Is there such a thing as caffeine in a needle? (Or something similar)?!

I always thought it would be handy to have a large dose of caffeine in a needle instead of having to drink full caffeinated beverages every time I need caffeine. While this idea of needles of caffeine is probably pure fantasy, I was wondering, does a legal substance that condenses caffeine into a small package exist? (I'm aware of things like espresso, 5 hour energy and the like; I don't mean those.)