An update on Kolo Toure today courtesy of Arsene Wenger:
"He wants to control his weight a little bit because that's where he has some problems and he took the product of his wife."
So it has been confirmed (and I'm assuming what Wenger has stated here is correct) that it was not a recreational drug or performance enhancing drug such as anabolic steroids or growth hormone that Toure took, but a diet pill that belonged to his wife that has contained a substance that is on the banned list. Neither City nor the FA have said which banned substance was found in Toure's sample. The World Anti-Doping Agency defines a specified substance as one that is "more susceptible to a credible, non-doping explanation."
Whether this changes the situation in terms of the potential length of ban Toure could face is obviously unknown at this point and there is still the possibility of going through the process of determining the results from the B-sample, which Toure has until next Wednesday to decide whether to request.