maximum plasma concentration

[uacvax]

What is the significance of this? I looked it up for adderall xr and it said it was about 8 hours or so, but I thought adderall was only supposed to last for about that long?

 

[fastandbulbous]

The extended release (XR) formulation means that the drug is continually released in the digestive system, so while the very first amphetamine released will have been metabolized/excreted, there would be a cumulative increase in plasma level while the release in the intestine was going on.

A peak plasma level at the 8 hour mark indicates that the XR formulation is designed to continually release amphetamine for 7-8 hours (amphet is absorbed from the intestines pretty quickly; 15-30 mins, so the active releasing period will be time to peak plasma level minus time to absorb from intestines