Invited Speaker

Novel in vitro Assay for the Characterisation of Phosphate Binders: Efficacy of IMH-Based Materials
Nuno Jorge Rodrigues Faria, K. Rau, DIA Pereira, and J.J. Powell
UK

Interstitial mineral hydroxides (IMH) are materials that comprise metal oxo-hydroxides doped with biologically compatible low molecular weight ligands, through ligand substitution of oxo/hydroxy groups. IMH have different tailorable physico-chemical properties compared to the parent metal oxide and are being explored by our group for therapeutic applications. In this work the IMH that we have explored is an adipate-doped iron oxide (FeO-Ad). It shows poor solubility and, compared to the parent oxide, has high phosphate binding and, therefore, may have application as a therapeutic for dietary phosphate binding in patients with end stage renal disease. No validated in vitro assay exists, however, for comparison of current or novel phosphate binders. Using human intestinal contents as the gold standard we have developed and validated a synthetic solution that mimics phosphate binding under gastrointestinal conditions. In terms of affinity FeO-Ad IMH >> Fosrenol =~ Renagel and in terms of capacity FeO-Ad IMH >> Fosrenol and the low affinity of Renagel did not allow capacity to be determined. This agent may have therapeutic application in renal disease.