This has probably already been asked, actually I think I've seen it on here, but I can't find it. You know how IR releases approx. 1/2 hour after you take it? At what minutes and hours are the different layers of XR supposed to be realeased?

I've read somewhere that half of those little balls in the pill are released immediately and the other half are released 4 hours later. So it should be about 1/2 hour or maximum 45 minutes.

Yes. I've heard amphetamines (IR, as in the first half of Adderall) get absorbed in the stomach within 30 minutes, then last effectively in the brain for 4 hours (but have a blood half-life of 12 hours).

Thanks! Although, I'm not asking how long they last really, just when each one gets released. So XR is just twice? Alright... seems like you could just as well break an IR in half and make that an XR. *shrug*

You wouldn't break an IR in half. 60mg of Adderall XR = 2x 30mg Adderall IR; seperated by roughly 4 hours.

You wouldn't break an IR in half. 60mg of Adderall XR = 2x 30mg Adderall IR; seperated by roughly 4 hours.

Yes thats true, IR is much different than XR. Taking 2 tablets of 30mgs IR throughout the day will make you feel much different that taking a 60mg of XR. The IR will be released very quickly and react differently with your body and 4 to 5 hours later you will feel a steep "crash", which can be remedied by taking the second 30mg IR. The second one will make you super focused again but not as much as the first one and again 4 to 5 hours later you will crash even harder. The 60mg XR on the other hand will last in total about 12 hours and not really notice a significant crash nor an a significant upper "high".

IR has much greater potential for abuse than XR but each medication is better for certain people and depending on how you need it to affect you.

The best thing for me is to take a 30mg XR in the morning and by the evening i take a 30mg IR to super focus on my intense homework, and by the time I finish (4 hours later), i feel really sleepy and "crash" which is perfect for the end of the night. :)

But then again, it all depends on the person and results vary somewhat.

i take one XR in the morning, and feel it about 1/2 to 1 hr later. It rises and ebbs throughout the day, and have no crash at the end.

On those days where it keeps working for 20 hours...i wish i would just crash so i could sleep.

I've never read the early studies but the newer spd465 (triple bead adderall that is most likely never coming out) is formulated for each type of bead to release upon a certain pH. Since Shire uses the Microtrol bead system, adderall XR probably is made so the first release is upon a pH of 2-3 (stomach) and the final release when the pH rises throughout the GI tract.

Here is a snipit from Mescape about the triple bead Adderall formulation.
Triple-Beaded MAS

Long-acting stimulants that are now clinically available have been designed to manage ADHD over a 12-hour period. Although this may offer sufficient coverage for many patients, some individuals report wear-off of stimulant benefit before their evening activities are completed, and may necessitate a prescription of a short-acting medication for evening tasks. A new formulation of MAS-XR was recently introduced, which is designed to last 16 hours. This formulation, triple-beaded MAS, is similar to MAS-XR but contains an additional third bead that releases a final bolus of active ingredient later in the day. The timing of this beaded delivery system is based on a pH-dependent polymer that dissolves at a predetermined pH level in the small bowel. The immediate-release bead is absorbed immediately in a gastric pH of 1-2. The second bead's surrounding polymer dissolves later when the pH rises to 4-5, and the third bead's polymer dissolves when the small bowel's pH rises to 7. This system allows for the delivery of MAS over a longer period throughout the day providing up to 16 hours of therapeutic duration.
J