@adamjfpickering @melihtas
Do we know the concentration of suramin that Ron Davis used in his nanoneedle test? I wonder if the experimenters in this thread trying suramin actually took an injectable dose which matched that nanoneedle concentration?
The problem with suramin is that it has a very high plasma protein binding of 99.7%. Ref:
here
That means almost all (99.7%) of the suramin you inject is going to be lost, because as it binds to proteins, it becomes biologically inactive. (This is known as the free drug principle, which states that the portion of the drug which binds to proteins becomes inactive).
I note that people here experimenting with suramin used 1000 mg doses. If we assume the body contains around 40 liters of fluids in which any administered drug will distribute to, then 1000 mg distributed in 40 liters equates to a concentration of 25 μg/ml.
But that 25 μg/ml is the total concentration of suramin in the blood: the sum of the free and protein bound suramin. We have to subtract from that the 99.7% of the suramin which is protein bound, in order to calculate the concentration of free and active suramin.
So the free suramin concentration will be 25 * (100 - 99.7) / 100 = 0.075 μg/ml = 75 ng/ml.
Thus
75 ng/ml is the blood concentration of free suramin you will get when injecting 1000 mg of suramin.
We need to compare this 75 ng/ml to the concentration of suramin that Davis used in vitro in his nanoneedle test. If this blood concentration is much lower than the nanoneedle concentration, that might explain why it did not work.