I would be very fearful of trying to drug one of these things for a number of reasons.
1. Dosage is mass dependent and type dependent. Not going to be a very accurate calculation.
2. Whatever you use, it can't be the same stuff used on other animals that in turn you must track long distances before it drops - these critters can cover some country fast.
3. This thing is not a dumb animal. I say it's 50/50 that you aren't immediately attacked by the one you hit with the tranquilizer - with ill intent.
4. I'm contrary to many here, as I'm saying that these things are usually NOT alone. You drug one, the other(s) may pull your head off or slam you up against a tree and crush you. And THEN pull you apart.
5. If you had some "habitat," after one gets tranquilized, you'll never see them on friendly terms ever again.