CONTRAST MEDIUM COMPOSITION AND PROCESS FOR PRODUCING SAME

摘要

Disclosed is a contrast medium or a contrast medium composition which is highly sensitive and enables the reduction in the amount of a contrast medium to be administered.  Also disclosed is a process for producing the contrast medium or the contrast medium composition. Specifically disclosed is a process for producing a contrast medium composition, which is characterized by comprising the following steps (A) to (C): (A) adjusting the pH value of an acidic solution having apoferritin dissolved therein and having a pH value of 1.5 to 3.0 to 3.5 to 5.0; (B) adding an X-ray contrast medium or an MRI contrast medium to the treatment solution produced in the step (A); and (C) adjusting the pH value of the treatment solution produced in the step (B) to 6.0 to 8.5.  The contrast medium composition produced by the process has such a structure that a molecule of a contrast medium is included in apoferritin, wherein the contrast medium is highly concentrated in apoferritin.