Pablosan: crack + ascorbic acid = water-soluble, shootable cocaine (cocaine ascorbate)
However, a dose of vitamin C in a pill is less than 1mg. But the pills are huge. The chewable guys probably weigh about a gram. Unless its a very tiny pill, you're putting a lot of unnecessary shit into your veins. I hope you're filtering it very very well. Harm reduction and all that, but at this time of the night a lot of that goes by the wayside.
Shooting crack and heroin, tell you if you're wrong? Well, it could fuck your day right up, do you know the dangers?
Again, as I said before, its very late at night here, so I don't have a lecture in me, but to answer your question, ascorbic acid will make crack shootable. There are many other safety precautions to consider though. I hope you know what you're doing mixing the two. I don't know if I can tell you to reconsider, but I hope I can at least tell you to do what you are doing as safely as possible. Vitamin C pills aren't your best bet. Pure citric or ascorbic acid from the store would be a much, much safer idea. Also, plain white distilled vinegar would do the trick, as it also will turn crack into cocaine acetate, a water-soluble shootable form.