I know something about injecting vit. c, since I did so on my dog.  the Vit. 
C has to be injected slowly into the additional input on an IV while the IV is 
dripping into the bloodstream.  Straight vit. c directly into the blood and 
done quickly can cause severe side effects.  The Vit. C has to be a special 
liquid form that is made for injection.  My vet ordered it for me and charged 
me 
twice the cost.
I would think that if one were to inject CS, it would have to be a very 
purified form since injecting anything directly into the blood can cause 
sepsis.  
But then again,
people who inject drugs are injecting much contamination along with their 
drugs.

Summer