Look under your tongue in the mirror and see all those blood vessels? The thin membrane of the bottom of your tongue is good at getting it into your blood and then wherever it needs to go from there to do it’s work.
It just takes a while because it still needs time to do it. It gets dissolved and you can’t see it but the medicine is in your spit. It’s not going to be able to do that half as well from any deeper inside your digestive track. Unless I suppose you put one in through the other end which I don’t recommend.
The best time my medicine works is when I take it before bed because I’m not swallowing. It is tough to do though any other time.