Investigation of binding of I-125-iodixanol to high molecular weight substances after incubation with rat liver homogenates

Purpose: It has recently been shown that incubation of iodixanol in rat liv er homogenates resulted in formation of iodixanol metabolites. The present study was performed to see if this incubation resulted in any binding of io dixanol to high molecular weight substances, as such a high molecular weigh t conjugate of iodixanol theoretically might cause initiation of an immune response against this contrast agent. Material and Methods: I-125-iodixanol was incubated with rat liver homogena tes for 1 h at 37 degreesC and 17 h at 25 degreesC followed by analysis of the supernatant fractions using gel-permeation chromatography with on-line radiochemical detection. Results: No traces of radioactivity could be detected in the chromatograms, except at the retention time of free iodixanol. Conclusion: No binding of iodixanol to high molecular weight substances cou ld be demonstrated after incubation of iodixanol with rat liver homogenates .