I think I understand what you’re asking?
there’s pills like these morphine’s I used to do that were tough to use, because the solution had to be heated up to a low simmer. And only then hit it quick because the solution will turn into a gel if it cools too much. I can’t recall the exact type of morphine pill but they were common where I was at the time and we were idiots for shooting that shit. Decent buzz but impossible to split, because it doesn’t unless it’s hot and that doesn’t last.
Then there was hydromorphs with the beads that needed to be crushed, preferably in a pestle and mortar. They’re tough to split but the job can be done with some care. I realize now that heating isn’t necessary but at the time that’s what I was taught to do to expedite the extraction of the hydromorphone into that solution.
then easy is like dilaudid which just crushes and dissolves, albeit leaving some residue behind.
easiest was heroin. Dissolves completely, get the full hit. Nothing to it.
That was my experience anyway.