Does this article clearly say that all drug candidates were administered in the same way, via the vein?

I would assume all candidates were administered in the same way, but if they were not, that could totally change things. Like if the levodopa were fed to the rats, it would have to go to the gut and be digested and metabolized before getting to the brain, and we all know what changes that process can wreak on the amount of drug getting to where it needs to be and when. If that were the case, it would hardly be comparable to directly injecting something into a vein. It would not be an apples to apples comparison.

Laura, could you provide a cite to this article when you get a minute? Thanks!