I know nothing about those, except that they exist.
Just came to my mind though that they could have tried to avoid that heat thing because it's widely known fact that people (addicted ones) always use tricks like apply heat to pad to make the drug absorb faster. That being said, I don't know how could it be possible to avoid that heat thingy... But, chemists may have succeed making such pad that locks the drug inside so that pad won't release more drug if heated, just because it is commonly used tactic, and bupe pads are primarily ment for addicts (who most likely use such tactics).
Of course, it could be impossible to do such a pad (because heat always makes things go faster)... I simply don't know... Just thinking it might be desirable to healt care professionals to make and have such a pad.
And the same thing applies to the soluability question as well......
