Hi Lindy,
I don't think I was the first to suggest it, but I have been pushing it for over 10 years now. I persuaded a UK company to investigate it, but they did some work then dropped it. It is now fairly widely used for other diseases. One reseasrcher who has worked on it for over 10 years is William Frey. As he said, "If bad things get into the brain through the nose, lets use it to get good things in".
There is a passage from the nose to the brain called the intranasal passage. It by-passes the BBB, and you get immediate entry to the brain.
It is the reason why smokers get immediate satisfaction by inhaling through the nose. The nicotine gives a fast "high". They don't have to wait an hour for it to get into the blood stream, across the BBB and into the brain, as we do with orasl drugs. The same reason why drug users snort their cocaine etc. THey get an immediate high.
Do not try it on sinomet containing carbidopa, you don't want that in the brain. It does not pass the BBB so is safe orally. But in all this time an experiment putting dopamine or levodopa into a nasal spray does not seem to have been done.
Ron