Ephedrine and pseudoephedrine have the same molecular forumula -- C10H15NO -- however they are stereoisomers of each other. In my favorite chemistry professor's terms, this means that ephedrine and pseudoephedrine are "non-superimposable mirror images of each other". Another analogy would be left and right hands -- stereoisomers are like left and right hands -- you can see they are very similar but not exactly the same.
Ephedrine is the (+) or S isomer, and when exposed to polarized light, the molecule rotates counterclockwise.
Pseudoephedrine is the (-) or R isomer, and when exposed to polarized light, the molecue rotates clockwise.
Chirality is the term that describes this property of molecules to rotate in one way or the other when exposed to polarized light.
Check out this
this link to compare 3-D images of ephedrine and pseudoephedrine.
Now, let's take a look at the l and d isomers of the aforementioned amphetamines (this applies to amphetamine, methamphetamine, and MDMA). In all cases, the d isomer is the more potent isomer (note: this is not the case with all chemicals, it just happens to be so for the amphetamines in question). The l isomer has no recreational value on its own. In the cases of amphetamine and methamphetamine, it is most desirable to have an enantiomerically pure product -- i.e., you just want the d-amph/meth, because the greater the percentage of your amph/meth that is d, the stronger your mixture will be. Most street amph/meth consists solely of the d isomer. If you get amph/meth that is not very strong, despite seeming pure and being crystalline, it is probably because some or all of the product is the l isomer. I know someone who once mistakenly made a batch of l isomer meth.
In the case of MDMA, the situation is slightly more complicated. As with the other amphetamines, isolated l-MDMA is not at all recreational. However, pure d-MDMA on its own feels a helluva lot like MDA/methamphetamine. The racemate version of MDMA (racemate = a 50/50 mixture of the l and d isomers) is the type almost always seen on the street, and somehow, the l-isomer adds to the effects of the MDMA. There is a synergy created by the presence of the l-MDMA (even though as you recall it has no effect on its own) in combination with d-MDMA. In fact, it is the presence of the l-MDMA that creates the unique 'lovey' feeling of racemate MDMA.
Adderall, being a combo of l and d amphetamine, is somewhere in between methamphetamine and MDMA in terms of how much is gained by the addition of some l-isomer. As with MDMA, there is some synergy with the addition of l-amphetamine, but the extra effects are not nearly as substantial. Adderall tends to be smoother (with a better, more gradual comedown) and lasts longer than dexedrine.
Dr. Rolls -- You aren't thinking about the drug enantiomerically. You have to take isomers into account.
For 5 mg of Adderall:
Dextroamphetamine Saccharate 1.25 mg
Amphetamine Aspartate 1.25 mg
Dextroamphetamine Sulfate USP 1.25 mg
Amphetamine Sulfate USP 1.25 mg
d-amph sacc. contains 1.25 mg d-amph
amph asp (racemate, so 50% d-amph and 50% l-amph) contains 0.625 mg d-amph and 0.625 l-amph
d-amph sulf contains 1.25 mg d-amph
amph sulf (again, a racemate) contains 0.625 d-amph and 0.625 l-amph
So total d-amph in 5 mg Adderall = 1.25 + 1.25 + 0.625 + 0.625 = 3.75 mg
[ 31 May 2002: Message edited by: fairnymph ]