(a) Does smoking invalidate the fast?
(b) Does Injection nullify the fast?

(A) Any form of inhaling smoke intentionally invalidates the fast. This applies to all intentional consumption and inhalation of anything whatsoever. (Al-Majmu` 6/326) However, smoke patches do not nullify the fast, as it does not involve any inhalation.

(B) Injecting in the body directly into the bloodstream does not nullify the fast, as the jurists have conditioned passage through the brain or the stomach for nullification of the fast.