you bought a creatine delivery system, like Cell-Tech, as opposed to straight creatine.
the longer creatine sits in liquid, the more it converts to creatinine. Creatinine is only 'toxic' if you already have kidney problems...and if that was the case you wouldn't be taking creatine in the first place is my guess.
But the more that converts to creatinine, the less creatine you have for the muscles.
My advice: take it immediately post workout - down your protein shake, down your creatine shake, and you're done.