ICG | Chemical & Physiological Information



Indocyanine Green (ICG) is a pharmaceutical which has been used for over 50 years in medicine for diagnostics. Initially it was used to measure cardiac output, but a wide range of further applications have been developed over the years. In its powder form it is very stable. Before use, ICG is dissolved in sterile water for injection and needs to be shaken well. When reconstituted, it has a pH of approximately 6.5 and appears as a dark green liquid.

When injected intravenously, ICG binds rapidly to the plasma proteins (98%) in the blood. Because of the molecular size of the proteins, the ICG cannot pass through the vessel walls and remains within the blood vessels. It can therefore be used to visualize the blood flow or perfusion of any tissue of interest. ICG is eliminated from the blood exclusively through the liver and is not reabsorbed in the intestines. There is no metabolic breakdown of the ICG and it is eliminated through bile. The intravenously injected ICG solution has a half-life of approximately 3-4 minutes in the blood. Thus, in a patient with normal liver function, ICG diagnostic measurements can be repeated every 15-20 minutes.


Chemical Description: Tricarboyanine Dye
Appearance: Green powder (lyophilisate)
Molecular Weight: 774.97 g/M
Empirical Formula: C43H47N2NaO6S2
Impurities: Sodium Iodide <5%