Yes, you can swallow it.. but no, it won’t work if you do. The active ingredient, buprenorphine, is ‘lipid soluble’– meaning that it is more like a ‘fatty’ molecule than a ‘watery’ molecule. Cell membranes are made of fats– or ‘lipids’. Buprenorphine sticks to the cell membranes in the mouth, an area where the surfaces are called ‘mucous membranes’. That type of surface has a thin layer of cells which the buprenorphine crosses before eventually entering small blood vessels– capillaries– where it enters the bloodstream, eventually transported to the brain. In the brain the buprenorphine leaves the capillaries and binds to receptors on neurons that recognize endorphins and opiate medications.
Buprenorphine will not diffuse as easily across other surfaces, such as the skin on your body– the cells are layered more deeply, so there is more to cross to get to a capillary. I would still expect a skin patch to be developed eventually.
If you swallow the tablet, the buprenorphine will pass through the stomach and into the intestine. There it will be taken up by the bloodstream, into the ‘portal vein’, which goes straight into the liver. The liver is a big detoxifier; it destroys many chemicals before they have the chance to get further into the body. This is called ‘first pass metabolism’– some drugs are broken down so efficiently that almost none of the amount taken will get to the brain. This is the case with buprenorphine. It is also the case with naloxone, the other ingredient in Suboxone… naloxone doesn’t dissolve in lipids though, so it does not get into the bloodstream through the mouth lining either.
To maximize absorption of buprenorphine three things are critical: first, the concentration of buprenorphine– since it diffuses down its concentration gradient in the mouth lining, you want a small amount of saliva, to make a high concentration of buprenorphine. Second is surface area– use all of the surfaces inside the mouth. More surface area allows more absorption. Third is time– the longer you keep the dissolved buprenorphine in contact with the lining of your mouth, the more will get absorbed (up to the point when it is all absorbed, of course).