All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
Such an injection does not invalidate the fast since it does not transfer food, drink or the like into the body. This differs from nourishment injections that substitute for food and drink.
Allaah Knows best.