The encapsulation of molecules provides a structure that provides the capability for timed release.
I know you didn't ask, I'm just making the statement.
Some have asked how can we accomplish the same things that a patch can.
The second part about having a shirt or sweater or skin to skin contact.
Once the encapsulated component is in the skin, there is less risk.
This following part I'm not sure of but I'll speculate.
The encapsulation of the molecules may provide some form of resistance to certain materials. Secondly, perhaps the skin itself would prevent the molecules to come out.