Binding of a metrizamide to human serum proteins

In connection with the introduction of the non-ionic radiographic contrast medium metrizamide (Amipaque) Salvesen & Frey reported that no significant albumin binding of metrizamide could be revealed by the use of equilibrium dialysis. The protein binding of metrizamide has now been investigated using whole human serum with the aid of an aqueous two-phase system and gel electrophoresis. No binding to serum proteins, at least not to others than albumin could be demonstrated. The possible existence of a minor (less than 1%) protein binding is discussed.