you could make just about any oral a liquid..
really not much different than chasing a cap with a shot of water, just mix them up
although typically to keep it sterile they will mix it with grain alcohol or something of that nature. It also helps disolve it.
Reforvit B has been around for a long time, its liquid. It has some pain killer in it too, think its lidocaine, and it gives you the numbies if you take it orally!