Encapsulation of closo -dodecaiodododecaborate in 2-hydroxypropyl-γ-cyclodextrin prevents hemolysis.

Na 2 B 12 I 12 has many of the properties desired by an X-ray contrast agent but is lethal at the concentrations needed for medical imaging. We demonstrate here that PBS solutions with >50 mM Na 2 B 12 I 12 induce hemolysis, consistent with the previously reported superchaotropic nature of the anion. The presence of <1 equiv. of 2-hydroxypropyl-γ-cyclodextrin prevents hemolysis and suggests a strategy for exploiting B 12 I 12 2- as an X-ray contrast agent.