SFAIK, no vitamins, at all, are approved by the FDA... they are supplements, not just patches, as you later point out....everyone should know that no vitamin patches have been rigorously evaluated or approved by the FDA. ...
As to getting things through the skin, nitroglycerin patches are FDA approved, and prescribed often by cardiologists.
Go figure why it works for nitro, and not for vitamins... probably has to do with their chemical makeup.