Sounds like a good question for the Company.
I don’t know the answer to your question but note that in an analysis of comparative transport performance of 474 CPPs which was published earlier this year, a standard concentration of 10
µM was chosen for all comparative cell uptake assays, as this was said to have been the concentration that had been used widely in other comparative studies.
Perhaps my thinking is simplistic, but I can’t see why researchers would bother doing comparative testing at concentrations of 10 µM, 4 µM, 2 and 1 µM if only 0.5 µM was relevant?
https://www.tandfonline.com/doi/full/10.1080/10717544.2018.1458921
(20min delay)