A major reason for the long-term and ongoing clinical success of ICG is its capacity to be excreted rapidly from the living subject without structural modification. More specifically, ICG is taken into liver hepatocytes by influx transporters such as the organic anion-transporting polypeptide 1B3 (OATP1B3) and subsequently excreted to bile canaliculi by efflux transporters such as multidrug resistance p-glycoprotein-3 (MDR3). With this pharmacokinetic behavior in mind, we compared the biodistribution of ICB and ICG in a living mouse after intravenous dosage. Separate cohorts of healthy female Foxn1 mice (each N=2) were injected with 10 nmol dose of either ICB or ICG. After 2 hours, the mice were euthanized, and their exposed abdomen cavities were imaged. The representative fluorescence images in Figures 5a and Figure , reveal a higher amount of ICG in the mouse intestines compared to ICB. Fluorescence images of the excised organs are shown in Figure along with a biodistribution bar graph (Figure , Figure , and Figure ). There was significant ICG accumulation in the liver and some in the kidneys.