I've never heard of people IVing methylphenidate, in any preparation, although I suppose it is possible.
actually, lots of people IV methylphenidate, as it does produce a decent rush.
i personally have experience with IVing the stuff. 15-20mg is a good dose, as long as you haven't had any caffeine or other stimulants recently, or else the experience can be slightly overbearing.
My thread that talks about IVing Ritalin:
http://www.bluelight.ru/vb/threads/498726-IV-Ritalin-and-IV-Oxycodone?highlight=ritalin
Another Bluelighter that talks about it:
http://www.bluelight.ru/vb/threads/...IV-ritalin(methylphenidate)?highlight=ritalin
Someone who had complications and had to have surgery:
http://www.bluelight.ru/vb/threads/499387-Injecting-IV-ritalin?highlight=ritalin
And another informative thread regarding the subject:
http://www.bluelight.ru/vb/threads/470713-shooting-ritalin?highlight=ritalin
A thread that talks about how to extract methylphenidate from pills, with lots of good input from PhreeX (god bless his soul. he really was a genius. RIP PhreeX):
http://www.bluelight.ru/vb/threads/37071-methylphenidate-extraction.?s=&highlight=methylphenidate (this link is also included in the thread that i talk about IV ritalin, which was the first hyperlink i provided)
All good reads too, so check them all out to make sure you get the real deal on it. It can be euphoric at first, and you'll find this route of administration is extremely efficient. I find the high best enjoyed after getting a slight alcohol buzz on (notice i said SLIGHT). Ritalin is similar in structure to cocaine, so when combined with alcohol it too produces a structure similar to the Cocaethylene chemical produced from a cocaine/alcohol combo (note: this chemical is toxic to the brain, but is sought after for its pleasant effects. it can be dangerous if the levels of each substance alone are too high). Injecting ritalin will give you one nasty comedown, so make sure you have some weed or benzos on hand. The ritalin i used to shoot was the 10mg white ones, which if i recall correctly were slightly cleaner since they didn't gunk like the blue ones, but i don't remember exactly if this is correct or not. I know they both contain microcrystalline cellulose, however. Please note that shooting ritalin over time is bad for your retinas, and there is also some info in the Case Studies thread where a forum member had to have a bunch of shit dug out of their arm as a result of injecting ritalin over a period of time.
Also, i would like to add that while the rush can be nice, i find that snorting it produces a much longer high (lasts about 2 hours, compared to about 50 mins-1hr when you IV), and the overall effects feel more "coke-like" when you snort.