How is Ritalin (Methylphenidate) broken down by your body

Could someone please explain in detail the stages/processes that Ritalin (Methylphenidate) goes through before leaving the body?

This is actually pretty interesting. I put some research into this for you.

I know that due certain processes in the stomach, the medicine is released from the pill and enters your blood stream. There's only a certain amount (like, 20mg or whatever the strength of your ritalin is) so that's why it won't last forever.

http://www.ehow.com/how-does_4597399_rit…
http://www.netdoctor.co.uk/medicines/100…

Hope this helps!