Iohexol osmolality

The aggregation of metrizamide in solution further reduced its osmolality to about 485 mOsm kg at 300 mgl mL [ 1 ]. Unfortunately, this agent could not be sterilized by autoclaving and, consequently, had to be lyophilized and reconstituted extemporaneously. In the mid-1970s, stable nonionic compounds such as iopamidol or iohexol superseded metrizamide. Further improvement was reached by stabilization of the hydrophilic sphere against external disruption, as shown with iobitridol [2]. 

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