Got no idea how to do that, but i do know that it most likely wouldnt be illegal.
During the prohibition of alcohol there were multiple compounds discovered that exist as solids and partially decompose upon hydration to give ethanol and another compound. These were not illegal (and could be sold i guess). I have no idea what these compounds were, but remember reading about them as a bit of trivia which came about during different areas of research. My guess is that they were never marketed (or used) because one of the decomposition products was toxic or had unwanted side effects. Research into the design of prodrugs (if it could be called one is this case) takes a lot of resources. Itd be a good excuse for a research grant if you could find a legit reason to do it, but id like to hear someone come up with one.