Compositions comprising metal ions or clusters such as ferrous and/or ferric iron compounds or magnesium, zinc, lanthanum and other metal ion compounds and fiber components such as gum Arabic in a complex, methods for preparing such compositions of matter, and the use thereof for treatment of adsorbing certain accessible targets in the gastrointestinal tract and in an extracorporeal system, are provided herein.本案提供一種包含呈複合物之金屬離子或簇(諸如二價鐵及/或三價鐵鐵化合物或鎂、鋅、鑭及其他金屬離子化合物)以及纖維組分(諸如阿拉伯膠)的組成物,製備此等標的組成物之方法,及其用於吸附胃腸道及體外系統中之特定可及標的之處置的用途。