cost-effective Iron oxide, or if you require the latest price of Iron oxide, please feel free to email contact mis-asia.
