The date on my prescribed bottle dates september 23, 2010
There is no direct answer. If you want to use your expired Adderall, it would still work.
The date you see on the bottle is what the drug manufacturer and FDA considers the last day for the drug to be 100% efficacious, for legal purposes. Obviously the drug will still work after that expiration date; it does NOT mean the drug becomes 0% efficacious on September 24, 2010 and beyond.
The potency of the drug will gradually decrease as the drug decomposes due to humidity, changes in temperature, etc. However, this degradation is quite slow.
Shelf Life Adderall